COLLEGE  of  MINING 

DEPARTMENTAL 
LIBRARY 

•  •  • 
BEQUEST  OF 


SAM  U  EL  B  E  NEDICTCHR1STY 

PROFESSOR  OF 
MINING  AND   METALLURGY 

1885-1914 


MANUAL 


OP 


TREATING  OF   THE    PRINCIPLES hOE   T 


WITH    SPECIAL   REFERENCE 


AMERICAN  GEOLOGICAL 


JAMES   D.  DAN 


SILLIMAN  PROFESSOR  OF  GEOLOGY  AND  MINERALOGY  IN  YALE  COLLEGE:  AUTHOR  OP  A  SYSTEM  OP 

MINERALOGY;  CORALS  AND  CORAL  ISLANDS;  REPORTS  OF  WILKES'S  EXPLORING  EXPEDITION, 

ON  GEOLOGY,  ON  ZOOPHYTES,  AND  ON  CRUSTACEA,  ETC. 


Nunquam  aliucl  natura  aliud  sapientia  dicet.  —  Juv. 

Licet  jam  oculis  quodammodo  contemplari  pulchritudinem  rerum  earum,  quas  divina 
providentia  dicimus  constitutas.  — Cic. 


ILLUSTRATED   BY   OVER  ELEVEN    HUNDRED   FIGURES,  MOSTLY   FROM   AMERICAN 
SOURCES,  AND  A  CHART  OF   TUB   WORLD. 


SECOND   EDITION. 


NEW    YORK: 
IVISON,   BLAKEMAN,    TAYLOR,    AND   CO.,    PUBLISHERS. 

1875. 


Entered,  according  to  Act  of  Congress,  in  the  year  1374,  by 

JAMES  D.  DANA, 
In  the  Office  of  the  Librarian  of  Congress,  at  Washington. 


RIVERSIDE,  CAMBRIDGE  : 
ELECTROTYPED  AND  PRINTED  BY 

H.    0.   HOUGHTON  AND    COMPANY. 


TO  THE  MEMORY  OF 

SEDGWICK  AND  MURCHISON  : 

UNITED  IN  THE  FOUNDATION  WORK  OF   GEOLOGICAL  SCIENCE, 
AND  EVER  AND  UNITEDLY 

TO   BE  HONORED 
BY  ALL  LABORERS  ON  THE  SUPERSTRUCTURE. 


PREFACE. 


Two  reasons  have  led  the  author  to  give  this  Manual  its  American 
character :  first,  a  desire  to  adapt  it  to  the  wants  of  American  stu 
dents  ;  and,  secondly,  a  belief  that  American  Geological  History,  on 
account  of  the  peculiar  simplicity  and  unity  of  the  system  of  progress, 
affords  the  best  basis  for  a  text-book  of  the  science.  North  America 
stands  alone  in  the  ocean,  a  simple  isolated  individual  continent, 
even  South  America  lying  to  the  eastward  of  its  meridians  ;  and,  con 
sequently,  the  laws  and  agencies  of  progress  have  been  undisturbed 
by  conflicting  conditions  and  movements  in  other  lands.  The  author 
has,  therefore,  written  out  North  American  Geology  by  itself,  and 
drawn  the  chief  illustrations  of  continental  development  from  its  rec 
ords.  Facts  from  other  continents,  however,  have  been  freely  added, 
because  required,  both  to  give  completeness  to  the  treatise,  and  to 
exhibit  the  comprehensiveness  of  geological  principles.  The  aim  has 
been  to  present  for  study  the  successive  phases  in  the  HISTORY  of 
the  Earth  ;  that  is,  of  its  Continents,  its  Seas,  its  Climates,  its  Life, 
and  of  all  its  various  characteristics,  and  not  a  mere  series  of  facts 
about  rocks  and  their  dead  fossils. 

The  author  has  endeavored  to  bring  the  volume  into  as  small  a 
compass  as  consistent  with  a  proper  exhibition  of  the  science  ;  and, 
if  some  find  its  pages  too  numerous,  he  feels  confident  that  quite  as 
many  would  prefer  greater  fullness.  The  details  introduced  have 
seemed  to  be  necessary,  in  order  that  the  march  of  events  should  be 
appreciated.  At  the  same  time,  the  work  has  been  adapted  to  the 
general  reader  and  literary  student,  by  the  printing  of  the  scientific 
details  in  finer  type.  The  convenience  of  a  literary  class  has  been 
further  provided  for  by  adding  to  the  Appendix  a  brief  synopsis  of 
the  part  in  coarser  type,  in  which  each  head  is  made  to  present  a 
subject,  or  question,  for  special  attention.  And,  as  many  may  not  be 
familiar  with  the  science  of  Zoology,  a  review  of  the  classification  of 
animals,  with  numerous  figures,  has  been  inserted  as  an  introduction 
to  the  Historical  part  of  the  Manual. 

The   illustrations   of   American   Paleozoic   life   have  been  largely 


Vlll  PREFACE. 

copied  from  the  reports  of  Professor  HALL.  A  few  of  the  Paleozoic 
figures,  and  many  of  those  of  later  periods,  are  from  original  draw 
ings,  made  by  Mr.  F.  B.  MEEK,  to  whose  artistic  skill  and  paleonto- 
logical  science  the  work  throughout  is  greatly  indebted.  The  draw 
ings  were  nearly  all  made  on  the  wood,  for  engraving,  by  Mr.  Meek ; 
and  the  paleontological  pages  have  had  the  benefit  of  his  revision. 
The  name  of  the  engraver,  LOCKWOOD  SAXFORD,  of  New  Haven, 
also  deserves  mention  in  this  place. 

The  preceding  paragraphs  have  been  taken,  with  little  change,  from 
the  Preface  to  the  first  edition  of  this  work,  dated  November  1st,  1862. 
They  remain  true  for  this  new  edition.  Yet  the  work  has  been  for 
the  most  part  rewritten,  and  is  greatly  enlarged.  The  changes  have 
been  made  necessary,  both  by  the  progress  in  geological  investigation 
over  the  United  States  and  British  America,  and  by  the  general  ad 
vance  of  geological  science. 

During  the  interval  since  1862,  surveys  have  been  going  forward, 
and  have  been  partly  or  wholly  completed,  in  California,  the  Terri 
tories  over  the  summit  and  slopes  of  the  Rocky  Mountains,  the  States 
of  Minnesota,  Iowa,  Missouri,  Louisiana,  Tennessee,  Illinois,  Indiana, 
Michigan,  Ohio,  North  Carolina,  and  New  Hampshire,  and  the  Prov 
inces  of  Canada,  New  Brunswick,  Nova  Scotia,  and  Newfoundland. 
These  surveys  have  greatly  extended  our  knowledge  of  American  rocks 
and  mineral  products,  besides  affording  aid  toward  a  deeper  insight  into 
principles,  and  a  clearer  comprehension  of  the  system  that  pervades 
the  earth's  structure.  Besides  all  this,  large  contributions  to  paleon 
tology  have  been  made  by  some  of  the  Reports,  and  most  prominently 
by  the  new  volume  of  the  New  York  series,  by  JAMES  HALL  ;  the 
volumes  of  the  Illinois  Survey,  by  MEEK,  WORTHEN,  NEWBERRY, 
and  LESQUEREUX  ;  of  the  Ohio  Survey,  by  NEWBERRY  and  MEEK  ; 
of  the  California  Survey,  under  J.  D.  WHITNEY,  by  MEEK  and  GABB  ; 
of  the  Survey  of  the  Territories,  under  F.  V.  HAYDEN,  by  MEEK, 
COPE,  LEIDY,  and  LESQUEREUX  ;  and  of  Canada,  under  Sir  WM.  E. 
LOGAN,  by  BILLINGS,  DAWS  ox,  and  HALL.  Various  important  me 
moirs  also  have  appeared  in  the  scientific  journals  and  in  the  publica 
tions  of  scientific  societies  and  academies,  and  some  have  been  issued 
as  independent  works. 

Since  the  year  1862,  through  SCUDDER,  we  have  our  first  knowl 
edge  of  the  Insect-life  of  the  Devonian ;  through  LEIDY,  COPE,  and 
MARSH,  we  have  seen  the  meagre  list  of  American  Cretaceous  Rep 
tiles  enlarged,  until  it  exceeds  that  from  all  the  world  besides ;  and 
through  the  same  geologists,  not  only  has  the  Mammalian  fauna  of 
the  American  Miocene  received  additions  of  many  species,  but  the 


PREFACE.  IX 

stranger  fauna  of  the  Rocky  Mountain  Eocene  has  been  first  made 
known  ;  through  MARSH,  also,  the  first  American  Cretaceous  Birds 
have  been  named,  and  the  announcement  has  come  of  a  Bird  with 
teeth  in  sockets,  like  some  of  the  higher  Reptiles.  In  addition,  the 
labors,  among  Invertebrates,  of  HALL,  MEEK,  BILLINGS,  and  others  ; 
among  Fishes,  of  NEWBERRY  ;  among  fossil  Plants,  of  LESQUEREUX 
and  DAWSON,  have  greatly  advanced  these  departments  of  American 
paleontology. 

The  discoveries  abroad,  also,  have  been  many  and  important,  though 
of  less  marked  character  than  the  American,  because  the  accessible 
field  had  already  been  well  explored.  Large  additions  have  been 
made  to  the  history  of  prehistoric  Man ;  and  the  frontispiece  of  this 
volume,  —  engraved,  by  Mr.  JOHN  KARST  of  New  York,  from  the  pho 
tograph  accompanying  the  memoir  of  E.  RIVIERE,  —  representing  a 
skeleton  of  an  inhabitant  of  Southern  Europe  in  the  early  Stone  age, 
just  as  it  lay  after  being  uncovered  from  the  stalagmite  of  a  cavern, 
exemplifies  one  of  the  classes  of  facts  which  have  been  elucidated.  Be 
sides,  much  new  light  has  been  thrown  on  the  successional  relations  of 
species,  and  also  on  the  right  methods  of  interpreting  geological  records. 
One  of  the  important  onward  steps  has  been  due  to  the  discovery  of 
Primordial  fossils  in  the  Cambrian  rocks  of  Great  Britain.  It  led  at 
once  to  the  announcement  that  those  Cambrian  fossiliferous  strata  were 
nothing  but  Primordial  beds.  And  since  they  are,  also,  conformable 
to  the  overlying  Silurian,  and  differ  from  the  latter  only  very  sub- 
ordinately  in  kinds  of  life,  no  good  reason  longer  remains  for  making 
the  Cambrian  a  grand  division  of  the  geological  series,  distinct  from 
the  Silurian. 

In  the  preparation  of  this  edition,  I  am  largely  indebted  to  many 
scientific  friends  :  in  the  first  place,  to  all  workers  in  the  department, 
through  the  land,  whose  published  results  have  made  the  edition  a 
necessity,  and  from  whose  works  I  have  freely  taken  facts  and  con 
clusions,  with  due  acknowledgment ;  also,  for  personal  aid,  to  the  able 
paleontologist,  F.  B.  MEEK,  to  whom  the  country  owes  a  world  of 
gratitude  for  his  labors  ;  to  O.  C.  MARSH,  for  facts  connected  with 
the  Vertebrate  life  of  the  American  Cretaceous  and  Tertiary  ;  to  A. 
H.  WORTHEN,  Director  of  the  Geological  Survey  of  Illinois,  from 
whom  the  volume  has  received  several  of  its  illustrations  ;  to  L.  LES 
QUEREUX,  for  information  with  regard  to  fossil  plants  ;  to  JAMES 
HALL,  the  eminent  paleontologist  of  New  York ;  to  J.  S.  NEAVBERRY, 
Chief  Geologist  of  the  State  of  Ohio  ;  to  A.  WINCHELL,  formerly 
State  Geologist  of  Michigan,  and  now  Chancellor  of  the  Syracuse 
University  ;  to  G.  K.  GILBERT,  Geologist  of  the  Explorations  under  G. 


X  PREFACE. 

M.  WHEELER,  First  Lieutenant  of  Engineers,  IT.  S.  A. ;  to  J.  COL- 
LETT,  of  the  Indiana  Geological  Survey  ;  to  J.  KNAPP,  of  Louis 
ville,  Kentucky  ;  to  G.  C.  BROADHEAD,  State  Geologist  of  Missouri ; 
to  J.  W.  DAWS  ON,  Principal  of  McGill  University,  Montreal ;  to 
E.  BILLINGS,  of  the  Canadian  Geological  Survey,  and  one  of  the 
best  workers  among  fossils  on  the  continent ;  to  S.  W.  JOHNSON,  Pro 
fessor  of  Agricultural  and  Analytical  Chemistry,  for  information  on 
chemical  subjects ;  to  the  Zoologist,  A.  E.  VERRILL,  for  the  revision  of 
the  zoological  pages  ;  to  F.  V.  HAYDEN,  Geologist  in  charge  of  the 
"  Geological  Survey  of  the  Territories,"  for  information  pertaining  to 
the  Geysers  and  the  geological  structure  of  the  Rocky  Mountain  re 
gion  ;  and,  through  Dr.  Hayden,  to  W.  H.  HOLMES,  his  artist,  for 
drawings  of  geological  scenes  in  the  mountains  ;  to  JAMES  T.  GARD 
NER,  Geographer  in  Surveys  of  the  Territories,  for  facts  with  regard 
to  the  topographical  features  of  the  summit  region  and  the  western 
slope  of  the  Rocky  Mountains  ;  and  to  G.  W.  II  A  WES,  assistant  in  the 
Sheffield  Scientific  School,  for  analyses  of  plants,  bearing  on  the  ques 
tion  of  the  origin  of  coal. 

To  F.  H.  BRADLEY,  I  am  under  still  greater  obligations.  For 
the  work,  besides  having  had  the  benefit  of  his  careful  and  untiring 
labor  in  the  revision  of  the  proofs,  has  profited  in  various  parts  by 
his  extensive  knowledge  of  American  Geology,  rendered  thorough  and 
critical  by  personal  investigations  in  several  of  the  States  and  Terri 
tories. 

The  general  arrangement  of  the  work  is,  in  the  main,  unchanged. 
The  science  still  seems  to  be  best  presented  by  bringing  forward  first 
the  Lithological  or  descriptive  part ;  next,  the  Historical,  with  inci 
dental  illustrations  of  the  methods  of  change  and  progress ;  and  then, 
the  Dynamical,  this  last  part  including  a  systematic  review  of  causes 
and  their  effects.  But  those  who  prefer  it  can  combine  the  descriptive 
and  dynamical  portions  at  their  pleasure.  It  is  best,  in  any  case, 
whenever  the  science  is  taught  by  recitations,  to  accompany  the  recita 
tions  on  the  Lithological  and  Historical  parts  by  lectures  on  the  vari 
ous  topics  under  the  Dynamical ;  and  then,  when  the  latter  part  of  the 
volume  is  reached  in  the  course,  the  student  will  be  prepared  to  make 
thorough  work  with  it. 

NEW  HAVEN,  CONN.,  March  1,  1874. 


TABLE   OF  CONTENTS. 


INTRODUCTION, 

PAGE 

Relations  of  the  Science  of  Geology         ........  1 

Subdivisions  of  Geology        .......... 

PAET  I,  —  Physiographic  Geology, 

1.  The  Earth's  General  Contour  and  Surface-subdivisions      .....  9 

2.  System  in  the  Reliefs  of  the  Land     .        ........  23 

3.  System  in  the  Courses  of  the  Earth's  Feature-lines      ......  29 

4.  System  of  Oceanic  Movements  and  Temperature     ......  38 

5.  Atmospheric  Currents  and  Temperature       ........  43 

6.  Distribution  of  Forest-regions,  Prairies,  and  Deserts       .....  44 

PART  II.-Lithological  Geology. 

I.  CONSTITUTION  OF  ROCKS    ........  47 

1.  Elements  constituting  Rocks     .......  43 

2.  Minerals  constituting  Rocks         ....  52 

3.  Kinds  of  Rocks          ........  g2 

II.  CONDITION,  STRUCTURE,  AND  ARRANGEMENT  OF  ROCK-MASSES  ...  79 

1.  Stratified  Condition  :  Structure  and  Arrangement  of  Strata    .         .  79 

2.  Unstratified  Condition  —  Veins  —  Dikes      ......  107 

BRIEF  REVIEW  OF   THE   SYSTEM  OF  LIFE    .....  114 

1.  General  Considerations          .......  -Q^ 

2.  Animal  Kingdom       .....                 ...  116 

3.  Vegetable  Kingdom      ........  133 


PART  III.  -Historical  Geology. 

GENERAL  DIVISIONS  IN  THE  HISTORY       .        .  13g 

I.  ARCHJ3AN  TIME       ...........  146 

1.  Laurentian  Period      ......         ...  151 

2.  Huronian  Period    ........  ^59 

3.  General  Conclusions  ......... 


xii  CONTENTS. 

PAGE 

II.  PALEOZOIC  TIME ...  162 

I.  AGE  OF  INVERTEBRATES,  OR  SILURIAN  AGE 162 

A.  Lower  Silurian 166 

1.  Primordial  or  Cambrian  Period 166 

2.  Canadian  Period 182 

3.  Trenton  Period .194 

4.  General  Observations  on  the  Lower  Silurian        .        .        .  210 

5.  Disturbances  at  the  close  of  the  Lower  Silurian  Era         .  212 

B.  Upper  Silurian 218 

1.  North  American  Upper  Silurian 218 

1.  Niagara  Period 218 

2.  Salina  Period 232 

3.  Lower  Ilelderberg  Period 236 

4.  Oriskany  Period 241 

2.  Foreign  Upper  Silurian 244 

3.  Observations  on  the  Upper  Silurian 249 

II.  AGE  OF  FISHES,  OR  DEVONIAN  AGE 254 

1.  American  ...........  254 

1.  Corniferous  Period 254 

2.  Hamilton  Period 266 

3.  Chemung  Period 276 

4.  Catskill  Period 279 

2.  Foreign  Devonian 282 

3.  General  Observations  on  the  Devonian  Age      ....  286 

4.  Disturbances  closing  the  Devonian  Age 289 

III.  CARBONIFEROUS  AGE 291 

Subdivisions  and  American  Distribution 291 

1.  Subcarboniferous  Period 293 

X  American       .         .         .         .         .         .         .    "     •         •         •  293 

2.  Foreign 306 

3.  Disturbances  preceding  the  Carboniferous  Period        .        .  308 

2.  Carboniferous  Period          ........  309 

1.  American       ..........  309 

2.  Foreign 344 

3.  General  Observations  on  the  Origin  of  Coal  and  the  Coal- 

measures          .........  351 

3.  Permian  Period 367 

1.  American   ........••  367 

2.  Foreign 3G9 

IV.  GENERAL  OBSERVATIONS  ON  THE  PALEOZOIC  AGES     .        .        .        373 

1.  Rocks  —  Sections  of  the  American  Paleozoic  Formations  in  dif 

ferent  States   

2.  Life 381 

3.  American  Geography 

4.  Oscillations  of  Level  —  Dislocations < 

V.  DISTURBANCES  CLOSING  PALEOZOIC  TIME 

1.  American ' 

2.  Foreign 402 

III.  MESOZOIC   TIME 403 

REPTILIAN  AGE 403 

1.  Triassic  Period 403 

1.  American 403 


CONTENTS.  Xlll 

III.  MESOZOIC   TIME  —  (continued).  PAGE 

2.  Foreign 423 

3.  General  Observations 429 

2.  Jurassic  Period 431 

1.  American  ..........  431 

2.  Foreign 433 

3.  General  Observations 450 

4.  Disturbances  closing  the  Jurassic  Period      .         .        .        .  452 

3.  Cretaceous  Period 453 

1.  American 454 

2.  Foreign 469 

3.  General  Observations 477 

4.  General  Observations  on  the  Mesozoic  Age       ....  481 

5.  Disturbances  closing  Mesozoic  Time     ......  487 

IV.  CENOZOIC  TIME 488 

I.  THE  TERTIARY,  OR  MAMMALIAN  AGE 489 

1.  American 490 

2.  Foreign 512 

3.  General  Observations .520 

II.  QUATERNARY  AGE,  AND  ERA  OF  MAN 527 

1.  Glacial  Period 527 

2.  Champlain  Period 542 

3.  Recent  Period 550 

4.  Life  of  the  Early  and  Middle  Quaternary 563 

5.  Modern  Era      " " 579 

III.  General  Observations  on  the  Cenozoic 585 

1.  Time-Ratios 585 

2.  Geograplw 586 

3.  Life 588 

V.  GENERAL  OBSERVATIONS   ON  GEOLOGICAL   HISTORY      .        .  590 

1.  Length  of  Geological  Time 590 

2.  Geographical  Progress 591 

3.  Progress  of  Life 592 


PART  IV,  — Dynamical  Geology, 


.GENERAL  SUBDIVISIONS 605 

I.  LIFE 606 

1 .  Protective  Effects 606 

2.  Transporting  Effects  ..........  607 

3.  Destructive  Effects G07 

4.  Contributions  to  Rock  Formations 608 

II.  COHESIVE  AND  CAPILLARY  ATTRACTION  — GRAVITATION      .        .        .627 

III.  THE  ATMOSPHERE 630 

IV.  WATER    ... .  635 

1.  Fresh  Waters 635 

A.  Superficial  Waters  — Rivers  and  Smaller  Lakes  .        .        .        .685 

1.  Erosion         ..........  637 

2.  Transportation        .........  647 

3.  Distribution  —  Alluvial  Formations 649 

B.  Subterranean  Waters    ....                 .        .                 .  653 


XIV  CONTENTS. 

IV.    WATER  —  (continued).  PAGE 

2.  The  Ocean  —  including  also  Large  Lakes 657 

1.  Oceanic  Forces  —  Currents  —  Waves     ......  663 

2.  Effects  of  Oceanic  Forces 663 

1.  Erosion   ......         .....  663 

2.  Transportation 665 

3.  Distribution  —  Marine  and  Fluvio-Marine  Formations         .  666 

4.  Action  over  a  Submerged  Continent 672 

3.  Freezing  and  Frozen  Water 674 

1.  Freezing  Water 674 

2.  Ice  of  Rivers  and  Lakes 674 

3.  Glaciers 675 

4.  Icebergs 686 

4.  Water  as  a  Chemical  Agent 687 

1.  Destructive  Work 687 

2.  Formative  Work          .........  691 

V.  HEAT 697 

1.  Sources  of  Heat 697 

2.  Expansion  and  Contraction 700 

3.  Igneous  Action  and  Results        ........  702 

1.  Volcanoes 702 

2.  ^on-volcanic  Igneous  Eruptions 716 

3.  Subordinate  Igneous  Phenomena  —  Hot  Springs,  Geysers  .        .  718 

4.  Sources  of  Igneous  Eruptions     .......  722 

4.  Metamorphism         ...........  724 

5.  Formation  of  Veins 731 

VI    THE  EARTH  A  COOLING  GLOBE:  ITS  CONSEQUENCES        ....  735 

1.  General  Considerations 735 

2.  Flexures,  Fractures,  Earthquakes  .......  739 

3.  Evolution  of  the  Earth's  Fundamental  Features        ....  744 

4.  Changes  in  Climate 754 

VII.  PROGRESS  IN  ACCORDANCE  WITH  THE  UNIVERSAL  LAW  OF  DEVELOP 

MENT       756 

VIII.  EFFECTS  REFERRED  TO  THEIR  CAUSES.    RECAPITULATION     .        .        .  758 

COSMOGONY 765 

APPENDIX, 

A.  Suggestions  to  Working  Geologists 771 

B.  Catalogue  of  American  Localities  of  Fossils 772 

C.  Brief  Synopsis  of  this  Manual 775 

D.  Authorities  for  the  Figures  of  Fossils,  Sections,  ,and  Views     ....  783 

INDEX  .  789 


ABBREVIATIONS. 


Ag. — L.  Agassiz.. 
B.— E.  Billings. 
Barr. — J.  Barrande. 
Beyr.— E.  Beyrich. 
Blum. — J.  F.  Blumenbacli. 
Blv.— D.  de  Blainville. 
Br.— H.  G.  Broun. 
Brngt. — Brongniart. 
Brod. — Broderip.    • 
Brug. — Bruguiere. 
Briinn. — Briinnich. 
Bu. — L.  von  Buch. 
Buckm. — Buckman. 
Chemn. — Chemnitz. 
Con.— T.  A.  Conrad. 
Couth.— J.  P.  Couthuoy. 
Cpr. — J.  G.  Cooper. 
Cuv. — Cuvier. 
D.— J.  D.  Dana. 
Dalm.— J.  W.  Dalman. 
Dav. — T.  Davidson. 
Defr. — Defrance. 
Desh.— G.  P.  Deshayes. 
Dn.— J.  W.  Dawson. 
D'Orb.— Alcide  d'Orbigny. 
E.  &  II.— Edwards  &  Haimc. 
Eg.— Ph.  Grey  Egerton. 
Ehr.— Ch.  G.  Ehrenberg. 
Eich.— E.  Eichwald. 
Emmr. — H.  F.  Emmrich. 
Fabr. — Fabricius. 
Falc.— H.  Falconer. 
Flem.— J.  Fleming. 
Per.—  Ferussac. 
G.  &  H.— Gabb  &  Horn. 
Gein. — Geinitz. 
Gld.— Gould. 
Gm. — Gmelin. 
Gopp.— H.  R.  Giippert. 
Goldb.— Golderberg. 
Goldf.— Goldfuss. 
H.— J.  Hall. 


H.  &M. -Hall  &  Meek. 

Hald.— S   S.  Haldeman. 

Rising. — W.  Hisinger. 

Hk.— E.  Hitchcock. 

Hux.— T.  II.  Huxley. 

Jag.— G.  F.  Jiiger. 

Kg.-W.  King. 

Kon. — L.  de  Koninck. 

L. — J.  Leidy. 

L.  &  C. — Lyon  &  Casseday. 

L.  &  H.— Lindley  &  Hutton. 

L.  &  M. — Lycett  &  Morriss. 

Lam. — Lamarck. 

Linn. — Linnaeus. 

Lmx. — Lamouroux. 

Lsqx. — L.  Lesquereux. 

Lye.— Lycett. 

M.— F.  B.  Meek. 

Mant— G.  Mantell. 

Mart. — Martin. 

Mg. — Montgomery. 

Mey. — II.  von  Meyer. 

Mh.-O.  C.  Marsh. 

Montf. — Denys  de  Montfort. 

Morr. — Morris. 

Mort— S.  G.  Morton. 

Mil.— Gr.  zu  Minister. 

Mii]l.— Mitller. 

Mtirch — R.  I.  Murchison. 

N.  &  P. — Norwood  &  Pratten. 

N.  &  W.— Newbeny  &  AYorthen 

Newb. — J.  S.  Newbernr. 

O.  &  N.— Owen  &  Norwood. 

Ow. — R.  Owen  (London). 

Park.— A.  S.  Packard. 

Park. — J.  Parkinson. 

Phill.— J.  Phillips. 

Plien. — T.  Plieninger. 

Portl.— J.  E.  Portlock. 

Qu._Fr.  A.  Quenstedt. 

R,— F.  Romer. 

Rem. — A.  R^mond. 


XVI 


ABBREVIATIONS. 


S.— J.  W.  Salter. 

Saff.— J.  M.  Safford. 

Sc.— S.  H.  Scudder. 

Schafh.— Schafhautl. 

Schlot.— E.  F.  von  Schlotheim. 

Schp.— W.  P.  Schimper. 

Sedg.— A.  Sedgwick. 

Shum. — B.  F.  Shumard. 

Sow. — Sowerby. 

St.— Stokes. 

Sternb.— K.  von  Sternberg. 


Stp.— W.  Stimpson. 

Stutch.— Stutchbury. 

Suck. — Suckow. 

T.  &  Hs. — Tuomey  &  Holmes. 

Ung.  -  linger. 

Van. — Vanuxem. 

Vern. — E.  de  Verneuil. 

Woodw.— J.  Woodward. 

Wiss. — Wissmann. 

Wulf.— Wulfen. 

Zimm. — Zimmermann. 


INTRODUCTION. 


Kingdoms  of  nature.  —  SCIENCE,  in  her  survey  of  ths  earth,  has 
recognized  three  kingdoms  of  nature,  —  the  animal,  the  vegetable,  and 
the  inorganic ;  or,  naming  them  from  the  forms  characteristic  of  each, 

the  ANIMAL  KINGDOM,  the  PLANT  KINGDOM,  and  the  CRYSTAL  KING 
DOM.  An  individual  in  either  kingdom  has  its  systematic  mode  of 
formation  or  growth. 

The  plant  or  animal,  (1)  endowed  with  life,  (2)  commences  from  a 
germ,  (3)  grows  by  means  of  imbibed  nutriment,  and  (4)  passes 
through  a  series  of  changes  and  gradual  development  to  the  adult 
state,  when  (5)  it  evolves  new  seeds  or  germs,  and  (6)  afterward  con 
tinues  on  to  death  and  dissolution. 

It  has,  hence,  its  cycle  of  growth  and  reproduction,  and  cycle  fol 
lows  cycle  in  indefinite  continuance. 

The  crystal  is  (1)  a  lifeless  object,  and  has  a  simpler  history ;  it  (2) 
begins  in  a  nucleal  molecule  or  particle  ;  (3)  it  enlarges  by  external 
addition  or  accretion  alone  ;  and  (4)  there  is,  hence,  no  proper  de 
velopment,  as  the  crystal  is  perfect,  however  minute ;  (5)  it  ends  in 
simply  existing,  and  not  in  reproducing ;  and,  (6)  being  lifeless,  there 
is  no  proper  death  or  necessary  dissolution. 

Such  are  the  individualities  in  the  great  kingdoms  of  nature  dis 
played  upon  the  earth. 

But  the  earth  also,  according  to  Geology,  has  been  brought  to  its 
present  condition  through  a  series  of  changes  or  progressive  forma 
tions,  and  from  a  state  as  utterly  featureless  as  a  germ.  Moreover, 
like  any  plant  or  animal,  it  has  its  special  systems  of  interior  and  ex 
terior  structure,  and  of  interior  and  exterior  conditions,  movements 
and  changes ;  and,  although  Infinite  Mind  has  guided  all  events  to 
ward  the  great  end,— a  world  for  mind,— the  earth  has,  under  this 
guidance  and  appointed  law,  passed  through  a  regular  course  of  history 
or  growth.  Having,  therefore,  as  a  sphere,  its  comprehensive  system 
of  growth,  it  is  a  unit  or  individuality,  not,  indeed,  in  either  of  the 
three  kingdoms  of  nature  which  have  been  mentioned,  but  in  a  higher, 

a  WORLD  KINGDOM.    Every  sphere  in  space  must  have  had  a  re- 


2  INTRODUCTION. 

lated  system  of  growth,  and  all  are,  in  fact,  individualities  in  this  King 
dom  of  Worlds. 

Geology  treats  of  the  earth  in  this  grand  relation.  It  is  as  much 
removed  from  Mineralogy  as  from  Botany  and  Zoology.  It  uses  all 
these  departments ;  for  the  species  under  them  are  the  objects  which 
make  up  the  earth  and  enter  into  geological  history.  The  science  of 
minerals  is  more  immediately  important  to  the  geologist,  because  ag 
gregations  of  minerals  constitute  rocks,  or  the  plastic  material  in  which 
the  records  of  the  past  were  made. 

The  earth,  regarded  as  such  an  individuality  in  a  world-kingdom, 
has  not  only  its  comprehensive  system  of  growth,  in  which  strata  have 
been  added  to  strata,  continents  and  seas  defined,  mountains  reared, 
and  valleys,  rivers,  and  jDlains  formed,  all  in  orderly  plan,  but  also  a 
system  of  currents  in  its  oceans  and  atmosphere,  —  the  earth's  circulat 
ing-system  ;  its  equally  world-wide  system  in  the  distribution  of  heat, 
light,  moisture  and  magnetism,  plants  and  animals ;  its  system  of 
secular  variations  (daily,  annual,  etc.)  in  its  climate  and  all  meteoro 
logical  phenomena.  In  these  characteristics  the  sphere  before  us  is 
an  individual,  as  much  so  as  a  crystal,  or  a  tree  ;  and,  to  arrive  at  any 
correct  views  on  these  subjects,  the  world  must  be  regarded  in  this 
capacity.  The  distribution  of  man  and  nations,  and  of  all  productions 
that  pertain  to  man's  welfare,  comes  in  under  the  same  grand  relation ; 
for,  in  helping  to  carry  forward  man's  progress  as  a  race,  the  sphere  is 
working  out  its  final  purpose. 

There  ar$,  therefore, 

Three  departments  of  science,  arising  out  of  this  individual 
capacity  of  the  earth. 

I.  GEOLOGY,  which  treats  of  (1)  the  earth's  structure,  and  (2)  its 
system  of  development,  —  the  last  including  (1)  its  progress  in  rocks, 
lands,  seas,  mountains,  etc. ;  (2)  its  progress  in  all  physical  conditions, 
as  heat,  moisture,  etc. ;   (3)   its  progress  in  life,  or  its  vegetable  and 
animal  tribes. 

II.  PHYSIOGRAPHY,  which  begins  where  Geology  ends,  —  that  is, 
with  the  adult  or  finished  earth,  — and  treats  (1)  of  the  earth's  final 
surface-arrangements  (as  to  its  features,  climates,  magnetism,  life,  etc.)  ; 
and  (2)  its  system  of  physical  movements  or  changes  (as  atmospheric 
and  oceanic  currents,  and  other  secular  variations  in  heat,  moisture, 
magnetism,  etc.). 

III.  THE   EARTH   WITH   REFERENCE  TO  MAN   (including  ordinary 
Geography)  :   (1)  the  distribution  of  races  or  nations,  and  of  all  pro 
ductions  or  conditions  bearing  on  the  welfare  of  man  or  nations  ;  and 
(2)  the  progressive  changes  of  races  and  nations. 

The  first  considers   the   structure  and  growth   of  the  earth  ;    the 


INTRODUCTION. 

second,  its  features  and  world-wide  activities  in  its  finished  state  ;  the 
third,  the  fulfillment  of  its  purpose  in  man,  for  whose  pupilage  it  was 
made. 

Relation  of  the  earth  to  the  universe.  —  While  recognizing  the 
earth  as  a  sphere  in  a  world-kingdom,  it  is  also  important  to  observe 
that  the  earth  holds  a  very  subordinate  position  in  the  system  of  the 
heavens.  It  is  one  of  the  smaller  satellites  of  tho  sun,  —  its  size  about 
1 -200,000th  that  of  the  sun.  And  the  planetary  system  to  which 
it  belongs,  although  3,000,000,000  of  miles  in  radius,  is  but  one  among 
myriads,  the  nearest  star  7,000  times  farther  off  than  Neptune.  Thus 
it  appears  that  the  earth  is  a  very  small  object  in  the  universe* 
Hence  we  naturally  conclude  that  it  is  a  dependent  part  of  the 
solar  system  ;  that,  as  a  satellite  of  the  sun,  in  conjunction  with  other 
planets,  it  could  no  more  have  existed  before  the  sun,  or  our  planetary 
system  before  the  universe  of  which  it  is  a  part,  than  the  hand  before 
the  body  which  it  obediently  attends. 

Although  thus  diminutive,  the  laws  of  the  earth  are  the  laws  of  the 
universe.  One  of  the  fundamental  laws  of  matter  is  gravitation ;  and 
this  we  trace  not  only  through  our  planetary  system,  but  among  the 
fixed  stars,  and  thus  know  that  one  law  pervades  the  universe. 

The  rays  of  light  which  come  in  from  the  remote  limits  of  space 
are  a  visible  declaration  of  unity ;  for  this  light  depends  on  molecular 
vibrations,  —  that  is,  the  ultimate  constitution  and  mode  of  action  of 
matter;  and,  by  the  identity  of  its  principles  or  laws,  whatever  its 
source,  it  proves  the  essential  identity  of  the  molecules  of  matter. 

Meteoric  stones  are  specimens  of  celestial  bodies  occasionally  reaching 
us  from  the  heavens.  They  exemplify  the  same  chemical  and  crystal- 
lographic  laws  as  the  rocks  of  the  earth,  and  have  afforded  no  new  ele 
ment  or  principle  of  any  kind. 

The  moon  presents  to  the  telescope  a  surface  covered  with  the 
craters  of  volcanoes,  having  forms  that  are  well  illustrated  by  some  of 
the  earth's  volcanoes,  although  of  immense  size.  The  principles  ex 
emplified  on  the  earth  are  but  repeated  in  her  satellite. 

Thus,  from  gravitation,  light,  meteorites,  and  the  earth's  satellite,  we 
learn  that  there  is  oneness  of  law  through  space.  The  elements  may 
differ  in  different  systems,  but  it  is  a  difference  such  as  exists  among 
known  elements,  and  could  give  us  no  new  fundamental  laws.  New 
crystalline  forms  might  be  found  in  the  depths  of  space,  but  the  laws  of 
crystallography  would  be  the  same  that  are  displayed  before  us  among 
the  crystals  of  the  earth.  A  text-book  on  Crystallography,  Physics, 
or  Celestial  Mechanics,  printed  in  our  printing-offices,  would  serve  for 
the  universe.  The  universe,  if  open  throughout  to  our  explorations, 
would  vastly  expand  our  knowledge,  and  science  might  have  a  more 
beautiful  superstructure,  but  its  basement-laws  would  be  the  same. 


4  INTRODUCTION. 

The  earth,  therefore,  although  but  an  atom  in  immensity,  is  im 
mensity  itself  in  its  revelations  of  truth ;  and  science,  though  gathered 
from  one  small  sphere,  is  the  deciphered  law  of  all  spheres. 

It  is  well  to  have  the  mind  deeply  imbued  with  this  thought,  before 
entering  upon  the  study  of  the  earth.  It  gives  grandeur  to  science 
and  dignity  to  man,  and  will  help  the  geologist  to  apprehend  the  loftier 
characteristics  of  the  last  of  the  geological  ages. 

Special  aim  of  geology,  and  method  of  geological  reasoning.  — 
Geology  is  sometimes  defined  as  the  science  of  the  structure  of  the 
earth.  But  the  ideas  of  structure  and  origin  of  structure  are  insepar 
ably  connected,  and  in  all  geological  investigations  they  go  together. 
Geology  had  its  very  beginning  and  essence  in  the  idea  that  rocks 
were  made  through  secondary  causes ;  and  its  great  aim  has  ever  been 
to  study  structure  in  order  to  comprehend  the  earth's  history.  The 
science,  therefore,  is  a  historical  science.  It  finds  strata  of  sandstone, 
clayey  rocks,  and  limestone,  lying  above  one  another  in  many  succes 
sions  ;  and,  observing  them  in  their  order,  it  assumes,  not  only  that  the 
sandstones  were  made  of  sand  by  some  slow  process,  clayey  rocks  of 
clay,  and  so  on,  but  that  the  strata  were  successively  formed;  that,  there 
fore,  they  belong  to  successive  periods  in  the  earth's  past ;  that,  con 
sequently,  the  lowest  beds  in  a  series  were  the  earliest  beds.  It  hence 
infers,  further,  that  each  rock  indicates  some  facts  respecting  the  con 
dition  of  the  sea  or  land  at  the  time  it  was  formed,  one  condition 
originating  sand  deposits,  another  clay  deposits,  another  lime,  —  and, 
if  the  beds  extend  over  thousands  of  square  miles,  that  the  several 
conditions  prevailed  uniformly  to  this  same  extent  at  least.  The  rocks 
are  thus  regarded  as  records  of  successive  events  in  the  history,  —  in 
deed,  as  actual  historical  records  ;  and  every  new  fact  ascertained  by 
a  close  study  of  their  structure,  be  it  but  the  occurrence  of  a  pebble, 
or  a  seam  of  coal,  or  a  bed  of  ore,  or  a  crack,  or  any  marking  what 
ever,  is  an  addition  to  the  records,  to  be  interpreted  by  careful  study. 

Thus  every  rock  marks  an  epoch  in  the  history ;  and  groups  of  rocks, 
periods  ;  and  still  larger  groups,  ages  ;  and  so  the  ages  which  reach 
through  geological  time  are  represented  in  order  by  the  rocks  that  ex 
tend  from  the  lowest  to  the  uppermost  of  the  series. 

If,  now,  the  great  beds  of  rock,  instead  of  lying  in  even  horizontal 
layers,  are  much  folded  up,  or  lie  inclined  at  various  angles,  or  are 
broken  and  dislocated  through  hundreds  or  thousands  of  feet  in  depth, 
or  are  uplifted  into  mountains,  they  bear  record  of  still  other  events 
in  the  great  history ;  and  should  the  geologist,  by  careful  study, 
learn  how  the  great  disturbance  or  fracture  was  produced,  or  succeed 
in  locating  its  time  of  occurrence  among  the  epochs  registered  in  the 
rocks,  he  would  have  interpreted  the  record,  and  added  not  only  a  fact 


INTRODUCTION.  5 

to  the  history,  but  also  its  full  explanation.  The  history  is,  hence,  a 
history  of  the  upturnings  of  the  earth's  crust,  as  well  as  of  its  more 
quiet  rock-making. 

If,  in  addition,  a  fossil  shell,  or  coral,  or  bone,  or  leaf,  is  found  in 
one  of  the  beds,  it  is  a  relic  of  some  species  that  lived  when  that  rock 
was  forming  ;  it  belongs  to  that  epoch  in  the  world  represented  by  the 
particular  rock  containing  it,  and  tells  of  the  life  of  that  epoch  ;  and, 
if  numbers  of  such  organic  remains  occur  together,  they  enable  us  to 
people  the  seas  or  land,  to  our  imagination,  with  the  very  life  that  be 
longed  to  the  ancient  epoch. 

Moreover,  as  such  fossils  are  common  in  a  large  number  of  the 
strata,  from  the  lowest  containing  signs  of  life  to  the  top,  —  that  is, 
from  the  oldest  beds  to  the  most  recent,  —  by  studying  out  the  char 
acters  of  these  remains  in  each,  we  are  enabled  to  restore  to  our 
minds,  to  some  extent,  the  population  of  all  the  epochs,  as  they  follow 
one  another  in  the  long  series.  The  strata  are  thus  not  simply  records 
of  moving  seas,  sands,  clays,  and  pebbles,  and  disturbed  or  uplifted 
strata,  but  also  of  the  living  beings  that  have  in  succession  occupied 
the  land  or  waters.  The  history  is  a  history  of  the  life  of  the  globe, 
as  well  as  of  its  rock-formations  ;  and  the  life-history  is  the  great  topic 
of  Geology  §  it  adds  tenfold  interest  to  the  other  records  of  the  dead 
rocks. 

These  examples  are  sufficient  to  explain  the  basis  and  general  bear 
ing  of  geological  history. 

The  method  of  interpreting  the  records  rests  upon  the  simple  principle  that  rocks" 
were  made  as  they  are  now  made,  and  that  life  lived  in  olden  time  as  it  now  lives; 
and,  further,  the  mind  is  forced  into  receiving  the  conclusions  arrived  at  by  its  own 
laws  of  action. 

For  example,  we  go  to  the  sea-shore,  and  observe  the  sands  thrown  up  by  the  waves: 
note  how  the  wash  of  the  waves  brings  in  layer  upon  layer,  though  with  inany  irregu 
larities  ;  how  the  progressing  waters  raise  ripples  over  the  surface,  which  the  next  wave 
buries  beneath  other  sands;  how  such  sand-beds  gradually  increase  in  extent;  how 
they  are  often  continued  out  scores  of  miles  beneath  the  sea,  as  the  bottom  of  the  shal 
low  shore-waters;  and  that  these  submerged  beds  are  formed  through  constant  deposi 
tions  from  the  ever  moving  waters.  Then  we  go  among  the  hard  rocks,  and  find  strata 
made  of  sand  in  irregular  layers,  much  like  those  of  the  beach ;  and  on  opening  some 
of  the  layers  we  discover  ripple-marks  covering  the  surface,  as  distinct  and  regular  as 
if  just  made  by  the  waves;  or,  in  another  place,  we  find  the  strata  made  up  of  regular 
layers  of  sand  and  clay  alternating,  such  as  form  from  the  gradual  settling  of  the 
muddy  material  emptied  into  the  ocean  by  rivers,  —  or,  in  another  place,  layers  of 
rounded,  water-worn  pebbles,  such  as  occur  beneath  rapidly-moving  waters,  whether  of 
waves  or  rivers.  We  remark  that  these  hard  rocks  differ  from  the  loose  sand,  clay,  or 
pebbly  deposits  simply  in  being  consolidated  into  a  rock.  Then,  in  other  places,  we 
discover  these  sand-deposits  in  all  states  of  consolidation,  from  the  soft,  movable  sand, 
through  a  half-compacted  condition,  to  the  gritty  sandstone ;  and,  further,  we  discover, 
perhaps,  the  very  means  of  this  consolidation,  and  see  it  in  its  progress,  making  rock 
out  of  sand  or  clay.  By  such  steps  as  these,  the  mind  is  borne  along  irresistibly  to 
the  conclusion  that  rocks  were  slowly  made  through  common-place  operatic 


ions. 


b  INTRODUCTION. 

We  may  see,  on  another  sea-shore,  extensive  beds  of  limestone  forming  from  shells 
and  corals,  having  as  firm  a  texture  as  any  marble ;  we  may  watch  the  process  of  ac 
cumulation  from  the  growth  of  corals  and  the  wear  of  the  waves,  and  find  the  remains 
of  corals  and  shells  in  the  compact  bed.  If  \ve  then  meet  with  a  limestone  over  the  con 
tinent  containing  remains  of  corals,  or  shells,  no  firmer,  not  different  in  composition, 
but  every  way  like  the  coral  reef-rock,  or  the  shell-rock  of  other  regions,  the  mind,  if 
allowed  to  act  at  all,  will  infer  that  the  ancient  limestone  was  as  much  a  slowly-formed 
rock,  made  of  corals,  or  shells,  as  the  limestone  of  coral  seas. 

In  a  volcanic  district,  we  witness  the  melted  rock  poured  out  in  wide-spread  layers 
and  cooling  into  compact  rock,  and  learn,  after  a  little  observation,  that  just  such  layers 
piled  upon  one  another  make  the  great  volcanic  mountain,  although  it  may  be  ten 
thousand  feet  in  height.  We  remark,  further,  that  the  fractured  crust  in  those  regions 
has  often  let  out  the  lava  to  spread  the  surface  with  i-ock,  even  to  great  distances  from 
the  opening. 

Should  we,  after  this,  discover  essentially  the  same  kind  of  rock  in  widespread  beds, 
and  trace  out  the  fractures  filled  with  it,  leading  downward  through  the  subjacent 
strata,  as  if  to  some  seat  of  fires,  and  discover  marks  of  fire  in  the  baking  of  the  under 
lying  beds,  we  use  our  reason  in  the  only  legitimate  way,  when  we  conclude  that  these 
beds  were  thrown  out  melted,  even  though  they  may  be  far  from  any  volcanic  centre. 

If  we  sec  skeletons  buried  in  sand  and  clay  that  we  do  not  doubt  are  real  skeletons 
of  familiar  animals,  and  then  in  a  bed  of  rock  discover  other  skeletons,  but  of  unfa 
miliar  animals,  yet  with  every  bone  a  true  bone  in  form,  texture,  and  composition,  and 
every  joint  and  limb  modelled  according  to  the  plan  in  known  species,  we  pass,  by  an 
unavoidable  step,  to  the  belief  that  the  last  is  a  relic  of  an  animal  as  well  as  the 
former,  and  that  it  lies  in  its  burial-place,  although  that  burial-place  be  now  the  solid 
rock. 

These  few  examples  elucidate  the  mode  of  reasoning  upon  which  geological  deduc 
tions  are  based. 

In  using  the  present  in  order  to  reveal  the  past,  we  assume  that  the 
forces  in  the  world  are  essentially  the  same  through  all  time ;  for  these 
forces  are  based  on  the  very  nature  of  matter,  and  could  not  have 
changed.  The  ocean  has  always  had  its  waves,  and  those  waves  have 
ever  acted  in  the  same  manner.  Running  water  on -the  land  has  ever 
had  the  same  power  of  wear  and  transportation  and  mathematical 
value  to  its  force.  The  laws  of  chemistry,  heat,  electricity,  and  me 
chanics  have  been  the  same  through  time.  The  plan  of  living  struc 
tures  has  been  fundamentally  one,  for  the  whole  series  belongs  to  one 
system,  as  much  almost  as  the  parts  of  an  animal  to  the  one  body  ; 
and  the  relations  of  life  to  light  and  heat,  and  to  the  atmosphere,  have 
ever  been  the  same  as  now. 

The  laws  of  the  existing  world,  if  perfectly  known,  are  consequently  a  key  to  the 
past  history.  But  this  perfect  knowledge  implies  a  complete  comprehension  of  nature 
in  all  her  departments,  —  the  departments  of  chemistry,  physics,  mechanics,  physical 
geography,  and  each  of  the  natural  sciences.  Thus  furnished,  we  may  scan  the  rocks 
with  reference  to  the  past  ages,  and  feel  confident  that  the  truth  will  declare  itself  to 
the  truth-loving  mind. 

As  this  extensive  range  of  learning  is  not  within  the  grasp  of  a  single  person,  special 
departments  have  been  carried  forward  by  different  individuals,  each  in  his  own  line  of 
research ;  for  Geology  as  it  stands  is  the  combined  result  of  the  labors  of  many  workers. 
But  the  system  is  now  so  far  perfected  that  the  ordinary  mind  may  readily  understand 
the  great  principles  of  the  science,  and  comprehend  the  unity  of  plan  in  the  earth's 
genesis. 


INTRODUCTION.  7 

SUBDIVISIONS  OF  GEOLOGY. 

(1.)  Like  a  plant  or  animal,  the  earth  has  its  systematic  external 
form  and  features,  which  should  be  reviewed. 

(2.)  Next,  there  are  the  constituents  of  the  structure  to  be  con 
sidered  :  first,  their  nature  ;  secondly,  their  general  arrangement. 

(3.)  Next,  the  successive  stages  in  the  formation  of  the  structure, 
and  the  concurrent  steps  in  the  progress  of  life,  through  past  time. 

(4.)  Next,  the  general  plan  or  laws  of  progress  in  the  earth  and 
its  life. 

(5.)  Finally,  there  are  the  active  forces  and  mechanical  agencies 
which  were  the  means  of  physical  progress,  —  spreading  ont  and  con 
solidating  strata,  raising  mountains,  ejecting  lavas,  wearing  out  valleys, 
bearing  the  material  of  the  heights  to  the  plains  and  oceans,  enlarging 
the  oceans,  destroying  life,  and  performing  an  efficient  part  in  evolving 
the  earth's  structure  and  features. 

These  topics  lead  to  the  following  subdivisions  of  the  science  :  — 

I.  PHYSIOGRAPHIC    GEOLOGY,  —  a  general  survey  of  the  earth's 
surface-features. 

II.  LITIIOLOGICAL  GEOLOGY,  —  a  description  of  the  rock-material 
of  the  globe,  its  elements,  rocks,  and  arrangement. 

III.  HISTORICAL    GEOLOGY,, — an   account   of  the   rocks   in    the 
order  of  their  formation,  and  the  contemporaneous  events  in  geological 
history,    including  both  stratigraphical  and  paleontological  geology ; 
and  closing  with  a  review  of  the  system  or  laws  of  progress  in   the 
globe  and  its  kingdoms  of  life. 

IV.  DYNAMICAL  GEOLOGY,  —  an  account  of  the  agencies  or  forces 
that  have  produced  geological  changes,  and  of  the    laws  and  methods 
of  their  action. 


PART   I. 

PHYSIOGRAPHIC    GEOLOGY. 


THE  systematic  arrangement  in  the  earth's  features  is  every  way  as 
marked  as  that  of  any  organic  species  ;  and  this  system  over  the  exte 
rior  is  an  expression  of  the  laws  of  structure  beneath.  The  oceanic 
depressions  or  basins,  with  their  ranges  of  islands,  and  the  continental 
plains  and  elevations,  all  in  orderly  plan,  are  the  ultimate  results  in 
the  whole  line  of  progress  of  the  earth ;  and,  by  their  very  compre 
hensiveness  as  the  earth's  great  feature-marks,  they  indicate  the  pro- 
foundest  and  most  comprehensive  movements  in  the  forming  sphere, 
just  as  the  exterior  configuration  of  an  animal  indicates  its  interior 
history.  This  subject  is  therefore  an  important  one  to  the  geologist, 
although  its  facts  come  also  within  the  domain  of  physical  geography. 
They  lie  at  the  top  in  geology  as  its  last  results,  and,  thus  situated, 
constitute  necessarily  the  arena  of  the  physical  geographer. 

The  following  are  the  divisions  in  this  department :  — 

1.  The  earth's  general  contour  and  surface-subdivisions. 

2.  System  in  the  reliefs  or  surface-forms  of  the  continental  lands. 

3.  System  in  the  courses  of  the  earth's  feature-lines. 
These  topics  are  followed  by  a  brief  review  of,  — 

4.  The  system  of  oceanic  movements  and  temperature. 

5.  The  system  of  atmospheric  movements  and  temperature. 

6.  The  general  law  for  the  distribution  of  forest-regions,  prairies, 
and  deserts. 

1.   THE  EARTH'S   GENERAL   CONTOUR   AND   SURFACE- 
SUBDIVISIONS. 

The  subjects  under  this  head  are  —  the  earth's  form ;  the  distribu 
tion  of  land  and  water ;  the  depth  and  true  outlines  of  the  oceanic 
depression  ;  the  subdivision  of  the  land  into  continents  ;  the  height  and 
kinds  of  surface  of  the  continents. 

(1.)  Spheroidal  form.  —  The  earth  has  the  form  of  a  sphere  with 
flattened  poles,  the  distance  from  the  centre  to  the  pole  being  about 


10 


PHYSIOGRAPHIC    GEOLOGY. 


1  -300th  (accurately,  -5$ 2.?)  shorter  than  from  the  centre  to  the  equator. 
The  earth's  equatorial  radius  being  3.963  miles,  the  polar  is  about  13^ 
miles  less  (exactly  13.2465  miles). 

This  is  a  fact  of  prime  importance  in  geology,  and  an  appropriate  introduction  to  the 
science,  inasmuch  as  it  is  the  most  obvious  proof  that  the  earth  has  a  history,  or  has 
been  in  course  of  progress  under  secondary  causes;-  for  this  flattening  is  in  amount  just 
that  which  the  revolution  at  its  actual  rate  would  produce  in  a  liquid  globe  having  the 
size  and  density  of  the  earth. 

(2.)  General  subdivisions  of  the  surface.  —  Proportion  of  Land 
and  Water.  —  In  the  surface  of  the  sphere  there  are  about  8  parts  of 
water  to  3  of  dry  land,  or,  more  exactly,  275  to  100  =  52  :32.  The 
proportion  of  land  north  of  the  equator  is  nearly  three  times  as  great 
as  that  south.  The  zone  containing  the  largest  proportion  of  land  is 
the  north-temperate,  the  area  equalling  that  of  the  water  ;  while  it  is 
only  one  third  that  of  the  water  in  the  torrid  zone,  and  hardly  one 
tenth  (2-21ths)  in  the  south-temperate. 

Out  of  the  197,000,000  of  square  miles  which  make  up  the  entire  surface  of  the  globe, 
144,500,000  are  water,  and  52,500,000  land.  In  the  northern  hemisphere  the  land  covers 
38,900,000  square  miles;  in  the  southern,  13,600,000  square  miles. 

Land  in  one  hemisphere.  —  If  a  globe  be  cut  through  the  centre  by 
a  plane  intersecting  the  meridian  of  175°  E.  at  the  parallel  of  40°  X., 
one  of  the  hemispheres  thus  made,  the  northern,  will  contain  nearly 

Fig.  i. 

180  -J£5  aJ^- 

M-       —        - 

135 


all  the  land  of  the  globe,  and  the  other  be  almost  wholly  water.     The 
annexed  map  represents  the  two  hemispheres. 

The  pole  of  the  land-hemisphere  in  this  map  is  in  the  western  half 
of  the  British  Channel  ;  and,  if  this  part,  on  a  common  globe,  be 
placed  in  the  zenith,  under  the  brass  meridian,  the  horizon-circle  will 
then  mark  the  line  of  division  between  the  two  hemispheres.  The 
portions  of  land  in  the  water-hemisphere  are  the  extremity  of  South 
America  below  25°  S.,  and  Australia,  together  with  the  islands  of  the 


GENERAL  FEATURES  OF  THE  EARTH.  11 

East  Indies,  the  Pacific,  and  the  Antarctic.     London  and  Paris  are 
situated  very  near  the  centre  of  the  land-hemisphere. 

General  arrangement  of  the  Oceans  and  Continents. l  —  Oceans  and 
continents  are  the  grander  divisions  of  the  earth's  surface.  But,  while 
the  continents  are  separate  areas,  the  oceans  occupy  one  continuous 
basin  or  channel.  The  waters  surround  the  Antarctic  and  stretch 
north  in  three  prolongations,  —  the  Atlantic,  the  Pacific,  and  the  In 
dian  Oceans.  The  land  is  gathered  about  the  Arctic,  and  reaches  south 
in  two  great  continental  masses,  the  occidental  and  oriental  ;  but  the 
latter,  through  Africa  and  Australia,  has  two  southern  prolongations, 
making  in  all  three,  corresponding  to  the  three  oceans.  Thus  the  con 
tinents  and  oceans  interlock,  the  former  narrowing  southward,  the 
latter  northward. 

The  Atlantic  is  the  narrow  ocean,  its  average  breadth  being  2,800 
miles.  The  Pacific  is  the  broad  ocean,  being  6,000  miles  across,  or 
more  than  twice  the  breadth  of  the  Atlantic.  The  Occident,  or 
America,  is  the  narrow  continent,  about  2,200  miles  in  average  breadth  ; 
the  orient,  the  broad  continent,  6,000  miles.  Each  continent  has, 
therefore,  as  regards  size,  its  representative  ocean.  This  great  dif 
ference  of  magnitude  has  an  important  bearing  on  the  earth's  geologi 
cal  history.  The  Pacific  ocean,  reckoning  only  to  62°  S.,  has  an  area 
of  62,000,000  square  miles,  or  nine  and  a  half  millions  beyond  the 
area  of  all  the  continents  and  islands. 

(3.)  Oceanic  depression.  —  (a.)  Outline.  —  The  oceanic  depression 
is  a  vast  sunken  area,  varying  in  depth  from  1,000  or  less  to,  probably, 
50,000  feet. 

The  true  outline  of  the  depression  is  not  necessarily  identical  with 
the  present  line  of  coast.  About  the  continents,  there  is  often  a  region 
of  shallow  depths,  which  is  only  the  submerged  border  of  the  con 
tinent.  On  the  North  American  coast,  off  New  Jersey,  this  submerged 
border  extends  out  for  80  miles,  with  a  depth,  at  this  distance,  of  only 
600  feet ;  and  from  this  line  the  ocean-basin  dips  off  at  a  steep  angle. 

The  true  outline  of  the  basin  on   this  and  other  coasts  is  shown  by 

1  In  illustration  of  this  part  of  the  workTthe  reader  is  referred  to  the  map  at  the  close 
of  the  volume.  It  is  a  Mercator's  chart  of  the  world,  which,  while  it  exaggerates  the 
polar  regions,  has  the  great  advantage  of  giving  correctly  all  courses,  that  is,  the  bear 
ings  of  places  and  coasts.  The  trends  of  lines  ("  trend  "  means  merely  course  or  bear 
ing)  admit,  therefore,  of  direct  comparison  upon  such  a  chart.  It  is  important  in  ad 
dition  that  the  globe  should  be  carefully  studied  in  connection,  in  order  to  correct  mis 
apprehensions  as  to  distances  in  the  higher  latitudes,  and  appreciate  the  convergences 
.between  lines  that  have  the  same  compass-course. 

The  low  lands  of  the  continents  on  this  chart,  or  those  below  800  feet  in  elevation 
above  the  sea,  are  distinguished  from  the  higher  lands  and  plateaus  by  a  lighter  shad 
ing,  and  the  axes  of  the  mountain-ranges  are  indicated  by  black  lines.  The  oceans  are 
crossed  by  isothermal  lines,  which  are  explained  beyond. 


12  PHYSIOGRAPHIC    GEOLOGY. 

the  dotted  line  on  the  chart.    The  slope  for  the  80  miles  is  only  1  foot 
in  700. 

Great  Britain  is,  on  the  same  principle,  a  part  of  the  European  continent:  the  separ 
ating  waters  are  under  600  feet  in  depth ;  and  a  large  part  of  the  German  Ocean  is  only 
93  feet.  The  true  oceanic  outline  extends  from  Southern  Norway  around  by  the  north 
of  Scotland  and  southward  into  the  Bay  of  Biscay.  (See  the  dotted  line  on  the  chart.) 
In  a  similar  manner,  the  East  India  Islands,  down  to  a  line  running  by  the  north  of 
New  Guinea  and  Celebes,  are  a  part  of  Asia,  the  depth  of  the  seas  intermediate  seldom 
exceeding  300  feet;  while,  south  ol  the  line  mentioned,  the  islands  are  but  fragments  of 
Australia,  the  water  being  no  deeper  than  over  the  submerged  Asiatic  plateau.1 

(b.)  Depth  of  the  Ocean.  —  The  depth  of  the  ocean  in  its  different 
parts  is  imperfectly  known.  Some  deep  soundings  have  been  made, 
and  a  few  are  stated  to  have  reached  to  a  depth  of  forty-five  thou 
sand  feet.2  Across  from  Ireland  to  Newfoundland,  tho  depth  has 
been  found  to  vary  between  6,000  and  15,000  feet.  The  Gulf  of 
Mexico  is  known  to  be  from  4,000  to  5,000  feet  in  depth.  According 
to  calculations  on  the  data  furnished  by  an  earthquake-wave  which,  in 
1855,  crossed  from  Simoda  in  Japan,  to  San  Francisco,  the  ocean  in 
that  line  lias  an  average  depth  of  about  13,000  feet.  Another  wave, 
in  1868,  indicated  for  the  mean  depth  of  the  southern  Pacific,  from 
Arica  south  of  west,  about  12,000  feet. 

The  mean  depth  of  the  oceanic  depression  is,  by  estimate,  about 
15,000  feet. 

(c.)  Character  of  the  Oceanic  Basins,  —  To  appreciate  the  oceanic 
basins,  we  must  conceive  of  the  earth  without  its  water,  —  the  de 
pressed  areas,  thousands  of  miles  across,  sunk  ten  to  perhaps  fifty 
thousand  feet  below  the  bordering  continental  regions,  and  covering 
five  eighths  of  the  whole  surface.  The  continents,  in  such  a  condition, 
would  stand  as  elevated  plateaus  encircled  by  one  great  uneven  basin. 
If  the  earth  had  been  left  thus,  with  but  shallow  lakes  about  the  bot 
tom,  there  would  have  been  an  ascent  of  five  miles  or  more  from  the 
Atlantic  basin  to  the  lower  part  of  the  continental  plateau,  and  one  to 
five  miles  beyond  this  to  scale  the  summits  of  the  loftier  mountains  of 
the  globe.  The  continents  would  have  been  wholly  in  the  regions  of 
the  upper  cold,  all  alpine  and  barren.  This  uneven  surface  of  the  At 
lantic  and  Pacific  has  been  levelled  off  to  a  plain  by  the  waters  of  the 
ocean,  the  heights  of  the  world  reduced  from  ten  or  fifteen  miles  to 
five,  and  the  intolerable  climates  of  such  extremes  of  surface  reduced 
to  a  genial  condition,  rendering  nearly  the  whole  land  habitable,  and 
giving  moisture  for  clouds,  rivers,  and  plants  ;  and,  by  the  same  means, 
distant  points  have  been  bound  together,  by  a  common  highway,  into 
one  arena  of  history. 

1  Earl,  Jour.  Indian  Arch.,  II.  ii.  278,  and  Wallace,  .Ifalay  Archipelago. 

2  Some  of  the  results  are  as  follow:    A  sounding  by  Capt.  Ross,  900   m.  S.W.  of 
St.  Helena,  27,600  feet  without  bottom;  by  Capt.  Denham,  in  36°  49'  S.,  37°  0'  \V.» 
40,236  feet  (7,706  fathoms)  found  bottom. 


GENERAL  FEATURES  OF  THE  EARTH.  13 

(4.)  General  view  of  the  land.  —  (a.)  Position  of  the  land.  —  The 
land  of  the  globe  has  been  stated  to  lie  with  its  mass  to  the  north, 
about  the  pole,  and  to  narrow  as  it  extends  southward  into  the 
waters  of  the  Southern  hemisphere.  The  mean  southern  limit  of  the 
continental  lands  is  the  parallel  of  45°,  or  just  half-way  from  the 
equator  to  the  south  pole- 

South  America  reaches  only  to  56°  S.  (Cape  Horn  being  in  55°  58X),  which  is  the 
latitude  of  Edinburgh  or  northern  Labrador;  Africa  to  34°  51/  (Cape  of  Good  Hope), 
nearly  the  latitude  of  the  southern  boundary  of  Tennessee,  and  60  miles  nearer  the 
equator  than  Gibraltar;  Tasmania  (Van  Diemen's  Land)  to  43^°  S.,  nearly  the  latitude 
of  Boston  and  northern  Portugal. 

(b.)  Distribution.  —  The  independent  continental  areas  are  three  in 
number :  America,  one  ;  Europe,  Asia,  and  Africa,  a  second  ;  Aus 
tralia,  the  third.  Through  the  East  India  Islands,  Australia  is  ap 
proximately  connected  with  Asia,  nearly  as  South  America  with  North 
America  through  the  West  Indies ;  and,  regarding  it  as  thus  united, 
the  great  masses  of  land  will  be  but  two,  —  the  American,  or  Oc 
cidental,  and  Europe,  Asia,  Africa,  and  Australia,  or  the  Oriental. 

These  great  masses  of  land  are  divided  across  from  east  to  west  by 
seas  or  archipelagoes.  The  West  Indies,  Mediterranean,  Red  Sea, 
and  East  Indies,  with  the  connecting  oceans,  make  a  nearly  com 
plete  band  of  water  around  the  globe,  as  Professor  Guyot  observes, 
subdividing  the  Occident  and  Orient  into  north  and  south  divisions. 
Cutting  across  37  miles  at  the  Isthmus  of  Darien,  where  at  the  lowest 
pass  the  greatest  height  above  mean  tide-level  does  not  exceed  660 
feet,  as  has  been  done  at  the  Isthmus  of  Suez,  where  the  summit-level 
is  only  40  feet  above  the  sea,  the  girth  of  water  would  be  unbroken. 

America  is  thus  divided  into  North  and  South  America.  The 
oriental  lands  have  one  great  area  on  the  north,  comprising  Eu 
rope  and  Asia  combined,  and  on  the  south  (1)  Africa,  separated 
from  Europe  by  the  Mediterranean,  and  (2)  Australia,  separated  from 
Asia  by  the  East  India  seas.  Thus  the  narrow  Occident  has  one 
southern  prolongation,  and  the  wide  Orient  two.  It  is  to  be  noted 
that  the  East  and  West  Indies  are  very  similar  in  form  and  position 
(see  chart)  ;  and  also  that  South  America  is  situated  with  reference  to 
North  America  very  nearly  as  Australia  is  to  Asia. 

The  Orient  is  thus  equivalent  to  two  Occidents  in  which  the  north 
ern  areas  coalesce,  —  Europe  and  Africa  one,  Asia  and  Australia  the 
other ;  so  that  there  are  really  three  doublets  in  the  system  of  con 
tinental  lands.  Moreover,  Europe  and  Asia  have  a  semi-marine  region 
between  them  ;  for  the  Caspian  and  Aral  are  salt  seas,  and  they  lie  in 
a  depression  of  the  continent  of  great  extent,  —  the  Aral  being  near 
the  level  of  the  ocean,  and  the  Caspian  80  to  100  feet  below  it. 


14  PHYSIOGRAPHIC    GEOLOGY. 

The  islands  adjoining  the  continents  are  properly  portions  of  the 
continental  regions.  Besides  the  examples  mentioned  on  page  12, 
Japan  and  the  ranges  of  islands  of  eastern  Asia  are  strictly  a  part  of 
Asia,  for  they  conform  in  direction  to  the  Asiatic  system  of  heights, 
and  are  united  to  the  main  by  shallow  waters.  Vancouver's  Island 
and  others  north  are  similarly  a  part  of  North  America  ;  Chiloe,  and 
the  islands  south  to  Cape  Horn,  a  part  of  South  America ;  and  so  in 
other  cases. 

The  body  of  the  continent  of  Africa  lies  in  those  latitudes  which 
arc  almost  wholly  water  in  the  American  section,  its  western  expan 
sion  corresponding  to  the  indentation  of  the  Caribbean  Sea  and  the 
Gulf  of  Mexico. 

(c.)  Oceanic  Islands.  —  The  islands  of  mid-ocean  are  in  lines,  and 
are  properly  the  summits  of  submerged  mountain-chains.  The  At 
lantic  and  Indian  Oceans  are  mostly  free  from  them.  The  Pacific 
contains  about  675,  which  have,  however,  an  aggregate  area  of  only 
80,000  square  miles.  Excluding  New  Caledonia  and  some  other  large 
islands  in  its  southeastern  part,  the  remaining  600  islands  have  an  area 
of  but  40,000  square  miles,  or  less  than  that  of  New  York  State.  The 
islands  stretch  off  in  a  train  from  the  Asiatic  coast  through  the  tropics 
in  an  east-southeast  direction,  and,  soon  crossing  the  equator,  lie 
mostly  in  the  southern  tropic.  The  train  extends  to  Easter  Island 
and  Sala-y-Gomez,  in  longitudes  110°  and  105°  TT.,  a  distance  of 
8,000  miles.  The  greatest  depth  of  the  ocean  should  be  looked  for 
outside  of  the  limits  of  this  train. 

(d.)  Mean  elevation. — The  mean  height  of  the  continents  above  the 
sea,  exclusive  of  Australia  and  Africa,  according  to  an  estimate  by 
ITumboldt,  is  about  1,000  feet;  and  this  is  probably  not  far  from  the 
truth  for  all  the  land  of  the  globe.  As  the  area  of  the  ocean  and  land 
is  as  8  to  3,  if  all  this  land  above  the  present  water-level  were  trans 
ferred  into  the  oceans,  it  would  fill  them  3-8ths  of  1,000  or  375  feet; 
and,  taking  the  average  depth  at  15,000  feet,  it  would  take  40  times 
this  amount  to  fill  the  oceanic  depressions. 

The*  mean  height  of  the  several  continents  has  been  stated  as  fol 
lows :  Europe,  670  feet;  Asia,  1,150;  North  America,  748  ;  South 
America,  1,132;  all  America,  930;  Europe  and  Asia,  1,010;  Africa, 
probably  about  1,600  feet;  and  Australia,  perhaps  500.  It  has  been 
estimated  that  the  material  of  the  Pyrenees  spread  over  Europe  would 
raise  the  surface  only  6  feet ;  and  the  Alps,  though  four  times  larger 
in  area,  only  22  feet. 

The  extremes  of  level  in  the  land,  so  far  as  now  known,  are,  1,300 
feet  below  the  level  of  the  ocean,  at  the  Dead  Sea,  and  29,000  feet 
above  it,  in  Mount  Everest  of  the  Himalayas.  Both  of  these  points 


GENERAL  FEATURES  OF  THE  EARTH.  15 

occur  on  the  continent  of  Asia,  which  has  also  its  great  depressed  Cas 
pian  area.  In  America,  below  the  ocean's  level,  Death's  Valley,  east 
of  the  Sierra  Nevada,  California,  about  latitude  36°,  is  100  to  200  feet 
below  the  ocean's  level. 

(5.)  Subdivisions  of  the  surface,  and  character  of  its  reliefs. — 
The  surfaces  of  continents  are  conveniently  divided  into  (1)  low  lands; 
(2)  plateaus,  or  elevated  table  lands;  (3)  mountains.  The  limits  be 
tween  %these  subdivisions  are  quite  indefinite,  and  are  to  be  determined 
from  a  general  survey  of  a  country  rather  than  from  any  specific  defi 
nitions. 

The  low  lands  include  the  extended  plains  or  country  lying  not  far 
above  tide-level.  In  general  they  are  less  than  1,000  feet  above  the 
sea ;  but  they  are  marked  off  rather  by  their  contrast  with  higher 
lands  of  the  mountain-regions  than  by  any  precise  altitude.  The  Mis 
sissippi  Valley  of  the  great  interior  region  of  the  North  American 
continent  is  an  example  ;  also  the  plains  of  the  Amazon ;  the  pampas 
of  La  Plata;  the  lower  lands  of  Europe  and  Asia.  The  surface  is 
usually  undulating,  and  often  hilly.  Frequently  the  surface  rises  so 
gradually  into  the  bordering  mountain-declivities  that  the  limit  is  alto 
gether  an  arbitrary  line,  as  in  the  case  of  the  Mississippi  plains  and 
the  Rocky  Mountain  slope. 

A  mountain  is  either  an  isolated  peak,  as  Mount  Etna,  Mount 
Washington,  Mount  Blanc ;  or  a  ridge ;  or  a  series  of  ridges,  some 
times  grouped  in  many  more  or  less  parallel  lines. 

A  mountain-range  is  made  up  of  a  series  of  ridges  or  elevations, 
closely  related  in  position  and  direction,  as  the  Green  Mountain  range, 
or,  simply,  the  Green  Mountains;  the  Sierra  Nevada,  the  Ozark 
Mountains,  etc.  A  sierra  is,  in  Spanish,  the  name  of  a  ridge  or  group 
of  ridges  of  serrated  or  irregular  outline. 

A  mountain-chain  consists  of  two  or  more  mountain  ranges,  which 
belong  to  a  common  region  of  elevation,  and  are  generally  either  par 
allel  or  in  consecutive  lines,  or  consecutive  curves,  with  often  inferior 
transverse  lines  of  heights.  Thus,  the  Blue  Ridge  or  range,  the  Alle- 
ghanies,  and  the  Green  Mountains,  are  parts  of  the  Appalachian  Chain, 
—  a  chain  of  heights  that  reaches  from  Canada  to  Alabama.  So  the 
Rocky  Mountain  chain  includes  many  different  ranges  over  a  common 
region  of  elevation,  the  ranges  composing  it  having  been  made  at  sev 
eral  different  epochs. 

A  cordillera  includes  all  the  mountain-chains  in  the  whole  great  belt 
of  high  land  that  borders  a  continent.  Thus  the  Western  Cordillera 
of  North  America  comprises  the  Rocky  Mountain  chain,  the  Wash 
ington  chain  (Sierra  Nevada  and  Cascade  ranges),  the  Coast  ranges, 
and  other  ranges  of  heights  on  the  Pacific  side  of  the  continent.  The 


16  PHYSIOGRAPHIC   GEOLOGY. 

Eastern  Cordillera  of  North  America  includes  the  Appalachian  chain, 
the  Adirondacks,  and  the  Nova  Scotia  range.  The  term  is  thus  used 
by  J.  D.  Whitney. 

The  ridges  of  a  common  chain,  and  even  those  of  a  range,  are  not 
generally  of  tho  same  age,  as  regards  origin.  Even  the  Green  Moun 
tains  contain  ridges  that  existed  long  before  the  main  range  had  been 
elevated.  The  Appalachian  chain  has,  in  the  Highlands  of  New  Jer 
sey,  and  the  Blue  Ridge,  ridges  of  pre-Silurian  age;  in  the  t Green 
Mountains,  others  which  are  mostly  of  middle-Silurian  age  ;  in  the 
Alleghariies,  others  that  are  post- Carboniferous.  Ridges,  in  topog 
raphy,  are  grouped  according  to  their  relations  in  position  and  some 
related  method  of  origin,  but  not  according  to  time  of  origin. 

A  plateau  is  an  extensive  elevated  region  of  flat  or  hilly  surface,  such 
as  often  occurs  in  mountainous  regions.  Any  extensive  range  of  coun 
try  that  is  over  a  thousand  feet  in  altitude  would  be  called  a  plateau. 
It  may  lie  along  the  course  of  a  mountain-chain,  or  occupy  a  wide  re 
gion  between  distant  chains.  The  "  Great  Basin  "  between  the  Salt 
Lake  and  the  Sierra  Nevada  is  a  plateau  of  the  Rocky  Mountain  chain, 
4,000  to  5,000  feet  in  elevation:  the  Salt  Lake  lies  in  its  northeast 
corner,  4,200  feet  above  the  sea.  The  plateau  or  table-land  of  Thibet 
lies  between  the  Himalayas  and  the  Kuen  Lun  Mountains  next  to  the 
north,  and  is  11,500  to  13,000  feet  in  altitude;  and  the  plateau  of 
Mongolia  (Desert  of  Gobi)  occupies  a  vast  region  farther  north,  hav 
ing  a  mean  elevation  of  4,000  feet.  The  State  of  New  York  is  an 
elevated  plateau,  1,500  to  1,700  feet  in  altitude  north  of  the  Mohawk 
Valley  (an  east-and-west  valley),  and  2,000  to  2,500  feet  south  of  it; 
it  lies  in  the  course  of  the  Appalachian  Mountains. 

Plateaus  often  have  their  mountain-ridges,  like  low  lands. 

MOUNTAINS.  —  The  form  of  an  isolated  mountain-peak,  depends  on 
its  general  slopes;  that  of  a  ridge,  on  (1)  its  slopes,  (2)  the  outline  of 
the  crest,  and  (3)  the  course  or  arrangement  of  the  consecutive  parts 
of  the  ridge  ;  that  of  a  chain,  on  all  these  points,  and  in  addition  (4) 
the  order  or  arrangement  of  the  ridges  in  the  chain. 

(a.)  Slopes  of  mountains. —  The  mountain-mass. —  The  slopes  of 
the  larger  mountains  and  mountain-chains  are  generally  very  gradual. 
Some  of  the  largest  volcanoes  of  the  globe,  as  Etna  and  Loa  (Ha 
waii),  have  a  slope  of  only  6  to  8  degrees:  the  mountains  are  low 
cones, having  a  base  of  50  miles  or  more. 

The  Rocky  Mountains,  Andes,  and  Appalachians  are  three  exam 
ples  of  mountain-chains.  The  average  eastern  slope  of  the  Rocky 
Mountains  seldom  exceeds  10  feet  in  a  mile,  which  is  about  1  foot  in 
500,  equal  to  an  angle  of  only  7  minutes.  On  the  west  the  average 
slope  is  but  little  less  gradual.  The  rise  on  the  east  continues  for  600 


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GENERAL    FEATURES    OF   THE   EARTH.  17 

miles,  and  the  fall  on  the  other  side  for  400  to  500  miles ;  the  passes 
at  the  summit  have  a  height  of  4,944  to  10,000  feet;  and  above  them, 
as  well  as  over  different  parts  of  the  slopes  (espe-  '  f.  2 

cially  on   the  west),  there  are  ridges  carrying  the 
altitude  above  14,000  feet,     The  highest  part  of 
the  range  is  in   Colorado,  where   the  passes  are 
11,000  to  13,000  feet  high;  while  in  latitude  32° 
the  passes  are  about  5,200  feet.     The  mountain- 
mass,  therefore,  is  not  a  narrow  barrier  between   ^||K| 
the  east  and  west,  as  might  be  inferred  from  the   kJilJ?! 
ordinary  maps,  but  a  vast  yet  gentle  swell  of  the   J-^if 
surface,  having  a  base  1,000  miles  in  breadth,  and   f  I Jfjff 
the  slopes  diversified  with  various  mountain -ridges,  r'«lr^ 
or  spreading  out  in  plateaus  at  different  levels. 

The  annexed  section  (Fig.  2)  of  the  Rocky  I 
Mountains  along  the  parallels  41°  and  42°,  from 
Council  Bluff,  on  the  east,  to  Benicia,  in  Califor 
nia,  illustrates  this  feature,  although  an  exagger 
ated  representation  of  the  slopes,  —  the  height 
being  seventy  times  too  great  for  the  length. 

In  the  Andes  the  eastern  slope  is  about  60  feet 
in  a  mile,  and  the  western  100  to  150  feet;  the 
passes  are  at  heights  from  12,500  to  16,160  feet, 
and  the  highest  peak  —  Sorata  in  Bolivia—  ~£~Q  J> 

25,290  feet.  The  slope  is  much  more  rapid  than 
in  the  Rocky  Mountains.  But  there  is  the  same 
kind  of  mountain-mass  variously  diversified  with 
ridges  and  plateaus.  The  existence  of  the  great 
mountain-mass  and  its  plateaus  is  directly  con 
nected  with  the  existence  of  the  main  ridges. 
But  it  will  be  shown  in  another  place  that  the 
ridges  may  have  existed  long  before  the  mass 
had  its  present  elevation  above  the  sea. 

In  the  Appalachians  —  which  include  all  the 
mountains  from  Georgia  to  the  Gulf  of  St.  Law 
rence  —  the  mountain-mass  is  very  much  smaller, 
and  the  component  ridges  are  relatively  more  dis 
tinct  and  numerous;  and  still  the  general  features 
are  on  the  same  principle.     The  greatest  heights 
—  those  of  North  Carolina  —  are  between  6,000      J-wl-" 
and  6,707  feet,  and  the  average  height  is  about      i  =  "i 
3,000  feet.  a,?^ 

The  Rocky  Mountains,  Andes,  and  Appalachians  represent  the  three 


; 


18 


PHYSIOGRAPHIC    GEOLOGY. 


types  of  chains  :  (1)  the  broad  and  lofty  plateau  type  ;  (2)  the  narrow 
and  lofty  ridgy  type,  of  which  the  Himalayas  are  another  example ; 
(3)  the  broad  and  many-folded  type,  of  which  the  Juras  are  another 
example. 

ILLUSTRATIONS. — It  is  common  to  err  in  estimating  the  angle  of  a  slope.  To  the 
eyes  of  most  travellers,  a  slope  of  60°  appears  to  be  as  steep  as  80°,  and  one  of  30°  to  be 
at  least  50°.  In  a  front  view  of  a  declivity  it  is  not  possible  to  judge  rightly.  A  pro 
file  view  should  always  be  obtained  and  carefully  observed  before  registering  an  opinion. 

Fig.  3. 


In  fig.  3  the  bluff  front  facing  the  left  would  be  ordinarily  called  a  vertical  precipice, 
Avhile  its  angle  of  slope  is  actually  about  65°;  and  the  talus  of  broken  stones  at  its  base 
would  seem  at  first  sight  to  be  60°,  when  really  40°. 

Fig.  4. 


Fig.  5. 

A. 


Fig.  4  represents  a  section  of  a  volcanic  mountain  3°  in  angle ;  5,  another,  of  7°,  — 
the  average  slope  and  form  of  Mount  Kea.  Hawaii ;  6,  the  same  slope  with  the  top 


Fig.  7. 


Fig. 


Fig.  9. 


rounded,  as  in  Mount  Loa;  7,  a  slope  of  15°;  8,  Jorullo,  in  Mexico,  which  has  one  side 
27°  and  the  other  34°,  as  measured  by  N.  S.  Manross;  9,  a  slope  of  40°,  —  the  steepest 
of  volcanic  cones.  The  lofty  volcanoes  of  the  Andes  are  not  steeper  than  in  number  8, 
although  frequently  so  pictured. 

With  a  clinometer  (see  Fig.  102)  held  between  the  eye  and  the  mountain,  the  angle  of 
slope  may  be  approximately  measured.  When  no  instrument  is  at  hand,  it  is  easy  to 
estimate  with  the  eye  the  number  of  times  a  vertical,  as  A  B  in  Fig.  5,  is  contained  in  the 
semi-base,B  C;  and,  this  being  ascertained,  the  angle  of  slope  maybe  easily  calculated. 
The  ratio  1 : 1  corresponds  to  the  angle  45°;  1 :  2  to  33°  4H' :  1 :  3  to  26°  34' ;  1 :  4  to  18° 
26' ;  1 :  5  to  11°  18^ ;  1 :  6  to  9°  28' ;  1 :  7  to  8°  8' ;  1 :  8  to  7°  7V ;  1 :  9  to  6°  20|' ;  1 : 10 
to  5D  42J';  i:  12  to  40  46';  1:  15  to  3°  49';  1:  20  to  2°  52'.  The  inclinations  correspond 
ing  to  several  of  these  ratios  are  represented  in  the  following  cut.  (Fig.  10.) 


GENERAL  FEATURES  OF  THE  EARTH. 


19 


(&.)  Composition  of  mountain-chains.  —  (1.)  Mountain-chains  have 
been  stated  to  include  several  mountain -ridges ;  and  even  the  ridges 


1:1 


Fig.  10. 


often  consist  of  subordinate  parts  sim 
ilar  in  arrangement.  In  the  great 
chain  of  western  North  America, —  the 
Rocky  Mountains, —  about  the  summit 

J  2:3 

there  are,  in  general,  two  prominent 
ranges  ;     then,  west   of    the    summit,  i :  2 
within  100  to  150  miles  of  the  coast, 

1  •  3 

there  is  the  Washington  Range,  in 
cluding  the  Cascade  of  Oregon  and  the  j !  - 
Sierra  Nevada  of  California,  each  with  1 :  6 
peaks  over  14,000  feet  in  height; 
between  this  range  and  the  summit  there  are  in  many  parts  several 
ridges  more  or  less  important ;  and  between  it  and  the  coast  other 
ridges  make  up  what  has  been  called  the  Coast  Range.  The  Appa 
lachians  also,  although  but  a  small  chain,  consist  of  a  series  of  nearly 
parallel  ridges.  In  Virginia  there  are,  beginning  at  the  east,  the  Blue 
Ridge,  the  Shenandoah  Ridge,  and  the  Alleghany,  besides  others  inter 
mediate. 

(2.)  The  ridges  of  a  chain  vary  along  its  course.  After  continu'hig 
for  a  distance,  they  may  gradually  become  lower  and  disappear  ;  and 
while  one  is  disappearing  another  may  rise  to  the  right  or  left ;  or 
the  mountain  may  for  scores  of  leagues  be  only  a  plateau  without  a 
high  ridge,  and  then  new  ranges  of  elevations  appear.  The  Rocky 
Mountains  exemplify  well  this  common  characteristic,  as  is  seen  on 
any  of  the  recent  maps.  The  Sierra  Nevada  dies  out  where  the  Cas 
cade  Range  begins;  and  each  has  minor  examples  of  the  same  princi 
ple.  The  Andes  are  like  the  Rocky  Mountains ;  only  the  parts  are 
pressed  into  narrower  compass,  and  the  crest  ranges  are  hence  con- 


Figs.  11  to  16. 


14 


tinuous  for  longer  distances.  The  Appalachian  ridges  are  rising  and 
sinking  along  the  course  of  the  chain.  The  high  land  of  the  south 
west  terminates  in  New  York  ;  and  just  east  stands  the  separate  line 


20 


PHYSIOGRAPHIC   GEOLOGY. 


of  the   Green  Mountains  ;  and   still  farther  eastward,  —  east    of  the 
Connecticut,  —  the  range  of  the  White  Mountains. 

The  general  idea  of  this  composite  structure  is  shown  in  Figs.  11  to 

Fig.  17. 


CENTRAL  CONNECTICUT. 
m  n,o  )>,  limits  of  Triassic. 
Black  areas,  trap  dikes. 
Dotted  Tries,  railroads. 
N.  H.  New  Haven.     H.  Hartford., 
M.  Mcriden.    X.  Midflletown.       | 


1 6,  where  each  series  of  lines  represents  a  series  of  ridges  in  a  com 
posite  range.  In  Fig.  11  the  series  is  simple  and  straight ;  in  12  it  is 
still  straight,  but  complex  ;  in  13  the  parallel  parts  are  so  arranged  as 
still  to  make  a  nearly  straight  composite  range;  while  in  14  and  15  the 
succession  forms  a  curve  ;  and  in  16  there  are  transverse  ridges  in  a 
complex  series.  In  ridges  or  ranges  thus  compounded,  the  component 
parts  may  lie  distinct,  or  they  may  so  coalesce  as  not  to  be  apparent. 


GENERAL  FEATURES  OF  THE  EARTH.  21 

These  several  conditions  of  interrupted  and  overlapping  lines,  constituting  straight 
and  curving  chains,  are  illustrated  among  the  islands  of  the  oceans,  the  direction  of 
coast-lines,  and  the  courses  of  all  the  reliefs  of  the  earth's  surface,  as  is  explained  in 
the  following  pages.  Figure  28  on  page  34,  representing  the  positions  of  the  Australa 
sian  islands  from  New  Hebrides  to  Sumatra,  well  exhibits  the  system  of  structure,  — 
also  Fig.  27,  giving  the  courses  and  relative  positions  of  the  central  groups  of  the  Pa 
cific,  and  Fig.  29,  representing  the  Azores  in  the  Atlantic;  for  the  courses  of  islands  are 
the  courses  of  mountain  chains.  The  South  Atlantic  and  North  Atlantic  are  two  over 
lapping  lines  parallel  in  course,  and  on  a  still  grander  scale,  one  of  them  being  much  in 
advance  or  to  the  westward  of  the  other,  and  each  several  thousand  miles  long. 

The  preceding  map  of  the  trap-ridges  of  Connecticut,  from  Percival's  Report,  pre 
sents  well  the  structure.  The  narrow  bands  running  nearly  north  and  south  represent 
the  trap-ridges;  they  are  in  many  nearly  parallel  lines;  each  consists  of  subordinate 
parts ;  and  in  several  the  parts  lie  in  advancing  or  receding  series.  The  extent  of  the 
series  is  small  compared  with  a  mountain-chain;  and  the  ridges,  few  of  which  exceed 
900  feet  in  height,  are  ejections  through  fissures  beneath.  But  the  parallelism  in 
structure  is  perfect.  The  curves  in  some  of  the  subordinate  ridges  have  arisen  from 
the  fact  that  the  fissures  come  up  through  a  tilted  sandstone,  and  the  ejected  rock 
escaped  partly  direct  from  the  fissure  and  partly  between  the  lifted  strata  of  sandstone, 
and  hence  in  a  direction  different  from  that  of  the  fissure,  the  two  directions  together 
making  the  curve. 

Solid  dimensions  of  mountains.  —  The  modec  of  calculating  the 
mass  of  a  mountain  are  the  same  that  are  given  in  treatises  on  men 
suration.  By  a  careful  system  of  averaging,  based  on  determinations 
of  the  slopes  and  altitudes,  as  far  as  practicable,  the  mountain-mass  is 
reduced  to  one  or  more  cones,  pyramids,  or  prisms ;  and  then  the  solid 
contents  of  the  cones  or  pyramids  are  obtained  by  multiplying  the 
area  of  the  base  into  one  third  the  altitude  ;  or,  for  a  triangular  prism 
lying  on  one  of  its  sides,  the  area  of  that  side  into  half  the  length  of 
a  line  drawn  vertical  to  it  from  the  opposite  edge. 

ELEVATED  PLATEAUS,  or  table-lands. —  Some  examples  of  these 
plateaus  have  been  mentioned  (p.  16).  The  Llano  Estacado  (Staked 
Plain)  in  New  Mexico  and  Upper  Texas,  southeast  of  Santa  Fe,  is 
another,  of  great  extent,  averaging  4,000  feet  in  elevation.  The 
great  Mexican  plateau,  in  which  the  city  of  Mexico  lies,  has  about 
that  city  a  height  of  7,482  feet,  and  slopes  from  this  to  5,000  on  the 
east  and  4,000  on  the  west ;  and  it  stretches  on  north  beyond  the  Mexi 
can  territory,  blending  with  the  plateaus  of  New  Mexico.  Above  it 
rise  many  lofty  volcanic  cones,  among  which  Popocatepetl  is  17,799 
feet  high,  Orizaba  17,373  feet,  and  Ixtaccihuatl  17,083.  South  Park  in 
Colorado  is  in  its  northern  part  9.500  to  10,000,  and  in  its  southern 
about  a  thousand  less  ;  and  the  average  height  of  Middle  Park  is  8.500 
feet. 

The  plateau  of  Quito,  in  the  Andes,  has  a  height  of  10,000  feet;  Quito  itself  9.540 
feet;  and  around  it  are  Cotopaxi,  18,775  feet,  Chimborazo,  21,421,  Pichincha,  15,924, 
Cayambe,  19.535.  The  plateau  of  Bolivia  is  at  an  elevation  of  12,900  feet,  with  Laks 
Titicaca,  12,8-30  feet,  and  the  city  of  Potosi  at  13,330  feet;  and  near  are  the  volcanic 
peaks  Illimani,  23,868  feet,  Sorata,  25.290,  Huayna  Potosi,  20,260.  In  Europe,  Spain 
is  for  the  most  part  a  plateau  about  2,250  feet  in  average  elevation;  Auvergne,  in 


PHYSIOGRAPHIC    GEOLOGY. 

France,  another,  at  about  1,100  feet;  Bavaria  another,  at  1,660  feet.  Persia  is  a  plateau 
varying  in  elevation  between  3,800  and  4,500  feet,  with  high  ridges  in  many  parts. 
The  Abyssinian  plateau,  in  Africa,  has  an  average  elevation  of  more  than  7,000  feet; 
the  region  of  Sahara,  abottt  1,500;  that  of  the  interior  of  Africa  south  of  the  equator 
about  2,500  feet. 

RIVER-SYSTEMS.  —  Plateaus  and  mountains  are  the  sources  of  rivers. 
They  pour  the  waters  along  many  channels  into  the  basin  or  low 
country  toward  which  they  slope  ;  and  the  channels,  as  they  continue 
on,  unite  into  larger  channels,  and  finally  into  one  or  more  trunks 
which  bear  the  waters  to  the  sea.  The  basin  and  its  surrounding 
slopes  make  up  a  river-system.  The  extent  of  such  a  region  will 
vary  with  the  position  of  the  mountains  and  ocean.  It  may  cover  but 
a  few  hundred  square  miles,  like  the  river-regions  on  a  mountainous 
coast,  or  it  may  stretch  over  the  larger  part  of  a  continent. 

The  interior  of  the  United  States  belongs  to  one  river-system,  — 
that  of  the  Mississippi ;  its  tributary  streams  rise  on  the  west  among 
the  snows  of  the  Rocky  Mountains,  on  the  north  in  the  central  plateau 
of  the  continent,  west  of  Lake  Superior,  near  lat.  47°  and  beyond, 
long.  93°- 96°,  1,680  feet  in  elevation,  and  on  the  east  in  the  Ap 
palachians,  from  western  New  York  to  Alabama.  Besides  the  Mis 
sissippi,  there  are  other  rivers  rising  in  the  Rocky  Mountains  and 
flowing  into  the  Gulf  of  Mexico ;  and,  in  a  comprehensive  view  of 
the  continent,  these  belong  to  the  same  great  river-system. 

The  St.  Lawrence  represents  another  great  river-system  in  North 
America,  — a  region  which  commences  in  the  head-waters  of  Lake  Su 
perior,  about  the  same  central  plateau  of  the  continent  that  gives  rise 
to  the  Mississippi,  and  embraces  the  great  lakes  with  their  tributaries 
and  the  rivers  of  Canada,  —  and  flows  finally  northeastward  into  the 
Atlantic,  following  thus  a  northeast  slope  of  the  continent.  North  of 
Lake  Superior  and  the  head-waters  of  the  Mississippi,  as  for  as  the 
parallel  of  55°,  there  are  other  streams,  which  also  flow  northeast 
ward,  deriving  some  waters  from  the  Rocky  Mountains  through  the 
Saskatchewan,  and  reaching  the  ocean  through  Hudson's  Bay.  Win 
nipeg  Lake  is  here  included.  These  belong  with  the  St.  Lawrence, 
the  whole  together  constituting  a  second  continental  river-system. 

The  Mackenzie  is  the  central  trunk  of  still  another  river-system.  — 
the  northern.  Starting  from  near  the  parallel  of  55°,  it  takes  in  the 
slopes  of  the  Rocky  Mountains  adjoining,  and  much  of  the  northern 
portion  of  the  continent,  Athabasca,  Slave,  and  Bear  Lakes  lie  in 
this  district. 

These  are  examples  from  among  the  river-systems  of  the  world. 

LAKES.  —  Lakes  occupy  depressions  in  the  earth's  surface  which, 
from  their  depths  or  positions,  are  not  completely  drained  by  the  exist 
ing  streams,  nor  kept  dry  by  the  heat  and  drought  of  the  climate. 


GENERAL  FEATURES  OF  THE  EARTH.  23 

They  occur  (1)  over  the  interior  of  table-lands,  as  about  the  head 
waters  of  the  Mississippi ;  (2)  along  the  depressions  between  the  great 
slopes  of  a  continent,  as  the  line  of  lakes  in  British  North  America 
running  northwest  from  Lake  Superior ;  (3)  in  confined  areas  among 
the  ridges  of  mountains.  The  natural  forms  of  continents  —  that  is, 
their  having  high  borders  —  tend  to  occasion  the  existence  of  lakes  in 
their  interior. 

If  a  lake  has  no  outlet  to  the  ocean,  its  water  is  usually  salt ;  and 
any  plain  or  plateau  whose  streams  dry  up  without  communicating  with 
the  sea  contains  salt  basins  and  efflorescences.  The  Caspian,  Aral, 
and  Dead  Sea  are  some  of  the  salt  lakes  of  Asia  ;  and  the  Great  Salt 
Lake  of  the  Rocky  Mountains  is  a  noted  one  on  this  continent.  Many 
parts  of  the  Rocky  Mountains,  the  Great  Basin  of  the  West,  the  Pam 
pas'  of  South  America,  and  all  the  desert  regions  of  the  globe,  afford 
saline  efflorescences. 

The  heights  of  some  American  lakes  are  as  follows:  Superior,  600  feet;  Huron  and 
Michigan,  574;  Erie,  570;  Ontario,  232;  Winnipeg,  1,100;  Lake  of  the  Woods,  1,640; 
Great  Salt  Lake,  4,285;  Yellowstone  Lake,  7,788;  Shoshone  Lake,  7,870;  Bear  Lake, 
5,931  feet. 

2.    SYSTEM    IN    THE    RELIEFS    OR    SURFACE-FORMS    OF    THE 
CONTINENTS. 

Law  of  the  system.  —  The  mountains,  plateaus,  low  lands,  and 
river-regions  are  the  elements  in  the  arrangement  of  which  the  system 
in  the  surface-form  of  the  continents  is  exhibited.  The  law  at  the 
basis  of  the  system  depends  on  a  relation  between  the  continents  and 
their  bordering  oceans,  and  is  as  follows  :  — 

First.  The  continents  have  in  general  elevated  mountain-borders 
and  a  low  or  basin-like  interior. 

Secondly.  The  highest  border  faces  the  larger  ocean. 

A  survey  of  the  continents  in  succession  with  reference  to  this  law 
will  exhibit  both  the  unity  of  system  among  them  and  the  peculiarities 
of  each  dependent  on  their  different  relations  to  the  oceans. 

(1.)  America.  —  The  two  Americas  are  alike  in  lying  between  the 
Atlantic  and  the  Pacific :  moreover,  South  America  is  set  so  far  to  the 
east  of  North  America  (being  east  of  the  meridian  of  Niagara  Falls), 
that  each  has  an  almost  entire  oceanic  contour.  Moreover,  each  is  tri 
angular  in  outline,  with  the  widest  part,  or  head,  to  the  north. 

North  America,  in  accordance  with  the  law,  has  on  the  Pacific  side 
—  the  side  of  the  great  ocean  —  the  Rocky  Mountains,  on  the  Atlan 
tic  side  the  low  Appalachians,  and  between  the  two  there  is  the  sreat 
plain  of  the  interior.  This  is  seen  in  the  annexed  section  (Fig.  18) 
from  west  to  east :  on  the  west,  the  Rocky  Mountains,  with  the  double 


PHYSIOGRAPHIC   GEOLOGY. 

Fig.  18. 


crest,  at  b  ;  the  Washington  range  at  a  ;  between  a  b  the  Great  Basin  ; 
at  d  the  Appalachians;  c  the  Mississippi;  and  between  d  and  b  a  section 
of  the  Mississippi  river-system. 

The  Cascade  and  Nevada  ranges  are  even  more  lofty  in  some  of  their  summits  than 
the  crest-ridges  of  the  Rocky  chain.  In  the  former  there  is  a  line  of  snowy  cones  from 
10,000  to  nearly  14,500  feet  in  elevation,  including  Mount  Baker,  near  Puget's  Sound, 
and,  to  the  south  of  this,  Mount  St.  Helen's,  Mount  Adams,  and  Mount  Rainier,  north 
of  the  Columbia,  and,  south,  Mount  Hood,  Mount  Pitt,  Mount  Jefferson,  and  the  Shasta 
Peak,  — the  last  14,440  feet,  according  to  Whitney.  Still  nearer  the  sea,  there  is  what 
is  called  the  Coast  Range,  consisting  of  lower  elevations.  Between  the  two  lie  the 
valley  of  the  Sacramento  and  Joaquin,  in  California,  and  that  of  the  Willamette,  in 
Oregon. 

The  Appalachians,  on  the  east,  reach  an  extreme  height  of  but  6,700 
feet,  and  are  in  general  under  2,500  feet. 

To  the  north  of  North  America  lies  the  small  Arctic  Ocean,  much 
encumbered  with  land  ;  and,  correspondingly,  there  is  no  distinct  moun 
tain-chain  facing  the  ocean.  The  mountains  of  Greenland  are  an  in 
dependent  system,  pertaining  to  that  semi-continent  by  itself. 

The  characteristics  of  the  interior  plain  of  the  continent  are  well 
displayed  in  its  river-systems :  the  great  Mississippi  system  turned  to 
the  south,  and  making  its  exit  into  the  Gulf  of  Mexico  between  the 
approaching  extremities  of  the  eastern  and  western  mountain-ranges ; 
the  St.  Lawrence  sloping  off  northeastward  ;  the  Mackenzie,  to  the 
northward;  the  central  area  of  the  plain  dividing  the  three  systems 
being  only  about  1,700  feet  above  the  ocean,  —  a  less  elevation  than 
about  the  head- waters  of  the  Ohio  in  the  State  of  New  York. 

South  America,  like  North  America,  has  its  great  western  range  of 
mountains,  and  its  smaller  eastern  (Fig.  19) ;  and  the  Brazilian  line  (b) 

Fig.  19. 

A* 

A*. 


is  closely  parallel  to  that  of  the  Appalachians.  As  the  Andes  (a)  face 
the  South  Pacific,  a  wider  and  probably  much  deeper  ocean  than  the 
North  Pacific,  so  they  have  more  than  twice  the  average  height  of  the 
Rocky  Mountains,  arid,  moreover,  they  rise  more  abruptly  from  the 
ocean,  with  narrow  shore-plains. 


GENERAL  FEATURES  OF  THE  EARTH.  25 

Unlike  North  America,  South  America  has  a  broad  ocean  on  the 
north,  —  the  North  Atlantic  in  its  longest  diameter ;  and,  accordingly, 
this  northern  coast  has  its  mountain-chain  reaching  along  through 
Venezuela  and  Guiana. 

The  drainage  of  South  America,  as  observed  by  Professor  Guyot, 
is  closely  parallel  with  that  of  North  America.  There  are,  first,  a 
southern  system,  —  the  La  Plata,  —  reaching  the  Atlantic  toward  the 
south,  between  the  converging  east-and-west  chains,  like  the  Mis 
sissippi  ;  second,  an  eastern  system,  —  that  of  the  Amazon,  —  corre 
sponding  to  the  St.  Lawrence,  reaching  the  same  ocean  just  north  of 
the  eastern  mountain-border ;  and,  third,  a  northern  system,  —  that  of 
the  Orinoco,  —  draining  the  slopes  or  mountains  north  of  the  Amazon 
system.  The  two  Americas  are  thus  singularly  alike  in  system  of 
structure :  they  are  built  on  one  model. 

The  relation  of  the  oceans  to  the  mountain-borders  u  so  exact  that 
the  rule-of-three  form  of  statement  cannot  be  far  from  the  truth.  As 
the  size  of  the  Appalachians  to  the  size  of  the  Atlantic,  so  is  the  size 
of  the  Rocky  chain  to  the  size  of  the  Pacific.  Also,  As  the  height  of 
the  Rocky  chain  to  the  extent  of  the  North  Pacific,  so  are  the  height 
and  boldness  of  the  Andes  to  the  extent  of  the  South  Pacific. 

(2.)  Europe  and  Asia.  —  The  land  covered  by  Europe  and  Asia  is 
a  single  area  or  continent,  only  partially  double  in  its  nature  (p.  13). 
Unlike  either  of  the  Americas,  it  lies  east-and-west,  with  an  extensive 
ocean  facing  Asia  on  the  south ;  and  its  great  feature-lines  are  in  a  large 
degree  east-and-west.  The  Arctic  Ocean  is  on  the  north  ;  the  North 
Atlantic  is  on  the  west ;  the  North  Pacific  on  the  east ;  Africa  and  the 
Indian  Ocean  are  on  the  south.  The  Atlantic  is  the  smallest  ocean  ; 
the  North  Pacific  next,  —  for  its  average  depth  is  probably  not  over 
13,000  feet  (p.  12),  and  it  is  much  encumbered  by  islands  to  the  west- 
of-south  ;  the  Indian  Ocean  next,  —  for  it  is  full  5,000  miles  wide 
in  front  of  the  Asiatic  coast,  and  singularly  free  from  islands.  The 
boundary  is  a  complex  one,  and  the  land  between  the  Atlantic  and 
Pacific  over  6,000  miles  broad. 

On  the  side  of  the  small  North  Atlantic,  there  are  the  mountains  of 
Norway  and  the  British  Isles,  the  former  having  a  mean  height  of 
4,000  feet,  On  the  Pacific  side,  there  are  loftier  mountains,  extending 
in  several  ranges  from  the  far  north  to  southern  China,  —  the  Stano- 
voi,  Jablonoi,  and  Khingan  ranges ;  and,  o'ff  the  coast,  there  is  still 
another  series  of  ranges,  now  partly  submerged,  —  viz.,  those  of  Japan 
and  other  linear  groups  of  islands.  These  stand  in  front  of  the  inte 
rior  chain,  very  much  as  the  Cascade  Range  and  Sierra  Nevada  of  the 
Pacific  border  of  America  are  in  advance  of  the  summit-ridges  of  the 
Rocky  Mountains,  and  both  are  alike  in  being  partly  volcanic,  with 
cones  of  great  altitude. 


26  PHYSIOGRAPHIC    GEOLOGY. 

Facing  the  still  greater  Indian  Ocean,  and  looking  southward,  stand 
the  Himalayas,  —  the  loftiest  of  mountains,  —  called  the  Himalayas  as 
far  as  Cashmere,  and  from  there,  where  a  new  sweep  in  the  curve  be 
gins,  the  Hindoo  Koosh, —  the  whole  over  2,000  miles  in  length:  not  so 
long,  it  is  true,  as  the  Andes,  but  continued  as  far  as  the  ocean  in  front 
continues.  The  mean  height  of  the  Himalayas  has  been  estimated  at 
1 6,000  feet ;  over  forty  of  the  peaks  surpass  Chimborazo.  The  Kuen 
Lun  Mountains,  to  the  north  of  the  Himalayas,  make  another  crest 
to  the  great  chain,  with  Thibet  between  the  two.  Going  westward, 
the  mountains  decline,  though  there  are  still  ridges  of  great  elevation. 

On  the  north  there  are  the  wide  Siberian  plains,  backed  by  the 
Altai,  about  half  the  Himalayas  in  height.  The  Altai  thus  have  the 

Fig.  20. 


same  relation  to  the  Himalayas  as  the  Appalachians  to  the  Rocky 
Mountains,  or  the  Brazilian  Mountains  to  the  Ancles,  yet  with  a 
striking  difference  in  the  immense  shore-plain  between  them  and  the 
sea. 

The  sketch  (Fig.  20)  presents  the  general  features  to  the  eye.  At 
«,  there  is  the  elevated  land  of  India  ;  between  a  and  b,  the  low  river- 
plain  at  the  base  of  the  Himalayas  ;  at  b,  the  Himalayas  ;  />  to  c, 
Plains  of  Thibet ;  c,  the  Kuen  Lun  ridge  ;  e  to  d.  Plains  of  Mongolia 
and  Desert  of  Gobi ;  at  d,  the  Altai ;  d  to  N,  the  Siberian  plains. 

The  interior  region  of  the  continent,  in  its  eastern  half,  is  the  plateau 
of  Gobi  and  Mongolia,  which,  at  4,000  feet,  is  low  compared  with  the 
mountains  in  front  and  rear.  More  to  the  westward,  the  region  c  d 
becomes  intersected  by  the  lofty  Thian-shan  Range.  Still  farther 
westward,  the  surface  declines  into  the  great  depression  occupied  by 
the  Caspian  and  Aral,  part  of  which  is  below  tide-level  (p.  13). 

The  interior  drainage-system  for  Asia  is  without  outlet.  The  waters 
are  shut  up  within  the  great  basin,  the  Caspian  and  Aral  being  the 
seas  which  receive  the  part  of  those  waters  not  lost  in  the  plains. 
The  Volga  and  other  streams,  from  a  region  of  a  million  of  square 
miles,  flow  into  the  Caspian. 

The  Urals  stand  as  a  partial  barrier  between  Asia  arid  Europe, 
parallel  nearly  with  the  mountains  of  Norway. 

Europe  has  its  separate  system  of  elevations  and  interior  plains  ; 
but  it  is  not  necessary  to  dwell  on  it  here. 


GENERAL   FEATURES    OF   THE   EARTH.  Sfl 

The  great  continental  mass  accords  with  the  law  stated  ;  —  high 
borders  proportioned  in  the  case  of  each  to  the  extent  of  the  bordering 
oceans,  and  a  general  basin-like  form. 

(3.)  Africa.  —  Africa  has  the  Atlantic  on  the  west,  the  larger  Indian 
Ocean  on  the  east,  with  Europe  and  the  Mediterranean  on  the  north, 
and  the  South  Atlantic  and  Southern  Ocean  on  the  south.  Its  system 
of  structure  has  been  well  explained  by  Professor  Guyot.  As  he  has 
stated,  the  northern  half  has  the  east-and-west  position  of  Asia,  and 
the  southern  the  north-and-south  of  America ;  and  its  reliefs  corre 
spond  with  this  structure.  The  Guinea  coast  belonging  to  the  north 
ern  half  projects  west  in  front  of  the  South  Atlantic,  and  is  faced  by 
the  east-and-west  Kong  Range  ;  and  opposite,  on  the  Mediterranean, 
there  are  the  Atlas  Mountains,  the  High  Plateau  of  which  is  about 
3,000  feet,  and  one  peak  in  the  Atlas  of  Marocco  is  13,000  feet  high,— 
although  the  ridges  are  generally  much  lower  (5,000  to  7,000  feet). 
The  two  thus  oppose  one  another,  like  the  Himalayas  and  Altai.  The 
southern  half  of  the  continent  has  a  border  mountain-range  the  most 
of  the  way  along  the  west  and  south.  On  the  latter,  which  has  a 
length  of  700  miles,  there  are  three  or  four  parallel  ridges,  and  some 
of  the  peaks  are  4,000  to  7,000  feet  high.  Along  the  southwestern 
coast,  the  ranges  are  4,000  to  5,000  feet,  and  on  the  Guinea  coast  the 
Kong  Mountains  2,000  feet.  Up  the  eastern  coast,  there  is  also  a 
mountain-border,  and  higher  than  the  western.  By  these  border-ranges 
the  interior  of  Africa  is  mostly  shut  off  from  the  sea :  it  is  a  shut-up 
continent,  as  Guyot  calls  it.  The  loftiest  mountains  are  in  Abyssinia 
and  Zanguebar,  facing  the  Indian  Ocean.  Abyssinia  is,  to  a  great 
extent,  an  elevated  plateau,  6,000  to  7,000  feet  in  height,  with  ridges 
reaching  to  15,000  feet;  and,  farther  south,  in  3°  40',  stands  the  snowy 
Kilima-Njaro  and  Ngai,  which  are  19,000  feet  high. 

The  interior  of  the  northern  or  east-and-west  half  consists  of  (1)  the 
Great  Sahara  region,  a  plateau  of  about  1,500  feet  elevation,  with  its 
undulations  and  ridges,  and  some  elevations  of  6,000  feet ;  (2)  an  east- 
and-west  depression  on  the  north,  between  Sahara  and  the  border- 
mountains,  below  the  ocean's  level  in  some  parts,  and  being  the  region 
of  the  oases,  all  of  which  are  100  to  200  feet  below  tide  level;  (3)  a 
partial  east-and-west  depression  about  the  parallels  10°  to  15°  N., 
separating  the  Sahara  plateau  from  the  southern,  and  containing  Lake 
Tchad,  at  an  elevation  of  800  feet.  The  interior  of  the  southern  half 
is  a  plateau  2,500  feet  in  average  height. 

Fig.  21. 


—c  a  N 

The  sections  Figs.  21  and  22  give  a  general  idea  of  these  features. 


28  PHYSIOGRAPHIC    GEOLOGY. 

Fig.  21  is  a  section  from  south  to  north  (the  heights  necessarily  much 
exaggerated  in  proportion  to  the  length)  ;  a,  the  southern  mountains  ; 
b,  the  southern  plateau  ;  c,  Lake  Tchad  depression  ;  c?,  Sahara  plateau ; 
e,  oases  depression  ;  /,  mountains  on  the  Mediterranean,  of  which 
there  are  two  or  three  parallel  ranges.  Fig.  22  represents  the  surface- 


outline  from  west  to  east  through  the  southern  half  of  the  continent. 
In  all  these  sections,  all  minor  details  are  omitted,  in  order  to  bring 
out  clearly  the  system,  or  continental  model. 

Africa  has,  therefore,  a  basin-like  form,  but  is  a  double  basin ;  and  its 
highest  mountains  are  on  the  side  of  the  largest  ocean,  the  Indian. 
The  height  of  the  mountains  adjoining  the  Mediterranean  is  the  only 
exception  to  the  relation  to  the  oceans  ;  and  this  is  small.  Moreover, 
the  position  of  the  head  of  the  continent  against  the  continent  of 
Europe  with  only  the  Mediterranean  between,  instead  of  an  ocean,  is 
a  sufficient  reason  for  the  exception.  Africa  has  some  resemblance 
to  America,  but  America  turned  about,  with  the  most  elevated  border 
on  the  east  instead  of  the  west. 

(4.)  Australia. — Australia  conforms  also  to  the  continental  model. 
The  highest  mountains  arc  on  the  side  of  the  Pacific,  —  the  larger  of 
its  border-oceans.  The  Australian  Alps,  in  New  South  Wales,  facing 
the  southeast  shores,  have  peaks  5,000  to  6,500  feet  in  height.  The 
range  is  continued  northward  in  the  Blue  Mountains,  which  are  3,000 
to  4,000  feet  high,  with  some  more  elevated  summits,  and,  beyond 
these,  in  ridges  under  other  names,  the  whole  range  being  mostly  be 
tween  2,000  and  6,000  feet  in  elevation.  On  the  side  of  the  Indian 
Ocean  the  heights  are  1,500  to  2,000  feet.  The  interior  is  a  low,  arid 
region.  The  centre  about  200  feet  above  the  sea. 

The  continents  thus  exemplify  the  law  laid  down,  and  not  merely  as 
to  high  borders  around  a  depressed  interior,  —  a  principle  stated  by 
many  geographers,  —  but  also  as  to  the  highest  border  being  on  the 
side  of  the  greatest  ocean.1  The  continents,  then,  are  all  built  on  one 
model,  and,  in  their  structures  and  origin,  have  a  relation  to  the  oceans 
that  is  of  fundamental  importance. 

It  is  owing  to  this  law  that  America  and  P^urope  literally  stand 
facing  one  another,  and  pouring  their  waters  and  the  treasures  of  the 
soil  into  a  common  channel,  the  Atlantic.  America  has  her  loftier 
mountains,  not  on  the  east,  as  a  barrier  to  intercourse  with  Europe, 

i  First  announced  American  Jour.  Sci.,  II.,  vols.  iii.  398,  iv.  92,  1847,  and  xxii.  335. 
1856. 


GENERAL  FEATURES  OF  THE  EARTH.  29 

but  off  in  the  remote  west,  on  the  broad  Pacific,  where  they  stand 
open  to  the  moist  easterly  winds  as  well  as  those  of  the  west,  to  gather 
rains  and  snows,  and  make  rivers  and  alluvial  plains  for  the  continent ; 
and  the  waters  of  all  the  great  streams,  lakes,  and  seas  make  their 
way  eastward  to  the  narrow  ocean  that  divides  the  civilized  world. 
Europe  has  her  slopes,  rivers,  and  great  seas  opening  into  the  same 
ocean ;  and  even  central  Asia  has  her  most  natural  outlet  westward 
to  the  Atlantic.  Thus,  under  this  simple  law,  the  civilized  world  is 
brought  within  one  great  country,  the  centre  of  which  is  the  Atlantic, 
uniting  the  land  by  a  convenient  ferriage,  and  the  sides  the  slopes  of 
the  Rocky  Mountains  and  Andes  on  the  west  and  the  remote  moun 
tains  of  Mongolia,  India,  and  Abyssinia  on  the  east.1 

This  subject  affords  an  answer  to  the  inquiry,  What  is  a  continent 
as  distinct  from  an  island  ?  It  is  a  body  of  land  so  large  as  to  have 
the  typical  basin-like  form, —  that  is,  mountain-borders  about  a  low  in 
terior.  The  mountain-borders  of  the  continents  vary  from  500  to 
1,000  miles  in  breadth  at  base.  Hence  a  continent  cannot  be  less 
than  a  thousand  miles  (twice  five  hundred)  in  width. 

3.  SYSTEM  IN  THE  COURSES  OF  THE  EARTH'S  FEATURE- 
LINES. 

The  system  in  the  courses  of  the  earth's  outlines  is  exhibited  alike 
over  the  oceans  arid  continents,  and  all  parts  of  the  earth  are  thus 
drawn  together  into  even  a  closer  relation  than  appears  in  the  prin 
ciple  already  explained. 

The  principles  established  by  the  facts  are  as  follows  :  That  (1)  two 
great  systems  of  courses  or  trends  prevail  over  the  world,  a  north 
western  and  a  northeastern,  transverse  to  one  another;  (2)  that  the 
islands  of  the  oceans,  the  outlines  and  reliefs  of  the  continents,  and 
the  oceanic  basins  themselves,  alike  exemplify  these  systems ;  (3)  that 
the  mean  or  average  directions  of  the  two  systems  of  trends  are  north- 
west-by-west  and  northeast-by-north  ;  (4)  that  there  are  wide  varia 
tions  from  these  courses,  but  according  to  principle,  and  that  these  va 
riations  are  often  along  curving  lines  ;  (5)  that,  whatever  the  variations, 
wrhen  the  lines  of  the  two  systems  meet,  they  meet  nearly  at  right 
angles  or  transversely  to  one  another. 

(1.)  Islands  of  the  Pacific  Ocean.  — The  lines  or  ranges  of  islands 
over  the  ocean  are  as  regular  and  as  long  as  the  mountain-ranges  of 
the  land.  To  judge  correctly  of  the  seeming  irregularities,  it  is  neces 
sary  to  consider  that,  in  chains  like  the  Rocky  Mountains,  or  Andes, 
or  Appalachians,  the  ridges  vary  their  course  many  degrees  as  they 
continue  on,  sometimes  sweeping  around  into  some  new  direction,  and 
1  See  Guvot's  Earth  and  Man. 


30 


PHYSIOGRAPHIC    GEOLOGY. 


then  returning  again  more  or  less  nearly  to  their  former  course,  and 
that  the  peaks  of  a  ridge  are  very  far  from  being  in  an  exact  line 
even  over  a  short  course  ;  again,  that  several  approximately  parallel 
courses  make  up  a  chain. 

A.  NORTHWESTERLY  SYSTEM  OF  TRENDS.  —  In  the  southwestern 
Pacific,  the  New  Hebrides  (Fig.  23)  show  well  this  linear  arrangement; 
and  even  each  island  is  elongated  in  the  same  direction  with  the  group. 
This  direction  is  nearly  northwest  (N.  40°  W.),  and  the  length  of  the 
chain  is  500  miles.  New  Caledonia,  more  to  the  southwest,  has 
approximately  the  same  course,  —  about  northwest.  Between  New 
Hebrides  and  New  Caledonia  lies  another  parallel  line,  the  Loyalty 
Group.  The  Salomon  Islands,  farther  northwestward,  are  also  a  linear 
group.  The  chain  is  mostly  a  double  one,  consisting  of  two  parallel 
ranges;  and  each  island  is  linear,  like  the  group,  and  with  the  same 
trend.  The  course  is  northwest-by-west,  the  length  600  miles. 

In  the  North  Pacific,  the  Hawaian  range  has  a  west-northwest 
course.  The  Sandwich  or  Hawaian  Islands  (Fig.  2-4),  from  Hawaii  to 

Fig.  23. 


170°  E 


15°  S 


Kauai,  make  up  the  southeasterly  part  of  the  range,  about  400  miles 
in  length.  Beyond  this,  the  line  extends  to  175°  E.,  making  a  total 
length  of  nearly  2,000  miles,  —  a  distance  as  great  as  from  Boston  to 
the  Great  Salt  Lake  in  the  Rocky  Mountains,  or  from  London  to 
Alexandria.  Moreover,  in  this  chain,  there  are  on  Hawaii  two  sum- 


GENERAL    FEATURES    OF   THE   EARTH. 
Fig.  24. 


31 


H,  Hawaii ;    M,  Maui ;   3,  Kahoolawe  ;  4,  Lanai ; 
5,  Molokai ;  0,  Oahu  ;  K,  Kauai. 

mits  nearly  14,000  feet  in  altitude  ;  and,  if  the  ocean  around  is  15,000 
feet  deep,  the  whole  height  of  these  peaks  is  just  that  of  Mount  Ever 
est  in  the  Himalayas. 

Between  these  groups  lie  the  islands  of  mid-ocean,  all  nearly  parallel 
in  their  courses.     Figs.  25,  26  are  examples. 

Fig.  25.  Fig.  26. 


I?  ( 

\ 

10°  s        ; 

Co 

(J 

>       £* 

\  0 

14-0 

°w     2 

1G°S                   150° 

-W  

'£5* 

'OS. 

*%,  . 
%* 

The  following  table  gives  the  courses  of  the  principal  chains  of  the  ocean :  — 

Course. 
.     N.  64°  W. 

X.  60°  W. 
.     X.  60^  w. 

X.  62°  W. 
.     N.  65°  W. 

X.  G8DW. 
.     N.  34°  W. 

N.  37°  W. 
.    X.  30°  W. 

X.  40°  W. 
.     X.  44°  W. 

X.  50°  W. 
.     X.  57°  W. 

X.  56°  W. 
,     X.  65°  W. 


Hawaian  range 

Marquesas  Islands    .... 
Paumotu  Archipelago 
Tahitian  or  Society  Islands 
Hervey  Islands     ..... 
Samoan  or  Navigator  Islands 
Tarawan,  Gilbert,  or  Kingsmill  Islands 
Ralick  group  .... 

Radack  group       ..... 
Xew  Hebrides  ..... 

New  Caledonia 

North  extremity  of  Xew  Zealand    . 
Salomon  Islands  .  ... 

Louisiade  group       .... 
New  Ireland         .... 


B.  NORTHEASTERLY  SYSTEM  OF  TRENDS.  —  The  body  of  New 
Zealand  has  a  northeast-hy-north  course.  The  line  is  continued  to  the 
south,  through  the  Auckland  and  Macquarie  Islands,  to  58°  S.  To 


32  PHYSIOGRAPHIC   GEOLOGY. 

the  north,  in  the  same  line,  near  30°  S.,  lie  the  Kermadec  Islands,  and 
farther  north,  near  20°  8.,  the  Tonga  or  Friendly  Islands. 

The  Ladrones,  north  of  the  equator,  follow  the  same  general  course. 
It  also  occurs  in  many  groups  of  the  northwesterly  system  character 
izing  subordinate  parts  of  those  groups.  Thus,  the  westernmost  of 
the  Hawaian  Islands,  Nihau,  lies  in  a  north-northeast  line,  and  the 
two  lofty  peaks  of  Hawaii  have  almost  the  same  bearing. 

PACIFIC  ISLAND-CHAINS.  —  The  groups  of  Pacific  islands,  with  a 
few  exceptions,  arc  not  independent  lines,  but  subordinate  parts  of 
island-chains.  There  are  three  great  island-chains  in  the  ocean 
which  belong  to  the  northwesterly  system,  —  The  Hawaian,  the  Poly 
nesian,  and  the  Australasian,  —  and,  excluding  the  Ladrones,  which 
pertain  to  the  western  Pacific,  one  belonging  to  the  northeasterly  sys 
tem,  viz. :  the  Tongan  or  New  Zealand  chain. 

(1.)   Hawaian  chain.  —  This  chain  has  already  been  described. 

(2.)  Polynesian  chain.  —  This  chain  sweeps  through  the  centre  of 
the  ocean,  and  has  a  length  of  5,500  miles,  or  nearly  one  fourth  the 
circumference  of  the  globe.  (See  Fig.  27.)  The  Paumotu  Archipel 
ago  (1),  and  the  Tahitian,  Rurutu,  and  Hervey  Islands  (2,  3,  4)  are 
parallel  lines  in  the  chain,  forming  its  eastern  extremity ;  westward 

Fig.  27. 


AS 


••*..       ^ 

vX  -S*-. 


\> 


1  to  10,  the  Polynesian  chain  :  1,  Paumotu  group  ;  2,  Tahitian  ;  3,  Rurutu  group  ;  4,  Hervey 
group;  5,  Samoan,  or  Navigators';  6,  Vakaafo  group;  7,  Vaitupu  group;  8.  Gilbert's 
group  ;  9,  Ralick  ;  10,  Radack  ;  11,  Carolines  ;  12,  Marquesas  ;  13,  Fanning  group  ;  14, 
Hawaian.  a  to  A,  part  of  the  Australasian  chain:  a,  New  Caledonia  ;  b  Loyalty  group: 
c.  New  Hebrides  ;  d,  Santa  Cruz  group ;  e,  Salomon  Islands ;  /,  Louisiade  group  ,  g.  New 
Ireland  ;  A,  Admiralty  group. 


GENERAL    FEATURES   OF   THE   EARTH.  33 

there  are  the  Samoan  (5)  and  Tarawan  (8)  groups,  and  others  inter 
mediate  ;  still  northwestward  there  are  the  Radack  and  Ralick  groups 
(9,  10),  and  in  20°  N.,  on  the  same  line,  Wakes  Island. 

(a.)  The  chain,  as  is  seen,  consists  of  a  series  of  parallel  ranges, 
succeeding  and  overlapping  along  the  general  course,  in  the  manner 
illustrated  on  page  19,  when  speaking  of  mountains,  (b.)  It  varies  its 
course  gradually  from  west-northwest  at  the  eastern  extremity  to  north- 
northwest  at  the  western,  (c.)  Its  mean  trend  is  northwest-by-west 
(N.  56°  W.),  the  mean  trend  of  all  the  groups  of  the  northwesterly 
system  in  the  ocean,  (d.)  The  chain  is  a  curving  chain,  convex  to  the 
southward,  and  marks  the  position  of  a  great  central  elliptical  basin  of 
the  Pacific  having  the  same  northwesterly  trend.  The  Hawaian  is  on 
the  opposite  side  of  it,  slightly  convex  to  the  north. 

The  Marquesan  range  (12,  Fig.  27)  lies  in  the  same  line  with  the  Fanning  group  (13) 
to  the  northwest,  just  noi'th  of  the  equator;  and,  if  a  connection  exists,  another  great 
chain  is  indicated,  — a  Marquesan  chain. 

(3.)  Australasian  chain  (Fig.  28).  —  New  Hebrides  (K)  and  New 
Caledonia  (M)  belong  to  the  Australasian  island-chain.  The  line  of 
New  Hebrides  is  continued  northwestward  in  the  Salomon  group  and 
New  Ireland  (I),  though  bending  a  little  more  to  the  westward,  and 
terminates  in  Admiralty  land  (G),  near  145°  E.,  where  it  becomes 
very  nearly  east-and-west :  the  length  of  the  range  is  about  2,000 
miles.  Taking  another  range  in  the  chain,  New  Caledonia  (M),  the 
course  is  continued  in  the  Louisiade  group  (H) ;  then  the  north  side 
of  New  Guinea  (E),  which  continues  bending  gradually  till  it  becomes 
east-and-west,  near  135°  E.  In  the  southeast,  belonging  to  the  same 
general  line,  there  is  the  foot  of  the  New  Zealand  boot  (O).  The  coral 
islands  between  New  Caledonia  and  Australia  appear  also  to  be  other 
lines  in  the  chain. 

From  New  Guinea  (E,  F),  the  east-and-west  course  is  taken  up  by 
Ceram  (D),  and  again,  more  to  the  south,  in  the  Java  line  of  islands 
(A,  B,  C)  ;  and  from  Java  (B)  the  chain  again  begins  to  rise  north 
ward,  becoming  northwest  finally  in  Sumatra  (A)  and  Malacca. 

The  several  ranges  make  up  one  grand  island-chain,  with  a  double 
curvature,  the  whole  nearly  6,000  miles  long.  In  figure  28,  a  line 
stands  for  each  group,  and  indicates  its  course.  The  composite  nature 
of  the^chain  is  here  apparent;  as  also  the  curving  course,  in  connec 
tion  with  a  prevailing  conformity  to  a  northwesterly  trend. 

(4.)  Blending  of  the  Australasian  and  Polynesian  island-chains.  — 
The  two  chains  blend  with  one  another  in  the  region  of  the  Carolines. 
(11,  Fig.  27.)  This  large  archipelago  properly  includes  the  Ralick  and 
Radack  groups  (9,  10).  At  the  Gilbert  group  (8)  the  Polynesian 
chain  divides  into  two  parts,  —  the  Ralick  and  Radack  ranges.  But 


34 


PHYSIOGRAPHIC    GEOLOGY. 


the  main  body  of  the  Archipelago  (11,  Fig.  27  and  the  chart)  trends 
off  to  the  westward,  and  is  a  third  branch,  conforming  in  direction  to 
the  Australasian  system,  (a  to  h,  Fig.  27,  are  the  same  as  M  to  G, 

Fig.  28.) 

Fig.  28. 


A,  B,  0,  Sumatra  and  Java  line  of  islands  ;  D,  Cerani  ;  E,  north  coa>t 
of  New  Guinea  ;  F,  South  New  Guinea  ;  G,  Admiralty  Islands  ;  H, 
Louisiade  group  ;  I,  Salomon  ;  J,  Santa  Cruz  group  ;  K,  New  Heb 
rides  ;  L,  Loyalty  group ;  M,  New  Caledonia ;  N,  high  lands  of 
northeast  Australia  ;  0,  New  Zealand  ;  a  b,  northwest  shore  of  Bor 
neo  :  c  d,  east  Borneo  ;  e/,  west  coast  of  Celebes  ;  g  A,  west  coast  of 
Gilolo. 


\ 


X 


In  other  words,  the  Caroline  Archipelago  forks  at  its  southeastern 
extremity,  —  one  portion,  the  Gilbert,  Radack,  and  Ralick  Islands 
(8,  9,  10  in  Fig.  27),  conforming  to  the  Polynesian  system,  while  the 
great  body  of  the  Caroline  Islands  trend  off  more  to  the  westward 
(No.  11),  parallel  with  New  Ireland  and  the  Admiralty  group  (g,  h  of 
the  same  cut),  and  others  of  the  Australasian  system. 

(5.)  New  Zealand  chain.  —  The  ranges  in  this  chain  are  mentioned 
on  p.  31.  The  whole  length,  from  Macquarie  Island,  on  the  south,  to 
Vavau,  a  volcanic  island  terminating  the  Tonga  range,  on  the  north,  is 
2,500  miles.  To  the  east  of  New  Zealand  lie  Chatham  Island,  Bev 
erly,  Campbell,  and  Emerald,  which  correspond  to  another  range  in 
the  chain. 

This  transverse  chain  is  at  right  angles  with  the  Polynesian  system 
at  the  point  where  the  two  meet.  Moreover,  it  is  nearly  central  to 
the  ocean  ;  and  in  its  course  farther  north  lie  the  Samoan  and  Hawaian 
Islands,  two  of  the  largest  groups  in  the  Polynesian  system. 

The  central  position,  great  length,  and  rectangularity  to  the  north 
west  ranges  give  great  significance  to  this  New  Zealand  or  northeast 
erly  system  of  the  ocean. 

The  large  Feejee  group  lies  near  the  intersection  of  the  three  Pacific  chains:  and 
hence  its  numerous  islands  do  not  conform  to  either  one,  though  the  larger  islands  ap 
proximate  most  nearly  to  the  last  in  direction. 


GENERAL  FEATURES  OF  THE  EARTH.  35 

(2.)  Pacific  and  Atlantic  Oceans.  —  The  trend  of  the  Pacific  Ocean 
as  a  whole  corresponds  with  that  of  its  central  chain  of  islands,  and 
very  nearly  with  the  mean  trend  of  the  whole.  It  is  a  vast  channel, 
elongated  to  the  northwest.  The  range  of  heights  along  northeastern 
Australia  (N,  Fig.  28)  runs  northwesterly  and  passes  by  the  head  of 
the  great  gulf  (Carpentaria)  on  the  north ;  and  the  opposite  side  of 
the  ocean  along  North  America,  or  its  bordering  mountain-chain,  has 
a  similar  mean  trend.  A  straight  line  drawn  from  northern  Japan 
through  the  eastern  Paumotus  to  a  point  a  little  south  of  Cape  Horn 
may  be  called  the  axis  of  the  ocean.  This  axial  line  is  nearly  half 
the  circumference  of  the  globe  in  length,  and  the  transverse  diameter 
of  the  ocean  full  one-fourth  the  circumference :  so  that  the  facts  relat 
ing  to  the  Pacific  chains  must  have  a  universal  importance. 

The  North  Atlantic  Ocean  trends  to  the  northeast,  —  or  at  right 
angles,  nearly,  to  the  Pacific  :  this  is  the  course  of  the  coasts,  and 
therefore  of  the  channel.  Taking  the  trend  of  the  southeast  coast  of 
South  America  as  the  criterion,  the  South  Atlantic  conforms  in  direc 
tion  to  the  North  Atlantic. 

The  Asiatic  coast  of  the  Pacific  has  the  direction  of  the  northeast 
erly  system.  The  course  is  not  a  nearly  straight  line,  like  the  corre 
sponding  eastern  coast  of  North  America,  but  consists  of  a  series  of 
curves,  which  series  is  repeated  in  the  island-chains  oflf  the  coast  arid 
in  the  mountains  of  the  country  back.  Moreover,  the  curves  meet  one 
another  at  right  angles. 

The  last  one,  which  is  1,800  miles  long,  commences  in  Formosa,  and 
extends  along  by  Luzon,  Palawan,  and  western  Borneo  (b  a,  Fig.  28) 
to  Sumatra,  and  terminates  at  right  angles  with  Sumatra  ;  and  another 
furcation  of  it  (d  c}  passes  by  eastern  Borneo  or  Celebes,  and  termi 
nates  at  right  angles  with  Java  and  the  islands  just  east.  The  rectan- 
gularity  of  the  intersections  is  thus  preserved  ;  and  the  curve  of  the 
Australasian  chain  has  in  this  way  determined  the  triangular  form  of 
Borneo. 

The  Aleutian  Islands  (range  No.  1)  make  a  curve  across  from  America  to  Kam 
chatka,  in  length  1,000  miles.  The  Kamchatka  range  (No.  2)  commences  at  right 
angles  with  the  termination  of  the  Aleutian,  and  bends  around  till  it  strikes  Japan  at  a 
right  angle.  The  Japan  range  (No.  3)  commences  north  in  Saghalien,  and  curves 
around  to  Corea.  The  Loochoo  range  (No.  4)  leaves  Japan  at  a  right  angle,  and  curves 
around  to  Formosa.  The  Formosa  range  (No.  5)  is  explained  above.  There  is  appar 
ently  a  repetition  of  the  Formosa  system  in  the  Ladrones  near  longitude  145°  E. 

(3.)  East  and  West  Indies.  —  The  general  courses  in  the  East 
Indies  have  been  mentioned  on  pp.  33,  34.  In  the  West  Indies  and 
Central  America  there  is  a  repetition  of  the  curves  in  the  East  Indies. 
The  course  of  the  range  along  Central  America  corresponds  to  Su 
matra  and  Java  ;  and  the  line  of  Florida  and  the  islands  to  the  south 
east  makes  another  range  in  the  same  system. 


36  PHYSIOGRAPHIC    GEOLOGY. 

The  East  and  West  Indies  are  very  similar  in  their  relations  to  the 
continents  and  oceans.  About  the  East  Indies  Asia  lies  to  the  north 
west  and  Australia  to  the  southeast,  just  as  North  and  South  Amer 
ica  lie  about  the  West  Indies ;  and  the  North  Pacific  and  Indian  Ocean 
have  the  same  bearing  about  the  former  as  the  North  Atlantic  and 
South  Pacific  about  the  latter.  The  parallelism  in  the  bends  of  the 
great  chains  is,  hence,  only  a  part  in  a  wide  system  of  geographical 
parallelisms. 

(4.)  The  American  continents.  —  In  North  America,  the  northwest 
system  is  seen  in  the  general  course  of  the  Rocky  Mountains,  the 
Cascade  Range  and  Sierra  Nevada;  in  Florida;  in  the  line  of  lakes, 
from  Lake  Superior  to  the  mouth  of  the  Mackenzie  ;  in  the  south 
west  coast  of  Hudson's  Bay  ;  in  the  shores  of  Davis'  Straits  and  Baf 
fin's  Bay  ;  and  with  no  greater  divergences  from  a  common  course 
than  occur  in  the  Pacific.  The  northeast  system  is  exemplified  in  the 
Atlantic  coast  from  Newfoundland  to  Florida,  and,  still  farther  to  the 
northeast,  along  the  coast  of  Greenland  ;  and  to  the  southwest,  along 
Yucatan,  in  Central  America.  The  Appalachian  Mountains,  the  river 
St.  Lawrence  to  Lake  Erie,  and  the  northwest  shore  of  Lake  Superior, 
repeat  this  trend. 

There  are  curves  in  the  mountain-ranges  of  eastern  North  America, 
like  those  of  eastern  Asia.  The  Green  Mountains  run  nearly  north- 
and-south  ;  but  the  continuation  of  this  line  of  heights  across  New 
Jersey  into  Pennsylvania  curves  around  gradually  to  the  westward. 
The  Alleghanies,  in  their  course  from  Pennsylvania  to  Tennessee  and 
Alabama,  have  the  same  curve.  There  appears  also  to  be  an  outer 
curving  range,  bordering  the  ocean,  extending  from  Newfoundland 
along  Nova  Scotia,  then  becoming  submerged,  though  indicated  in  the 
sea-bottom,  and  continued  by  southeastern  New  England  and  Long 
Island. 

Between  this  latter  range  and  that  of  the  Green  Mountains  lies  one 
of  the  great  basins  of  ancient  geological  time,  while  to  the  westward 
of  the  Green  Mountains  and  Alleghanies  was  the  grand  Interior  basin 
of  the  continent.  The  two  were  to  a  great  extent  distinct  in  their  ge 
ological  history,  being  apparently  independent  in  their  coal-deposits 
and  in  some  other  formations. 

In  South  America,  the  north  coast  has  the  same  course  as  the  Ha- 
waian  chain,  or  pertains  to  the  northwest  system  ;  and  the  coast  south 
of  the  east  cape  belongs  to  the  northeast  system.  Hence  the  outline 
of  the  continent  makes  a  right  angle  at  the  cape.  The  northwest 
system  is  repeated  in  the  west  coast  by  southern  Peru  and  Bolivia, 
and  the  northeast  in  the  coast  of  northern  Peru  to  Darien  :  so  that  this 
northern  part  of  South  America,  if  the  Bolivian  line  were  continued 


GENERAL  FEATURES  OF  THE  EARTH.  37 

across,  would  have  nearly  the  form  of  a  parallelogram.  South  of 
Bolivia  the  Andes  correspond  to  the  northeast  system,  although  more 
nearly  north-and-south  than  usual. 

(5.)  Islands  of  the  Atlantic.  —  The  Azores  have  a  west-northwest 
trend,  like  the  Hawaiau  chain,  and  are  partly  in  three  lines,  with  evi- 

Fig.  29. 


Azores,  or  Western   Islands. 

dences  also  of  the  transverse  system.  The  Canaries,  as  Von  Buch  has 
shown,  present  two  courses  at  right  angles  with  one  another,  —  a 
northwest  and  a  northeast. 

Aii'ain,  the  line  of  the  southeast  coast  of  South  America  extends 
across  the  ocean,  passing  along  the  coast  of  Europe  and  the  Baltic  ; 
and  the  mountains  of  Norway  and  the  feature-lines  of  Great  Britain 
arc  parallel  to  it. 

(6.)  Asia  and  Europe.  —  In  Asia,  the  Sumatra  line,  taken  up  by 
Malacca,  turns  northward,  until  it  joins  the  knot  of  mountains  formed 
by  the  meeting  of  the  range  facing  the  Pacific  and  that  facing  the  In 
dian  Ocean.  At  this  point,  and  partly  in  continuation  of  a  Chinese 
range,  commence  the  majestic  Himalayas,  —  at  first  east-and-west,  at 
right  angles  with  the  termination  of  the  Malacca  line,  then  gradu 
ally  rising  to  west-northwest.  The  course  is  continued  northwestward 
in  the  Hindoo  Koosh,  extending  toward  the  Caspian,  —  in  the  Cau 
casus,  beyond  the  Caspian,  and  in  the  Carpathians,  beyond  the  Black 
Sea.  The  northwest  course  appears  also  in  the  Persian  Gulf,  and 
the  plateaus  adjoining,  in  the  Red  Sea,  the  Adriatic  and  the  Apen 
nines. 

Recapitulation.  —  From  this  survey  of  the  continents  and  oceans  it 
follows  :  — 


38  PHYSIOGRAPHIC    GEOLOGY. 

That,  while  there  are  many  variations  in  the  courses  of  the  earth's  fea 
ture-lines,  there  are  two  directions  of  prevalent  trends,  —  the  northwes 
terly  and  the  northeasterly ;  that  the  Pacific  and  Atlantic  have  thereby 
their  positions  and  forms,  the  islands  of  the  oceans  their  systematic 
groupings,  the  continents  their  triangular  and  rectangular  outlines,  and 
the  very  physiognomy  of  the  globe  an  accordance  with  some  compre 
hensive  law.  The  ocean's  islands  are  no  labyrinths;  the  surface  of  the 
sphere  is  no  hap-hazard  scattering  of  valleys  and  plains  ;  but  even  the 
continents  have  a  common  type  of  structure,  and  every  point  and 
lineament  on  their  surface  and  over  the  waters  is  an  ordered  part  in 
the  grand  structure. 

It  has  been  pointed  out,  first  by  Professor  R.  Owen,  of  Indiana,1  that  the  outlines  of  the 
continents  lie  in  the  direction  of  great  circles  of  the  sphere,  which  great  circles  are,  in 
general,  tangential  to  the  arctic  or  antarctic  circle.  By  placing  the  north  pole  of  a  globe 
at  the  elevation  23°  28'  (equal  to  the  distance  of  the  arctic  circle  from  the  pole  or  the 
tropical  from  the  equator),  then,  on  revolving  the  globe  eastward  or  westward,  part  of 
these  continental  outlines,  on  coming  down  to  the  horizon  of  the  globe,  will  be  found  to 
coincide  with  it;  and,  on  elevating  the  south  pole  in  the  same  manner,  there  will  be 
other  coincidences.  Other  great  lines,  as  part  of  those  of  the  Pacific,  are  tangents  to 
the  tropical  circles  instead  of  the  arctic.  But  there  are  other  equally  important  lines 
which  accord  with  neither  of  these  two  systems,  and  a  diversity  of  exceptions  when  we 
compare  the  lines  over  the  surfaces  of  the  continents  and  oceans. 

Still,  the  coincidences  as  regards  the  continental  outlines  are  so  striking  that  they 
must  be  received  as  a  fact,  whether  we  are  able  or  not  to  find  an  explanation,  or"  bring 
them  into  harmony  with  other  great  lines. 

4.  SYSTEM  IN  THE  OCEANIC  MOVEMENTS  AND  TEMPERATURE. 

(1.)  System  of  oceanic  movements.  —  The  general  courses  of  the 
ocean's  currents  are  much  modified  by  the  forms  and  positions  of  the 
oceans ;  but  the  plan  or  system  for  each  ocean,  north  or  south  of  the 
equator,  is  the  same.  This  system  is  illustrated  in  the  annexed  figure 
(Fig.  30),  in  which  all  minor  movements  are  avoided  in  order  to  pre 
sent  only  the  predominant  courses.  W  E  is  the 
equator  in  either  ocean  ;  30°,  60°,  the  parallels  so 
named  ;  N,  S,  the  opposite  polar  regions  :  the  ar 
row-heads  show  the  direction  of  the  movement. 
The  main  facts  are  as  follow :  — 
(1.)  A  flow  in  either  tropic  (see  figure)  from 
the  east,  and  in  the  higher  temperate  latitudes 
from  the  west,  the  one  flow  turning  into  the  other, 
making  an  elliptical  movement.  The  tropical 
waters  may  pass  into  the  extratropical  regions  in 
all  longitudes;  but  the  movement  is  appreciable 
only  toward  the  sides  of  the  oceans. 

(2.)  A   flow  of  a   part  of  the  easterly-flowing 

1  Key  to  the  Geology  of  the  Globe,  8vo,  New  York,  1857,  and  Am.  Jour.  Sci.,  II. 
xxv.  130. 


60° 


w :.:^v':::;;-    — E 


GENERAL  FEATURES  OF  THE  EARTH.  39 

extratropical  waters  (see  Fig.  30)  outward  toward  the  polar  region, 
to  return  thence  with  the  polar  waters  mainly  along  the  western  side 
of  the  ocean  (though  partly  by  the  eastern). 

(3.)  A  flow  of  the  colder  current  under  the  warmer  when  the  two 
meet,  since  cold  water  is  heavier  than  warm. 

(4.)  A  lifting  of  the  deep-seated  cold  currents  to  the  surface  along 
the  sides  of  a  continent  or  island,  or  over  a  submerged  bank,  as  on 
the  west  coast  of  South  America. 

(5.)  A  movement  of  the  circuit,  as  a  whole,  some  degrees  to  the 
north  or  south  with  the  change  of  the  seasons,  or  as  the  sun  passes  to 
the  north  or  south  of  the  equator. 

(6.)  On  the  west  side  of  an  ocean  (see  Fig.  30),  the  cold  northerly 
current  is  mainly  from  the  polar  latitudes  ;  on  the  east  side,  it  is  mainly 
from  the  high  temperate  latitudes,  being  the  cooled  extratropical  flow 
on  its  return. 

(7.)  The  tropical  current  has  great  depth,  being  a  profound  move 
ment  of  the  ocean,  and  it  is  bent  northward  in  its  onward  course  by 
the  deep,  submerged  sides  of  the  continents.  The  Gulf  Stream  has 
consequently  its  main  limit  80  to  100  miles  from  the  American  coast, 
where  the  ocean  commences  its  abrupt  depths  (p.  11).  Hence,  a  sub 
mergence  of  a  portion  of  a  continent  sufficient  to  give  the  body  of  the 
current  a  free  discharge  over  it  would  have  to  be  of  great  depth,  — 
probably  two  thousand  feet  at  least. 

The  usual  explanation  of  the  courses  is  as  follows :  As  the  earth 
rotates  to  the  eastward,  the  westward  tropical  flow  is  due  simply  to  a 
slight  lagging  of  the  waters  in  those  latitudes.  But  transfer  these 
waters  toward  the  pole,  where  the  earth's  surface  moves  less  rapidly 
(the  rate  of  motion  varies  as  the  cosine  of  latitude),  and  then  they 
may  move  faster  than  the  earth's  surface,  and  so  have  a  movement  to 
the  eastward.  The  earth's  rotation  is  not  supposed  to  be  a  cause  of  mo 
tion  in  the  waters  ;  but,  there  being  a  movement,  for  other  reasons 
(which  it  is  not  necessary  here  to  consider),  from  the  equator  toward 
the  poles,  and  from  the  higher  latitudes  toward  the  equator,  it  gives 
easting  to  the  flow  in  the  former  direction,  and  westing  to  the  flow  in 
the  latter. 

On  the  same  principle,  any  waters  flowing  from  the  polar  regions 
(where  the  earth's  motion  at  surface  is  slow)  toward  the  equator  would 
be  thrown  mainly  against  the  west  side  of  the  oceans  (as  the  Labrador 
current  in  the  North  Atlantic);  for  they  have  no  power  to  keep  up 
with  the  earth's  motion.  But  the  waters  flowing  toward  the  pole,  that 
have  not  lost  much  of  their  previous  eastward  moving  force,  may 
descend  to  lower  latitudes  along  the  east  side  of  the  ocean. 

Put  the  above  figure  in  either  the  Atlantic  or  Pacific,  and  the  sys 
tem  for  the  ocean  will  be  apparent  at  a  glance. 


40  PHYSIOGRAPHIC    GEOLOGY. 

In  the  North  Atlantic,  the  deep  tropical  current  from  the  east  is 
turned  to  the  northward  along  the  West  India  islands,  and  there  be 
comes  the  Gulf  Stream  ;  it  flows  by  Florida  to  the  northeast,  follow 
ing  nearly  the  outline  of  the  oceanic  basin ;  it  passes  the  New 
foundland  bank,  and  stretches  over  toward  Europe ;  then  a  part  bends 
southeastward  to  join  the  tropical  current  and  complete  the  ellipse, 
the  centre  of  which  is  the  Sargasso  Sea,  abounding  in  seaweeds 
and  calms.  Another  large  portion  continues  on  northeastward,  over 
the  region  between  Britain  and  Iceland,  to  the  poles.  From  the  polar 
region,  it  returns  along  by  Eastern  Greenland,  Davis'  Straits  and  other 
passages,  pressing  against  the  North  American  coast,  throwing  cold 
water  into  the  Gulf  of  St.  Lawrence,  bringing  icebergs  to  the  New 
foundland  banks,  arid  continuing  on  southward  to  the  West  India 
islands  and  South  American  coast,  where  it  produces  slight  effects  in 
the  temperature  of  the  coast-waters.  Cape  Cod  stands  out  so  far  that 
the  influence  of  the  cold  current  is  less  strongly  felt  on  the  shores 
south  than  north  ;  and  Cape  Hatteras  cuts  off  still  another  portion. 

In  the  South  Atlantic,  there  is  the  tropical  flow  from  the  east ;  the 
bending  south  toward  Rio  Janeiro ;  the  turn  across  toward  Cape  of 
Good  Hope  ;  and  the  bending  again,  northward,  of  the  waters  now 
cold.  But,  owing  to  the  manner  in  which  the  channels  of  the  South 
Atlantic  and  North  Atlantic  are  united,  a  large  part  of  the  tropical 
current  of  the  former  goes  to  swell  the  tropical  current  and  Gulf 
Stream  of  the  latter. 

In  the  North  Pacific,  there  is  the  same  system,  modified  mainly  by 
this,  that  the  connection  with  the  polar  regions  is  only  through  the  nar 
row  and  shallow  Behring  Straits.  There  is  a  current  answering  to  the 
"  Gulf  Stream  "  off  Japan,  and  another  corresponding  to  the  "  Labra 
dor  current "  along  the  whole  length  of  the  Asiatic  coast,  perceptible 
by  the  temperature  if  not  by  the  movement. 

In  the  South  Pacific,  there  are  traces  of  a  "  Gulf  Stream  "  —  that 
is,  of  an  outward-bound  tropical  current  —  off  Australia,  noticed  by 
Captain  Wilkes.  The  inward  extratropical  current,  chilled  by  its 
southern  course,  is  a  very  important  one  to  Western  South  America, 
as  it  carries  cool  waters  quite  to  the  equator. 

In  the  Indian  Ocean,  the  system  exists,  but  with  a  modification  de 
pending  on  the  fact  that  the  ocean  has  no  extended  northern  area. 
The  outward  tropical  current  is  perceived  off  southeastern  Africa. 

The  surface-currents  of  the  ocean  are  more  or  less  modified  by 
changes  in  the  winds.  On  this  and  on  other  related  topics  barely 
glanced  at  in  this  brief  review,  the  reader  may  refer  to  treatises  on 
Meteorology  or  Physical  Geography. 

(2.)   Oceanic  temperature.  —  The   movement   of  the  oceanic  cur- 


GENERAL  FEATURES  OF  THE  EARTH.  41 

rents  tends  to  distribute  tropical  heat  toward  the  poles,  and  polar 
cold,  in  a  less  degree,  toward  the  tropics  ;  and  hence  the  courses  of 
the  currents  modify  widely  the  distribution  of  oceanic  heat.  The 
chart  at  the  close  of  this  volume  contains  a  series  of  oceanic  isother 
mal  lines  drawn  through  places  of  equal  cold  for  the  coldest  month  of 
the  year.  The  line  of  68°  F.,  for  example,  passes  through  points  in 
which  the  mean  temperature  of  the  water  in  the  coldest  month  of  the 
year  is  68°  F. ;  so  with  the  lines  of  62°,  56°,  etc.1  All  of  the  chart  be 
tween  the  lines  of  68°,  north  and  south  of  the  equator,  is  called  the 
Torrid  Zone  of  the  ocean's  waters  ;  the  region  between  68°  and  35°, 
the  Temperate  Zone,  and  that  beyond  35°,  the  Frigid  Zone.  The  line 
of  68°  is  that  limiting  the  coral-reef  seas  of  the  globe,  so  that  the 
coral-reef  seas  and  Torrid  Zone  thus  have  the  same  limits. 

The  regions  between  the  successive  lines,  as  80°  and  80°,  80°  and  74°,  74°  and  68°, 
68°  and  62°,  62°  and  56°,  56°  and  50°,  and  so  on,  have  special  names  on  the  chart. 
They  are  as  follow :  — 

1.  TOIUUD  ZONE.  —  Super-torrid,  torrid,  and  sub-torrid  regions. 

2.  TKMPEKATE  ZONE.  —  Warm-temperate,  temperate,  sub-temperate,  cold-temperate, 
and  sub-frigid  regions. 

3.  FRIGID  ZONE. 

They  are  convenient  with  reference  to  the  geographical  distribution  of  oceanic 
species. 

Since  the  tropical  (the  westward)  currents  are  warm,  and  the  extra- 
tropical  (the  eastward)  necessarily  cold,  the  elliptical  interplay  ex 
plained  must  carry  the  warm  waters  away  from  the  equator  on  the 
west  side  of  the  oceans,  and  the  cold  waters  toward  the  equator  on  the 
east  side.  The  distribution  of  temperature  thus  indicates  the  currents. 
In  each  elliptical  circuit,  therefore,  the  line  of  G8°  F.  should  be  an  ob 
lique  diagonal  line  to  the  ellipse ;  and  thus  it  is  in  the  North  Atlantic, 
the  South  Atlantic,  the  North  Pacific,  the  South  Pacific  (though  less 
distinctly  here,  as  the  ocean  is  so  broad),  and  the  Indian  Ocean.  The 
torrid-temperature  zones  are  very  narrow  to  the  eastward  and  broad 
to  the  westward.  The  temperate  zones  press  toward  the  equator 
against  western  Africa  and  Europe,  and  western  America.  On  the 
South  American  coast,  this  is  so  marked  that  a  tropical  temperature 
does  not  touch  the  whole  coast,  except  near  the  equator,  and  does  not 
even  reach  the  Galapagos  under  the  equator  off  the  coast,  as  shown  by 
the  course  of  the  isothermal  line  of  68°.  So,  in  the  South  Atlantic,  the 
colder  waters  extend  north  to  within  six  degrees  of  the  equator,  where 
the  line  of  68°  leaves  the  African  coast.  The  continuation  of  the 
Gulf  Stream  up  between  Norway  and  Iceland  is  shown  by  the  great 
loops  in  the  lines  of  44°  and  35°.  The  effect  of  the  Labrador  or  polar 

1  As  the  lines  are  lines  of  equal  extreme  cold,  instead  of  heat,  such  a  chart  is  named 
an  isocrymal  chart  (from  Icros,  equal,  and  K/DU/XO?,  extreme  cold). 


42  PHYSIOGRAPHIC    GEOLOGY. 

current,  in  cooling  the  waters  on  the  coast  of  America,  is  also  well  ex 
hibited  in  the  bending  southward  near  the  coast  of  all  the  lines  from 
68°  to  35°.  The  polar  current  is  even  more  strongly  marked  in  the  same 
Fig.  31.  way  on  the  Asiatic  coast.  The  lines  from 

74°  to  35°  have  long  flexures  southward 
adjoining  the  coast,  and  the  line  of  G8° 
comes  down  to  within  fifteen  degrees 
of  the  equator.  These  waters  pass  south 
ward  mostly  as  a  submarine  current,  and 
are  felt  in  the  East  Indies,  making  a 
southward  bend  in  the  heat  equator. 

In  figure  31,  the  elliptical  line  (A'B'  AB)  represents  the  course  of  the  current  in  an 
ocean  south  of  the  equator  (EQ).  If  now  the  movement  in  the  circuit  were  equable, 
an  isothermal  line,  as  that  of  68°,  would  extend  obliquely  across,  as  n  n :  it  would  be 
thrown  south  on  the  west  side  of  the  ocean  by  the  warmth  of  the  torrid  /one,  and  north 
on  the  east  side  by  the  cooling  influence  derived  from  its  flow  in  the  cold-temperate 
zone.  But,  if  the  current,  instead  of  being  equable  throughout  the  area,  were  mainlv 
apparent  near  the  continents  (as  is  actually  the  fact),  the  isothermal  line  should 
take  a  long  bend  near  the  coasts,  as  in  the  line  A/  »•'  r  r  r  r  A,  or  a  ghoi'ter  bend  A'  s  s', 
according  to  the  nature  of  the  current.  This  form  of  the  isothermal  line  of  G8°  on  the 
chart,  indicates  the  existence  of  the  circuit  movement  in  the  ocean,  and  also  some  of  its 
characteristics.1 

The  following  are  some  of  the  uses  of  this  subject  to  the  geolo 
gist  :  — 

1 .  A  wide  difference  is  noted  between  the  water-temperatures  of  the 
opposite  sides  of  an  ocean.     The   regions  named  temperate  and  sub- 
temperate  occupy  the  most  of  the  Mediterranean  Sea,  and  the  Spanish 
and  part  of  the  African  coast,  on  the  European  side,  and  yet  have  no 
existence  on  the  American,  owing  to  the  meeting  at  Cape  Hatteras  of 
the   cold   northern    waters  with  the  warm    southern.     Compare  also 
other  oceans  and  coasts  on  the  map. 

2.  Consequently,  the  marine   productions   of  coasts   or  seas  in  the 
same  latitudes  differ  widely.     Corals  grow  at  the  Bermudas  in  34°  N., 
where  the  warmth  of  the  Gulf  Stream  reaches,  and,  at  the  same  time, 
are  excluded  from  the  Galapagos  under  the  equator.      Other  examples 
of  the  same  principle  are  obvious  on  the  chart. 

3.  The  west  side  of  an  ocean  (as  in  the  northern  hemisphere)  feels 
most  the  cold  northerly  currents,  when  the  continent  extends  into  the 
polar  latitudes;  but  the  east  side  (as  in  the  southern  hemisphere),  if 
the  continent  stops  short  of  those  latitudes.     There  is  hence,  in  the 
present  age,  a  striking  difference  between  the  northern  and  southern 
hemispheres. 

4.  Changes  of  level  in  the  lands  of  the  globe  have  caused  changes 
of  climates  in  the  ancient  world. 

1  See  paper  by  the  author,  in  Amtr,  Jour.  Sci.,  II.  xxvi.  231. 


GENERAL  FEATTRES  OF  THE  EARTH.  43 

5.  Knowing  the  temperature  limiting  the  coral-reefs  of  the  pres 
ent  era,  or  any  species  of  plants  or  animals,  the  geologist  has  a  gauge 
for  comparing  the  present  distribution  of  temperature  and  life  with 
the  past. 

5.  ATMOSPHERIC  CURRENTS  AND  TEMPERATURE. 
General  System.  —  The  system  of  atmospheric  movement  has  a 
general  parallelism  with  that  of  the  ocean.  In  the  tropics,  the  flow  is 
from  the  east,  constituting  what  are  called  the  trades ;  in  high-tempe 
rate  latitudes,  it  is  from  the  ivest ;  and  the  two  pass  into  one  another  in 
mutual  interplay.  Between  these  there  is,  in  mid-ocean,  a  region  of 
calms.  The  extratropical  winds  also  in  part  pa.ss  on  to  the  poles, 
to  return,  as  northeast,  north,  and  northwest  winds,  toward  the  equa 
tor. 

The  cause  of  the  motion  is  not  now  considered,  as  it  is  here  in  place  only  to  present 
in  a  comprehensive  manner  the  earth's  exterior  features.  The  causes  varying  the  direc 
tions  consist  in  —  (1)  the  temperature  of  the  land  and  ocean;  (2)  the  form  of  the  land 
(mountains  being  barriers  to  a  flow,  retarding  by  friction,  etc.);  (3)  difference  of  density 
of  cold  and  warm  air;  (4)  changing  seasons,  etc.  But  these  sources  of  disturbance 
only  modify  without  suspending  the  system  of  movement. 

Climate.  —  Climate,  while  dependent  largely  on  the  latitude,  is 
modified  by  the  atmospheric  and  oceanic  movements  and  the  distribu 
tion  of  land  and  water.  A  few  general  facts  are  here  mentioned,  in 
order  to  complete  this  survey  of  the  earth's  physiography. 

1.  The  land  takes  up  heat  rapidly  in  summer,  and,  in  the  north,  be 
comes  frozen  and  snow-clad  in  winter.     Land-winds  may,  consequently, 
be  intensely  hot  or  intensely  cold ;  and  hence  lands  have  a  tendency 
to  produce  extremes  of  climate. 

A  place  on  the  continents  having  a  mean  January  temperature  of  50°  (a  very  warm 
temperature  for  that  season)  is  to  be  found  only  in  warm  latitudes,  and  one  with  a  mean 
July  temperature  of  50°  (a  cold  temperature  for  the  season)  only  in  the  colder  zones  of 
the  globe.  The  mean  January  temperature  of  New  York  is  31^°  F.,  while  the  mean  July 
temperature  is  73°.  Now,  in  North  America,  the  January  isothermal  line  of  50°  almost 
touches  the  Gulf  of  Mexico,  and  the  July  line  of  50°  passes  near  the  mouth  of  Mac 
kenzie  River,  or  the  Arctic  circle,  —  the  extreme  winters  and  intense  summers  causing 
this  great  change.  In  Asia,  again,  the  January  line  of  50°  runs  just  north  of  Canton, 
near  26°  N.,  and  the  July  line  of  50°  touches  the  Arctic  Ocean  at  the  mouth  of  the  Lena, 
in  72°  N.,  making  a  difference  of  46°  of  latitude,  or  nearly  3,000  miles,  as  the  effect  of  the 
land  on  the  climate. 

2.  The  waters  of  the  oceans  remain  unfrozen  even  far  toward  the 
pole,  unless  crowded  with    lands,    their  perpetual    movements    tend 
ing   to   produce   a  uniformity  of   temperature    over   the   globe  ;    and 
hence  winds  from  the  oceans  or  any  large  body  of  water  are  mod 
erating,  and  never  very  cold.     They  produce  what  is  called  an  insular 
climate. 


44  PHYSIOGRAPHIC    GEOLOGY. 

Great  Britain  is  tempered  in  its  climate  by  its  winds  and  the  oceanic  current  (the 
Gulf  Stream).  Fuegia,  which  is  almost  surrounded  by  water,  also  has  an  insular  cli 
mate,  —  the  winter's  cold  falling  little  below  32°,  although  below  53°  S.  latitude. 

3.  Absence  of  land  from  high  latitudes  is  equivalent  to  an  absence 
of  the  source  of  extreme  cold ;  and  from  tropical  latitudes,  that  of  ex 
treme  heat ;  and  the  sinking  of  all  lands  would  diminish  greatly  both 
extremes.  But  sinking  high-latitude  lands  also  diminishes  the  extreme 
of  heat,  since  the  lands  become  very  much  heated  in  summer,  and  this 
heat  is  diffused  by  the  winds.  Fuegia,  on  this  principle,  has  a  sub  al 
pine  climate  with  alpine  vegetation  ;  and  Britain  might  approximate 
to  the  same  condition  if  the  Gulf  Stream  could  be  diverted  into  an 
other  ocean. 

The  mean  temperature  of  the  Northern  hemisphere  is  stated,  by 
Dove  at  60°  F.,  and  of  the  Southern  at  56°  F.,  while  the  extremes  for 
the  globe,  taking  the  annual  means,  are  80°  F.  and  zero.  If  there 
were  no  land,  the  mean  temperature  would  probably  be  but  little 
above  what  it  is  now,  or  not  far  from  60°  for  the  whole  globe. 

6.  DISTRIBUTION  OF  FOREST-REGIONS,   PRAIRIES,   AND 
DESERTS. 

The  laws  of  the  winds  are  the  basis  of  the  distribution  of  sterility 
and  fertility. 

1.  The  warm  tropical  winds,  or  trades,  are  moist  winds  ;  and,  blow 
ing  against  cooler  land,  or  meeting  cooler  currents  of  air,  they  drop 
the  moisture  in  rain   or  snow.     Consequently,  the  side  of  the  conti 
nents   or  of  an  island  struck  by  them  —  that  is,  the  eastern,  —  is  the 
moister  side. 

2.  The  cool  extratropical  winds  from  the  westward  arid  high  lati 
tudes  are  only  moderately  moist  (for  the  capacity  for  moisture  depends 
on  the  temperature)  ;  blowing  against  a  coast,  and  bending  toward  the 
equator,  they  become  warmer,  and  continue  to  take  more  moisture  as 
they  heat  up  ;  and  hence  they  are  drying  winds.      Consequently,  the 
side  of  a  continent   struck  by  these  westerly  currents  —  that  is,  the 
western  —  is  the  drier  side. 

There  is,  therefore,  double  reason  for  the  difference  in  moisture  be 
tween  the  opposite  sides  of  a  continent. 

Consequently,  the  annual  amount  of  rain  foiling  in  tropical  South 
America  is  116  inches,  while  on  the  opposite  side  of  the  Atlantic  it  is 
76  inches.  In  the  temperate  zone  of  the  United  States  east  of  the 
Mississippi,  the  average  fall  is  about  44  inches  ;  in  Europe,  only  32. 
America  is  hence,  as  styled  by  Professor  Guyot,  the  Forest  Conti 
nent  ;  and,  where  the  moisture  is  not  quite  sufficient  for  forests,  she 
has  her  great  prairies  or  pampas. 


CLIMATE.  45 

The  particular  latitudes  of  western  coasts  most  affected  by  the  dry 
ing  westerly  winds  —  those  between  28°  and  o2°  —  are  generally  ex 
cessively  arid,  and  sometimes  true  deserts.1 

The  desert  of  Atacama,  between  Chili  and  Peru,  the  semi-desert  of 
California,  the  desert  of  Sahara,  and  the  arid  plains  of  Australia  lie  in 
these  latitudes.  The  aridity  on  the  North  American  coast  is  felt  even 
beyond  Oregon,  through  half  the  year.  The  snowy  peak  of  Mount 
St.  Helen's,  12,000  feet  high,  in  latitude  43°,  stands  for  weeks  together 
without  a  cloud.  The  region  of  the  Sacramento  has  rain  ordinarily 
only  during  three  or  four  months  of  the  year. 

As  the  first  high  lands  struck  by  moist  winds  usually  take  away  the 
moisture,  these  winds'  afterward  have  little  or  none  for  the  lands  be 
yond.  Here  is  the  second  great  source  of  desert-regions.  For  this 
reason,  the  region  of  the  eastern  Rocky  Mountain  slope,  and  the  sum 
mits  of  these  mountains,  are  dry  and  barren  ;  and,  on  the  same  prin 
ciple,  an  island  like  Hawaii  has  its  wet  side  and  its  excessively  dry 
.side. 

Under  the  influence  of  the  two  causes,  the  Sahara  is  continued  in  an 
arid  country  across  from  Africa,  over  Arabia  and  Persia,  to  Mongolia 
or  the  Desert  of  Gobi,  in  central  Asia. 

It  is  well  for  America  that  her  great  mountains  stand  in  the  far 
west,  instead  of  on  her  eastern  borders,  to  intercept  the  atmospheric 
moisture  and  pour  it  immediately  back  into  the  ocean.  The  waters  of 
the  great  Gulf  of  Mexico  (which  has  almost  the  area  of  the  United 
States  east  of  the  Mississippi)  and  those  of  the  Mediterranean  are  a 
provision  against  drought  for  the  continents  adjoining.  It  is  bad  for 
Africa  that  her  loftiest  mountains  are  on  her  eastern  border. 

It  is  thus  seen  that  prairies,  forest-regions,  and  deserts  are  located 
by  the  winds  and  temperature  in  connection  with  the  general  configu 
ration  of  the  land. 

The  movements  of  the  atmosphere  and  ocean's  waters,  and  the  sur 
face-arrangements  of  heat  and  cold,  drought  and  moisture,  sand-plains 
arid  verdure,  have  a  comprehensive  disposing  cause  in  the  simple  rota 
tion  of  the  earth.  Besides  giving  an  east  and  west  to  the  globe,  and 
zones  from  the  poles  to  the  equator,  this  rotation  has  made  an  east  and 
west  to  the  atmospheric  and  oceanic  movements,  and  thence  to  the 
continents,  causing  the  eastern  borders  of  the  oceans  and  land  to  differ 
in  various  ways  from  the  western,  and  producing  corresponding  pecu 
liarities  over  their  broad  surface.  The  continents,  though  in  nearly 
the  same  latitudes  on  the  same  sphere,  have  thence  derived  many  of 
those  diversities  of  climate  and  surface  which,  through  all  epochs  to 
the  present,  have  impressed  on  each  an  individual  character,  —  an  in- 
i  W.  C.  Redfield,  in  Amer.  Jour.  Scl.,  xxv.  139,  3834,  and  xxxiii.  261,  1838. 


46  PHYSIOGRAPHIC    GEOLOGY. 

dividuality  apparent  even  in  its  plants  and  animals.  The  study  of  the 
existing  Fauna  and  Flora  of  the  earth  brings  out  this  distinctive  char 
acter  of  each  with  great  force ;  but  the  review  of  geological  history 
makes  it  still  more  evident,  by  exhibiting  the  truth  in  a  continued  suc 
cession  of  faunas  and  floras,  giving  this  individuality  a  history  looking 
back  to  "  the  beginning." 

The  great  truth  is  taught  by  the  air  and  waters,  as  well  as  by  the 
lands,  that  the  diversity  about  us,  which  seems  endless  and  without 
order,  is  an  exhibition  of  perfect  system  under  law.  If  the  earth  has 
its  barren  ice-fields  about  the  poles,  and  its  deserts,  no  less  barren, 
toward  the  equator,  they  are  not  accidents  in  the  making,  but  results 
involved  in  the  scheme  from  its  very  foundation. 


PART  II. 
LITHOLOGICAL    GEOLOGY. 


LITHOLOGICAL  GEOLOGY  treats  of  the  materials  in  the  earth's 
structure  :  first,  their  constitution  ;  secondly,  their  arrangement  or  con 
dition. 

The  earth's  interior  is  open  to  direct  investigation  to  a  depth  of 
only  fifteen  or  sixteen  miles  ;  and  hence  the  science  is  confined  to  a 
thin  crust  of  the  sphere,  sixteen  miles  being  but  one  five-hundredth  of 
the  earth's  diameter. 

I.  CONSTITUTION  OF  ROCKS. 

Rocks.  —  A  rock  is  any  bed,  layer  or  mass  of  the  material  of  the 
earth's  crust.  The  term,  in  common  language,  is  restricted  to  the  con 
solidated  material.  But  in  Geology  it  is  often  applied  to  all  kinds, 
whether  solid  or  uncompacted  earth,  so  as  to  include,  besides  granyte, 
limestone,  conglomerates,  sandstone,  clay-slates,  arid  the  like  solid  rocks, 
gravel-beds,  clay-beds,  alluvium,  and  any  loose  deposits,  whenever 
arranged  in  regular  layers  or  strata  as  a  result  of  natural  causes. 

The  constituents  of  rocks  are  minerals.  But  these  mineral  con 
stituents  may  be  either  of  mineral  or  of  organic  origin. 

(1.)  The  material  of  organic  origin  is  that  derived  from  the  remains 
of  plants  or  animals.  Of  this  origin  is  the  material  of  nearly  all  the 
great  limestone  formations;  for  the  substance  of  the  rock  was  made 
from  shells,  corals,  or  crinoids,  triturated  into  a  calcareous  earth  by 
the  sea  (if  not  too  minute  to  require  it),  and  consolidated,  just  as  corals 
are  now  ground  up  and  worked  into  great  coral  reef-rocks  in  the  West 
Indies  and  Pacific.  In  other  cases,  only  a  small  part  of  a  rock  is  or 
ganic,  the  rest  being  of  mineral  origin.  Such  rocks  usually  contain 
distinct  remains  of  the  shells  or  corals  that  have  contributed  to  their 
formation  :  these  relics,  whether  of  plants  or  animals,  are  called  fossils 
or  organic  remains^  and  the  rocks  are  said  to  be  fossil  if erous.  They 
are  also  often  called  petrifactions,  though  not  always  really  pet 
rified. 


48  LITHOLOGICAL    GEOLOGY. 

(2.)  The  material  of  mineral  origin  includes  all  that  is  not  directly 
of  organic  origin,  —  all  the  sand,  clay,  gravel,  etc.,  derived  from  the 
trituration  or  wear  of  other  rocks  ;  the  material  from  chemical  de 
position,  like  some  limestones,  or  from  volcanic  action,  like  lavas  and 
trap  or  basalt. 

But,  whether  organic  or  mineral  in  origin,  the  material,  when  in  the 
rock,  though  sometimes  under  the  form  of  fossils,  is  almost  solely  in 
the  mineral  condition.  The  topics  for  consideration  in  connection 
with  this  subject  are,  then,  the  following :  — 

1.  The  elements  constituting  rocks. 

2.  The  mineral  material  constituting  rocks. 

3.  The  kinds  of  rocks. 

1.  ELEMENTS  CONSTITUTING  ROCKS. 

General  considerations.  —  In  the  foundation-structure  of  the  globe, 
firmness  and  durability  are  necessarily  prime  qualities,  while  in  liv 
ing  structures,  instability  and  unceasing  change  are  as  marked  charac 
teristics. 

These  diverse  qualities  of  the  organic  and  inorganic  world  pro 
ceed  partly  from  the  intrinsic  qualities  of  the  elements  concerned  in 
each. 

In  the  inorganic  kingdom  (which  includes  minerals  and  rocks), — 

(1.)  The  elements  which  combine  with  oxygen  to  become  the  es 
sential  ingredients  of  rocks,  are  mainly  hard  and  refractory  substances  : 
as,  for  example,  silicon,  the  basis  of  quartz  ;  aluminum,  the  basis  of 
clay ;  magnesium,  the  basis  of  magnesia. 

(2.)  Or,  if  unstable  or  combustible  elements,  they  are  put  into  stable 
conditions  by  combination  with  oxygen.  Thus,  carbon,  which  we 
handle  and  burn  in  charcoal,  becomes  burnt  carbon  (that  is,  carbon 
combined  with  oxygen,  forming  carbonic  acid)  before  it  enters  into  the 
constitution  of  rocks.  So  all  minerals  are  made  of  burnt  compounds, 
—  called  burnt  because  ordinary  combustion  consists  in  union  with 
oxygen  and  the  production  of  stable  oxyds.  They  are  therefore  dead 
or  inert  in  ordinary  circumstances,  and  hence  fit  for  dead  nature. 

In  organic  nature  (or,  plants  and  animals)  on  the  contrary,  — 

(1.)  The  essential  elements  are  combustible  substances,  and  mostly 
gases,  —  oxygen  combined  with  carbon  and  hydrogen  forming  plants, 
and  oxygen  with  carbon,  hydrogen,  and  nitrogen  forming  animal  sub 
stances.  Nitrogen  is  present  only  very  sparingly  in  plants. 

(2.)  The  elements  in  living  beings,  moreover,  are  not  saturated  with 
oxygen  :  they  are  therefore  in  an  unstable  and  constrained  condition. 
Both  from  their  nature  and  their  peculiar  condition,  they  have  a  strong 
tendency  to  take  oxygen  from  the  atmosphere  with  which  they  are 


CONSTITUENT    ELEMENTS    OF   ROCKS.  49 

bathed  or  penetrated,  and  combine  with  it.  This  state  of  strong  at 
traction  for  oxygen  —  for  something  not  in  the  structure  itself — is 
the  source  of  activity  in  the  vital  functions,  and  involves  unceasing 
change  as  the  means  of  existence  and  growth,  and  a  final  dissolution 
of  the  structure  at  the  cessation  of  life. 

Hence,  strength  and  durability  belong  to  the  basement-material  of 
the  globe,  and  instability  to  living  structures. 

But  inorganic  nature  is  still  riot  without  change.  For  there  are 
diversities  of  attraction  among  the  elements  and  their  compounds. 
The  changes  are,  however,  slow,  and  not  essential  to  the  existence  of 
the  compounds.  The  processes  of  solution,  of  oxidation  and  deoxid- 
ation,  and  other  chemical  interactions,  changes  by  heat,  and  other 
molecular  and  mechanical  influences,  give  a  degree  of  activity  even  to 
the  world  of  rocks.  But  this  topic  belongs  to  the  dynamics  and 
chemistry  of  geology. 

Characteristic  elements.  —  The  elements  most  important  in  rocks 
are  the  following  :  — 

(1.)  Oxygen.  —  Oxygen  is  a  constituent  of  all  rocks,  and  composes 
about  one-half  by  weight  of  the  earth's  crust. 

Sand  is,  by  weight,  more  than  half  oxygen;  quartz,  the  principal  material  of  sand,  is 
about  53  percent,  oxygen;  common  limestone,  48  per  cent.;  alumina,  nearly  47  per 
cent. ;  feldspar,  46  to  50  per  cent. ;  common  clay,  50  per  cent. :  and  thus  it  is  with  the 
various  ordinary  rocks.  Besides,  the  atmosphere  contains  23  per  cent,  of  oxygen,  and 
water  —  the  material  of  the  oceans,  lakes,  and  rivers  —  89  per  cent. 

(2.)  Silicon. —  After  oxygen,  silicon  is  the  element  next  in  abun 
dance,  constituting  at  least  a  fourth  of  the  earth's  crust.  It  is  un 
known  in  nature  in  the  pure  state ;  but,  combined  with  oxygen,  and 
thus  forming  silica,  or  quartz,  it  is  common  everywhere.  This  silica 
is  an  acid,  although  tasteless  ;  and  its  combinations  with  alumina, 
magnesia,  lime,  and  other  bases  (called  silicates),  along  with  quartz, 
are  the  principal  constituents  of  all  rocks  except  limestones.  Silica 
constitutes  about  60  per  cent,  of  these  ingredients ;  and,  including  the 
limestones,  50  per  cent,  of  all  rocks.  Silicon  has  therefore  the  same 
prominent  place  in  the  mineral  kingdom  as  carbon  in  the  organic. 

Granyte  and  gneiss  are  nearly  three-fourths  silica,  —  half  of  it  as  pure  quartz,  and 
the  rest  as  silicates;  mica  schist  and  roofing-slate  are  about  two-thirds  silica;  trap  and 
lavas  are  one-half;  porphyry,  two-thirds;  sandstones  are  sometimes  all  silica,  and  usu 
ally  at  least  four-fifths. 

Silica  is  especially  adapted  for  this  eminent  place  among  the  arch 
itectural  materials  of  the  globe  by  its  great  hardness,  its  insolubility 
and  resistance  to  chemical  and  atmospheric  agents,  and  its  infusibility. 
As  it  withstands  better  than  other  common  minerals  the  wear  of  the 
waves  or  streams,  besides  being  very  abundant,  it  is  the  prevailing 


50  LITHOLOGICAL   GEOLOGY. 

constituent  of  sands,  and  of  the  movable  material  of  the  earth's  sur 
face,  as  well  as  of  many  stratified  rocks  ;  for  the  other  ingredients  are 
worn  to  the  finest  powder  by  the  quartz,  under  the  constant  trituration, 
so  as  to  be  drifted  away  by  the  lightest  currents.  It  is  also  fitted  for 
its  prominent  place  by  its  readiness  in  forming  siliceous  compounds 
and  the  durability  of  these  silicates.  Moreover,  although  infusible 
and  insoluble  alone,  when  mixed  with  different  oxyds  it  melts  and 
forms  glass ;  or,  if  but  a  trace  of  alkali  be  contained  in  waters,  those 
waters,  if  heated,  have  the  power  of  dissolving  it ;  and,  thus  dissolved, 
it  may  be  spread  widely,  either  to  enter  into  new  combinations,  or  to 
fill  with  quartz  any  fissures  and  cavities  among  the  rocks,  thereby 
making  veins  and  acting  as  a  general  cement  and  solidifier. 

Its  applications  in  world-making  are,  therefore,  exceedingly  various. 
In  all,  its  action  is  to  make  stable  and  solid. 

(3.)  Aluminum.  —  Aluminum  is  a  white  metal,  between  tin  and 
iron  in  many  of  its  qualities,  but  as  light  as  chalk.  Combined  with 
oxygen,  it  forms  alumina  (A12O3),  the  basis  of  clay.  This  alumina 
constitutes  the  gem  sapphire,  which  is  next  in  hardness  to  the  diamond, 
and  of  extreme  infusibility  and  insolubility.  It  is  the  most  common 
base  in  the  silicates,  thereby  contributing  to  a  large  part  of  all  siliceous 
minerals,  and  therefore  of  all  rocks.  With  quartz,  these  compounds 
(aluminous  silicates)  make  granyte,  gneiss,  mica  schist,  syenyte,  and 
some  sandstones,  and  alone  they  form  trachyte  and  some  other  igneous 
rocks.  Nearly  all  the  rocks,  except  limestones  and  many  sandstones, 
are  literally  ore-beds  of  the  metal  aluminum. 

(4.)  Magnesium.  —  This  metal  combined  with  oxygen  forms  mag 
nesia  (MgO),  a  very  refractory  and  insoluble  base,  producing  with 
silica  a  series  of  durable  silicates,  very  widely  distributed  :  some  are 
quite  hard,  as  hornblende  and  pyroxene ;  others  are  soft,  and  have  a 
greasy  feel,  like  talc,  soapstone,  and  serpentine. 

Unlike  alumina,  magnesia  unites  with  carbonic  acid,  forming  car 
bonate  of  magnesia  (MgO,  CO'2). 

(5.)  Calcium.  —  The  oxyd  of  the  metal  calcium  is  common  quick 
lime.  Like  magnesia,  it  enters  into  various  silicates ;  and  it  also 
forms  a  carbonate,  carbonate  of  lime  (CaO,C02),  and  this  carbonate 
is  the  material  of  limestones.  Moreover,  with  sulphuric  acid  and 
water,  it  forms  sulphate  of  lime,  or  gypsum. 

The  peculiar  position  of  lime  in  the  system  of  nature  is  that  of  a 
medium  between  the  organic  and  inorganic  world.  Carbonate  of  lime 
is  soluble  in  water,  when  a  little  carbonic  acid  is  present  in  solution  5 
and  both  this  and  the  sulphate  are  found  in  river,  marine,  and  well 
waters.  It  is  made  into  shells,  corals,  and  partly  into  bone,  by  ani 
mals,  and  then  turned  over  to  the  inorganic  world  to  make  rocks. 


CONSTITUENT    ELEMENTS    OF   ROCKS.  51 

Lime  is,  therefore,  the  medium  by  which  organic  beings  aid  in  the  in 
organic  progress  of  the  globe,  as  above  stated :  far  the  greater  part  of 
limestones  have  been  made  through  the  agency  of  life,  either  vegetable 
or  animal. 

Lime  also  unites  with  phosphoric  acid,  forming  phosphate  of  lime, 
the  essential  material  of  bone,  and  a  constituent  also  of  other  animal 
tissues.  Like  the  carbonate,  this  phosphate  is  afterward  contributed 
to  the  rock-material  of  the  globe,  and  is  one  source  of  mineral  phos 
phates. 

(6.)  (7.)  Potassium  and  Sodium. — Potassium  is  the  metallic  base 
of  potash,  and  sodium  of  soda.  The  alkalies  potash  and  soda,  besides 
some  other  oxyds,  form  glass  or  fusible  compounds  with  silica  ;  and 
this  fact  indicates  one  of  their  special  functions  in  the  earth's  structure. 
Silica,  alumina,  and  the  pure  silicates  of  alumina  are  quite  infusible  ; 
but,  by  the,  addition  of  the  alkalies,  or  the  oxyds  of  iron  or  lime,  fusi 
ble  compounds  are  formed.  And,  as  the  earth's  early  history  was  one 
of  universal  fusion,  the  alkalies  performed  an  important  part  in  the 
process,  as  they  have  since  in  all  igneous  operations.  Feldspars,  which 
are  found  in  all  igneous  rocks,  are  silicates  of  alumina  with  potash, 
soda,  or  lime.  A#  heated  solution  of  potasn  or  soda  will  also  dissolve 
silica,  and  so  aid  in  distributing  quartz  or  making  silicates. 

Sodium  is  likewise  the  basis  of  common  salt  in  sea-water. 

(8. )  Iron.  —  Iron  combines  with  oxygen  and  forms  two  compounds, 
a  protoxyd  FeO,  and  a  sesquioxyd  Fe2O3,  and  one  or  the  other  occurs, 
along  with  alumina,  magnesia,  or  lime,  in  many  silicates,  which  are 
mostly  fusible.  Silica  and  magnesia  or  lime  with  protoxyd  of  iron 
make  part  of  the  very  abundant  mineral  hornblende,  found  in  syenyte, 
hornblendic  slate,  etc. ;  and  also  the  equally  common  pyroxene,  char 
acteristic  of  the  heavy,  dark-colored  lavas. 

(9.)  Carbon.  —  Carbon  is  well  known  in  three  different  states,  — 
that  of  the  diamond,  the  hardest  of  known  substances,  that  of  graphite 
or  black  lead,  and  that  of  charcoal.  Combined  with  oxygen,  it  forms 
carbonic  acid  (CO2)  ;  and  carbonic  acid  combined  with  lime  makes 
carbonate  of  lime,  or  common  limestone ;  with  magnesia,  carbonate  of 
magnesia,  or  rnagnesite  ;  with  protoxyd  of  iron,  carbonate  of  iron  or 
siderite;  etc. 

Carbonic  acid  exists  in  the  atmosphere,  constituting  ordinarily  about 
one  part  in  twenty-five  hundred  by  weight. 

This  acid  is  the  only  acid  in  the  mineral  kingdom,  in  addition  to  silica,  which  enters 
very  largely  into  the  constitution  of  rocks;  and,  while  silica  has  alumina  and  other  ses- 
quioxyds  wholly  to  itself,  carbonic  acid  shares  with  it  in  the  magnesia,  lime,  and  alka 
lies,  that  is,  in  all  the  protoxyds.  Carbon,  we  have  said,  performs  as  fundamental  a 
part  in  living  nature  as  silicon  in  dead  nature;  and  it  is  mainly  through  living  beings 
that  it  reaches  the  mineral  kingdom  and  forms  limestones  and  coal-beds.  The  deposits 


52  LITHOLOG1CAL    GEOLOGY. 

of  carbonate  of  lime  that  have  been  produced  by  direct  chemical  deposition  from  the 
waters  of  the  globe  are  small  compared  with  those  made  of  organic  remains  of  plants 
or  animals. 

The  nine  elements  above  mentioned,  oxygen,  silicon,  aluminum,  magnesium,  calcium, 
potassium,  sodium,  iron,  and  carbon,  are  the  prominent  constituents  of  rocks,  making 
up  977-lOOOths  of  the  whole. 

(10.)  Sulphur.^ —  Sulphur  exists  native  in  volcanic  and  some  other  regions.  In  com 
bination  with  various  minerals,  it  forms  ores  called  sulphids,  as  sulphid  of  iron,  or  pyrite. 
sulphid  of  copper,  sulphid  of  silver.  But  these  sulphids  do  not  constitute  properly 
beds  of  rock;  although  two  of  them,  pyrite  and  pyrrhotite,  are  very  abundant.  Sulphur 
forms  with  oxygen  two  acids,  sulphurous  acid  (SO'2),  and  sulphuric  acid  (SO3).  Sul 
phuric  acid  united  with  lime  makes  sulphate  of  lime,  or  gypsum,  which  sometimes 
occurs  in  extensive  beds.  There  are  also  many  other  sulphates,  but  none  are  true  rock- 
constituents. 

(11.)  Hydrogen  with  oxygen  constitutes  water;  and  water,  besides  being  abundant 
over  the  earth's  surface,  is  a  constituent  of  many  minerals.  Gypsum  contains  21  per 
cent.,  serpentine  13  per  cent.,  talc  5  per  cent. 

(12.)  Chlorine  with  sodium  forms  chlorid  of  sodium,  or  common  salt,  which  is  found 
in  large  beds,  and  also  dissolved  in  sea-water  and  brine-springs. 

(13.)  Nitrogen  is  an  ingredient  of  the  atmosphere,  —  making  77  per  cent,  of  it.  With 
oxygen  it  forms  nitric  acid  (NO5) ;  but  no  nitrates  enter  prominently  into  the  structure 
of  rocks. 

The  thirteen  elements  mentioned  are  all  that  occur  as  important 
rock-constituents.  Others  require  attention  in  discussing  topics  con 
nected  with  chemical  geology,  in  which  department  the  profoundest 
knowledge  of  chemistry  and  mineralogy  is  none  too  much.  But  in  a 
general  review  of  rocks  only  these  thirteen  need  be  considered. 

2.   MINERALS   CONSTITUTING  ROCKS. 

The  minerals  which  are  the  principal  constituents  of  rocks  are  the 
following :  — 

1.  Those  containing  silica:    as  quartz;   the  feldspars;  the  micas; 
hornblende  ;  pyroxene  ;  talc  ;  serpentine  ;  chlorite. 

2.  Carbonates :  as  carbonate  of  lime,  or  calcite ;  carbonate  of  lime 
and  magnesia,  or  dolomite. 

3.  Sulphates :  as  sulphate  of  lime  or  gypsum. 

Th  especial  characteristics  of  these,  and  of  other  less  frequent  min 
eral  constituents,  will  be  learned  from  a  Manual  of  Mineralogy.  The 
following  are  the  prominent  characters  of  the  most  common  kinds : l  — 

(1.)  QUARTZ.  —  Quartz  is  the  first  in  importance.  It  occurs  in  crys 
tals,  like  Figs.  32  and  33  ;  also  massive,  with  a  glassy  lustre.  It  is  too 
hard  to  be  scratched  with  a  knife.  It  varies  in  color  from  white  or 

1  The  ordinary  characters  by  which  minerals  are  distinguished  are — relative  hard 
ness,  as  ascertained  by  a  file,  or  the  point  of  a  knife,  or  by  scratching  one  mineral  with 
another;  specific  gravity,  or  relative  weight:  lustre  and  color;  crystalline  form ;  clearage 
(cleavage  being  a  facility  of  cleaving  or  breaking  in  some  one  or  more  directions,  and 
affording  even,  lustrous  surfaces,  as  in  mica,  gypsum,  feldspar);  fusibility ;  chemical 
composition. 


CONSTITUENT    MINERALS    OF   ROCKS.  53 

colorless   to   black,  and  in   transparency  from  transparent  quartz  to 

opaque.    It  has  no  cleavage,  —  that  is,  it  breaks 

...  -. .         .  ,         -,.,          -,  Fiff-  32.  I1  iff-  33, 

as  easily  in  one  direction  as  another,  like  glass. 

Specific  gravity,  2-65.  Before  the  blowpipe  it 
is  infusible,  unless  heated  with  soda,  when  it 
fuses  easily  to  a  glass.  Clear  kinds  are  called 
limpid  quartz  ;  violet  crystals  are  the  amethyst ; 
compact  translucent,  with  the  colors  in  bands 
or  clouds,  agate  ;  the  same,  without  bands  or  clouds,  chalcedony  ;  mas 
sive,  of  dark  and  dull  color,  with  the  edges  translucent,  flint;  the 
same,  with  a  splintery  fracture,  hornstone ;  the  same,  more  opaque, 
lydianstone  or  basanite  ;  the  same,  of  a  dull  red,  yellow,  or  brown 
color,  and  opaque,  jasper  ;  in  aggregated  grains,  sandstone  or  quart- 
syte  ;  in  loose,  incoherent  grains,  ordinary  sand. 

Silica  also  occurs  in  another  state,  constituting  opal,  a  well-known 
mineral.  In  this  state  it  is  never  crystallized,  and  is  easily  dissolved  in 
a  heated  solution  of  potash,  while  quartz  is  so  with  difficulty.  Opal 
usually  contains  some  water,  and  is  a  little  softer  than  quartz.  Silica 
exists  also  in  a  third  state  called  tridymite,  having  the  specific  gravity 
2-3.  Unlike  quartz,  it  crystallizes  in  hexagonal  tables. 

(2.)  FELDSPAR.  —  The  feldspars  are  next  in  abundance  to  quartz. 
They  have  a  lustre  nearly  like  quartz,  but  often  somewhat  pearly  on 
smooth  faces  ;  are  very  nearly  as  hard  as  quartz,  with  about  the  same 
specific  gravity  (2-4-2-6)  ;  and  in  general  have  light  colors,  mostly 
white  or  fiesh-colored,  though  occasionally  dark  gray,  brownish,  or 
green.  They  differ  from  quartz  in  having  a  perfect  cleavage  in  one 
direction,  yielding  under  the  hammer  a  smooth  lustrous  surface,  and 
another  nearly  as  perfect  in  a  second  direction,  inclined  84°  to  90°  to 
the  first ;  also  in  being  fusible  before  the  blowpipe,  though  not  easily 
so ;  also  in  composition,  the  feldspars  consisting  of  silica  combined 
with  alumina  and  an  alkali  —  this  alkali  being  either  potash,  soda,  or 
lime,  or  two  or  all  of  these  combined. 

(3.)  MICA.  —  The  transparent  mineral  often  used  in  the  doors  of 
stoves  and  lanterns  is  mica,  often  wrongly  called  isinglass.  It  is  re 
markable  for  splitting  easily  into  very  thin  elastic  leaves  or  scales,  — 
even  thinner  than  paper, — and  for  its  brilliant  lustre.  It  occurs  color 
less  to  brown,  green,  reddish  and  black ;  and  either  in  small  scales 
disseminated  through  rocks,  —  as  in  granyte  —  or  in  plates  a  yard  in 
diameter.  Consists  of  silica  and  alumina  with  either  potash,  magnesia, 
or  iron,  and  some  other  ingredients.  Fluorine  is  sometimes  present. 
It  is  of  several  kinds,  which  differ  in  composition  and  optical  charac 
ters  more  than  in  appearance.  Some  of  the  varieties  resemble  crys 
tallized  talc  and  chlorite,  from  which  they  differ  in  being  elastic  (un 
less  weathered). 


54 


LITHOLOGICAL    GEOLOGY. 


Fig.  34. 


Fig.  35. 


Feldspar  and  mica  each  include  a  number  of  distinct  kinds  or  species. 
Under  feldspar,  these  species  differ  in  the  proportion  of  silica  (the  acid)  to  the  other 

ingredients  (buses),  and  in  the  particular  alkali 
(potash,  soda  or  lime)  predominant.  The  more  im 
portant  kinds  are  as  follows,  —  (1)  Orihoclase,  or 
common  feldspar,  a  />(><rt.«/<-feldspar;  silica  about 
64  to  66  per  cent,  of  the  whole,  the  oxygen  ratio  of 
the  silica  to  the  bases  being  3  to  1 ;  the  cleavages 
make  a  right  angle  with  one  another,  whence  the 
name,  signifying  cleaving  (it  a  right  angle.  Fig 
ures  34,  35  represent  crystals  of  this  species.  Cleavage  takes  place  parallel  to  the  faces 
0  and  li. 

In  the  following  kinds  the  cleavages  make  an  oblique  angle  with  one  another,  of 
84° -87°,  and  hence  they  are  sometimes  called  atwrthic  feldspars. 

(2.)  Albite,  a  soda  feldspar;  O.  ratio  of  the  silica  to  the  bases  3  to  1,  as  in  orthoclase. 
(3.)  Oligoclase,  a  soda-lime  feldspar,  the  soda  predominating  ;  O.  ratio  of  the  silica  to 
the  bases  2j  to  1.  (4.)  Labradorite.,  a  lime-soda  feldspar,  often  iridescent;  O.  ratio  of  the 
silica  to  the  bases  1^  to  1.  (5.)  Anorthite,  a  lime-  feldspar;  O.  ratio  of  the  silica  to  the 
bases  1 : 1.  Orthoclase  and  Albite  are  eminently  acuJic  feldspars,  and  Labradorite  and 
Anorthite  as  eminently  basic.  Andesite  is  another  feldspar,  between  oligoclase  and  lab- 
radorite  in  composition. 

Under  mica,  the  more  common  kinds  are  the  following  :  (1.)  Muscovite,  or  potash 
mica  (muscovy  glass,  of  early  mineralogy)  usually  whitish  to  brown  in  color.  (2.)  Biotlte 
(named  after  Biot,  the  French  physician),  a  magnesia-iron  mica,  usuallv  black.  (3.) 
Lejndomelftne,  an  iron-mica,  not  elastic,  of  black  color.  (4.)  Phlogopite,  a  magnesia- 
mica  of  light  brown  to  white  color,  common  in  connection  with  crystalline  limestones. 
(5,  6.)  Margarodite  and  Damourite,  micas  like  muscovite  in  composition,  except  the 
presence  of  some  water  (whence  called  hydromicas)-  also  like  muscovite  in  color,  but 
more  pearly  in  lustre,  and  less  elastic ;  often  look  and  feel  like  talc,  and  the  slaty  rocks 
consisting  largely  of  them  have  been  often  called  talcose  slates,  because  soapy  to  the 
touch,  when  really  hydromica  slates.  (7.)  Paragonite  is  a  hydrous  soda  mica. 

HORNBLENDE  (often  called  AMPHIBOLE).  —  The  most  common 
kind  in  rocks  is  an  iron-bearing  variety,  in  black  cleavable  grains  or 
oblong  black  prisms,  cleaving  longitudinally  in  two  directions  inclined 
to  one  another  124°  30'.  It  occurs,  also,  in  distinct  prisms  of  this 
angle,  and  of  all  colors  from  black  to  green  and  white.  Figures  36, 
37,  and  38  represent  these  common  forms,  and  39  tufts  of  crystals  as 
they  often  appear  in  some  rocks.  The  green  kind  is  called  actinolite, 
—  a  common  form  of  its  crystals  is  shown  in  Fig.  38  ;  the  white  (a  kind 
common  in  crystalline  limestones,  and  containing  much  lime),  tremolite. 
Fig.  36.  Fig.  37.  Fig.  39. 


Fig.  38. 

mr  iw 


The  mineral  is  common  in  fibrous  masses ;  and,  when  the  fibres  are  as 


MINERAL    CONSTITUENTS    OF    ROCKS.  55 

fine  as  flax,  the  mineral  is  called  asbestus.  The  principal  constituents 
of  the  mineral  are  silica,  magnesia,  oxyd  of  iron,  and  lime ;  but,  unlike 
the  feldspars,  it  contains  little  or  no  alumina. 

PYROXENE  (including  Augite).     Like  hornblende   in  most  of  its 

characters,  its  variety  of  colors  and  its   chemical 

/  ,  ,       Fig.  40.       I  ig.  41. 

composition.     But  the  crystals,  as  in  the  annexed 

figures,  40,  41,  instead  of  being  prisms  of  124° 
30',  are  prisms  of  87°  5'  or  nearly  (angle  I  on 
I),  and  are  often  eight-sided  from  the  truncation 
of  the  four  edges,  as  in  Fig.  41.  Black  and 
dark-green  pyroxene  in  short  crystals  is  called 
Augite  ;  it  is  an  iron-bearing  kind,  and  is  common  in  igneous  rocks. 

TALC,  SERPENTINE,  CHLORITE.  Talc  and  serpentine  are  silicates 
of  magnesia  containing  water.  They  are  soft  minerals,  talc  being 
easily  impressed  with  the  nail,  and  serpentine  easily  cut  with  a  knife  ; 
and  both,  but  especially  the  talc,  feeling  greasy  in  the  fingers. 

Talc  occurs  in  broad,  pale  green  or  whitish  plates,  looking  like  mica; 
but  the  plates  are  much  softer,  and  have  no  elasticity.  Common  steatite 
or  soapstone  is  nothing  but  a  massive  talc.  Talc  consists  of  silica 
62-12,  magnesia  32-94,  water  4-94  =  100. 

Serpentine  is  usually  compact  massive,  not  granular  at  all,  of  a  dark- 
green  color,  but  varying  from  pale  green  to  greenish  black.  There  is 
a  fibrous  variety  occurring  in  seams  in  massive  serpentine,  which  is 
called  chrysotile.  The  species  contains  silica  43-6,  magnesia  43-4, 
water  13-0  =  100. 

Chlorite  occurs  of  dark  green  color,  sometimes  thin  foliated  like 
mica,  but  inelastic,  oftener  granular  massive.  It  is  a  very  soft  mineral, 
being  in  hardness  between  talc  and  serpentine.  Besides  silica,  mag 
nesia  and  water,  it  contains  alumina  and  oxyd  of  iron. 

Among  the  Carbonates,  the  most  common  is  CALCITE,  or  carbonate 
of  lime,  one  of  the  most  universal  of  minerals.  It  is  the  ingredient  of 
a  very  large  part  of  the  limestones  of  the  world,  and  these  include  the 
various  true  marbles.  When  free  from  impurities,  it  consists  of  car 
bonic  acid  44-0,  lime  56-0  =  100.  It  is  easily  scratched  with  the 
point  of  a  knife-blade  ;  and,  when  dropped  in  powder  into  muriatic 
(chlorhydric)  acid  diluted  with  one  half  water,  it  effervesces  strongly, 
giving  off  carbonic  acid.  The  following  are  some  of  the  forms  it  pre 
sents  when  crystallized.  It  cleaves  alike  in  three  directions  making  the 
angle  105°  5'  with  one  another,  and  the  resulting  form,  Fig.  42  A,  is 
called  a  rhombohedron.  When  crystallized,  calcite  is  often  transparent 
and  colorless.  But  the  mineral  occurs  of  various  colors  from  white  to 
black,  and  the  massive  kinds  from  translucent  to  opaque. 

DOLOMITE,  or  carbonate  of  lime  and  magnesia,  resembles  calcite  so 


56 


LITHOLOGICAL    GEOLOGY. 


closely  that  the  two  cannot  often  be  distinguished  except  by  chemical 
means.    Like  calcite,  it  constitutes  many  limestone  strata,  both  massive 


Fig.  42. 


and  crystallized.  When  dropped  in  powder  into  dilute  muriatic 
acid,  it  effervesces  very  feebly,  if  at  all,  in  the  cold  ;  but,  on  heating 
the  acid,  there  is  a  brisk  effervescence  produced.  The  angles  between 
its  cleavage  faces  is  106°  15',  and  this,  with  crystallized  specimens,  is  an 
important  means  of  distinction.  Composition,  carbonate  of  lime  54-4, 
carbonate  of  magnesia  45-6  =  100. 

Among  sulphates,  the  only  very  common  species  is  GYPSUM.  It  is  a 
very  soft  mineral,  one  of  the  few  that  may  be  easily  impressed  with 
the  teeth,  and  without  producing  a  grating  sensation.  It  is  often  mas 
sive  and  very  fine  granular,  and  of  various  colors  from  white  to  black  ; 
the  white  is  common  alabaster.  It  also  occurs  in  crystals  and  crystal 
line  masses.  Figures  44,  45  give  two  of  the  forms  of  the  crystals. 
Fig.  44.  Fig.  45.  -^  cleaves  in  broad  pearly  plates  or 

folia,  which  look  like  mica,  but  are  softer 
and  not  elastic.  Unlike  limestone  and 
other  minerals,  a  little  heat  reduces  it  to 
powder,  making  the  common  plaster  of  par  is  of  the  shops.  It  consists 
of  sulphuric  acid  46-51,  lime  32-56,  water  20-93  =  100. 

Sulphate  of  lime  also  occurs  without  water,  and  is  then  called  anhy 
drite  \  the  crystallization  is  very  different,  cleavage  affording  rectangular 
blocks  or  plates. 

Besides  these  very  abundant  rock-making  species,  there  are  the  following  of  quite 
common  occurrence. 

ANHYDROUS  SILICATES.  Neph  elite,  a  colorless  to  grayish-green  and  greenish  min 
eral  (also  of  other  shades),  related  somewhat  to  the  feldspars,  and  having  the  place  of  a 
feldspar  in  some  igneous  rocks.  Its  crystals  are  hexagonal  prisms.  Silica,  alumina, 
soda  and  potash  are  the  principal  constituents. 

Leucite.  A  white  or  grayish-white  mineral  occurring  in  24-sided  crystals  resembling 
Fig.  47;  it  takes  the  place  of  a  feldspar  in  igneous  rocks,  at  Vesuvius  and  some  other 
European  localities.  Silica,  alumina,  and  potash  are  its  constituents. 


MINERAL   CONSTITUENTS    OF   ROCKS. 


57 


Chrysolite  (called  also  Olicine),  occurring  in  green  glassy  grains  or  crystals,  and  com 
mon  in  many  basaltic  rocks.     Consists  of  silica,  magnesia,  and  iron. 

Garnet,  in  crystals  of  the  forms  in  Figs.  46,  47,  disseminated  in  various  crystalline 

Fig.  4(5.  Fig.  47. 


Fio-.  48. 


rocks;  colors  usually  red  to  black;  rarely  green.    Consists  of  silica,  alumina, 
magnesia,  lime,  and  iron 

Efridote,  in  yellowish-green  prismatic  crystals  and  masses ;  also  of  brown 
and  grav-white  colors.  Constituents  as  in  garnet. 

Scapolite,  in  four-square  and  eight-sided  erect  prisms,  white  to  gray, 
and  sometimes  greenish  or  reddish.  One  of  the  forms  of  its  crystals  is 
shown  in  Fig.  48.  Constituents,  silica,  alumina,  lime,  and  usually  some 
soda. 

Andalusite,  in  whitish,  grayish,  prismatic  crystals,  nearly  square,  imbedded  in  slaty 
Fig.  49.  Fig.  50. 


rocks.  Crystals  having  the  interior  tessellated  with  black,  as  in  figure  49,  are  called 
Chiastolite.  Composition:  silica  37'0,  alumina  63'0. 

Staurolite,  in  rhombic  prisms  of  129°  2(K,  imbedded  in  slaty  rocks.  Usual  colors, 
brown  to  black.  The  crystals  are  often  crossed  as  in  Fig.  50,  and  hence  the  name, 
from  the  Greek  for  cross.  Composition:  silica  29*3,  alumina  53'5,  sesquioxyd  of  iron 
17-2  =  100. 

Cyanite  (spelt  also  Kyanite),  in  thin  and  often  long-bladed  crystals  of  sky-blue  to 
white  color.  Same  composition  as  Andalusite.  Xaniecl  from  the  Greek  for  blue. 

Tourmaline.  —  Usually  in  three-sided  or  six-sided  black  crystals,  showing  no  distinct 
cleavage,  and  thus  differing  from  hornblende.  Figs.  51,  52  show  two  of  the  forms;  and 


Fig.  53. 


Fig.  51. 


12  i2 


58 


LITHOLOGICAL    GEOLOGY. 


Fig.  53,  the  appearance  of  the  crystals  in  the  rock  (often  quartz).  Besides  black,  there 
are  also  brown,  green,  red  and  white  tourmalines.  Constituents:  silica,  alumina,  mag 
nesia,  with  fluorine  and  some  boracic  acid. 

Topaz,  in  rhombic  prisms  of  124°  19',  remarkable  for  cleav 
ing  with  ease  and  brilliancy  parallel  to  the  base  of  the  prism. 
Colors,  yellowish  to  white ;  also  brown.  Two  of  the  forms  of 
its  crystals  are  shown  in  figures  54,  55. 

Beryl,  in  six-sided  prisms,  usually  pale  green,  but  deep  green 
in  the  variety  emerald. 

All  the  above  anhydrous  minerals  are  too  hard  to  be 
scratched  with  a  file.  The  following  contain  water,  and  are 
softer. 

2.  HYDROUS  SILICATES.  —  Besides  the  hydrous  micas,  there  are  the  common  species: 
Agalmatolitc,  a  compact  mineral,  soapy  to  the  touch,  often  resembling  a  compact  soap- 
stone.     Like  serpentine  and  massive  pyrophyllite,  it  is  often  cut  into  images  in  China. 
Consists  of  silica,  alumina,  potash,  and  water. 

Pyropliyllite.  —  A  mineral  resembling  talc  in  color,  cleavage,  and  soapy  feel,  when 
crystallized,  and  like  some  fine-grained  soapstone  when  massive.  Consists  of  silica, 
alumina,  and  water.  It  differs  from  talc  in  containing  alumina  in  place  of  magnesia. 

Glauconite  or  Green  Earth,  the  material  of  the  New  Jersey  marl,  or  Green  sand  of  the 
Cretaceous  and  other  rocks.  It  is  a  soft,  dark  or  light  green  silicate  of  alumina,  iron, 
and  potash,  with  water. 

Clay  is  not  ordinarily  a  simple  mineral,  but  a  mixture  of  powdered  feldspar  and 
quartz.  But  the  soft  clay,  soapy  to  the  touch,  found  in  some  places,  is  the  species  kao- 
linite,  or  the  material  of  kaolin  —  the  clay  which  is  used  in  the  manufacture  of  porcelain. 
It  is  a  result  of  the  decomposition  of  some  kind  of  feldspar  containing  potash  or  soda, 
and  consists  of  silica  41*5,  alumina  34*4,  and  water  24*1  =  100. 

3.  CARBONATES,  SULPHATES,  PHOSPHATES,  AND   FLUOKIDS.  —  Among  these  min 
erals,  there  are  a  few  species  common  enough  to  be  here  enumerated. 

Slderite  or  Carbonate  of  Iron,  like  calcite  in  cleavage,  and  white  or  grayish  white, 
but  changing  readily  to  a  brown  color  on  exposure,  and  finally  to  the  hydrous  oxyd  of 
iron  called  limonite. 

Magnetite,  or  Carbonate  of  Magnesia,  white  and 
like  calcite  in  cleavage,  but  often  occurring  massive 
and  looking  like  porcelain  biscuit. 

For  other  related  carbonates,  reference  must  be 
made  to  the  Mineralogy. 

Barite,  or  Heavy  Spar,  is  a  sulphate  of  baryta.  It 
occurs  in  tabular  crystals,  some  of  the  forms  of  which 
are  given  in  Fig.  56.  It  is  remarkable  for  its  high 
specific  gravity,  whence  the  name,  from  the  Greek 
for  weight.  It  contains  sulphuric  acid  34*33,  baryta 
6567  =  100. 

Apatite  is  a  phosphate  of  lime.  It  commonly  oc 
curs  in  six-sided  prisms,  greenish  in  color,  and  look 
ing  like  beryl,  from  which  it  differs  in  being  easily 
scratched  with  a  knife.  Its  crystals  are  sometimes 
transparent  and  colorless,  or  bluish,  and  occasionally 
brown . 

Fluorite,  or  Fluor  Spar,  a  fluorid  of  calcium.  Its  crystals  are  cubes,  octahedrons, 
and  other  related  forms.  All  of  them  cleave  easily  in  four  directions,  parallel  to  the 
faces  of  the  regular  octahedron,  the  faces  of  cleavage  making  angles  with  one  another 
of  109°  28'.  It  is  often  granular-massive.  It  is  easily  scratched  with  a  file.  Its  colors 
are  clear  purple,  yellow,  blue,  often  white,  and  of  other  shades.  When  powdered  and 
thrown  on  a  shovel  heated  nearly  to  redness,  it  phosphoresces  brightly.  Composition: 
fluorine  487,  calcium  51-3. 


MINERAL    CONSTITUENTS    OF   BOOKS.  59 

4.  Tin:  METAL-BEARING  MINERALS  OR  ORES,  COMMON  ix  ROCKS.  —  Pi/rite,  a  com 
pound  of  sulphur  and  iron,  in  the  proportion  of  53-3  to  467,  and  having  a  very  pale 
brass-like  color,  much  less  yellow  than  copper  pyrites;  it  is  unlike  the 
latter  also  in  striking  tire  with  a  steel,  whence  the  name,  from  the 
Greek  forjire.  Occurs  often  in  cubes  like  Fig.  57.  The  stria?  of  the 
adjoining  surfaces,  when  any  are  present,  are  at  right  angles  with  one 
another.  Another  compound  of  sulphur  and  iron,  called  pyrrhotite, 
contains  40  per  cent,  of  sulphur  to  60  of  iron,  and  is  soft  like  the  fol 
lowing  species,  but  is  of  a  pale  bronze  color. 

Ckalcopyrite,  or  Copper  Pyrites.  —  A  compound  of  sulphur,  copper, 
and  iron,  of  a  deep  brass-yellow  color,  easily  scratched,  and  yielding  a  dark  green  pow 
der  (and  thus  distinguished  from  pyrite);  and  when  a  solution  is  made  with  dilute  nitric 
acid,  a  blade  of  iron  put  into  it  becomes  red  from  a  coating  of  copper. 

Galenite,  or  Galena,  the  most  common  ore  of  lead.  A  compound  of  sulphur  and  lead 
in  the  proportion  13-4  to  86-6,  of  a  lead-gray  color,  soft  and  brittle.  It  occurs  in  cubes, 
dodecahedrons  and  other  forms,  and  cleaves  easily  into  cubes. 

Blende  (sphalerite),  a  compound  of  sulphur  and  zinc,  in  the  proportion  of  33  to  67; 
of  resin-yellow  and  brown  colors,  also  black,  and  sometimes  looking  metallic,  but  giving 
a  whitish  powder.  Crystalline  masses  cleave  easily,  yielding  rhombic  dodecahedrons. 

Hematite  or  Specular  Iron,  Magnetite,  and  Limonite  are  the  more  common  oxyds  of 
iron  occurring  as  ores. 

Hematite,  or  specular  iron  ore  (Fe'203),  is  often  in  dark  steel-gray  crystals  or  masses, 
and  also  in  deep-red  earthy  masses,  and  has  a  red  powder.  Magnetite  (Fe304)  is  in 
dark  iron-gray  crystals  (often  octahedrons  or  dodecahedrons),  and  also  massive,  and 
has  a  black  powder.  Limonite  (2Fe'203+3H'20)  occurs  black  and  also  in  brownish-yel 
low  earthy  masses,  and  is  distinguished  by  a  brownish  yellow  powder.  Menaccanite, 
or  Titanic  iron,  is  an  ore  like  hematite  in  its  crystals,  but  blacker  in  color,  and  black 
in  its  powder.  It  contains  titanium  as  well  as  iron  and  oxygen. 

Graphite,  called  also  Plumbano,  and  Black  Lead  (the  material  of  lead  pencils),  looks 
like  a  metallic  substance;  but  it  is  simply  carbon,  neither  lead  nor  iron  occurring  in  the 
pure  mineral. 

7.  Materials  of  organic  origin. 

The  materials  of  organic  origin  —  that  is,  those  derived  from  plants 
or  animals  —  may  be  arranged  in  four  groups. 

(1.)  The  calcareous,  or  those  of  which  limestones  have  been  formed : 
namely,  corals,  corallines,  shells,  crinoids,  etc.  The  specific  gravity  of 
corals  is  2-4-2-82  ;  of  shells,  2-4-2-86,  —  the  highest  from  a  Chama 
(Silliman  Jr.). 

(2.)  The  siliceous,  or  those  which  have  contributed  to  the  silica  of 
rocks,  and  may  have  originated  flint :  namely,  (a)  the  microscopic  sili 
ceous  shields  of  the  infusoria  called  Diatoms  (p.  135),  which  are  now 
regarded  as  plants ;  (b)  the  microscopic  siliceous  spicula  of  Sponges 
(p.  132)  ;  (c)  the  microscopic  siliceous  shells  of  Polycystines,  a  kind  of 
minute  animal  life  ;  (d)  the  minute  teeth  of  Mollusks. 

(3.)  The  phosphatic,  or  those  which  have  contributed  phosphates, 
especially  phosphate  of  lime ;  as  bones,  excrements,  the  shells  of  Lin- 
gulce,  Discing,  and  a  few  other  mollusks,  and  those  of  crustaceans  and 
insects,  as  well  as  ordinary  animal  tissues ;  also  the  stems,  leaves,  and 
fruit  of  plants,  —  especially  the  edible  grains.  Fossil  excrements  are 


60  LITHOLOGICAL   GEOLOGY. 

called  coprolites  ;  when  in  large  accumulations  (as  sometimes  made  by 
birds  or  bats),  guano. 

The  remains  of  animals  have  also  afforded  traces  of  fluorine. 

(4.)  The  carbonaceous,  or  those  which  have  afforded  coal,  mineral 
oil,  and  resin,  as  plants. 

Besides  these,  there  is  a  fifth  kind,  though  of  little  importance  geo 
logically,  viz.,  the  animal  tissues  themselves.  Only  in  a  few  cases  do 
any  of  these  tissues  remain  in  fossils,  except  in  some  groups  belonging 
to  the  later  geological  epochs.  These  tissues  contain  traces  of  phos 
phates  and  fluorids  which  they  have  contributed  to  the  muds  of  which 
rocks  have  been  made. 

(1.)  CALCAREOUS.  —  The  following  are  a  few  analyses:  1  and  2,  corals,  Madrepora 
palmata,  and  Oculina  arbuscula  by  S.  P.  Sharpies  (Am.  Jour.  Sci.,  III.  i.  168)  ;  3, 
shell  of  a  Terebratula,  by  the  same :  — 

Madrepora.  Oculina.  Terebratula.  Oyster-shelL 

Carbonate  of  lime    ....     97'19  95'37                    98'39                    93-9 

Phosphate  of  lime    ....       078  0'84  \                   0'61                      O5 
Sulphate  of  lime      ....                                                                                             1-4 

Water  and  organic  matters  .       2-81  3-79  )                   1-00                     3-9 
Carbonate  of  magnesia                    -                                                                             0*3 

In  many  shells,  the  inner  pearly  layer  consists  of  carbonate  of  lime  in  the  condition  of 
aragonite;  while  the  outer  (or  the  whole,  if  no  part  is  pearly)  is  usually  common  car 
bonate  of  lime,  or  calcite.  The  spines  of  fossil  Echini  are  calcite. 

In  corals  of  the  genus  Millepora,  according  to  Damotir,  there  is,  besides  carbonate -of 
lime,  some  carbonate  of  magnesia,  amounting  in  one  species  to  19  percent.,  while  but 
little  in  others.  These  corals  have  been  shown  by  Agassiz  to  be  the  secretions  of  Acalephs, 
and  not  of  ordinary  polyps.  Forchhammer  found  6 '36  per  cent,  of  carbonate  of  magnesia 
in  the  Ms  nobilis,  and  2-1  per  cent,  in  the  Corallium  nobile,  or  "  precious  coral  "  of  the 
Mediterranean. 

The  Nullipores  and  Corallines  are  vegetation  having  the  power  of  secreting  lime,  like 
the  coral  animals.  The  shells  of  Rhizopods  (called  also  Polythalamia  and  Foraminifera) 
are  calcareous. 

The  shell  of  a  lobster  (Palinurus)  afforded  Fremy,  carbonate  of  lime,  49 '0,  phosphate 
of  lime,  6 '7,  organic  substance,  44-3. 

(2.)  SILICEOUS. — The  organic  silica  is,  in  part  at  least,  in  that  condition  charac 
terizing  opal  (p.  53).  This  is  the  case  with  the  siliceous  spicula  of  sponges  and  with 
diatoms. 

(3.)  PHOSPHATIC.  —Analyses  of  bones:  1,  2.  human  bones,  according  to  Frerichs;  3, 
fish  (Haddock),  according  to  Dumenil;  4,  shark  (Sqnalus  cornubicus),  according  to 
Marchand;  5,  fossil  bear,  id.;  6,  shell  of  Lingula  avails,  Hunt. 

1-                2.               3  4.                5.              6. 

Phosphate  of  lime 50'24        59-50        55-26  32-46  62-11       85'79 

Carbonate  of  lime 11-70          9-46          0-16  )  ...  13-24       11-75 

Sulphate  of  lime -                                _    \  12-25 

Organic  substance 38-22        30-94        37-63  58-07  4-20 

Traces  of  soda,  etc 1-22  3-80 

Fluorid  of  calcium 1-20  2-12 

Phosphate  of  magnesia      .     .     .  1/03  Q'50         2*80 

In  No.  4,  a  little  silica  and  alumina  are  included  with  the  fluorid.    No.  5  contains  also 


MINERAL    CONSTITUENTS    OF   ROCKS. 


61 


silica  2 '12,  and  oxyds  of  iron  and  manganese,  etc.,  3-46.  In  No.  6,  the  2-80  is  mag 
nesia. 

The  enamel  of  teeth  contains  85  to  90  per  cent,  of  phosphate  of  lime,  2  to  5  of  car 
bonate  of  lime,  and  5  to  10  of  organic  matters.  The  shells  of  a  fossil  Obolus  afforded 
Kupffer  the  composition  nearly  of  a  fluor-apatite  (Am.  Jour.  Sci.,  III.  vi.  146). 

Fish-scales  from  a  Lepidosteus  afforded  Fremy  40  per  cent,  of  organic  substance,  51*8 
of  phosphate  of  lime,  7'6  of  phosphate  of  magnesia,  and  4*0  of  carbonate  of  lime. 
Other  fish-scales  contained  but  a  trace  of  the  magnesia-phosphate  and  more  of  organic 
matters. 

The  ashes  of  ordinary  meadow-grass  afford  8  per  cent,  of  phosphoric  acid;  of  rye 
straw,  4  per  cent. ;  of  clover,  18  per  cent. ;  of  wheat  and  rye,  50  per  cent. ;  of  peas  and 
beans,  33-38  per  cent. ;  of  sea-weeds  of  the  genus  Fucus,  1-2  to  4  per  cent. ;  of  the  genus 
Laminaria,  3 -4  to  5  per  cent.  (Schweitzer);  of  the  species  Iridea  edulis,  11 '4  per  cent. 
(Forchhammer). 

Phosphatic  nodules,  possibly  coprolitic,  in  the  Lower  Silurian  rocks  of  Canada  (on  river 
Ouelle),  afforded  T.  S.  Hunt  (see  Am.  Jour.  Sci.,  II.  xv.  and  xvii. ),  in  one  case,  phos 
phate  of  lime,  40-34,  carbonate  of  lime,  with  fluorid,  5*14,  carbonate  of  magnesia  9*70, 
peroxyd  of  iron,  Avith  a  little  alumina,  12-62,  sand  25-44,  moisture  2-13  =95*37.  In  a 
hollow  cylindrical  body  from  the  same  region,  there  were  67 '53  per  cent,  of  phosphate. 

ANALYSES  OF  COPKOLITES  (Fossil  Excrements).  —  Nos.  1  and  2  by  Gregory  and 
Walker;  3  and  4  by  Connell;  5  by  Quadrat;  6  by  Rochleder  (a  coprolite  from  the 
Permian). 


Phosphate  of  lime  .  . 
Carbonate  of  lime  .  . 

Silica 

Organic  material  .  .  . 
Carbonate  of  magnesia  . 
Sesquioxyd  of  iron  .  . 

Alumina 

Water 

Lime  of  organic  part  . 
Chlorid  of  sodium  .  . 


1. 

2. 

3. 

4. 

5. 

6. 

Burdie- 
house. 

Fife- 
shire. 

Burdie- 

house. 

Burdie- 
house. 

Kosch- 

titz. 

Oberlan- 
genau. 

9-58 

63-60 

85-08 

83-31 

50-89 

15-25 

61-00 

24-25 

10-78 

15-11 

32-22 

4-57 

j  4-13 

trace 
3-38 

0-34 
3-95 

0-2S) 
1-47 

0-14 

7-38 

74-03 

13-57 

2-89 

- 

- 

- 

2-75 

6-40 

trace 

- 

- 

2-08 

_ 

6-42 


5-33 


144 

1-96 


100-01         97-45         100-15 


100-18        99-13        100-00 


(4.)  CARBONACEOUS.  —  Mineral  coal  consists  mainly  of  carbon,  with  some  hydrogen 
and  oxygen,  traces  of  nitrogen,  and  more  or  less  of  earthy  impurities  called  the  ash. 
The  hydrogen  and  oxygen  are  supposed  to  be  combined  with  part  or  all  of  the  carbon, 
so  that  most  coal  consists  of  ox}-genated  hydrocarbons.  When  heated,  they  usually  af 
ford  much  volatile  matter,  although  containing  none,  this  arising  from  the  decomposition 
by  heat  of  some  of  the  hydrocarbons  present:  the  volatile  matter  is  mostly  hydrocarbon 
oils  (some  kind  of  petroleum)  or  gas,  with  a  little  water.  The  dry  porous  carbon  left 
behind  is  called  coke.  Coals  affording  much  volatile  matter,  and  burning  with  a  yel 
low  flame,  are  said  to  be  bituminous;  and  those  affording  little,  and  burning  with  a 
a  pale  blue  flame,  non-bituminous.  The  varieties  are :  — 

A.  Anthracite. — Non-bituminous,  or  nearly  so.     A  hard,   lustrous  coal,   breaking 
with  a  conchoidal  fracture  and  clean  surface,  and  burning  with  very  little  flame,  as  the 
coal  of  Lehigh,  Wyoming,  and  other  places  of  central  Pennsylvania,  also  that  of  Rhode 
Island. 

B.  Bituminous  coal.  —  Bituminous.    Softer  than  anthracite,  less  lustrous,  often  look 
ing  a  little  pitchy.     The  amount  of  volatile  substances  yielded  varies  from  10  to  60 
per  cent. 

a.  Brown  coal  is  black  or  brownish  black  coal,  containing  much  oxygen,  and  occur- 
ing  in  Mesozoic  and  more  modern  deposits.  It  is  often  called  Lignite.  True  lignite  re- 


62  LITHOLOGICAL   GEOLOGY. 

tains  the  form  and  structure  of  the  original  wood,  and  burns  with  an  empyreumatic 
odor.  Jet  is  a  compact  black  lustrous  lignite.  Peat  is  imperfect  coal,  or  partially 
carbonized  vegetable  material,  from  modern  swamps. 

On  coals,  see  further,  page  314;  also,  author's  Mineralogy,  pp.  753-760,  on  Min 
eral  oils,  pp.  723-730,  on  Asphalt,  etc.,  pp.  751-753. 

Fossils.  —  From  the  above  account  of  the  composition  of  the  hard 
parts  of  organic  beings,  their  influence  on  the  composition  of  rocks  is 
readily  inferred. 

But  the  fossils  themselves  seldom  retain  completely,  even  in  the 
case  of  such  stony  secretions  as  shells  and  corals,  their  original  con 
stitution.  There  is  usually  a  loss  of  the  organic  matter.  There  is 
often  a  further  change  of  the  carbonate  of  lime  into  a  new  molecular 
condition,  manifest  in  the  fact  that  the  fossil  has  the  oblique  cleavage 
of  calcite;  and  in  this  change  there  is  a  loss  of  part  or  all  of  the 
phosphate  or  fluorid.  There  is  sometimes,  again,  a  change  to  dolomite, 
in  which  the  carbonate  of  lime  becomes  a  carbonate  of  lime  and  mag 
nesia.  In  other  cases,  of  very  common  occurrence,  all  the  fossils  of  a 
rock,  whether  it  be  limestone  or  sandstone,  are  changed  to  silica 
(quartz)  by  a  silicifying  process.  Silicified  trunks  of  trees,  as  well  as 
shells,  occur  in  rocks  of  various  geological  ages.  In  some  cases,  fossils 
have  been  altered  to  an  oxyd  or  sulphid  of  iron,  or  to  other  ores. 

In  many  cases,  the  fossils  are  entirely  dissolved  out  by  percolating 
waters,  leaving  the  rock  full  of  cavities.  This  happens  especially  in 
sandstones,  through  which  waters  percolate  easily,  and  not  in  clays, 
which  latter  preserve  well  the  fossils  committed  to  them ;  and  hence 
sands,  gravel,  conglomerates  and  quartzose  sandstones  contain  few  or 
ganic  remains. 

3.  KINDS  OF  ROCKS. 

General  subdivisions.  —  Rocks  are  conveniently  divided  into  frag 
mented  and  crystalline. 

1.  Fragmental  —  Rocks  that  are  made  up  of  pebbles,  sand,  or  clay, 
the  particles  of  sand,  and  even  of  clay,  being  strictly  fragments  broken 
from  the  rocks  of  the  globe,  either  deposited  as  the  sediment  of  mov 
ing  waters,  or  formed  and    accumulated   through  other  means, —  as 
ordinary  conglomerates,  sandstones,  clay-rocks,  tufas,  and  nearly  all  lime 
stones.     The  larger  part  of  the  rocks  here  included  are  made  of  sedi 
mentary  material,  that  is  material  deposited  as  sediments  by  marine  or 
fresh  waters ;  and  are  hence  commonly  called  sedimentary  rocks.    They 
are   stratified  rocks,  —  that  is,  consist  of  layers  spread  out  one  over 
another.     Many  of  them  are  fossiliferous  rocks,  or  contain  fossils. 

2.  Crystalline.  —  Rocks  that  have  a  crystalline  instead  of  a  frag- 
niental   character.     The  grains,  when  large  enough  to  be  visible,  are 


CHARACTERISTICS    OF   ROCKS.  63 

crystalline  grains,  and  not  water-worn  particles  or  fragments  of  other 
rocks.     Examples,  granyte,  gneiss,  mica  schist,  basalt. 
The  crystalline  rocks  may  have  been  crystallized,  — 

a.  From  fusion,  like  lava  or  basalt,  when  they  are  called  igneous 
rocks.     Igneous  rocks  are  often  called  intrusive  rocks,  a  term  signifying 
that  they  have  been  ejected  from  below,  through  fissures  intersecting 
other  rocks. 

b.  From  solution,  as  with  some  limestone. 

c.  Through  long-continued  heat  without  complete  fusion.     By  this 
last  method,  sedimentary  beds,   that  is,  those  made  originally  from 
mud,  clay,  etc.,  have  been  altered  into  granyte,  gneiss,  or  mica  schist, 
and  compact  limestone  into  statuary -marble. 

Since,  in  such  cases,  a  bed  originally  sedimentary  has  been  meta 
morphosed  into  a  crystalline  one,  rocks  of  this  altered  kind  are  called 
metamorphic  rocks. 

In  the  following  descriptions,  a  separate  subdivision  is  made  of  the 
calcareous  rocks  or  limestones,  which  are  mostly  sedimentary  in  original 
accumulation,  but  generally  lose  that  appearance  as  they  solidify. 

Characteristics  of  Rocks.  —  Independently  of  the  characters  above 
mentioned,  rocks  differ  in  kinds  :  — 

a.  First.  As  to  STRUCTURE  :  whether  — 

Massive,  like  sandstone,  or  granyte,  breaking  one  way  about  as  easily  as  another. 

Schistose  or  laminated,  breaking  into  slabs,  like  flagging-stone:  schistose  is  usually 
restricted  to  the  crystalline  rocks,  like  gneiss  and  mica  schist. 

Slaty,  breaking  into  thin  and  even  plates,  like  roofing-slate. 

Shalij,  breaking  unevenly  into  plates,  and  fragile,  like  the  slate  or  shale  of  the  coal 
formation,  the  Utica  shale,  etc. 

Concretionary,  having  the  form  of,  or  containing,  spheroidal  concretions;  some  va 
rieties  are  also  called  ylobuliferous,  when  the  concretions  are  isolated  globules  and  evenly 
distributed  through  the  texture  of  a  rock;  others  are  odlitic,when  made  of  an  aggrega 
tion  of  minute  concretions,  not  larger  than  the  roe  of  a  tish,  the  word  coming  from  the 
Greek  woe,  egy. 

b.  Second.  As  to  HARDNESS  and  FIRMNESS  :  — 
Compact,  or  well  consolidated. 

Friable,  or  crumbling  in  the  fingers. 

Porous,  so  loose  or  open  in  texture  as  to  absorb  moisture  readily. 

Uncomp acted,  or  like  loose  eai'th. 

Flinty,  very  hard,  and  breaking  with  a  smooth  surface  like  flint. 

c.  Third.  As  to  the  ROCK  or  MINERAL  NATURE  of  the  constituents. 
Granytic,  like  granyte,  or  made  of  granite   materials. 

Siliceous,  consisting  mainly  of  quartz. 

Quartzose,  containing  much  quartz.  Quartzytic,  consisting  in  part  of  quartzyte,  as 
quartzytic  gneiss.  Arenaceous,  consisting  of,  or  containing,  quartz  grains  in  a  feebly 
coherent  condition. 

Micaceous,  characterized  eminently  by  the  presence  of  mica. 

Calcareous,  of  the  nature  of  limestone,  or  containing  considerable  carbonate  of  lime, 
as  a  calcareous  rock,  a  calcareous  mica  schist. 


64  LITHOLOGICAL    GEOLOGY. 

Argillaceous,  having  a  clayey  nature  or  constitution,  or  containing  much  clav,  as 
shale  is  argillaceous,  a  sandstone  may  be  argillaceous. 

Ferruginous,  containing  oxyd  of  iron;  sometimes  having  a  red,  brownish-red,  or 
brownish-yellow  color,  in  consequence  of  the  disseminated  oxyd  of  iron;  sometimes  con 
taining  the  ore  in  plates  or  masses  of  a  metallic  lustre. 

Pyritiferous,  containing  pyrite  (p.  59)  disseminated  through  the  mass,  either  in 
cubic  crystals,  or  in  grains  or  masses. 

Basaltic,  made  of  material  derived  from  basalt;  also  like  basalt. 

Pumiceous,  made  of  pumice. 

Garnetiferous,  containing  garnets. 

So,  also,  staurolitic,  containing  staurolite;  anthophyllitic,  containing  acicular  horn 
blende  of  the  variety  anthophyllite. 

Sedimentary  rocks  differ,  further  (c?),  as  to  the  mechanical  condition 
of  the  constituents  :  whether  — 

(a)  Rounded  stones  or  pebbles ;  or  (b)  angular  stones;  or  (c)  sand ;  or  (d)  clay. 

Crystalline  rocks  differ,  further,  — 

e.  As  to  the  number  and  kinds  of  mineral  constituents,  as  explained 
beyond. 

f.  As  to  the  kind  of  crystalline  aggregation  or  structure :  — 

Granular  (plianerocrystalline,  or  distinctly  crystalline),  which  may  be  either  coarse 
granular,  as  in  granite  and  much  architectural  marble,  or  fine  granular,  as  in  some 
statuary  marble. 

Cryptocrystalline,  or  concealed  crystalline,  as  in  flint,  no  particles  being  distinct. 

Granytoid,  having  each  of  the  mineral  constituents  separately  crystallized  and  distinct, 
as  in  granite,  syenyte,  dioryte. 

Other  terms  bearing  on  structure  are  as 
follow :  — 

Porphyritic.  —  Having  the  feldspar  in 
distinct  crystals  through  the  mass  of  the 
rock,  or  speckling  it  with  spots  of  white 
or  a  light  color,  that  are  often  rectangular 
or  nearly  so  (Fig.  58). 

The  term  porphyritic  is  sometimes  applied  also  where  hornblende  or  pyroxene  is  in 
distinct  crystals  in  the  rock-mass,  the  rock  in  this  case  being  described  as  porphyritic 
with  hornblende  or  with  pyroxene. 

The  feldspar  crystals  are  often  double  or  twin  crystals,  as  shown  by  a  line  of  division 
through  the  middle  (see  Fig.  58),  and  by  the  difference  in  lustre  of  the  two  halves. 
Granite,  dioryte,  doleryte,  and  lavas,  as  well  as  porphyry,  are  sometimes  porphyritic, 
and  the  feldspar  crystals  may  be  very  large  or  very  small. 

Homogeneous,  having  the  mineral  ingredients  not  separately  distinguishable,  but 
forming  a  homogeneous  mass,  granular  or  otherwise,  like  argillyte  and  most  trap  or 
doleryte. 

Amygdaloidal  (from  amygdalum,  an  almond).  Having  numerous  spheroidal  or 
almond-shaped  cavities  filled  with  minerals  foreign  to  the  rock,  such  as  quartz,  calcite, 
and  the  zeolites.  Trap  (doleryte)  and  basalt  are  often  amygdaloidal. 

Scoriaceous.  —  Slag-like,  very  open  cellular,  or  inflated,  like  the  scoria  of  a  volcano 
or  slag  of  a  furnace. 

It  should  be  further  observed  that  a  rock  — 

When  Quartz  predominates, is  hard  and  often  gritty.     G.  r=  2.5-2.8 


KINDS    OF    ROCKS.  65 

Feldspar —  hard,  usually  light-colored.  G.  =  2-5-2-8.  Either  cleavably  crystalline  or 
cryptocrystalline. 

Hornblende  and  Pyroxene  —  hard,  usually  dark-green  to  black  ;  heavy.  G.  =  2-8-3-4. 
Often  tough. 

Mica  —  slaty,  glistening  with  mica  scales,  not  very  hard,  not  greasy  to  the  touch. 
G.  =2-5-2-8.  " 

Hydrous  mica — often  slaty,  somewhat  glistening,  a  greenish,  grayish,  or  brownish 
color,  not  very  hard;  a  yreasy  fed.  G.  =2'4-2-7. 

Chlorite  —  often  slaty,  soft,  an  olive-green  color:  a  little  greasy  to  the  touch.  G.  = 
2-7-3-2. 

Serpentine  —  massive;  rather  soft;  dark  or  light  green;  but  little  greasy  to  the  touch. 
G.  =2-4-2-6. 

Carbonate  of  lime  —  moderately  soft,  effervescing  readily  with  acids.  G.  =2.5-2.8. 
Usually  massive ;  white  to  black. 

Carbonate  of  lime  ami  magnesia,  or  Dolomite  —  like  the  preceding;  but  not  effervescing 
readily  unless  the  acid  is  heated. 

In  the  names  of  rocks,  the  termination  ite  is  here  changed  to  yte,  as  done  in  the 
author's  System  of  Mineralogy  (1868),  in  order  to  distinguish  them  from  the  names  of 
minerals. 

1.  Fragmental  Rocks,  exclusive  of  Limestones. 

(1.)  CONGLOMERATE.  —  A  rock  made  up  of  pebbles  or  fragments 
of  rocks  of  any  kind,  (a)  If  the  pebbles  are  rounded,  the  conglom 
erate  is  a  pudding-stone  ;  (b)  if  angular,  a  breccia. 

Conglomerates  are  named,  according  to  their  constituents,  siliceous 
or  quartzose,  granitic,  calcareous,  porphyritic,  ptimiceous,  etc.,  using 
these  terms  as  already  explained.  The  cementing  ingredient  may  be 
calcareous,  siliceous,  ferruginous,  and  occasionally  of  other  kinds. 

(2.)  GRIT,  GRIT-ROCK.  —  A  hard,  gritty  rock,  consisting  of  sand 
and  small  pebbles,  called  also  millstone  grit  and  grindstone  grit,  be 
cause  used  sometimes  for  grindstones.  Also  applied  to  a  hard,  gritty 
sandstone. 

(3.)  SANDSTONE.  —  A  rock  made  from  sand  agglutinated.  There 
are  siliceous,  granitic,  micaceous  sandstones,  according  to  the  char 
acter  of  the  material.  There  are  also  compact,  friable,  argillaceous 
(containing  clay),  ferruginous  (containing  iron),  concretionary,  marly 
(containing  some  carbonate  of  lime),  flexible  and  other  kinds  of  sand 
stone. 

4.  Sand-rock.  —  A  rock  made  of  sand  of  any  kind,  especially  if  riot 
siliceous  or  granitic.  If  the  sand  is  calcareous,  it  is  called  a  calcareous 
sand-rock,  as  beds  of  pulverized  corals  or  shells  ;  if  basaltic,  it  is  a 
basaltic  sand-rock  ;  and  so  on. 

(4.)   SHALE.  —  A  soft,  fragile  rock,  made  from  clay  (hence  an  argil 
laceous  rock,  argilla  being  the  Latin  for  clay),  having  an  uneven  slaty 
structure.     Shales  are  gray  to  black   in  color,  and  sometimes  of  dull 
greenish,  purplish,  reddish,  and  other  shades. 
5 


66  LITHOLOGICAL    GEOLOGY. 

Among  the  varieties  there  are  — 

Bituminous  shale.  —  Impregnated  with  petroleum,  or  with  coaly  material  yielding 
mineral  oil  or  related  bituminous  matters  when  heated,  or  the  odor  of  bitumen  when 
struck.  Called  also  Carbonaceous  shale  (Brandschiefer  in  German). 

Coaly  shale.  —  Containing  coaly  impressions  or  impregnations. 

Alum  shale.  —  Impregnated  with  alum  or  pyrites  —  usually  a  crumbling  rock.  The 
alum  proceeds  from  the  alteration  of  pyrite,  or  the  allied  pyrrhotite  (page  59). 

(5.)  TUFA.  POZZUOLANA.  —  Tufa  is  an  earthy  rock,  not  very 
hard,  made  from  comminuted  volcanic  rocks,  or  volcanic  cinder,  more 
or  less  decomposed,  and  often  forming  beds  of  great  extent.  It  is 
usually  of  a  yellowish-brown,  gray,  or  brown  color. 

The  color  varies  with  the  nature  of  the  material :  basaltic  rocks  or  lavas  produce 
brownish  colors  (the  color  is  owing  to  the  hydrous  oxyd  of  iron  present,  derived  from 
the  pyroxene  or  magnetic  iron  of  the  original  rock,  altered  by  the  action  of  water); 
feldspathic  lavas  produce  light-grayish  colors.  Pumiceous  tufa,  which  belongs  to  the 
latter  division,  consists  mainly  of  pumice  in  grains  and  fragments,  more  or  less  altered. 

Pozzuolana  is  a  light-colored  tufa,  found  in  Italy,  near  Rome  and  elsewhere,  and  used 
for  making  hydraulic  cement. 

WACKE. — An  earthy,  dark-brownish  rock,  resembling  an  earthy  trap  or  doleryte, 
and  usually  made  up  of  trappean  or  dolerytic  material  compacted  into  a  rock  that  is 
rather  soft. 

(6.)  SAND.  GRAVEL. —  Sand  is  comminuted  rock  of  any  kind; 
but  common  sand  is  mainly  comminuted  quartz,  or  quartz  and  feld 
spar,  while  gravel  is  the  same  mixed  with  pebbles  or  stones.  Occa 
sionally,  sand  contains  scales  of  mica,  and  has  a  glistening  lustre.  Vol 
canic  sand,  or  peperino,  is  sand  of  volcanic  origin,  either  the  "  cinders  " 
or  "  ashes  "  (comminuted  lava)  formed  by  the  process  of  ejection,  or 
from  lava  rocks  otherwise  comminuted. 

(7o)  ALLUVIUM.  SILT.  TILL. —  Alluvium  is  the  earthy  deposit 
made  by  running  streams,  especially  during  times  of  flood.  It  consti 
tutes  the  flats  on  either  side  of  the  stream,  and  is  usually  in  thin  layers, 
varying  in  fineness  or  coarseness,  being  the  result  of  successive  depo 
sitions.  Silt  is  the  same  material  deposited  in  bays  or  harbors,  where 
it  forms  the  muddy  bottoms  and  shores.  Till  is  an  earthy  deposit, 
coarse  or  fine,  following  the  courses  of  valleys  or  streams,  like  allu 
vium,  but  without  division  into  thin  layers,  although  in  very  thick 
deposits.  The  till  of  the  Alpine  valleys  is  formed  of  pulverized  rock 
derived  from  glaciers.  Detritus  (from  the  Latin  for  worn)  is  a  general 
term  applied  to  earth,  sand,  alluvium  and  the  like. 

2.  Metamorphic  Rocks,  not  Calcareous. 

Metamorphic  rocks  are  made  from  the  sedimentary  rocks  above 
enumerated,  by  some  crystallizing  process,  and  vary  exceedingly  in  the 
perfection  of  the  crystallization  they  have  undergone.  Granite  stands 


KINDS    OF   ROCKS.  67 

at  one  end  of  the  series,  and  hard  sandstones  called  quartzyte,  hard 
slates  like  roofing-slate,  and  partially  crystallized  limestones,  at  the 
other ;  so  that  a  distinct  line  between  them  and  the  sedimentary  beds 
cannot  always  be  drawn. 

The  common  ingredients  are  quartz,  feldspar  of  different  kinds, 
mica,  hornblende,  pyroxene,  talc,  epidote,  chlorite,  serpentine  ;  to  which 
garnet,  andalusite,  staurolite,  tourmaline,  topaz,  graphite  may  be  added 
as  characterizing  a  number  of  varieties.  The  rocks  are  aggregates  in 
general  of  two  or  more  of  the  above-mentioned  minerals  ;  and,  as  the 
proportions  may  vary  indefinitely,  the  kinds  of  rocks  are  not  well 
defined ;  they  may  imperceptibly  graduate  into  one  another. 

Metamorphic  rocks  may,  for  the  most  part,  be  distributed  into 
three  series  parallel  with  one  another.  These  are  the  mica-bearing 
series,  containing  granite,  gneiss,  mica  schist,  etc. ;  the  hornblendic, 
characterized  by  the  presence  of  hornblende  or  the  allied  pyroxene, 
as  in  syenyte,  hornblendic  gneiss,  etc. ;  and  the  hydrous  magnesian 
series,  containing  talc,  chlorite,  and  serpentine  rocks.  Besides  these, 
there  arc  other  groups,  which,  with  the  foregoing,  are  described  beyond 
in  the  following  order :  — 

1.  Mica-bearing  series. 

2.  Hornblendic  series. 

3.  Felsitic,  epidotic,  and  garnet  rocks,  having  the  mass  or  body  of  the  rock  compact 
(cryptocrystalline). 

4.  Hydrous  magnesian  series. 

5.  Hvdrous    aluminous   series,  or    rocks   consisting   essentially  of   agahnatolite    or 
pyrophyllite. 

6.  Quartz  rocks. 

7.  Iron-ore  rocks. 

1.    The  Mica-bean  ng  Series. 

The  mica-bearing  series  commences  with  granite,  the  most  highly 
crystalline,  and  descends  through  gneiss  and  mica  schist  to  argillyte 
or  roofing  slate,  and  also  to  quartzyte,  which  is  but  little  removed  from 
a  sandstone.  Quartz  is  a  constant  ingredient,  as  well  as  mica.  The 
series  branches  off  into  crystalline  feldspathic  rocks  like  granulyte. 
containing  little  or  no  mica.  The  specific  gravity  is  between  2*4 
and  2-8. 

(1.)  GRANITE. —  A  granular  crystalline  rock,  consisting  of  quartz, 
feldspar,  and  mica,  having  no  appearance  of  layers  in  the  arrangement 
of  the  mica  or  other  ingredients.  The  mica  is  in  scales,  usually  white, 
black,  or  brownish,  easily  separable  into  thinner  elastic  scales  by 
means  of  the  point  of  a  knife  ;  the  quartz  is  usually  grayish  white, 
glassy,  and  without  any  appearance  of  cleavage  ;  the  feldspar  is  com 
monly  whitish  or  flesh-colored,  less  glassy  than  the  quartz,  and 
showing  a  flat,  polished  cleavage  surface  in  one  or  two  directions. 


68  LITHOLOGICAL   GEOLOGY. 

Metamorphic  granite  is  common  in  Connecticut  and  other  parts  of 
New  England,  where  gneiss  may  be  often  seen  graduating  into  granite, 
or  in  alternating  lajers  with  it. 

a.  Common  Granite.  —  A   granite    in  which    the    feldspar    is    chiefly  orthoclase  or 
potash  feldspar,  the  most  common  kind  ;  oligoclase  also  is  often  present.     The  color 
is  grayish  or  flesh-colored,  according  as  the  feldspar  is  white  or  reddish.     The  texture 
varies  from  a  tine  and  even-grained  to  a  coarse  granite,  in  which   the  mica,  feldspar, 
and  quartz — especially  the   two  former — are  in  large  crystalline  masses.     There  are 
often  two  kinds  of  mica  present,  a  light-colored  (muscovite  or  else  margarodite),  and 
a  black  (biotite,  sometimes  lepidomelane).     An  average  granite    (mean  of  11  analyses 
of  Leinster  granite,    by  Haughton),  consists  of  —  Silica  72*07,  alumina  14*81,  protoxyd 
and  sesquioxyd  of  iron  2*52,  lime  1*63,  magnesia  0*33,  potash  5*11,  soda  2*79,  water 
1-09  =  100  -3o'. 

b.  Porphyritic  Granite  has  the  feldspar  distributed  in  distinct  crystals,  which  appear 
as  rectangular  whitish  blotches  on  a  surface  of  fracture.     Hornblemlic  Granite  contains 
black  scales  or  grains  of  hornblende  besides  the  mica. 

c.  Albitic  Granite  contains  albite  in  place  of  part  of  the  orthoclase  ;  and, in  — 

'/.  Oliyoclase  Granite  (a  much  more  common  kind),  oligoclase  replaces  part  of  the 
orthoclase. 

2.  PEGMATYTE,  or  Graphic  Granite.  —  A  very  coarse  granitic    rock,  consisting  of 
common  feldspar  and  quartz,  with  but  lit-  „.  f 

tie  whitish  mica  ;  in  the  graphic  variety, 

the  quartz  is  distributed  through  the  feld-         //~T~~7' /\  P=® 

spar  in  forms  looking  like  Oriental  char-  A  »  /^  1^  ^      '    x\    /\\ 

acters  (Fig.  59).  f>      ^  \  '       /   sJ>    ^\ 

3.  GKAXULYTK.  —A  tine-grained  gran-  K  fe>      /    (      \    ^*    (Li  ^A 
itic    rock,  consisting   mainly  of   granular  W     \      ^^\^^    <f\^J\        ^  \ 
feldspar  with  little  quartz,  and  often  im-  |<  fl     ^jj      iL     .  (^  ^  /  /  /    ^  ^"'/'i 
perfectly  schistose  in  structure,  from  the  ^       /& 

arrangement  of   the    quartz.       It    is    also       j^T*      J^    "    \ 
called    Euryte   and    Leptynijte  ;    and    the       V — /?    V  "*j\  ^ 
flinty  kind,  Petrosilex  or  Felsyte.     (See  beyond,  p.  71.) 

(4.)  GXEISS.  —  Like  granite,  but  with  the  mica  more  or  less  dis 
tinctly  in  layers.  A  gneissoid  granite  is  a  rock  intermediate  between 
granite  and  gneiss.  Gneiss  breaks  most  readily  in  the  direction  of 
the  mica  layers,  and  thus  affords  slabs,  or  is  schistose  in  structure. 

Porphyritic  Gneiss  has  distinct  feldspar  crystals  disseminated  through  it,  like  por- 
phyritic  granite.  Gneiss  may  abound  in  garnets,  or  be  yarnetiferous ;  or  contain  an 
excess  of  mica,  when  it  is  called  micaceous  gneiss;  or  much  epidote,  becoming  an 
epidotic  yneiss.  Gneiss  graduates  into  — 

(o.)  MICA  SCHIST.  —  The  same  constituents  as  granite  and  gneiss, 
but  with  more  quartz,  less  feldspar,  and  much  more  mica— therefore 
glistening  in  lustre  ;  slaty,  or  very  schistose,  in  structure,  breaking 
into  thin  slabs  ;  often  friable,  or  wearing  easily. 

Mica  schist  often  abounds  in  garnets  and  staurolite,  and  sometimes  in 
tourmaline.  It  passes  at  times  into  hornblende  schist. 

The  variety  plumbayinous  schist  contains  plumbago  (p.  59)  in  its  layers.  Calcareous 
mica  schist  contains,  disseminated  through  it,  bods  of  carbonate  of  lime  or  cnlcite. 
Hornblcndic,  anthophyllitic,  and  concretionary  varieties  occur. 


>>r  ^-/i 
&+-44 

^A/Le^ 


KINDS    OF   ROCKS.  69 

(6.)  MICA  SLATE.  —  Of  the  same  constitution  as  mica  schist,  but 
with  a  smoother  surface,  the  mica  being  not  visibly  in  scales,  unless 
magnified.  It  is  intermediate  between  mica  schist  and  clay  slate. 

(7.)  HYDROMICA  SLATE.  —  Like  the  last  in  general  characters,  but 
containing  a  hydrous  mica,  and,  therefore,  feeling  more  or  less  greasy^ 
and  looking  pearly.  On  account  of  this  peculiarity,  it  was  formerly 
considered  a  talcose  or  magnesian  slate,  and  has  been  called  also  talcoid 
slate.  A  chloride  variety  is  common.  Sericite  slate  and  Paragonite 
slate  or  schist  are  related  rocks. 

(8.)  CLAY  SLATE  or  AKGILLYTE.  —  A  line-grained  slaty  rock  of 
various  colors,  grayish  to  black,  and  sometimes  greenish,  reddish, 
purplish.  The  evenly  splitting  kinds  are  roofing  slate  and  writing 
slate.  It  consists  usually  of  pulverized  quartz  and  feldspar,  with 
sometimes  a  little  chlorite.  Another  kind  of  the  same  color  contains 
much  chlorite.  Another,  undistinguishable  by  the  eye,  contains  no 
alkalies,  and  hence  no  feldspar.  The  common  imbedded  minerals  are 
andalusite,  staurolite,  garnet,  phyllite  (chloritoid). 

2.  HornUendic  Series. 

The  hornblendic  series  commences  in  a  granite -like  species,  called 
syenyte,  containing  quartz  and  one  or  more  fe Idspars,  along  with  horn 
blende  in  place  of  mica.  Hornblende  is  not  so  cleavable  into  leaves 
as  mica,  and  is  brittle  instead  of  elastic.  It  is  also  tough  and  heavy ; 
and  hence  hornblende  rocks  are  generally  tough  and  heavy,  the 
specific  gravity  between  2*7  and  3-5.  From  syenyte  the  series  runs 
dowrn  through  syenytic  gneiss  to  hornblendic  schist  and  hornblende 
rock;  then  to  rocks  of  very  even  texture  and  compactness,  called 
diabasyte  and  aphanyte,  the  last  like  hornstone  in  fracture  and  sur 
face.  Often  pyroxene  replaces  hornblende  ;  and  occasionally  epidote. 

The  species  of  rock  depends  largely  on  the  kind  of  feldspar  pres 
ent  :  syenyte  arid  hyposyenyte  contain  chiefly  orthoclase  ;  true  dioryte 
contains  oligoclasc  or  albite ;  hypersthenyte  and  diabasyte  contain 
labradorite,  passing  into  andesite  and  anorthite,  and  are  included  by 
Hunt  under  the  general  name  anorthosyte. 

The  hornblendic  series  blends  laterally  with  the  magnesian  series,  especially  through 
the  chloride  rocks  of  the  latter,  chlorite  being  near  hornblende  and  pyroxene  in  com 
position,  though  containing  water.  It  also  blends  with  the  mica  series,  through 
granites  and  schists  that  contain  both  hornblende  and  mica.  Through  the  pyroxenic 
varieties,  it  also  passes  into  the  igneous  series. 

(1.)  SYENYTE.  —  Resembles  granite,  but  contains,  in  place  of  mica, 
the  mineral  hornblende,  which  is  in  cleavable  grains  and  either  black 

^ 

or  greenish  black  in  color.     The  feldspar  may  be  orthoclase  or  oligo- 
clase,    and  sometimes    the  quartz    is    nearly  wanting.      Named  from 


70  LITHOLOGICAL    GEOLOGY. 

Syene,  in  Egypt,  where  the  rock  occurs.     When  like  gneiss  in  struc 
ture,  it  is  called  (1  b)  SYENYTIC  GNEISS. 

(2.)   HYPOSYENYTE.  —  Like   syenyte,  but   containing  little    or    no 
quartz.      (2  b)   ZIRCON-SYENYTE  is  a  similar  rock  containing  zircon. 

Some  writers  on  rocks  restrict  the  name  Syenyte  to  the  rock  without  quartz,  here 
named  hyposyenyte,  and  call  the  other  a  variety  of  granyte.  But  this  is  contrary  to 
original  use;  moreover,  it  separates  syenyte  from  the  hornblendic  series,  where  it  be 
longs,  and  with  whose  species  it  is  usually  associated,  especially  in  Archaean  regions. 

(3.)  DIOKYTE. —•Granular-crystalline,  of  a  grayish-green  to  dark-green  color;  con 
sists  of  hornblende  and  oligoclase  or  albite  (a  triclinic  feldspar);  very  tough.  Sp.  gr. 
2'7-3'0.  Graduates  into  a  compact  cryptocrystalline  rock,  of  a  grayish  or  greenish 
color.  A  slaty  kind  (3  b)  is  called  Dioritic  slate.  It  graduates  sometimes  toward  dia 
base  and  chloritic  slate.  A  kind  (3  c)  containing  the  feldspar  in  isolated  crystals  is 
Porphyrltic  Dioryte.  A  kind  (3  d)  containing  anorthite  has  been  called  Anorthite- 
dioryte ;  but  it  is  more  properly  an  Artorthite-diabasyte. 

(4.)  HYPEISSTHENYTE.  — Granyte-like  in  texture,  and  of  rather  dark  color,  consist 
ing  of  cleavable  Inbradorite  (p.  54),  usually  dark  and  dull  in  color,  either  grayish, 
reddish,  or  brownish,  with  often  bright-colored  internal  reflections)  ;md  Jiypersthene  (a 
lamellar  cleavable  variety  of  pyroxene.  Common  in  northern  New  York  and  Canada. 
Noryte  of  Scheerer  (not  of  Esmark)  is  a  similar  rock. 

(5.)  DIABASYTE.  —  Fine  crystalline-granular,  of  grayish-green  to  dark-green  colors. 
Sp.  gr.  2'7-2*95.  Consists  of  labradorite,  with  sometimes  oligoclase  or  anorthite,  and 
pyroxene  (or  hornblende?)  and  also  some  chlorite  There  is  also  (5  b)  a  Porphyritic 
Di<(b«syte.  It  graduates  on  one  side  into  dioryte,  and  on  the  other  into  chlorite  slate. 
It  passes  also  into  a  compact  kind  (5  c)  almost  flintv  in  fracture,  which  is  called 
Aphanyte,  sometimes  called  hor-n-rock ;  or  into  (5  d)  an  Aphanytic  Slate. 

(6.)  HORNBLENDE  SCHIST. — A  schistose  rock  consisting  mainly  of  greenish-black 
hornblende  with  some  feldspar;  another  variety,  of  hornblende  and  quartz;  another  is 
nearly  pure  hornblende;  another  is  epidotic. 

(7.)  HOHNBLENDYTE. — A  very  tough,  granular,  crystalline  rock,  consisting  of  horn 
blende,  and  hardly  schistose  in  structure.  Color,  greenish-black  to  black. 

(8.)  ACTINOLYTE.  — A  tough  rock  made  of  actinolite.     Color,  grayish  green. 

(9.)  PYKOXEXYTE  (Auyite  Rock).  —  Coarse  or  fine  granular  pyroxene  rock,  con 
sisting  of  granular  pyroxene  of  a  green,  grayish  green,  to  brown  color,  often  streaked 
or  clouded  with  darker  or  lighter  shades  of  color. 

(10.)  LTIERZOLYTE. —  Consists  mainly  of  pyroxene,  enstatite  or  hypersthene,  and 
chrysolite.  (From  L.  Lherz.) 

(11.)  OSSIPYTE. — Coarse  crystalline-granular,  like  a  syenyte,  but  consisting  of  lab 
radorite  and  chrysolite  with  some  kind  of  hornblende,  and  titaniferous  magnetite. 

(12.)  UXAKYTE.  —  A  coarse  syenyte,  in  which  green  epidote  replaces  hornblende. 
(Unaka  Mountains,  North  Carolina  and  East  Tennessee.) 

3.  Fehitic,  Epidotic,  and  Garnet  Rocks  having  the  mass  or  base  com 
pact  (cryptocrystalline\) 

These  felsitic  rocks  may  be  simply  feldspathic,  or  the  base  ma}*  be  partly  horn 
blendic  or  quartzose.  When  they  contain  hornblende,  garnet  or  epidote,  it  is  apparent 
in  the  higher  specific  gravity.  (1.)  Some  of  the  light-colored  rocks  included  are  trans 
lucent  and  very  tough,  and  contain  grass-green  diallage  (called  also  smaragdite)  in 
laminae;  these  are  called  eiiplwtides:  they  consist  of  feldspar,  hornblende,  epidote,  or 
garnet.  (2.)  Others  are  opaque  and  often  dark -colored,  and  usually  contain  crystals  of 
feldspar  disseminated  through  the  mass:  these  are  porphyries.  (3.)  The  rocks  con 
stituting  the  base  of  the  euphotides  without  the  diallage  are  called  fdsytes  or  petro- 
silex. 


KINDS    OF   ROCKS.  71 

a.  Felsytes. 

(1.)  ORTHOCLASE-FELSYTE.  —Color,  whitish,  greenish;  lustre  somewhat  waxy,  dull; 
specific  gravity,  2 '6-2 -7.  A  greenish-gray  specimen  from  Brittany  consists  of  ortho- 
clase  and  some  quartz. 

(2.)  ALBITE-FELSYTE.  —  Similar  to  the  preceding.  A  variety  from  Orford,  Canada, 
afforded  T.  S.  Hunt  (Logan's  Report  for  1853-56)— Silica  78-55,  alumina  11-81,  soda 
4-42,  potash  1-93,  lime  0-84,  magnesia  0*77,  protoxyd  of  iron  0'72,  loss  by  ignition 
0-90  =  99-94. 

(3.)  DIORYTE-FELSYTE.  —  Compact  diorite,  and  consisting,  therefore,  of  albite  or 
oligoclase  and  hornblende.  Color,  grayish  white,  greenish  white.  Occurs  in  Orford, 
Canada  (T.  S.  Hunt,  Logan's  Report,  1853-56). 

(4.)  GARNET-FELSYTE. — A  pure,  compact,  garnet  rock  of  a  whitish  color,  with 
spots  of  disseminated  serpentine.  Specific  gravity,  3-3-3-5.  Exceedingly  hard  and 
tough.  Graduates  into  garnet-euphotide.  Occurs  at  Orford  and  St.  Francois,  Canada 
(Hunt). 

b.  Porphyroid  Rocks. 

1.  COMMON  FELDSPAR-PORPHYRY,  or  ORTHOPIIYRE.  —  Consists  of  a  base  of  ortho- 
clase-felsyte,  red,  brown,  or  whitish  in  color,  and  much  like  jasper  in  lustre  and  fracture, 
with  disseminated  crystals  of  orthoclase. 

2.  ELVANYTE,   or  QUARTZ-PORPHYRY. — Gray,    bluish-gray  to  brown  and  red,  in 
color  of  base.    This  base  a  felsyte, consisting  of  a  feldspar  with,  usually,  quartz,  and  con 
taining  disseminated  grains  or  crystals  of  quartz  and  feldspar.     The  feldspar  is  some 
times  oligoclase.     The  crystals  of  feldspar  are   sometimes  wanting.     Some  compact 
slate-rock  has  the  same  composition. 

3.  PORPHYRITIC   DIABASYTE. — The  antique  green  porphyry  of  Greece  (southern 
Morea)  is  here  included.     Specific  gravity,  2-91-2-932.     Color,  dark  green;    dissemi 
nated  feldspar  crystals,  large,  greenish  white.     Composition  of  the  base:  silica  53-55, 
alumina  19*43,  protoxyd  of  iron  7'55,  protoxyd  of  manganese  0-85,  lime  8*02,  mag 
nesia  and  alkali,  7-93,  water,  2*67.     The  iron  and  magnesia  indicate  the  presence  of 
hornblende  or  pyroxene. 

Porcelanyte,  or  Porcelain-Jasper.  —  A  baked  clay,  having  the  fracture  of  flint  and  a 
gray  to  red  color:  it  is  somewhat  fusible  before  the  blowpipe,  and  thus  differs  from 
jasper.  Formed  by  the  baking  of  clay-beds  when  they  consist  largely  of  feldspar. 
Such  clay-beds  are  sometimes  baked  to  a  distance  of  thirty  or  forty  rods  from  a  trap 
dike. 

Other  porphyries  are  the  porphyritic  varieties  of  granyte,  gneiss,  dioryte,  doleryte, 
basalt,  trachyte  ;  they  are  sometimes  badly  named  granyte-porphyry,  dioryte-por- 
phyry,  etc. ;  they  are  simply  varieties  of  other  species,  characterized  by  having  the  feld 
spar  in  distinct  crystals,  a  distinction  of  small  geological  importance. 

c.  Euphotides. 

(1.)  FELDSPAR-EUFHOTIDE.  —Tough,  compact,  light  green  or  grayish,  consisting  of 
a  minutely-granular  feldspathic  base  with  disseminated  diallage  or  smaragdite. 

(2. )  EPIDOTE-EUPHOTIDE.  —  Similar  to  the  preceding,  but  more  tough,  and  heavy. 
Specific  gravity,  3-1-3-4.  The  base  a  compact  whitish  epidote  (called  hitherto  saus- 
surite),  according  to  T.  S.  Hunt.  From  the  Alps-  Gabbro,  in  part. 

(3)  ECLOGYTE,  or  GARNET-EUPHOTIDE.  — Either  whitish^  greenish,  or  reddish;  very 
tough  and  heavy.  Specific  gravity,  3-2-3-5.  The  eclogyte  of  Europe  contains  grass- 
green  smaragdite  in  a  reddish  garnet  base.  A  related  rock  from  Canada,  according  to 
T.  S.  Hunt  (Logan's  Report  for  1853-56,  p.  450),  contains  grayish  cleavable  hornblende 
or  pyroxelie,  in  a  whitish  or  yellowish  base. 

4.    Chrysolite  (or  Olivine)  Rocks. 
Dunyte  consists  of  granular  chrysolite, and  occurs  with  serpentine  in  Mt.  Dun,  Xe\v 


C±  LITHOLOGICAL    GEOLOGY. 

Zealand,  and  in  North  Carolina.  Lherzolyte  (p.  70)  is  chrysolite  and  pyroxene. 
Picryte,  from  Moravia,  is  half  chrysolite,  the  rest  feldspar,  diallage,  hornblende,  and 
magnetite.  Ossipyte  (p.  70)  is  chrysolite  and  labradorite.  (Peridotyte  is  a  chrysolitic 
rock  of  igneous  origin.)  Chrysolite  rocks  are  sometimes  partly  altered  to  serpentine. 

5.  Hydrous  Magnesian  Series. 

The  hydrous  magnesian  series,  characterized  by  the  presence  of  the 
hydrous  magnesian  minerals  talc,  serpentine,  or  chlorite  (p.  55),  ranges 
from  a  granite -like  rock  called  protogine  (containing  the  constituents 
of  granite,  excepting  talc  or  chlorite  in  place  of  mica)  down  to  the 
semicrystalline  talcose  and  chlorite  slates  ;  and  also  to  compact  flinty 
rocks  near  aphanite.  Besides  these,  there  are  the  serpentine  rocks. 
Talc  and  serpentine  are  silicates  of  magnesia  and  water  alone,  while 
chlorite  contains  also  alumina  and  oxyd  of  iron.  The  chloritic  rocks, 
consequently,  often  abound  in  hornblende,  and  are  frequently  asso 
ciated  with  rocks  of  the  hornblendic  series.  The  color  of  the  rocks 
is  some  shade  of  dull  grayish,  brownish,  olive,  or  blackish  green. 
Specific  gravity,  2*4  to  3  ;  or  over  3,  if  containing  hornblende. 

(1.)  PROTOGINE.  —  A  granular  crystalline  or  granite-like  rock, 
usually  gneissoid  in  structure  and  really  a  kind  of  gneiss,  consisting  of 
quartz,  feldspar,  and  chlorite  (or  talc  ? ),  with  sometimes  a  little  mica 
(micaceous  protogine).  The  feldspar  may  be  orthoclase  or  oligoclase, 
or  both  (both  in  the  Alps),  and  is  sometimes  in  distinct  crystals. 
Color,  grayish  white  or  greenish  white.  A  protogine  occurs  at  Lit 
tleton,  N.  H.,  in  Devonian  beds,  which  contains  a  serpentine-like 
mineral  in  disseminated  grains. 

(3.)  TALCOSE  SLATE. — A  slaty  rock,  soapy  to  the  touch,  consist 
ing  largely  of  talc  or  soapstone.  Not  common,  except  in  local  beds. 
The  most  of  the  rocks  that  have  been  called  talcose  slates  are  hydro- 
mica  slates  (p.  54). 

(4.)  STEATYTE,  or  SOAPSTONE  (p.  55). — A  massive,  more  or  less 
schistose  rock,  fine-granular ;  color,  gray  to  grayish-green  and  white  ; 
feel,  very  soapy  ;  composition,  that  of  talc. 

Rensselaeryte  is  soapstone  of  compact  texture,  and  either  gray,  whitish,  greenish, 
brownish,  or  even  black,  color.  Occurs  in  the  towns  of  Fowler,  De  Kalb,  Gouverneur, 
and  others,  St.  Lawrence  Co.,  N.  Y.,  and  also  in  Grenville,  Canada. 

(5.)  Chlorite  Slate.  —  Slaty,  of  a  dark  green  to  greenish-black  and 
grayish-green  color ;  but  little  if  any  greasy  to  the  touch,  and  little 
shining.  Consists  of  chlorite,  quartz,  and  often  more  or  less  feldspar. 
Sometimes  contains  chlorite  in  scales,  or  in  concretions  ;  frequently  it 
is  micaceous  ;  there  often  occur  in  it  hornblende,  magnetite  ;  some 
times  tourmaline,  garnet,  pyroxene. 

(6.)  Chloritic  Argillyte,  Chlorargillyte. — Argillyte  like  that  described  on  p.  69.  but 
consisting  in  part  of  chlorite,  and  showing  it  in  its  proportion  of  iron  and  water,  and 
in  its  specific  gravity,  while  not  in  color  or  texture.  Here  belongs  some  roofing-slate. 


KINDS    OF   ROCKS.  73 

(7.)  SERPENTINE  (p.  55).  — A  massive  uncleavable  rock,  of  dark- 
green  to  greenish-black  color,  easily  scratched  with  a  knife,  and  often 
a  little  greasy  to  the  feel  when  a  surface  is  smoothed.  Although 
generally  of  a  dark-green  color,  it  is  sometimes  pale  grayish  and 
yellowish  green,  and  mottled. 

(8.)  OPHIOLYTE  (or  Verd-antique  marble).  —  A  variegated  mixture 
of  serpentine  and  either  carbonate  of  lime  (calcareous  ophiolyte),  do 
lomite  (dolomitic  ophiolyte),  or  carbonate  of  magnesia  or  magnesite 
(magnesitic  ophiolyte).  Color,  dark  green,  mottled  with  lighter  green 
or  white. 

It  often  contains  chromic  iron  sparsely  disseminated  through  it,  forming  irregular, 
black,  submetallic  spots;  also  some  talc,  asbestus,  sahlite;  and  analysis  often  detects 
nickel  as  well  as  chrome.  T.  S.  Hunt  has  found  both  nickel  and  chrome  in  the  ser 
pentines  or  ophiolytes  of  the  Green  Mountain  range,  in  those  of  Roxbury,  Vt.,  New 
Haven,  Ct,  Hoboken,  N.  J.,  Cornwall,  England,  Banffshire,  Scotland,  Vosges,  France. 
They  occur  also  in  the  pyrosclerite  and  williamsite  of  Chester  (Jo.,  Pa.,  and  in  the 
antigorite  of  Piedmont.  Hunt  found  no  nickel  in  serpentine  from  Easton,  Pa.,  Mont- 
ville,  N.  J.,  Philipstown,  N.  Y.,  Modum,  Norway,  Newburyport,  Mass.,  and  none  from 
the  Archtean  series  of  rocks. 

(9.)  SCHILLEKYTE,  or  Schiller  rock,  Diallage  rock. — A  dark-green  to  greenish- 
black  rock,  made  up  of  Schiller  spar.  It  is  often  associated  with  serpentine,  chlorite, 
and  talc-schist. 

6.  Hydrous  Aluminous  rocks. 

These  rocks  consist  largely  of  agalmatolite  or  pyrophyllite,  and  have  a  close  re 
semblance  to  talcose  and  serpentine  rocks  in  feel,  hardness,  and  appearance. 

PAROPHYTE. — Essentially  agalmatolite  (p.  58)  in  composition.  Its  fine-grained  tex 
ture  and  somewhat  soapy  feel  are  its  striking  peculiarities.  It  occurs  both  as  a  slate 
and  as  a  rock,  and  the  slate  closely  resembles  talcose  slate.  The  dysyntribyte  of  Shep- 
ard,  found  in  northern  New  York,  is  a  rock  variety. 

PYKOPHYLLYTK  and  PYROPHYLLYTE  SLATE.  —  Like  the  preceding  in  appearance 
and  soapy  feel,  but  having  the  composition  of  pyrophyllite  (p.  58).  The  color  is  white 
and  gray,  or  greenish  white.  Occurs  in  North  Carolina;  one  of  the  varieties  from  the 
Deep  River  region  is  used  for  slate  pencils. 

7.    Quartzose  rocks. 

(1.)  QUARTZYTE,  or  Granular  Quartz  Rock.  —  A  hard,  compact 
rock,  consisting  of  quartz  grains  or  sand,  and  usually  either  white, 
gray,  or  grayish-red  in  color.  Sometimes  contains  disseminated  feld 
spar  or  mica,  and  is  often  laminated  or  schistose.  It  is  but  a  step 
removed  from  ordinary  sandstone,  and  owes  its  peculiarities  to  meta- 
morphic  agencies.  It  sometimes  graduates  into  gneiss. 

(2.)  SILICEOUS  SLATE.  —  A  schistose,  flinty,  quartz  rock,  not  distinctly  granular  in 
texture.  Sometimes  passes  into  mica  slate  or  schist 

(3.)  CHERT. — An  impure  flint  or  hornstone  rock,  occurring  imbedded  in  some 
stratified  rocks;  also  flinty  siliceous  rock,  forming  layers  in  siliceous  schist  or  slates.  It 
often  resembles  felsyte,  but  is  mainly  quartz,  and  is  therefore  infusible.  Colors 
various.  Sometimes  oolitic.  Kinds  containing  iron  ore  graduate  into  jasper  and  clay- 
ironstone. 

(4.)  ITACOLUMYTE. — A  schistose  quartz  rock,  consisting  of  quartz  grains  with 
hydrous  mica.  On  account  of  the  mica  in  the  lamination,  the  finer  kind  is  sometimes 
flexible,  and  is  called  flexible  sandstone. 


74  LITHOLOGICAL    GEOLOGY. 

(5.)  JASPER  ROCK.  — A  flinty  siliceous  rock,  of  dull  red,  yellow,  or  green  color,  or 
some  other  dark  shade,  breaking  with  a  smooth  surface  like  flint.  It  consists  of  quartz, 
with  more  or  less  clay  and  oxyd  of  iron.  The  red  contains  the  oxyd  of  iron  in  an  an 
hydrous  state,  the  yellow  in  a  hydrous;  on  burning  the  latter,  it  turns  red. 

(6.)  BCHRSTONE.  —  A  cellular  siliceous  rock,  flinty  in  texture.  It  is  used  for  mill 
stones.  Found  mostly  in  connection  with  Tertiary  rocks,  and  formed  apparentlv  from 
the  action  of  siliceous  solutions  on  preexisting  fossiliferous  beds. 

8.  Iron-  Ore  rocks. 

SPECULAR  IKON-ORE  (Hematite}  and  MAGNETIC  IRON-ORE  occur 
as  rocks  of  considerable  thickness  among  the  metarnorphic  rocks, 
especially  the  hornblendic  and  chloritic  kinds.  There  are  schistose  or 
laminated  as  well  as  massive  varieties.  These  iron-ore  beds  occur 
extensively  in  northern  New  York,  Canada,  Michigan,  and  Missouri ; 
in  New  Jersey  and  North  Carolina :  also  in  Sweden  arid  elsewhere. 
Their  alternation,  in  these  regions,  with  chloritic  and  other  schists 
and  gneissoid  rocks  shows  that  they  are  metamorphic  as  well  as  the 
schists.  Devonian  strata  full  of  fossils,  in  Nova  Scotia,  at  Moose 
River,  contain  a  bed  of  magnetic  iron  ore  ;  and  at  Nictaux,  a  bed  six 
feet  thick  of  hematite.  (Dawson.)  Titanic  iron-ore  occurs  in  great 
beds  of  like  extent  in  Canada,  and  is  mixed  with  the  magnetite  of 
northern  New  York  and  western  North  Carolina.  (Sea  p.  154.) 

Franklinite,  an  iron-zinc  ore,  is  also  one  of  the  metamorphic  rocks  in  northern  New 
Jersey. 

3.  Calcareous  Rocks.  —  Carbonates  and  Sulphates. 

(1.)  MASSIVE  LIMESTONE.  —  Uncrystalline  Limestone.  —  Most  lime 
stones  have  been  formed  from  shells  and  corals  ground  up  by  the  action 
of  the  sea  and  afterward  consolidated.  The  colors  are  dull  gray, 
bluish,  brownish,  to  black.  The  composition  is  usually  the  same  as 
that  of  calcite,  carbonate  of  lime  (p.  55),  except  that  impurities,  as 
clay  or  sand,  are  often  present.  In  texture,  they  vary  from  an  earthy- 
looking  limestone  to  a  very  compact  semi-crystalline  one  ;  and  from 
this  kind  the  passage  is  gradual  also  to  the  true  crystalline. 

(2.)  MAGNESIAN  LIMESTONE  or  DOLOMYTE  (page  55).  —  Consists 
of  carbonate  of  lime  and  magnesia,  but  is  not  distinguishable  in  color 
or  texture  from  ordinary  limestone.  The  amount  of  carbonate  of 
magnesia  present  varies  from  a  few  per  cent,  to  that  in  dolomite. 
Much  of  the  common  limestone  of  the  United  States  is  magnesian. 
That  of  St.  Croix,  Wisconsin,  the  "Lower  Magnesian,"  afforded 
Owen  42-43  per  cent,  of  carbonate  of  magnesia,  48-24  carbonate  of 
lime,  with  8-84  of  sand,  oxyd  of  iron  and  alumina,  and  0*40  moisture. 

In  some  limestones  the  fossils  are  magnesian,  while  the  rock  is  common  limestone. 
Thus,  an  Orthoceras  in  the  Trenton  limestone  of  Bytown,  Canada  (which  is  not  mag 
nesian),  afforded  T.  S.  Hunt — Carbonate  of  lime  56 '00,  carbonate  of  magnesia  37-80, 


KINDS    OF   ROCKS.  75 

carbonate  of  iron  5*95  =  99*75.  The  pale-yellow  veins  in  the  Italian  black  marble, 
called  "Egyptian  marble,"  are  dolomite,  according  to  T.  S.  Hunt ;  and  a  limestone  at 
Dudswell,  Canada,  is  similar. 

(3.)  HYDRAULIC  LIMESTONE.  —  An  impure  or  earthy  limestone 
containing  some  clay,  and  affording  a  quicklime  the  cement  made  of 
which  will  set  under  water.  An  analysis  of  a  kind  worked  at 
Rondout,  N.  Y.,  afforded  Beck  —  Carbonic  acid  34-20,  lime  25-50, 
magnesia  12-35,  silica  15*37,  alumina  9*13,  sesquioxyd  of  iron  2*25. 

(4.)  OOLYTE,  OR  OOLYTIC  LIMESTONE. —  A  rock  consisting  of 
minute  concretionary  spherules,  and  looking  like  the  petrified  roe 
of  fish  :  the  name  is  from  the  Greek  o>o^,  egg.  It  is  sometimes  mag- 
nesian. 

(5.)  CHALK.  — A  white,  earthy  limestone,  easily  leaving  a  trace  on 
a  board.  Composition,  the  same  as  that  of  ordinary  limestone. 

(G.)  MARL.  —  A  clay  containing  a  large  proportion  of  carbonate 
of  lime,  —  sometimes  40  to  50  per  cent.  If  the  marl  consists  largely 
of  shells  or  fragments  of  shells,  it  is  called  shell-marl 

(7.)  SHELL  LIMESTONE.  CORAL  LIMESTONE.  —  A  rock  made  out 
of  shells  or  corals. 

(8.)  BIRDSEYE  LIMESTONE.  —  A  compact  limestone  having  crys 
talline  points  disseminated  through  it. 

(9.)  TRAVERTINE.  — A  massive  but  porous  limestone,  formed  by  deposition  from 
springs  or  streams  holding  carbonate  of  lime  in  solution  in  the  state  of  bicarbonate. 
The  rock  abounds  on  the  river  Anio,  near  Tivoli,  and  it  is  there  used  as  a  building 
material.  St.  Peter's,  at  Rome,  is  constructed  of  it.  The  name  is  a  corruption  of  7V- 
burtine. 

(10.)  STALAGMITE,  STALACTITK. — Depositions  from  waters  trickling  through  the 
roofs  of  limestone  caverns  form  calcareous  cones  and  cylinders  pendent  from  the  roofs, 
which  are  called  staktctiten,  and  incrustations  on  the  floors,  which  are  called  stalagmite. 
The  waters,  filtering  down  from  the  overlying  soil,  contain  a  little  carbonic  acid,  and 
are  thus  enabled  to  dissolve  the  limestone,  which  is  deposited  again  on  evaporation. 
The  layers  of  successive  deposition  are  usually  distinct,  giving  the  material  a  banded 
appearance. 

2.    Crystalline  Limestone. 

GRANULAR  LIMESTONE  (p.  55)  (Statuary  Marble).  —  Limestone 
having  a  crystalline  granular  texture,  white  to  gray  color,  often 
clouded  with  other  colors  from  impurities.  The  impurities  are  often 
•mica  or  talc,  tremolite,  white  or  gray  pyroxene,  or  scapolite  ;  sometimes 
serpentine  (through  combination  with  which  it  passes  into  ophiolyte, 
p.  73).  occasionally  chondrodite,  apatite,  corundum. 

DOLOMYTE.  —  Not  distinguishable  by  the  eye  from  granular  lime 
stone  (p.  55). 

3.  Consisting  of  Sulphate  of  Lime. 

GYPSUM.  —  Sulphate  of  lime,  as  described  on  p.  56.  The  earthy 
kinds  often  contain  the  crystallized  mineral  in  spots  or  fissures  ;  and 


76  LITHOLOGICAL   GEOLOGY. 

in  many  places  it  is  associated  with  anhydrite,  or  sulphate  of  lime 
containing  no  water  (p.  56).  The  borate  of  magnesia  (boracite)  and 
polyhalite  are  often  found  in  gypsum-beds ;  also,  rarely,  hydrous 
borate  of  lime  (hayesine),  as  in  Nova  Scotia. 

4.  Igneous  or  Eruptive  Rocks. 

Igneous  rocks  are  those  which  have  been  ejected  in  a  melted  state 
either  from  volcanoes  or  through  fissures  in  the  earth's  crust.  Their 
most  general  characteristics  are:  (1)  the  presence  of  a  feldspar  as  one 
of  their  constituents  ;  (2)  the  near,  when  not  total,  absence  of  free 
quartz  ;  (3)  their  frequent  occurrence  in  fissures  (pp.  714,  716),  as  well 
a,s  in  overlying  masses,  or  intercalated  between  layers  of  stratified 
rocks.  Igneous  rocks  are  riot  always  easily  distinguished  from  meta- 
morphic  rocks,  and  a  few  kinds  of  the  two  divisions  are  identical. 

In  the  metamorphic  process,  a  stratified  rock  has  sometimes  been  reduced  to  a  pasty 
state,  and  in  this  condition  has  been  forced  into  fissures,  and  so  has  taken  the  position, 
arid,  as  it  cooled,  the  crystalline  texture  and  aspect,  of  an  igneous  rock.  Some  granite 
is  an  example.  Again,  true  igneous  rocks  have  at  times  resulted  from  the  fusion  (or  an 
equivalent  softening)  of  preexisting  crystalline  rocks  (granite,  syenyte,  and  the  like), 
and  so  have  derived  a  constitution  more  or  less  resembling  that  of  the  rock  out  of  which 
they  were  made.  Thus  igneous  rocks,  although  generally  containing  little  or  no  quartz, 
may  in  some  cases  abound  in  grains  of  this  mineral 

There  are  two  series  of  igneous  rocks  — 

1 .  A  feldspathic  series,  the  species  containing  little  or  no  hornblende 
or   pyroxene,  and  hence   but  little  iron,  and  of  low  specific  gravity 
(2-4-2-7). 

2.  A  hornUende-and-pyroxene  series,  the  species  containing  as  prom 
inent    ingredients   iron-bearing  varieties   of  hornblende  or  pyroxene, 
with  often  magnetite  (or  titaniferous  iron),  and   hence  of  high  specih'c 
gravity  (2-7-3-5).     In  nature,  the  series,  however,  graduate  into  one 
another. 

1.  Feldspathic  Series. 

(1.)  GRANITE. —  (For  description  of  granite  seep.  67.)  Whenever  a  granite  presents 
in  some  parts  a  gneiss-like  structure,  or  alternates  in  layers,  however  thick,  with  gneiss 
or  a  related  metamorphic  rock,  it  is  metamorphic  granite.  It  may  also  be  a  metamor 
phic  rock  when  no  such  characters  exist  to  distinguish  it.  The  granite  of  granite-veins 
is  in  general  a  result  of  infiltration  (called,  at  times,  segregation),  and  is  not  of  true 
igneous  origin.  (See  p.  721.) 

(2.)  GRANULYTE  (p.  68).  —  Consists  of  orthoclase  in  crystalline  grains,  with  often 
small  disseminated  crystals  of  mica,  or  hornblende.  Color  whitish,  grayish,  or  pale 
yellowish.  G.  =2'5-2'64.  Often  graduates  into  porphyritic  trachyte. 

A  similar  rock,  but  not  properly  granulyte — called  sometimes  white  trap  —  consists 
of  albite  or  oUyoclase  instead  of  orthoclase.  (See  Hunt,  in  Geol.  Can..  1863,  p.  657.) 
The  feldspar  may  also  be  labradorite,  a  kind  into  which  doleryte  sometimes  graduates. 

(3.)  PORPHYRY.  —  See  page  71,  much  of  the  so  called  porphyry  being  a  metamorphic 
rock.  Another  part  includes  porphyritic  varieties  of  trachyte,  phonolyte,  doleryte,  etc. 
Still  another  part  is  a  volcanic  conglomerate,  in  which  both  the  pebbles  and  the  base 


KINDS    OF    ROCKS.  li 

are  spotted  with  feldspar  crystals,  and  the  mass  looks  homogeneous  until  closely  ex 
amined.  There  is,  besides,  a  true  feldspar-porphyry,  of  igneous  origin,  differing  little 
in  composition  from  much  trachyte,  but  having  a  very  compact  texture  and  smooth 
surface  of  fracture. 

(4.)  PHONOLYTE  (Clinkstone).  —  Compact,  of  grayish  blue  and  other  shades  of  color, 
more  or  less  schistose  or  slaty  in  structure ;  tough,  and  usually  clinking  under  the  ham 
mer  like  metal  when  struck,  whence  the  name.  !Sp.  gr.  2-4-2'6.  Consists  of  glassy 
feldspar  (orthoclase  or  oligoclase),  with  nephelite  and  hornblende;  G.  Jenzsch gives, 
for  the  composition  of  the  Bohemian  phonolyte,  —  Sanidin  (glassy  orthoclase)  53 '55, 
nephelite  3176,  hornblende  9'34,  sphene  3'67,  pyrite  0'04.  Under  treatment  with  acids, 
the  nephelite  is  dissolved  out.  Zeolites,  according  to  the  later  examinations,  are  not  an 
original  constituent  of  the  rock. 

(5.)  TRACHYTE.  — Color,  pale  grayish  blue,  rarely  greenish,  whitish,  yellowish,  red 
dish;  texture  peculiarly  rough  to  the  fee!,  and  usually  porous,  owing  to  the  angular 
form  of  the  particles.  Often  contains  disseminated  crystals  of  glassy  feldspar  (sanidin) 
and  hornblende,  also  mica  and  magnetite.  G.  =:  2 '5-2 7.  Silica  usually  60  to  65  per 
cent.  Decomposed  by  the  action  of  muriatic  acid,  into  a  soluble  and  an  insoluble  sili 
cate,  the  former  in  less  proportion  than  in  clinkstone,  or  10  to  14  per  cent.  Com 
position  of  the  whole  (from  Drachenfels),  according  to  Abich,  -  Silica  67-09,  alumina 
15'64,  potash  3*47,  soda  5'08,  lime  2~25,  oxyds  of  iron  4*59,  magnesia  0-98,  protoxyd 
of  manganese  0*15,  titanic  acid  0'38,  water,  etc.  0'45. 

Trachytes  sometimes  contain  also  free  quartz,  and  are  then  called  quartz-trachytes, 
in  which  the  silica  amounts  to  70  per  cent,  or  more.  The  feldspar  in  trachytic  rocks 
may  be  either  of  the  species,  and  thus  there  are  as  many  varieties  of  trachyte.  There  is 
wide  variation  also  in  texture,  from  a  porous  pumice-like  trachyte,  through  the  usual 
rough  granular  forms,  to  a  gray  syenyte-like  trachyte,  consisting  of  glassy  feldspar  and 
hornblende  crystals  with  some  mica  ;  and  also  to  porphyritic  trachyte  and  ftklspar- 
porphyry. 

(6.)  Mhyolytt.  A  feldspathic  rock  containing  more  or  less  free  silica,  but  undistin- 
guishable  by  the  eye.  The  paste  is  white,  gray,  yellow,  green,  red,  or  brown  in  color, 
usually  of  light  shades.  Texture  glassy  to  pearly;  passes  into  lithoid  and  micro-crys 
talline  kinds, which  are  quartz-trachytes.  Contains  sometimes  disseminated  crystals  of 
glassy  feldspar.  Obsidian  in  part,  pearlstone,  ami  pumice  are  here  included. 

(«.)  PUMICE.  —  Very  light,  porous,  with  the  pores  minute,  capillary,  and  parallel. 
Color,  pale  grayish,  greenish,  yellowish,  and  sometimes  of  darker  shades.  It  is  a  kind 
of  porous  trachyte.  Contains  69  to  70  per  cent,  of  silica,  and  probably,  therefore, 
some  free  quartz.  Often  contains  glassy  feldspar,  and  sometimes  hornblende,  mica, 
leucite. 

(b.)  OBSIDIAN.  — A  volcanic  glass,  taking  its  characters  from  the  composition  of  the 
volcanic  lavas.  The  lavas  cooling  slowly  form  stony  lava,  and  those  cooling  rapidly  a 
glassy,  — the  two  being  different  conditions  of  the  same  substance. 

Spherulitic  obsidian  contains  small  feldspathic  concretions. 

(c.)  PEARIJSTONE. — Xear  pitchstone,  but.  less  glassy  and  more  pearly  in  lustre: 
usaully  grayish  in  color,  also  yellowish,  brownish,  and  reddish.  The  peculiar  pearly 
appearance  is  due  to  an  intimate  mixture  of  a  portion  of  the  rock  in  the  glassy  state 
with  another  larger  portion  in  the  stonv  state.  It  often  contains  spherical  concretions, 
called  xpherulites,  which  consist  of  feldspar  with  an  excess  of  silica.  The  silica  varies 
from  68  to  80  per  cent. 

(d.)  PITCHSTONE  (Retinyte). — An  imperfectly-glassy  volcanic  rock,  pitch-like  in 
appearance,  and  of  various  colors  from  gray  to  black,  through  greenish,  reddish,  and 
brownish  shades.  It  contains  70  to  73  per  cent,  of  silica,  and,  in  some  of  the  published 
analyses,  8  to  10  per  cent,  of  water.  It  is  partly  Rhyolyte,  like  the  preceding. 

2.  Hornbleude-and- Pyroxene  series. 

This  series  includes  three  sections.  (1.)  The  Syenytic,  comprising  syenyte,  hypo- 
syenyte  and  dioryte,  which  also  occur  as  metamorphic  rocks;  (2.)  The  basaltic,  includ 
ing  melaphyres,  doleryte,  and  peridotyte,  to  which  three  rocks  the  name  basalt  was 


78  LITHOLOGICAL    GEOLOGY. 

earl\'  applied  ;  and  also  nephelinyte  and  amphigenyte,  nephelite  in  the  former,  and 
leucite  in  the  latter  replacing  for  the  most  part  the  labradorite.  The  term  trap  was 
early  applied  in  Sweden  (from  trappa,  step)  to  the  compact  columnar  variety  of  basaltic 
rock. 

(1.)  SYENYTE.  For  description  see  p.  69. 
(2)  HYPOSYENYTE.     For  description  see  p.  70. 

(3.)  DIOHYTK.  (Greenstone.)  For  description  see  p.  70.  A  related  rock  has  been 
c&\\&t>jpropylyte,  and  a  variety  containing  free  quartz  from  Transylvania  Dacite. 
Andesyte,  a  rock  consisting  of  hornblende  with  oligoclase  or  andesite,  is  closely  related 
to  dioryte. 

(4.)  MELAPHYKE  (a  name  variously  used;  here  restricted  to  the  oligoclase  kinds). 
Crystalline-granular  to  cryptocrystalline.  Dark  gray  to  grayish,  greenish  and  brown 
ish-black;  sp.  gr.  2-65-2-90.  Consists  of  oligoclase  and  pyroxene  (augite),  with  some 
times  disseminated  grains  of  magnetite.  Sometimes  porphyritic  or  amygdaloidal. 
Looks  like  doleryte,  but  has  less  density  and  contains  more  silica  (55  to  62  per  cent.). 
Two  kinds  from  the  Harz  (having  G.  =2-71,  and  2'78)  afforded  Streng— Silica  56-22, 
57-72,  alumina  15-56,  10'58,  protoxyd  of  iron  8*07, 10*55,  prot.  manganese  0-00,  0-17,  lime 
6-36,  7-59,  magnesia  5-97,  6-77,  potash  3'29,  1-89,  soda  2-40,  2-00,  water  2.75,  1-70,  car 
bonic  acid  l-95,  3'56  =  102-57,  102-53.  The  name  has  been  used,  as  well  as  diabase, 
for  a  chloride  doleryte  (see  below).  The  variety  of  andesyte  which  contains  augite,  in 
place  of  hornblende,  is  essentially  the  same  in  constitution  with  melaphyre. 

Trachydoleryte  is  near  melaphyre,  it  consisting  of  oligoclase  and  hornblende,  or 
augite, with  some  magnetite;  G.  =:2-74-2-80.  (From  Teneriffe,  Moravia,  etc.) 

(5.)  DOLERYTE.  —  Crystalline-granular  to  cryptocrystalline;  dark  gray  to  grayish, 
bluish  or  greenish  black,  brownish,  reddish;  Sp.  gr.  =  2-75-3-2.  Consists  of  labradorite 
and  augite, with  usually  disseminated  grains  of  magnetite.  Silica  commonly  48  to  52 
per  cent.  A  variety  from  Meissner  (having  G.  —  2-75)  afforded  Heusser  —  Silica  48-00, 
alumina  16'28,  protox.  iron  15*55,  lime  9'50,  magnesia  3*85,  potash  2-01,  soda  2-01, 
water  and  loss  2*80  =  100;  and  Rammelsberg  makes  it  a  mixture  of  47-60  labradorite, 
49 '60  augite,  with  magnetite.  The  cryptocrystalline  and  scoriaceous  variety  is  often 
called  basalt,  and  a  gray  fine-grained  variety  anamesite. 

Occurs porphyritic,  having  the  labradorite  in  distinct  crystals;  amyqdaloidal,  contain 
ing  small  rounded  or  almond-shaped  nodules;  chloritic,  owing  to  the  presence  of  dis 
seminated  chlorite  arising  from  partial  alteration,  either  through  the  action  of  moisture 
gaining  access  while  the  ejection  was  in  progress,  or  subsequently  through  infiltration; 
scoriaceous,  as  in  the  common  dolerytic  lavas.  Sometimes  it  is  zeolitic  as  well  as 
chloritic,  through  alteration. 

Doleryte  graduates  into  melaphyre  through  the  presence  of  oligoclase  in  addition  to 
labradorite.  Diabasyte  (or  Diabase)  includes  both  metamorphic  (p.  70)  and  eruptive 
rocks;  and  to  the  latter  section  belong  the  weak-lustred  chloritic  dolerytes. 

(6.)  PEHIDOTYTK.  Of  the  color,  specific  gravity,  and  texture  of  doleryte.  and  hav 
ing  the  same  constituents,  with  the  addition  of  disseminated  grains  of  chrysolite  (olivine), 
like  green  bottle-glass  in  color.  Often  called  chrysolitic  doleryte.  Occurs  porphyritic, 
amygdaloidal,  and  scoriaceous.  The  last  is  a  very  common  kind  of  lava. 

(7.)  AMPHIGENYTE. —Dark  gray,  fine-grained,  and  more  or  less  celhilar,  constitut 
ing  the  lavas  of  Vesuvius  and  some  other  European  volcanic  regions.  Sp.  gr.  2-7-2-9. 
Consists  chiefly  of  leucite  in  place  of  most  of  the  labradorite,  along  with  augite  and 
some  disseminated  magnetite.  The  leucite  is  in  disseminated  grains  or  in  24-faced 
crystals.  Called  also  Leucitophyre. 

(8.)  XEPHELIXYTE.  — Crystalline-granular;  ash-gray  to  dark  gray ;  resembling  some 
what  amphigenyte,  but  consisting  chiefly  of  nephelite  and  augite,  with  some  magnetite 
in  grains.  The  nephelite  is  partly  in  distinct  crystals. 

Dolerytic  glass,  or  obsidian,  is  a  black  glass  often  formed  in  volcanoes  where  the  lavas 
are  doleryte  or  peridotyte.  At  Kilauea,  the  glass  contains,  according  to  Silliman,  22  to 
30  per  cent,  of  protoxyd  of  iron,  approaching  the  so-called  fayalite,  and  iron- chryso 
lite.  Tachylyte  is  a  kind  found  with  basalt,  containing  55  per  cent,  of  silica,  13  of 
protoxyd  of  iron,  etc.  They  are  mixtures  and  not  mineral  species. 


KINDS   OF   ROCKS.  79 

Lavas  are  varieties  of  all  the  above  rocks  from  melaphyre  to  nephelinyte,  and  also 
of  trachytic  and  phonolytic  rocks  of  the  feldspathic  series. 

Wacke  is  an  earthy  rock  made  of  basaltic  earth  partly  compacted,  or  an  earthy 
altered  dolerytic  rock. 

Tufas  and  conglomerates  of  volcanic  regions  are  noticed  on  page  66. 

(3.)  Acidic  and  basic  series  of  igneous  rocks.  —  As  silica  is  the  acid  element  in  igneous 
rocks,  the  other  ingredients  being  basic,  the  kinds  in  which  the  silica  exceeds  55  per 
cent,  are  referred  to  an  acidic  series,  and  those  with  less  to  a  basic  series.  The  acidic 
series  includes  granite,  granulyte,  trachyte,  phonolyte,  rhyolyte,  and  part  of  syenyte ; 
and  the  basic,  most  hyposyeriite  and  dioryte.  with  melaphyre.  doleryte,  peridotyte, 
amphigenyte,  nephelinyte.  The  rocks  of  the  feldspathic  series  belong  with  the  former, 
excepting  those  in  which  the  feldspar  is  andesine,  labradorite.  or  anorthite;  and  those 
of  the  hornblendic  and  pyroxene  (or  the  iron-bearing)  series  with  the  latter,  excepting 
syenyte  (containing  quartz),  and  the  varieties  of  hyposyenyte  and  dioryte,  in  which 
orthoclase  or  albite  is  the  chief  feldspar.  The  average  per-centage  of  silica  in  the 
former  is  about  70,  and  in  the  latter  about  51;  and  the  oxygen  ratio  for  the  bases  and 
silica  is  in  the  former  about  1  to  3,  and  in  the  latter  2  to  3.  The  two  series  pass  into 
one  another. 

The  principal  recent  works  on  Lithology  are  the  following:  VON  COTTA'S  Treatise, 
an  English  edition  of  which  has  been  published  in  London;  BLUM'S  "  Handbuch  der 
Lithologie,"  Erlangen,  1860;  SENFT'S  "  Beschreibung  der  Felsarten,:' Breslau,  1857; 
COQUAND'S  "  Trait 6  des  Roches,"  Paris,  1857. 

II.   CONDITION,    STRUCTURE,    AND    ARRANGEMENT 
OF  ROCK-MASSES. 

The  rock-masses  of  the  globe,  or  terranes,  as  they  are  called,  occur 
under  three  CONDITIONS:  (1)  the  stratified,  (2)  the  unstratified, -and 
(3)  the  vein  condition.  Under  each,  there  are  peculiarities  of  STRUC 
TURE  and  Of  ARRANGEMENT. 

1.  STRATIFIED  CONDITION. 

Under  this  head  the  subjects  for  consideration  are,  —  1.  The  nature 
of  stratification ;  2.  The  structure  of  layers ;  3.  The  positions  of 
strata,  —  both  their  natural  positions  and  their  dislocations  ;  4.  The 
general  arrangement  of  strata,  or  their  chronological  order. 

1.  Nature  of  Stratification. 

Stratified  rocks  are  those  which  are  made  up  of  series  of  layers 
or  strata.  The  annexed  sketch  represents  a  section  of  the  strata  as 
exhibited  along  Genesee  River,  at 
the  falls  near  Rochester.  The  whole 
height  of  the  section  is  400  feet. 
At  bottom  there  is  a  thick  stratum 

^•i/*  : 

of    sandstone    (1)  ;    next    above    it        j 

lies  a   hard,  gray  layer  (2),   which    5l\ 

has  been  called  the  Gray  Band.     On 

this  rests  (3)  a  thick  bed  of  greenish  shale,  a  fragile,  imperfectly  slaty 

rock.     Next  (4)  is  a  compact  limestone,  forming  a  widespread  stratum 


80  LITHOLOGICAL   GEOLOGY. 

resting  on  the  shale.  Above  this  (5)  is  another  greenish  shale, 
much  like  that  below.  Then  (G)  is  another  great  stratum  of  lime 
stone  ;  then  (7)  another  thick  bed  of  shale;  and,  finally  (8),  at 
the  top,  is  a  limestone  wholly  different  from  those  below.  The 
transition  from  one  stratum  to  another  is  quite  abrupt ;  and,  more 
over,  each  may  be  traced  for  a  great  distance  through  the  adjoining 
country. 

Throughout  far  the  larger  part  of  America,  as  well  as  all  the  other 
continents,  the  rocks  lie  similarly  in  layers,  so  that  stratified  rocks  are 
of  almost  universal  distribution.  They  make  up  the  mass  of  the 
Appalachians ;  cover  nearly  all  of  New  York  ;  underlie  the  great 
plains  of  the  Ohio  and  Mississippi ;  occur  over  the  larger  part  of  the 
slopes  arid  summit  of  the  Rocky  Mountains ;  along  much  of  the 
Pacific  border,  as  well  as  the  Atlantic ;  and  exist  as  red  sandstone  in 
the  Connecticut  valley.  They  are  the  prevailing  rocks  of  Britain, 
including  within  their  series  the  chalk,  oolite,  coal  strata,  and  others. 
They  occur  over  nearly  all  Europe,  spread  throughout  the  great 
plains  of  Russia,  through  Asia  nearly  to  the  tops  of  the  Himalayas, 
over  South  America  to  some  of  the  summits  of  the  Andes,  and 
through  Africa  and  Australia.  These  stratified  rocks  are  in  striking 
contrast  with  the  unstratified, — granyte,  for  example,  which  may 
show  no  appearance  of  layers  even  through  heights  of  a  thousand  feet 
or  more.  Many  volcanic  masses  of  rock  are  unstratified.  Yet  the 
volcanic  mountain  has  usually  a  stratified  arrangement,  successive 
layers  of  lava  and  volcanic  sand  or  earth  being  piled  up  to  make  the 
cone.  Even  among  crystalline  rocks,  the  distinction  of  strata  may 
often  be  made  out,  although  much  disguised  by  changes  in  the  course 
of  their  history, 

The  succession  of  strata  in  stratified  rocks  is  exceedingly  various. 
In  the  section  given,  there  are  alternations  of  limestones,  shales,  and 
sandstone.  In  others,  as  at  Trenton  Falls,  N.  Y.,  there  are  only  lime 
stones  in  sight ;  but,  were  the  rocks  in  view  to  a  much  greater  depth, 
sandstone  strata  would  be  seen.  In  still  other  regions,  there  are  al 
ternations  of  conglomerates  and  shales  ;  or  conglomerates  with  shales 
and  coal-beds ;  or  conglomerates  with  limestones  and  sandstones  ;  or 
shales  and  sandstones  alone. 

The  thickness  of  each  stratum  also  varies  much,  being  but  a  few 
feet  in  some  cases,  and  hundreds  of  feet  in  others  ;  and  the  same 
stratum  may  change  in  a  few  miles  from  100  feet  to  10,  or  disappear 
altogether.  In  the  Coal-formation  of  Nova  Scotia  there  are  15,000 
feet  of  stratified  beds,  consisting  of  a  series  of  strata  mainly  sand 
stones,  shales,  and  conglomerates,  with  some  beds  of  coal  ;  and  in  the 
Coal-formation  of  Pennsylvania  there  are  6,000  to  7,000  feet  of  similar 
character. 


STKATIFICATION.  81 

After  these  illustrations,  the  following  definitions  will  be  under 
stood. 

a.  Stratification.  —  A  succession  of  rock-layers,  either   of  the  same 
or  of  different  kinds. 

b.  A  layer.  —  A  single  member  or  bed  in  a  stratified  rock.     It  may 
be  thick  or  thin,   and  loosely  or  strongly  attached  to   the  adjoining 
layers.     In  the  section,  Fig.  60,  the  limestones   4  and   0  consist  of 
great  numbers  of  layers  ;  and  in  all  limestone  regions  many  are  piled 
together  to  make  the  great  mass  of  limestone. 

c.  A  stratum.  —  The  collection  of  layers  of  one  kind  which  form  a 
rock  as  it  lies  between  beds  of  other  kinds.     In  the  section  referred 
to    (Fig.  60),   the  limestones  4,  6,  and  the  shale   masses  3,  5,  7,  are 
each  a  stratum.     A  stratum  may  consist  of  many  layers. 

d.  A  formation.  —  A  series  of  strata  comprising  those  that  belong  to 
a  single  geological  age,  or  to  a  single  period  or  subdivision  of  an  age, 
and  which,  consequently,  have  a  general  similarity  in  their  fossils  or 
organic  remains.     The    Coal-formation  includes  many  strata  of  sand 
stone,  shales,  limestones,  and  conglomerates. 

Geologists  speak  of  the  Silurian  formation,  Devonian  formation,  Carboniferous  (or 
Coal)  formation,  etc.,  making  each  cover  a  geological  aye.  But  they  often  apply  the 
term  also  to  subordinate  parts  of  these  formations.  Thus,  under  Silurian,  we  have  the 
Upper  Silurian  formation,a\i(l  the  Lower  Silurian  formation  ;  and  under  each  of  these 
there  are  subordinate  formations,  as  the  Trenton  formation,  including  the  strata  of  the 
Trenton  epoch  in  the  Lower  Silurian ;  the  Niagara,  formation,  for  one  of  the  lower  sec 
tions  of  the  Upper  Silurian.  These  subdivisions  embrace  generally  many  strata,  and 
have  striking  peculiarities  in  their  organic  remains ;  and  hence  this  use  of  the  word 
formation. 

e.  A  terrane.  —  This  term  is  used  for  any  single  rock  or  continuous 
series  of  rocks,  of  a  region,  whether  the  formation  be  stratified  or  not. 
It  is  applied  especially  to  metamorphic  and  igneous  rocks,  as  a  basaltic 
terrane,  etc. 

/.  A  seam  is  a  thin  layer  intercalated  among  the  layers  of  a  rock, 
and  differing  from  them  in  composition.  Thus,  there  are  seams  of 
coal,  of  quartz,  of  iron-ore.  Seams  become  beds,  or  are  so  called,  when 
they  are  of  considerable  thickness  ;  as,  for  example,  coal-beds. 

These  strata,  which  constitute  so  large  an  extent  of  the  earth's  crust, 
have  been  formed  mainly  by  the  action  of  water.  As  the  ocean  now 
makes  accumulations  of  pebbles  and  sand,  and  muddy  flats  along  its 
borders,  and  muddy  bottoms  for  scores  of  miles  in  width  along  various 
sea-shores,  so  it  formed,  by  the  same  means,  many  of  the  strata  of  sand 
and  clay  which  now  constitute  the  earth's  rocks ;  and,  in  this  work,  the 
sea  often  had  the  advantage,  in  early  times,  of  sweeping  widely  over 
the  just-emerging  continent.  Again,  as  the  rivers  bring  down  sand 
and  mud,  and  spread  them  in  vast  alluvial  flats,  making  deltas  about 
6 


82 


LITHOLOGTCAL   GEOLOGY. 


their  months  thousands  of  square  miles  in  area,  so  in  ancient  time  beds 
of  sand  and  clay  were  accumulated  by  these  very  means,  and  after 
ward  consolidated  into  rocks.  Again,  as  shells  and  corals,  by  grow 
ing  in  the  ocean  where  shallow,  under  the  action  of  the  waves,  pro 
duce  the  accumulating  and  rising  coral-reef  some  hundreds  of  miles 
long  in  the  present  age,  so  in  former  ages  shells  and  corals  grew  and 
multiplied  and  made  coral-reefs  and  shell-rocks,  and  these  old  reefs 
are  the  limestone  strata  of  the  world.  The  agency  of  water  and  life 
in  these  great  results  is  particularly  considered  under  Dynamical 
Geology. 

2.   Structure  of  Layers. 

The  structure  of  layers  is  due  either  to  the  original  deposition  of 
the  material,  or  to  subsequent  changes. 

(1.)  Kinds  of  structure  and  markings  originating  in  the  act  or 
mode  of  deposition.  —  The  kinds  of  structure  are  illustrated  in  the  an 
nexed  figures,  and  are  as  follow :  a,  the  massive ;  6,  the  shaly  ;  c,  the 
laminated;  d,  e,  and  f,  the  compound  or  irregularly  bedded.  These  terms, 

Fig.  61. 


m 


excepting  the  last,  have  been  already  explained  (p.  63).  The  massive 
is  especially  characteristic  of  pure  sandstones  and  conglomerates.  But, 
if  sandstones  are  argillaceous,  that  is,  contain  some  clay,  they  are  lam 
inated,  and  therefore  break  readily  into  slabs,  like  ordinary  flagging- 
stones  ;  and  the  thinness  of  the  flags  increases  with  the  amount  of 
clay.  A  clayey  rock  is  usually  shaly. 

Compound  structure  is  of  different  kinds. 

a.  Beach  structure.  —  The  upper  part  of  a  beach,  above  high  tide 
level,  is  made  by  the  toss  of  the  waves,  and  especially  in  storms,  and 
is  generally  irregularly  bedded,  as  represented  in  the  upper  part  of 
Fig  61  e.  But  the  lower  part,  swept  by  the  tide,  has  usually  an  even 
seaward  slope ;  and  the  beach  deposits  over  it  have  therefore  a  corre- 


STRATIFICATION. 


83 


spending  inclination  —  usually  5°  to  8°,  but  sometimes  steeper.  When 
the  sands  are  coral  or  shell  sands,  they  become  cemented  iiito  a  calca 
reous  sand-rock. 

b.  Ebb-and-flow  structure  —  This  kind  of  bed,  although  it  be  but  a 
few  feet  thick,  consists  of  layers  of  various  kinds,  some  of  which  are 
horizontally  laminated,  and  others  obliquely  so,  with  great  regularity,  as 
in  Fig.  61  e.    The  succession  indicates  frequent  changes  in  the  currents 
during  the  deposition,  such  as  attend  the  ebb  and  flow  of  tidal  or  river 
currents  over  a  shallow  bottom.     The  oblique  lamination,  observed  in 
three  of  the  layers  of  this  figure,  arises  from  a  strong  flow  pushing  up 
the  sands  before  it. 

When  the  flow  is  accompanied  by  powerful  waves  or  plunging  of 
the  water,  the  thrust  at  each  plunge,  besides  bearing  off  part  of  what 
had  before  been  laid  down,  deposits  the  sand  in  successive  portions,  as 
in  Fig.  6iy^  each  obliquely  and  divergently  laminated;  each  such  por 
tion  is  often  two  or  three  yards  long  and  six  inches  or  a  foot  thick, 
but  varying  much.  Beds  having  this  flow-and-plunge  structure  may 
alternate  with  others  horizontal  in  bedding.  In  obliquely  laminated 
beds,  the  lamination  dips  toward  the  direction  from  which  the  current 
came. 

c.  Sand-drift  structure.  —  The  layers  consist  of  subordinate  parts 
dipping  in  various  directions  (Fig.  61  d),  as  if  a  laminated  hillock  made 
by  sand  drifted  by  the  winds  on  a  coast  (for  the  sands  of  such  drifts  are 
always  in  layers)  had  been  partly  carried  away,  and  then  other  layers 
had  been  thrown  over  it  by  the  drifting  winds  at  a  new  inclination,  and 

Fig.  63. 


this  violent  removal  and  replacement  had  been  often  and  variously 
repeated.  Fig.  61  d,  representing  this  mode  of  structure,  is  from 
Foster  &  Whitney's  "  Report  on  the  Sandstone  Rocks  of  Lake  Supe 
rior.' 


Fig.  61  e  is  also  from  the  same  work. 


84 


LITHOLOGICAL    GEOLOGY. 


Besides  these  kinds  of  structure,  there  are  markings  in  the  strata 
which  are  of  related  origin,  —  viz. :  ripple-marks,  wave-marks,  rill- 
marks,  mud -cracks,  and  rain-drop  impressions. 

(1.)  Ripple-marks  (Fig.  G2).  —  A  series  of  wavy  ridgelets,  like  the 
ripples  on  a  sand-beach. 

(2.)  Wave-marks.  —  Faint  outlinings  on  a  sandstone  layer,  like  the 
outline  left  by  a  wave  along  the  limit  where  it  dies  out  upon  a  beach, 
marking  the  outline  of  a  very  thin  deposit  of  sand. 

(o.)  Rill-marks  (Fig.  G3). —  Little  furrows  made  by  the  rills  that 
ilow  down  a  beach  after  the  retreating  wave  or  tide,  and  which  become 
apparent  especially  where  a  pebble  or  shell  lies,  the  rising  of  the  water 
upon  the  pebble  causing  a  little  plunge  over  it  and  a  slight  gullying 
of  the  surface  for  a  short  distance. 


Fig.  64. 


Fig.  65. 


(4.)  Mad-cracks  (Figs.  64  and  05).  —  Cracks  intersecting  very  ir 
regularly  the  surface  or  a  portion  of  a  layer,  and  formed  by  the  dry 
ing  of  the  material  of  the  rock  when  it  was  in  the  state  of  mud,  just 
as  a  mud-flat  left  exposed  to  the  drying  sun  now  cracks.  The  original 
cracks  are  usually  filled  with  a  material  harder  than  the  rock,  so  that, 
when  it  becomes  worn,  the  surface  has  a  honeycomb  appearance,  from 
the  prominence  of  the  intersecting  ridgelets,  as  in  Fig.  65.  Moreover, 
these  ridges  are  generally  double,  the  filling  having  been  solidified 
against  either  wall  of  the  crack  until  the  two  sides  met  at  the  centre 
and  became  more  or  less  perfectly  united.  Specimens  of  rock  thus 
honeycombed  are  sometimes  called  septaria  (from  septum,  partition), 
but  the  term  is  little  used  in  science. 

(5.)  Rain-prints  (Fig.  66).  —  Rounded  pits  or  depressions,  made 
by  drops  of  rain  on  a  surface  of  clay  or  half-dry  mud.  On  a  reversed 
layer,  the  impressions  appear  raised  instead  of  depressed,  being  casts 
made  in  the  pits  which  the  rain  had  formed. 


CONCRETIONARY    STRUCTURE. 


85 


(6.)  There  are  also  markings  which  are  attributed  to  the  flowing  of 
thick  mud.     There  are  others,  produced  apparently  by  small  eddyings 

Fig.  66. 


of  water  in  clay  or  mud  which  work  out  concavities  that  afterward 
become  filled  with  clay  and  look  as  if  made  by  the  valves  of  shells. 

(2.)  Kinds  of  structure  not  properly  a  result  of  deposition,  and 
mostly  of  subsequent  origin.  —  The  kinds  of  structure  here  included 
are  (a)  the  concretionary,  (b)  the  jointed.,  and  (c)  the  slaty.  They 
are  produced  either  in  the  process  of  consolidation  or  during  subse 
quent  changes. 

a.  The  Concretionary  Structure.  —  This  kind  of  structure  has  been 
briefly  explained  on  p.  63,  and  is  here  further  illustrated.  Concretions 

Figs.  67-79. 
,68 


in  massive   sandstones   are  usually  spherical,  but  in  laminated  sand 
stones  or  shales  more  or  less  flattened. 


86 


LITHOLOGICAL    GEOLOGY. 


Fig.  67  is  a  sphere,  —  a  very  common  form.  The  sphericity  is 
frequently  as  perfect  as  in  a  bullet,  though  the  form  is  usually  more 
or  less  ovoidal,  and  sometimes  quite  distorted.  The  size  varies  from 
a  mustard-seed  and  less  to  a  yard  or  more ;  and  generally  those  that 
are  together  in  a  layer  of  rock  approach  a  uniformity  in  size.  They 
often  have  a  shell,  or  a  fragment  of  a  plant,  or  some  other  object, 
at  the  centre.  In  other  cases  they  are  hollow  and  filled  with  crystals. 
The  structure  is  often  in  concentric  layers. 

Figs.  68  to  75  are  views  of  sections  showing  the  interior.  In  08  there  is  a  fossil  shell 
as  a  nucleus;  in  some  cases  a  fossil  fish  forms  the  interior  of  a  concretion. 

The  structure  in  Fig.  08  is  solid  without  concentric  layers.  In  Fig.  69,  it  is  concentric. 
In  70,  it  is  radiated  or  consists  of  crystalline  fibres  diverging  from  the  centre  and  show 
ing  crystalline  apices  Over  the  exterior  surface.  In  Fig.  71,  the  exterior  is  concentric, 
but  the  interior  radiated. 

In  Figs.  72,  73,  the  interior  was  cracked  in  drying;  when  these  cracks  are  subse 
quently  filled  by  carbonate  of  lime,  heavy  spar,  or  other  material,  by  a  process  of 
infiltration,  it  becomes  a  kind  of  septarium,  and  is  frequently  beautiful  when  pol 
ished.  In  Fig.  74,  the  interior  is  hollow,  and  filled  around  with  a  layer  of  crystals 
(quartz  crystals  are  the  most  common  in  such  a  condition),  forming  what  is  called  a 
geode,  —  a  little  crystal  grotto.  In  Fig.  75  the  concretion  is  hollow  and  contains  another 
small  concretion ;  a  variety  not  uncommon. 

Figs. 76  a,  b  are  different  views  of  flattened  or  disk-shaped  concretions;  77  is  another, 
approaching  a  ring  in  shape ;  78,  79,  combinations  of  flattened  concretions.  Fig.  80  is 

Fig.  81. 


part  of  a  clay  layer  made  up  of  flattened  concretions.  A  concretionary  layer  often  grad 
uates  insensibly  into  one  in  which  no  concretions  are  apparent,  through  the  coalescence 
of  the  whole.  Fig.  81  represents  a  rock  made  up  of  concretions  of  the  size  of  peas,  — 
a  calcareous  rock  called  pisolite  (frompisum,  a.  pea).  Each  concretion  has  a  concentric 
structure,  the  layers  easily  pealing  off.  Oolyte  (named  from  u>6v,  egg)  is  similar,  ex 
cept  that  the  concretions  are  in  size  like  the  roe  of  fish  or  even  grains  of  sand. 

Fig.  82  exhibits  a  crystalline  rock  with  spherical  concretions  imbedded  in  its  mass 
and  not  separable  from  it, —each  layer  (of  the  three  represented  in  each  concretion) 
consisting  of  different  minerals:  for  example,  garnets  the  centre,  feldspar  the  middle 
layer,  and  mica  the  outer;  and  all  making  a  solid  mass.  The  constitution  of  such  con 
cretions  is  very  various.  In  rocks  containing  feldspar,  they  usually  consist  largely  of 
feldspar,  and  sometimes  of  feldspar  alone,  or  of  feldspar  with  some  quartz.  The  con 
cretions  in  pitchstone  and  pearlstone  (called  spherulites)  are  almost  purely  feld- 
spathic,  and  often  separate  easily  from  the  rock. 

Fig.  83  represents  basaltic  columns,  like  those  of  the  Giants'  Causeway,  having  the 
tops  concave:  at  each  joint  in  the  columns,  in  such  a  case,  there  would  be  the  same 
concavity.  This  tendency  to  break  with  concave  or  convex  surfaces  is  an  example  of 
concretionary  structure:  and,  in  the  case  referred  to,  each  column  is  an  independent  line 


CONCRETIONARY    STRUCTURE. 


87 


of  concretionary  solidification  distinct  from  the  others.  This  concretionary  structure, 
when  wholly  unobservable  in  the  solid  unaltered  rock,  is  frequently  developed  by 
the  action  of  atmospheric  agencies,  and  sometimes  so  perfectly  that  the  mass  separates 
into  thin  concentric  plates.  This  takes  place  in  some  kinds  of  both  granite  and  sand- 


Fig.  82. 


Fig.  83. 


stone.  The  rock,  after  partial  alteration,  peels  off  in  concentric  layers;  and  a  bluff  of 
granite  which  has  undergone  the  change  sometimes  appears  as  if  made  up  of  huge 
rounded  bowlders  piled  together.  A  sandstone  often  looks  like  an  excellent  building- 
stone,  which,  after  an  exposure  of  a  few  months,  will  fall  to  pieces  in  concentric  shells. 


Fig.  84. 


Fig.  84  is  a  case  of  concretion  in  a  sandstone  alongside  of  a  small  fissure,  observed 
in  Australia.  The  two  concretions  measured  twenty  feet  across.  They  consisted  of 
layers  from  half  an  inch  to  two  inches  thick,  which  separated  rather  easily.  The  rock 
elsewhere  was  without  concretions. 


Fig.  85. 


Fig.  85  is  from  an  argillaceous  sandstone  which  before  consolidation  had  been  inter 
sected  by  slender  mud- cracks,  and  subsequently,  on  hardening,  each  areolet  became  a 
separate  concretion.  The  action  of  the  sea  had  worn  the  surface  and  brought  the 
structure  out  to  view. 


88 


LITHOLOGICAL    GEOLOGY. 


Fig.  80. 


In  Fig.  80,  the  lower  sandstone  layer  (1)  has  no  concretions;  another  (3)  contains 
spherical  concretions ;  in  the  upper  layer  (4),  an  argillaceous 
sandstone,  the  concretions  are  somewhat  flattened  and 
coalescent;  in  the  shaly  layer  (2),  they  are  very  much 
flattened,  and  in  its  lower  part  coalescent. 

A  radiated  arrangement  is  common  when  no  distinct 
concretions  are  formed,  as  with  quartz  crystals  in  irregulr.r 
cavities.  Sometimes  different  points  become  centres  of 
radiation,  producing  a  blending  of  distinct  radiations,  a* 
in  Fig.  87. 

Very  many  of  the  mineral  species  shoot  into  stellar  and 
globular  radiated  crystallizations.  Others,  like  pyrites, 
readily  collect  in  balls  or  nodules  around  a  foreign  body 
as  a  nucleus,  or,  if  none  is  at  hand,  around  the  first  mole 
cule  of  pyrites  that  commences  the  crystallization.  This 
tendency  in  nature  to  concentric  solidification  is  so  strong 
that  no  foreign  nucleus  is  needed.  The  iron  ore  of  coal- 
regions  is  mostly  in  concretions  in  certain  layers  of  the 
Coal-measures.  The  rounded  masses  often  lie  imbedded 
in  the  cla3rey  layer,  or  are  so  numerous  as  to  coalesce  into  a  solid  bed. 

Concretions  sometimes  take  fanciful  or  imitative  shapes;  and  every  geologist  has 
had  petrified  turtles,  toads,  human  bones  and  skulls,  brought  him,  which  were  only 
examples  of  the  imitative  freaks  of  the  concretionary  process.  The  turtles  arc  usually 
what  are  mentioned  as  septaria  on  page  84.  Occasionally  concretions  take  long  cylin 
drical  forms,  from  consolidation  around  a  hole  bored  by  a  worm  or  mollusk,  the  hole 
giving  passage  to  the  concreting  ingredient;  or  they  derive  their  form  from  some  rootlet 
or  stem  of  a  plant,  in  which  case  they  are  often  branched ;  or  they  were  stalactites  de 
scending  from  the  roof  of  a  cavity. 

b.  The  Jointed  Structure.  —  Joints  in  rocks  are  planes  of  fracture 
or  divisional  planes  cutting  directly  across  the  stratification  and  ex 
tending  through  great  depths.  The  planes  of  division  are  often  per 
fectly  even,  while  they  may  not  be  open  enough  to  admit  the  thinnest 
paper.  These  joints  may  be  in  one,  two,  or  more  directions  in  the 
same  rock,  and  they  often  extend,  with  nearly  uniform  courses,  througli 
regions  that  are  hundreds  of  miles  in  length  or  breadth.  The  accom 
panying  sketch  represents  the  falling  cliffs  of  Cayuga  Lake,  and  the 


fortress-shapes  and  buttresses  arising  from  the  natural  joints  intersect 
ing  the  rocks.  The  wear  of  the  waters  from  time  to  time  tumbles 
down  an  old  surface,  and  exposes  a  new  range  of  structures. 


SLATY    STRUCTURE. 


89 


Fig.  88  A. 


Traversing  the  surface  of  a  region  thus  intersected,  the  joints  ap 
pear  as  mere  fractures,  and  are  remarkable  mainly  for  their  great 
extent,  number  and  uniformity.  In  case  of  two  systems  of  joints,  — 
the  case  most  common,  —  the  rock  breaks  into  blocks,  which  are  rect 
angular  or  rhomboidal,  according  as  the  joints  cross  at  right  angles  or 
not.  The  main  system  of  joints  is  usually  parallel  to  the  strike  of 
the  uplifts,  or  else  to  the  range  of  elevations  or  mountains  in  the 
vicinity,  or  to  some  general  mountain-range  of  the  continent ;  and  the 
directions  are  studied  with  much  interest,  because  of  their  bearing 
upon  the  geological  history  of  the  country. 

In  many  cases,  a  rock  is  so  evenly  and  extensively  jointed  as  to 
become  thereby  laminated,  and  in  such  a  case  the  joints  may  be  easily 
mistaken  for  planes  of  stratification,  especially  when  the  latter  have 
been  obliterated.  Sometimes  there  are 
sudden  transitions  from  the  regular 
stratification  to  vertical  joints,  as  in  Fig. 
88  A.  This  case  occurs  in  a  section  of 
part  of  a  quartzyte  bluff  on  the  railroad 
near  Poughquag,  Dutchess  Co.,  N.  Y. 
«,  «,  a,  are  ordinary  joints  in  the  strati 
fied  rock ;  b,  b,  is  a  portion  of  the  rock, 
which  has  lost  its  stratification  entirely, 
and  has  become  jointed  vertically  ;  the  transition  from  the  stratified  to 
the  part  £,  &,  is  so  abrupt  that  the  latter  has  the  aspect  of  an  inter 
secting  dike,  or  of  a  portion  of  the  laminated  sandstone  set  erect. 

c.  The  Slaty  Structure.  —  The  slaty  structure  or  slaty  cleavage,  as 
it  is  called  —  is  in  some  cases  parallel  with  the  planes  of  deposition 
or  bedding  of  a  rock  ;  and  such  examples  of  it  come  under  a  former 
head.  But  in  many  of  the  great  slate  regions,  as  in  that  of  AVales, 
the  slate  lamination  is  transverse  to  the  bedding,  as  shown  in  Fig.  89, 
in  which  the  lines  a,  b,  c,  d  show  the  lines  of  bedding,  and  the  oblique 
lines  the  direction  of  the  slates.  Whole  mountains  have  sometimes 
this  kind  of  oblique  or  transverse  lamination. 

The  sketch,  Fig.  89,  by  Mather, 
is  from  the  slate  region  of  Columbia 
County,  N.  Y. 

Occasionally,  the  lines  of  deposition  are  in 
dicated  by  a  slight  flexure  in  the  slate  near 
them,  as  in  Fig.  90.  In  other  cases,  there 
is  a  thin  intermediate  layer  which  does  not 
partake  of  the  cleavage.  Fig.  91  represents 

an  interstratification  of  clay-layers  with  limestone,  in  which  the  former  have  the 
cleavage,  but  not  the  latter, — though  the  limestone  sometimes  shows  a  tendency  to 
it  when  argillaceous.  Fig.  92  represents  a  rock  with  two  cleavage-directions;  and 


Fig.  89. 


90 


LITHOLOGICAL    GEOLOGY. 


Fig.  91. 


Fig.  90. 


93,  a  quartzose  sandstone  which  has  irregular  cleavage-lines.  These  last  two  cases, 
together  with  that  represented  in  Fig.  88  A,  show  that  the  jointed  structure  and 
cleavage-structure  have  the  same  origin. 

Fig.  92. 

Fig.  93. 


Sedgwick  first  detected  the  true  lines  of  bedding,  and  ascertained  that  the  slaty 
structure  was  one  that  had  been  superinduced  upon  the  clayey  strata  by  some  process 
carried  on  since  they  were  first  deposited. 

Foliation. — The  foliated  structure  (or  foliation)  of  mica  schist,  gneiss,  and  related 
schistose  rocks  may  sometimes  be  transverse  to  the  bedding,  like  most  slaty  cleavage. 
But  it  is  not  generally  so. 

(o.)  Markings  which  result  from  movements  of  rocks.  —  Grooving 
and  planing,  and  often  polishing,  of  rock  surfaces  occur  in  the  walls  of 
fractures  (as  those  of  veins,  for  veins  occupy  fractures),  which  have 
resulted  from  the  friction  of  one  wall  against  the  other,  usually  pro 
duced  when  the  fracture  was  made  ;  and  sometimes  on  the  surfaces  of 

Fig.  93  A. 


Drift  groovings  or  scratches. 

layers,  from  a  sliding  of  one  over  another  through  some  subterranean 
movement,     They  also  occur  on  exposed  surfaces  of  rocks,  where  they 


STRATIFICATION. 


91 


have  been  made  by  stones,  gravel,  or  sand,  transported  by  the  winds, 
water,  or  ice,  or  by  any  other  cause  of  movement.  Figure  9o  A  repre 
sents  scratches  made  by  glacial  action. 

3.  Positions  of  Strata. 

The  natural  positions  of  strata  as  formed,  and  the  positions  result 
ing  from  the  disturbance  or  dislocations  of  strata,  are  two  distinct 
topics  for  consideration  in  this  place. 

1.  The  natural  positions  of  strata  as  formed.  —  Strata  in  their 
natural  positions  are  commonly  horizontal,  or  very  nearly  so.  The 
level  plains  of  alluvium  and  the  extensive  delta  and  estuary  flats  show 
the  tendency  in  water  to  make  its  depositions  in  nearly  horizontal 
planes.  The  deposits  formed  over  soundings  along  sea-coasts  are 
other  results  of  sea-action  ;  and  here  the  beds  vary  but  little  from 
horizontally.  Off  the  coast  of  New  Jersey,  for  eighty  miles  out  to 
sea,  the  slope  of  the  bottom  averages  only  1  foot  in  700,  —  which  no 
eye  could  distinguish  from  a  perfect  level.  As  the  processes  of  the 
present  period  along  coasts  illustrate  the  grand  method  of  rock-accu 
mulation  in  past  time,  it  is  plain  that  strata,  when  in  their  natural 
positions,  are  very  nearly,  if  not  quite,  horizontal.  Over  a  consider 
able  part  of  New  York  and  the  States  west  and  southwest,  and  in 
many  other  regions  of  the  globe,  the  strata  are  actually  nearly  hori 
zontal  at  the  present  time.  In  the  Coal-formation,  the  strata  of 
which  have  a  thickness,  as  has  been  stated,  of  five  to  fifteen  thousand 
feet,  there  is  direct  proof  that  the  beds  were  horizontal  when  formed ; 
for  in  many  of  the  layers  there  are  fossil  trees  or  stumps  standing  in 
the  position  of  growth,  arid  sometimes  several  of  these  rising  from 
the  same  layer.  Fig.  94  represents  these 
tilted  coal-beds  c,  c,  with  the  stumps  s,  s,  s. 
Since  these  trees  must  have  grown  in  a  verti 
cal  position,  like  all  others,  and  as  now  they 
are  actually  at  right  angles  to  the  layers,  and 
parallel  to  one  another,  they  prove  that  the 
beds  originally  were  horizontal.  The  position 
of  shell-accumulations  and  coral-reefs  in  modern 
seas  shows,  further,  that  all  limestone  strata  must  have  been  nearly 
or  quite  horizontal  when  they  were  in  the  process  of  formation. 

Fig.  95. 


Fig.  94. 


In  sedimentary  deposits,  however,  some  variation  from  horizontally 


92 


LITHOLOGICAL   GEOLOGY. 


may  be  produced  by  the  slope  of  the  sea-bottom  in  certain  cases ;  and, 
off  the  mouths  of  rivers,  in  lakes  (Fig.  95),  quite  a  considerable  incli 
nation  may  result  from  the  fact  that  the  successive  layers  derived 
from  the  inflowing  waters  have  taken  the  slope  of  the  bottom  on 
which  they  fell.  The  sand  deposits  made  over  the  slope  of  a  sea- 
beach  between  low  and  high  tide  are  another  example  ;  they  take  the 
slope  of  the  beach,  as  stated  on  page  82.  Cases  of  inclined  position 
from  this  cause  are  necessarily  of  limited  extent,  bince  the  conditions 
required  are  not  likely  to  exist  on  a  large  scale. 

It  follows  from  these  facts,  that,  unless  strata  have  been  disturbed 
from  their  natural  positions,  the  order  in  which  they  lie  is  the  order  of 
relative  age,  —  the  most  recent  being  highest  'in  the  series. 

(2)  Dislocations  of  strata.  —  Strata,  although  generally  in  hori 
zontal  positions  when  formed,  are  often,  at  the  present  time,  tilted,  or 
inclined,  and  the  inclinations  vary  from  a  small  angle  to  verticality, 
or  even  beyond  verticality.  They  have  been  raised  into  folds,  each 
fold  often  many  miles  in  sweep  and  equal  to  a  mountain-ridge  in 
extent.  They  have  been  crumpled  up  into  groups  of  irregular  flex 
ures,  one  fold  or  flexure  succeeding  to  another,  till  like  a  series  of 
wrinkles  —  and  necessarily  coarse  wrinkles  —  on  the  earth's  surface. 
Every  mountain-region  presents  examples  of  these  flexures  ;  and  most 
intermediate  plains  have  at  least  some  undulations  in  conformity  with 
the  system  in  the  mountains. 

In  connection  with  all  this  uplifting,  there  have  been  fractures  on  a 
grand  scale  ;  and  strata  thus  broken  have  been  displaced  or  dislocated 
by  a  sliding  of  one  side  of  such  a  fracture  on  the  other,  through  vary 
ing  distances  from  a  few  feet  to  miles,  —  one  side  dropped  down  to  this 
extent,  or  the  other  side  shoved  up. 

The  subject  of  the  dislocations  of  strata  is  hence  an  important  one 
in  Geology. 

Uplifts,  folds.  Dislocations.  —  The  following  sections  illustrate  the 
general  facts  respecting  these  uplifts,  dislocations,  and  folds. 


Fig.  96. 


Fig.  97. 


Fig.  96  represents  a  part  of  the  Coal-formation, dislocated  along  the 
lines  of  fracture  a  a  and  b  b,  the  beds  (the  coal-beds  1  and  2  and  the 
other  layers)  being  displaced  as  well  as  disjoined  in  the  fracturing. 


DISLOCATIONS    OF   STRATA. 


93 


Such  a  dislocation  along  a  fracture  is  called  a  fault.  Faults  vary  from 
an  inch  or  less  of  displacement  to  thousands  of  feet.  Along  the  line 
b  b,  there  is  not  only  a  fault  but  also  at  the  junction  a  bending  of  the 
layers,  arising  from  the  friction  of  one  side  against  the  other  when  the 
dislocation  took  place.  In  Fig.  97,  the  fracture  is  an  opened  one  filled 
with  rock.  In  97  A,  the  fracture  was  a  crooked  one,  and  consequently 
the  sliding  of  one  side  on  the  other  left  a  series  of  open  spaces  to  be 
come  subsequently  filled.  On  p.  Ill, other  faults  are  represented. 
Fig.  98  is  an  actual  section,  by  Rogers,  of  a  part  of  the  Appala- 

Fig.  98. 


chians,  six  miles  in  length,  showing  the  foldings  and  contortions  of  the 
strata  in  those  mountains.  The  different  strata  are  numbered,  and  by 
these  numbers  the  bendings  of  a  given  stratum  may  be  followed.  Thus 
in  bends  over  n,  to  the  left  of  the  middle  of  the  figure,  and  the  right 
portion  descends  to  come  up  again  in  in  at  the  right  end  of  the  figure ; 
again,  iv,  to  the  left,  rises  and  bends  over  in  and  n,  though  disjoined 
about  the  top  of  the  fold  by  denudation. 

Some  of  the  kinds  of  flexures  and  curvatures  are  shown  in  the  an- 


Fig.  99. 


nexed  figures  A-E,  to  appreciate  which  it  must  be  understood  that  pli 
cations  vary  in  extent  from  an  inch  and  less  to  scores  of  miles ;  that 
they  stretch  over  vast  regions,  and  sometimes  make  lofty  mountains. 

The  plaitings  and  smaller  foldings,  but  a  few  feet  or  yards  in 
breadth,  are  local  and  superficial,  confined  often  to  single  layers  or 
thin  beds  ;  and  this  is  usually  true  of  those  that  are  many  scores  of 
yards  broad.  It  is  always  of  the  highest  importance  to  distinguish 
these  local  flexures  from  the  profound  bendings  of  great  formations, 
in  the  course  of  which  they  occur. 

The  foldings  of  a  region  are  generally  in  ranges  nearly  parallel  to 
one  another  ;  and,  where  one  fold  dies  out  along  the  range,  another 


94 


LITHOLOGICAL    GEOLOGY. 


may  rise  beyond  in  the  same  line,  or  else  in  another  line  to  one  or  the 
other  side,  making  often  overlapping  series.  Thus  all  the  positions 
represented  in  the  lines  in  Figs.  11  to  16,  p.  1 9,  may  occur  ;  and,  in 
fact,  they,  for  the  most  part,  do  occur  in  the  Appalachian  range. 

The  two  slopes  of  a  fold  may  be  alike  ;  or,  as  in  B,  c,  D,  E,  one 
may  be  much  steeper  than  the  other.  The  line  a  x  shows  the  posi 
tion  of  the  axial  plane  of  the  fold  in  each  case. 

The  ridge-line  of  a  fold  may  be  horizontal,  but  more  commonly  it  is 
inclined,  and  reaches  gradually  its  greatest  elevation. 

Such  are  some  of  the  various  conditions  which  have  been  observed, 


Fig.  100. 


especially  in  mountainous  regions.  Fig.  100  represents  a  section,  by 
Logan,  from  the  Archaean  rocks  of  Canada.  The  folded  rocks  are 
often  overlaid  by  others  of  more  recent  date. 

113.  In  describing  the  positions  of  strata,  the  following  terms  are 
used  :  — 

a.  Outcrop.  —  A  ledge  or  mass  of  rock  coming  to  the  surface,  or 
cropping  out  to  view  at  the  surface  or  above  it  (Fig.  101).  Outcrop 
ping  edges  are  sometimes  called  basset-edges. 

Fig.  101. 


b.  Dip.  —  The  slope  or  pitch  of  the  strata,  or  the  angle  which  the 
layers  make  with  the  plane  of  the  horizon  ;  as  ap  (Fig.  101).     The 
direction  of  the  dip  is  the  point  of  the  compass  toward  which  the  strata 
slope  ;  for  example,  the  dip  may  be  25°  to  the  southeast,  or  15°  to  the 
west,  and  so  on. 

c.  Strike.  —  The  direction  at  right  angles  with  the  dip,  or  the  course 
of  a  horizontal  line  on  the  surface  of  the  inclined  beds,  as  s  t. 

The  strike  and  dip  are  always  observed  with  care,  in  the  study  of  strata;  for  the 
strike  is  in  general  at  right  angles  approximately  to  the  direction  of  the  force  that  up 
turned  the  beds,  and  indicates  therefore  an  important  fact  with  regard  to  the  origin  of 
the  upturning;  and  the  dip  is  but  little  less  important,  since  it  illustrates  the  amount 


DISLOCATIONS   OF   STRATA. 


95 


and  character  of  the  upturning.  In  making  observations,  see  (1)  that  the  outcrop  is 
not  that  of  a  bowlder;  or  (2)  of  layers  displaced  by  the  growing  roots  of  trees  or  other 
wise;  also  whether  (3)  the  dip  and  strike  are  those  of  merely  local  or  superficial  flex 
ures,  or  of  the  great  and  general  bendings  of  the  rocks.  Also  consider  (4)  that,  when 
one  fold  dies  out  and  another  begins  at  the  same  time  to  rise  on  one  side  or  the  other, 
there  will  be,  as  a  consequence,  transverse  strikes  over  the  region  between  the  approxi 
mate  ends  of  the  two  folds.  As  all  folded  strata  were  once  horizontal,  the  study  of  the 
flexures  of  strata  is  the  study  of  bent  or  warped  surfaces ;  and  the  results  of  observa 
tions  cannot  be  right  unless  they  are  consistent  with  one  another  in  this  view. 

d.  Anticlinal,  Synclinal.  —  In  folded  strata,  the  layers  bend  upward 
and  downward  successively  ;  the  upward  is  an  anticlinal  flexure  (from 
avri,  opposite,  and  /<AiVu>,  I  incline),  and  the  downward  a  synclinal  (from 
aw,  together,  and  /cA.iW).  In  the  anticlinal  (Fig.  99,  A,  c,  D,  and 
either  summit  of  B),  a  x  is  the  anticlinal  axis,  or  that  away  from 
which  the  layers  slope  ;  and  in  the  synclinal  (middle  part  of  Fig. 
99  B),  a1  x'  is  the  synclinal  axis,  toward  which  the  layers  slope.  In 
Fig.  100,  a,  a  mark  the  positions  of  two  anticlinal  axes,  and  a',  ar  those 
of  two  synclinal  axes.  The  roofs  of  ordinary  houses  are  examples  of 
aiiticlinals,  and  the  ridgepole  has  the  direction  of  the  anticlinal  axis. 
If  the  ridge-line  of  a  fold  is  inclined,  then  the  anticlinal  axis  is  said  to 
be  inclined.  In  a  monoclinal  ridge,  the  beds  all  dip  in  one  direction. 

The  direction  of  the  strike  and  the  dip  are  ascertained  by  means 
of  an  instrument  called  a  clinometer,  which  is  in  part  a  pocket  compass. 
A  common  kind  is  a  pocket  compass  of  the  size  of  a  watch,  having 
a  pendulum  at  centre  to  note  by  its  position  the  angle  of  dip.  The 
best  has  a  diameter  of  3£  inches,  and  a  square  base  whose  sides  are 
parallel  to  the  principal  diameters  of  the  circle.  The  part  of  Fig. 
102  to  the  right  illustrates  the  use  of  the  pendulum,  and  shows  how  a 

Fig.  102. 


cheap  form  of  clinometer  may  be  made.  On  placing  the  side  c  d  on 
an  inclined  plane  (A  B),  the  angle  is  marked  by  the  position  of  the 
pendulum,  which  of  course  hangs  vertical.  Another  kind  of  clinometer 
is  shown  in  the  upper  part  of  the  same  figure. 


96 


LITHOLOGICAL    GEOLOGY. 


When  only  the  under  surface  of  projecting  strata  can  be  reached,  the  upper  side  of 
the  instrument  («  b,  in  Fig.  102)  should  be  applied  to  the  rocks.  By  holding  the  in 
strument  between  the  eye  and  the  sloping  outline  of  a  distant  hill  or  mountain,  mak 
ing  a  b  or  c  d  coincide  with  this  outline,  the  angle  of  slope  may  be  measured.  The 
strike  of  inclined  strata,  when  they  are  seen  in  profile,  may  be  taken  by  holding  the 
instrument  with  the  edge  ab  horizontal  (as  ascertained  by  the  pendulum),  and  then 
sighting  along  ft  b  and  finding  thus  a  point  on  the  edge  of  the  sloping  layers  (or  in  the 
line  of  such  an  edge  produced  downward,  if  the  rocks  are  above  the  level  of  the  eye); 
the  direction  of  this  point  is  the  strike.  Then,  by  making  the  edge  a  b  to  coincide,  by 
sighting  across,  with  the  slope  of  the  layers,  the  dip  may  be  taken.  Before  applying  a 
clinometer  to  a  layer  of  rock,  a  strip  of  board  should  be  placed  upon  the  layer,  so  that 
any  unevenness  of  the  surface  may  not  lead  to  error. 

The  directions  obtained  by  a  compass  will  always  need  correction  for  the  magnetic 
variation. 

Faults.  —  The  term  fault  is  defined  on  p.  93.  In  Fig.  9 6,  the  parts 
of  each  faulted  bed  are  of  equal  thickness  on  the  two  sides  of  the  line 
of  fault.  When,  in  a  dislocation,  there  is  a  lateral  or  oblique  shove,  as 
is  often  the  case,  the  thickness  may  differ,  provided  the  bed  is  not 
throughout  of  uniform  thickness.  This  difference  of  thickness  may  in 
dicate  a  lateral  movement  when  there  is  no  proof  of  a  vertical. 

Complexities  in  stratified  deposits  arising  from  denudation  and  other 
agencies.  —  By  the  denuding  action  of  waters,  strata  are  removed  over 

Fig.  103. 


Fig.  104. 


extensive  territories,  the  tops  or  sides  of  folds  are  carried  away,  and 
various  kinds  of  sections  made  of  the  stratified  beds,  which  are  often 
perplexing  to  the  student. 

One  of  the  simplest  of  these  effects  is  the  entire  removal  of  the 
rocks  over  wide  intervals,  so  that  the  continuation  of  a  stratum  is  met 
with  many  miles  distant,  as  in  Figs.  103,  104. 

The  result  is  more  troublesome  among  the  flexed  or  folded  strata. 
A  series  of  close  flexures,  like  Fig.  105,  worn  off  at  top  down  to  the 
Fig.  105.  Fig.  106  a.  Fig.  106  b. 


1     2   3    3' 2'  1' 


line  a  b,  loses  all  appearance  of  folds,  and  seems  like  a  series  of  layers 
dipping  in  a  common  direction.     This  is  best  seen  from  a  single  fold 


DISLOCATION    OF   STRATA.  97 

(Fig.  106  o).  If  the  part  above  the  line  a  b  were  absent,  the  five 
layers  would  seem  to  be  a  single  regular  series,  with  1  as  the  top  layer, 
3,3'  the  middle,  and  I/  the  bottom  one  ;  while  the  fact  is  that  1  and  I/ 
are  the  same  layer,  and  3,3'  is  actually  a  double  one.  In  a  number  of 
such  folds,  the  same  layer  which  is  made  two  in  one  fold  would  be 
doubled  in  every  other,  so  that  in  a  dozen  folds  there  would  seem  to 
be  twenty-four,  when  in  fact  but  one.  A  mistake  as  to  the  order  of 
succession  would  therefore  be  likely  to  be  made,  also  as  to  the  number 
of  distinct  layers  of  a  kind,  and  also  as  to  the  actual  thickness  of  the 
middle  layer.  Instances  of  a  coal-layer  doubled  upon  itself,  like  3,3', 
and  of  others  made  to  appear  like  many  distinct  layers,  occur  in  Penn 
sylvania.  On  this  point  special  facts  are  mentioned  in  the  section  on 
the  Coal  formation. 

Other  effects  of  denudation  are  exemplified  in  Fig.  98,  page  93.  The  stratum  No. 
III.  is  a  folded  one,  with  its  top  partly  removed;  the  layers  within  a  short  distance  dip 
in  opposite  directions.  The  layer  No.  IV.,  as  has  been  explained,  is  widely  disjoined. 
Again,  V.  lies  upon  the  top  of  the  highest  summit,  nearly  horizontally,  and  in  a  shallow 
basin:  yet  it  is  part  of  the  stratum  V.  to  the  left,  which  is  obviously  much  folded.  The 
observer  finds  it  necessary  to  study  the  alternations  of  the  beds  with  great  care,  in 
order  to  succeed  in  throwing  into  system  all  the  facts  in  such  a  region.  The  coal-regions 
of  Pennsylvania,  the  whole  Appalachians,  all  New  England,  and  much  of  Great  Britain 
and  Europe,  illustrate  these  complexities  arising  from  flexures  and  denudation. 

There  is  difficulty  also  in  ascertaining  the  true  dip  of  strata  from  ex 
posed  sections.  In  Fig.  107,  stuv  is  the  upper  layer  of  an  out 


cropping  ledge  of  rock,  d  p  the  line  of  dip,  s  t  the  strike.  The  ledge 
shows  four  sections  1,  2,  3,  4.  On  1,  the  edges  have  the  same  dip  as 
dp  ;  but, on  2,  3,  and  4, the  angle  as  obtained  from  the  exposed  edges 
would  be  different;  and  on  the  last, the  edges  would  be  horizontal  or 
nearly  so.  Thus  all  sections  except  the  one  in  the  direction  of  the  true 
line  of  dip  (or  at  right  angles  to  the  strike)  would  give  a  false  dip.  By 
linding  the  surface  of  a  layer  exposed  to  view,  the  true  direction  of  the 
dip  or  slope  may  be  ascertained,  and  the  error  avoided. 

The  following  figures  (Fig.  108)  still  further  illustrate  this  subject,  by  showing  the 
variations  of  direction  that  may  be  obtained  from  the  sections  of  a  single  folded  ridge. 
For  simplicity  of  explanation,  the  fold  is  supposed  to  be  a  symmetrical  one,  though 


98 


LITHOLOGICAL    GEOLOGY. 


with  the  ridge-line  or  anticlinal  axis  (a  b  in  A)  inclined.     In  A  the  section  is  vertical; 
but,  to  obtain  from  the  measurement  of  the  exposed  edges  the  true  dip,  it  should  have 

Fig.  108. 


the  direction  of  the  arrows,  that  is,  be  at  right  angles  to  the  strike ;  for  the  layers  fold 
over  the  ridge  in  this  direction.  In  B  the  section  is  very  obliquely  inclined;  in  C  it  is 
horizontal,  and  the  edges  show  nothing  of  the  actual  dip;  in  D  the  section  follows  the 
line  of  strike ;  in  E  it  is  oblique  behind ;  in  F  it  is  an  oblique  section  on  one  side ;  and  m 
G  a  vertical  section  in  the  axial  plane.  All  of  these  sections  give  wrong  results  to  the 
clinometer,  —  a  section  in  the  direction  of  the  arrows  in  Fig.  A  being  the  only  one  in 
which  the  dip  of  the  exposed  edges  is  the  dip  of  the  layers  or  strata. 

If  the  axis  of  the  fold  make  a  very  small  angle  with  the  horizon,  then  the  two  sides 
in  a  horizontal  section  (such  as  may  result  from  denudation)  will  be  much  elongated  as 
in  Fig.  108  I,  instead  of  short  as  in  Fig.  C ;  and  if  the  axis  is  horizontal  the  two  sides 
will  not  meet  at  all,  and  the  fact  of  the  existence  of  a  fold  is  not  apparent.  Even  in 
the  former  case  there  might  be  difficulty  in  determining  the  fact  of  a  fold,  if  the  part 

Fitr.  108  I. 


where  the  sidee  unite  were  concealed  from  view  by  the  soil  or  otherwise.  But  in  each 
case  there  may  be  evidence  of  a  fold  in  the  order  of  the  beds  on  the  two  sides ;  for  this 
order  on  one  side  would  be  just  the  reverse  of  that  on  the  other.  If,  in  Fig.  108  I, 
c  c  represent  a  coal  or  iron-ore  bed  having  its  border  d  more  impure  than  the  rest,  this 
border,  if  it  were  on  the  east  side  in  one  half  of  the  fold,  would  be  on  the  west  side  in 
the  other  half. 

The  difficulties  in  the  way  of  correct  observation  on  folded  rocks  are  further  en 
hanced  when  the  axial  plane  of  the  fold  is  inclined,  —  especially  when  it  is  so  inclined 
that  both  sides  of  the  fold  have  the  same  dip  (Fig.  106  «).  Still  closer  study  is  required 
when  several  folds  are  irregularly  combined,  as  is  common  in  nature. 

This  important  subject  maybe  further  studied  by  uniting  sheets  of  differently-colored 
card-board  together,  bending  them  into  a  fold,  and  then  cutting  them  through  in 
.different  directions. 

Distortions  of  fossils.  —  Uplifts  of  the  rocks,  besides  disturbing  the 
strata  themselves,  cause  distortion  in  imbedded  fossils,  —  either  (1)  a 
flattening  from  simple  pressure  ;  or  (2)  an  obliquity  of  form ;  or 
(3)  a  shortening ;  or  (4)  an  elongation. 


DISLOCATION    OF    STRATA. 


99 


The  following  figures,  from  a  paper  b}'  D.  Sharpe,  illustrate  some  of  these  distortions 
occurring  in  a  slate  rock  in  Wales.  They  represent  two  species  of  shells,  the  Spirifer 
dlsjunctus  (Nos.  1  to  4)  and  the  Spirifer  yiyanteus  (Nos.  5  to  8).  No.  1  is  the  natural 
form  of  S.  disjunctus ;  the  others  are  distorted.  The  lines  z  z  show  the  lines  of  cleavage 
in  the  slate:  2  lay  in  the  rock  inclined  60°  to  the  planes  of  cleavage,  and  is  shortened 
one-half:  3  lay  obliquely  at  an  angle  of  10°  or  15°;  it  is  shortened  above  the  middle 
and  lengthened  below  it:  4  is  a  cast,  the  upper  part  pressed  beneath  that  shown,  while 
the  lower  is  much  drawn  out:  5  is  like  3,  the  angle  with  the  cleavage-plane  being  less 
than  5°;  the  lower  part  has  lost  its  plications  by  the  pressure  and  extension:  6  has  a 
similar  angle  to  the  cleavage-plane,  but  a  different  position :  7  intersects  the  cleavage- 
plane  at  only  1°,  and  its  lower  part  is  very  much  prolonged.  Compression,  a  sliding 
of  the  rock  at  the  cleavage-planes,  and  more  especially  a  spreading  of  the  rock  itself 
under  the  pressure,  are  the  causes  which  have  produced  these  distortions.  All  fossils 
are  liable  to  become  similarly  misshapen  under  the  same  conditions. 


Calculating  the  thickness  of  strata.  —  When  strata  are  inclined,  as 
in  Fig.  110,  the  thickness  is  ascertained  by  measuring  the  extent 
along  the  surface,  and  also  the  angle  of  dip,  and  then  calculating  the 
thickness  by  trigonometry.  The  thickness  of  the  strata  from  a  to  b  is 
b  d,  the  line  b  d  being  drawn  at  right  angles  to  the  strata.  Measuring 
a  5,  and  the  dip,  which  is  the  angle  bad,  the  angles  and  hypothenuse 
of  the  triangle  a  b  d  are  given  to  determine  one  side  b  d.  Or,  with 
the  distance  a  e,  the  side  c  e  would  be  found. 

But  it   is  important,  for  trustworthy  results,  that  the  absence  of 


faults  be  first  ascertained.     The  figure  (110)  represents  a  fault  at  b  g, 
so  that  the  strata  1,  2,  3,  4  to  the  left  are  repeated   to  the  right ;  and 


100 


LITHOLOGICAL    GEOLOGY. 


hence  the  whole  thickness  is  b  d  instead  of  c  e.  There  may  be  -many 
such  faults,  in  the  course  of  a  few  miles ;  and  each  one  would  increase 
the  amount  of  error,  if  not  guarded  against. 

It  is  seen,  from  Fig.  110,  that  a  single  inclined  stratum  consisting 
of  the  layers  1,  2,  3,  4  would  have  a  surface-width  (width  at  the 
earth's  surface  or  on  a  horizontal  plane)  of  a  b.  But,  by  means  of 
the  fault,  another  portion  is  brought  up  to  the  surface,  and  a  b  is 
increased  to  a  e. 


Fig.  111. 


So  other  faults  might  go  on  increasing  the  extent  of  the  surface-exposure.  This  is 
further  illustrated  in  Fig.  111.  Let  A  be  a  stratum  10,000  feet  thick  (a  to  c)  and 
100,000  feet  long  (a  to  b).  Let  it  now  be 
faulted  as  in  Fig.  B,  and  the  parts  uplifted 
to  a  dip  of  15°,  —  taking  a  common  angle 
for  the  parts,  for  the  sake  of  simplicity  of 
illustration.  The  projecting  portions  being 
•worn  off  by  the  ordinary  processes  of  de 
nudation,  it  is  reduced  to  Fig.  C,  m  n  be 
ing  the  surface  exposed  to  the  observer. 
The  first  error  that  might  be  made  from 
hasty  observation  would  be  that  there 
were  four  distinct  outcropping  coal-layers 
(calling  the  black  layer  thus),  instead 
of  one  ;  and  the  second  is  the  one  above 
explained  with  regard  to  calculating  the 
thickness  of  the  whole  stratum  from  the 
entire  length  in  n  in  connection  with  the 
dip.  If  the  stratum  were  inclined  at  15° 
without  faulting,  it  would  stand  as  in 
Fig.  D;  and,  if  then  worn  off  to  a  horizon 
tal  surface,  the  widest  extent  possible  would  be  c  r,  —less  than  half  what  it  has  with 
the  three  faults. 

Conformable  and  unconformable  strata.  —  Strata  are  conformable, 
when  they  conform  to  one  another  in  superposition,  that  is,  lie  one 
over  the  other  with  the  same  dip  ;  and  they  are  unconformable  when 
one  overlies  the  upturned  edges  of  another  stratum,  with  no  con 
formity  in  dip'or  position.  Fig.  112  represents  cases  in  which,  after 

Fig.  112. 


the  rocks  below  had  been  f  >1  -led  or  upturned,  other  strata  were  laid 
down  at  a  b  and  e  f  horizontally  on  the  inclined  beds ;  these  are 
examples  of  imconformability.  Below  e  f,  there  are  really  two  sets  of 
unconformable  beds  in  a  synclinal  valley;  and,  moreover,  the  lower 
strata  were  much  faulted  and  upturned,  before  the  upper  were  laid 
down  upon  them.  The  Connecticut  River  sandstone,  like  the  latter, 


DISLOCATION    OF   STRATA.  101 

lies  on  upturned  older  rocks,  is  more  or  less  faulted,  and  is  overlaid 
by  horizontal  alluvial  beds. 

In  such  cases  of  luiconformability,  the  upturning  of  the  lower  beds 
must  have  taken  place  before  the  deposition  of  the  overlying  beds. 
The  time  of  the  upturning,  therefore,  was  between  the  period  to  which 
the  upturned  rocks  belong  and  that  of  the  overlying  deposits. 

When,  after  the  deposition  of  beds  in  a  continental  sea,  or  along  its 
borders,  a  sinking  of  the  region  takes  place,  the  next  deposits  there 
made  would  extend  beyond  the  limits  of  the  preceding,  and  overlap 
on  those  outside.  In  such  cases,  although  both  deposits  are  approxi 
mately  horizontal,  there  is  still  a  kind  of  unconformability  called  an 
overlap. 

When  strata  are  faulted,  there  may  be  perfect  conformity  of  dip  between  the  beds 
either  side  of  the  fault,  as  in  Figs.  110  and  111  C,  and  yet  no  conf amiability,  since  this 
relates  to  superposition.  So  there  may  be  unconformity  as  to  dip  on  two  sides  of  a 
fault  without  unconf or  mobility.  It  is  easy  to  be  led  astray  by  such  appearances  of  un 
conformability,  especially  in  regions  of  metamorphic  rocks.  Actual  superposition  must 
be  seen,  before  the  fact  of  unconformability  can  be  safely  asserted. 

Deposits  like  those  at  e  f  are  true  basin  —  or  trough  —  deposits  ;  for  they  are  formed 
in  basins  or  depressions  of  the  surface.  Such  deposits  may,  in  general,  be  distinguished 
by  their  thinning  out  toward  the  sides  of 
the  basin.  Yet,  when  synclinal  valleys 
are  shallow,  it  is  easy,  and  not  uncommon, 
to  mistake  beds  conformable  with  the 
strata  below  for  such  basin-formations. 
The  beds  a  b  (Fig.  1131  lie  in  the  synclinal 
valley  m  n,  like  a  basin-deposit,  though 

not  so.  They  were  formed  before  the  folding  of  the  beds,  and  not  after  it,  —  an  his 
torical  fact  to  be  determined  in  all  such  cases  with  great  care. 

4.    Order  of  arrangement  of  Strata. 

The  true  order  of  arrangement  of  strata  is  the  order  in  which  they 
were  made,  or  their  chronological  order.  All  strata  of  the  same  era,  as 
nearly  as  can  be  ascertained,  are  said  to  be  equivalent  strata,  or  those 
of  the  same  geological  horizon. 

As  geological  eras,  even  the  shorter  divisions,  have  in  general  been  of  very  long  dura 
tion,  the  equivalent  strata  of  distant  regions  cannot  be  known  to  be  precisely  synchro 
nous  in  origin.  A  long  time,  measured  by  thousands  of  years,  may  in  fact  have  inter 
vened  between  the  commencement  of  beds  that  are  most  alike  in  all  those  points  by 
which  we  determine  age  and  equivalency. 

Huxley,  in  view  of  the  impossibility  of  determining  true  synchronism,  has  proposed 
to  designate  by  the  term  homotaxial  (from  the  Greek  6/u.o?,  same,  and  rdfi?,  order)  those 
strata,  in  regions  more  or  less  widely  separated,  that  have  apparently  the  same  relative 
position  in  the  geological  series. 

Difficulties.  —  The  following  are  some  of  the  difficulties  encoun 
tered  in  the  attempt  to  make  out  a  chronological  order:  — 

The  stratified  rocks  of  the  globe  include  an  indefinite  number  of 


102  LITHOLOGICAL    GEOLOGY. 

limestones,  sandstones,  shales,  and  conglomerates ;  and  they  occur 
horizontal  and  displaced  ;  conformable  and  unconformable  ;  part  in 
America  and  part  in  Europe,  Asia,  and  Australia ;  here  and  there 
coming  to  view,  but  over  wide  areas  buried  beneath  soil  and  forests. 

Moreover,  even  the  same  bed  often  changes  its  character  from  a 
sandstone  to  a  shale,  or  from  a  shale  to  a  limestone  or  a  conglomerate, 
or  again  to  a  sandstone,  within  a  few  miles  or  scores  of  miles,  and 
sometimes  within  a  few  rods ;  or,  if  it  retains  a  uniform  composition, 
it  changes  its  color  so  as  not  to  be  recognized  by  the  mere  appearance. 
In  the  United  States,  many  a  sandstone  in  New  York  and  Pennsyl 
vania  is  represented  by  a  limestone  in  the  Ohio  and  Mississippi  valleys, 
—  that  is,  the  two  were  of  cotemporaneous  origin ;  some  rocks  in 
eastern  New  York  are  not  found  in  the  western  part  of  that  State,  and 
some  in  the  central  and  western  not  in  the  eastern. 

In  all  eras,  sand-beds,  mud-beds,  clay-beds,  pebble-beds,  and  lime 
stone-beds  have  been  simultaneously  in  progress  over  different  parts  of 
the  globe ;  and,  if  an  era  is  known  in  geology  as  solely  an  era  of  lime 
stone,  it  is  because  science  has  not  yet  discovered  where  the  beds  of 
sand,  mud,  or  pebbles  of  that  era  were  being  deposited  while  the  lime 
stone  was  making  over  its  regions.  The  idea  of  an  era  of  sandstone 
making,  or  of  limestone  making,  is  therefore  an  absurdity  ;  for  sand 
deposits  are  local ;  a  short  distance  off,  there  may  have  been,  in  all 
times,  as  now,  mud  deposits.  Still,  it  is  true  that,  over  continental  seas, 
the  prevailing  depositions  have  sometimes  been  of  limestone  material, 
and  sometimes  of  mud  or  sand ;  yet  this  has  been  true  for  certain  great 
regions  in  the  seas  of  a  continent,  rather  than  for  all  its  seas  at  once. 

Again,  a  stratum  of  one  age  may  rest  upon  any  stratum  in  the  whole 
of  the  series  below  it,  —  the  Coal  measures  on  either  the  Archaean, 
Silurian,  or  Devonian  strata ;  and  the  Jurassic,  Cretaceous,  or  Terti 
ary  on  any  one  of  the  earlier  rocks,  the  intermediate  being  wanting. 
The  Quaternary  in  America  in  some  places  rests  on  Archaean  rocks, 
in  others  on  Silurian  or  Devonian,  in  others  on  Cretaceous  or  Tertiary. 
And,  if  so  great  diversity  of  condition  exists  in  one  country,  far  greater 
may  be  expected  between  distant  continents. 

In  addition,  denudation  and  uplifts  have  thrown  confusion  among 
the  beds,  by  disjoining,  disarranging,  and  making  complex  what  once 
was  simple. 

Amidst  all  these  sources  of  difficulty,  how  is  the  true  order  ascer 
tained? 

Means  of  determination.  —  It  is  plain,  from  the  preceding  remarks, 
that  the  true  method  cannot  consist  in  grouping  rocks  of  a  kind  to 
gether,  as  limestones,  shales,  or  sandstones.  It  is  irrespective  of  kinds, 
and  is  founded  on  a  higher  principle,  —  the  same  which  is  at  the  basis 


ARRANGEMENT    OF   STRATA.  103 

of  all  history,  —  successiveness  in  events.  The  following  are  the 
means  employed. 

(1.)  Order  of  superposition.  —  When  strata  are  little  disturbed,  ver 
tical  sections  give  the  true  order  in  those  sections,  arid  afford  valuable 
information.  Or,  where  the  strata  outcrop  over  the  surface  of  a  coun 
try,  the  succession  of  outcropping  layers  affords  a  section,  and  often 
one  of  great  range.  The  vertical  extent  of  such  a  section  may  be  as 
certained  as  explained  on  p.  99.  In  using  this  method  by  superposi 
tion,  several  precautions  are  necessary. 

Precaution  1st. —  Proof  should  be  obtained  that  the  strata  have  not 
been  folded  upon  one  another,  so  as  to  make  an  upper  layer  in  any 
case  a  lower  one  in  actual  position  (see  p.  97),  —  a  condition  to  be 
suspected  in  regions  where  the  rocks  are  much  tilted,  but  not  where 
the  tilting  is  small. 

Precaution  2d.  —  It  should  be  seen  that  the  strata  under  examina 
tion  are  actually  continuous. 

A  fault  in  the  rocks  may  deceive ;  for  it  makes  layers  seemingly 
continuous  which  are  not  so.  Such  faults  are  common,  and  often  ex 
tensive,  in  regions  of  upturned  or  much  displaced  rocks,  and  may 
occur  when  the  dip  is  slight.  In  some  cases,  beds  forming  the  upper 
part  of  a  bluff  (as  a  b,  Fig.  114)  have  settled  down  bodily  (c)  to  the 
bottom,  so  as  to  seem  to  be  continuous  with  the  older  ones  of  the  bot 
tom  (as  c  with  d).  In  other  cases,  caverns  in 
rocks  have  been  filled  through  openings  from 
above,  and  the  same  kind  of  mistake  made. 
When  the  continuity  can  be  established,  the 
evidence  may  sometimes  lead  to  unexpected 
results.  For  example,  it  may  be  found  that 
a  coal-bed,  followed  for  some  miles  to  one  side 
or  the  other,  is  continuous  with  a  shale,  and 

both  are  actually  one  layer ;  that  a  sandstone  is  one  with  a  limestone 
a  few  miles  off;  that  an  earthy  limestone  full  of  fossils  is  identical 
with  a  layer  of  white  crystalline  marble  in  a  neighboring  district ;  or 
that  a  fossiliferous  shale  of  one  region  is  the  same  stratum  with  the 
mica  schist  of  another. 

Precaution  3d.  —  Note  whether  the  strata  overlie  one  another  con 
formably  or  not. 

Precaution  ^th.  —  Remember  that,  where  one  bed  overlies  another 
conformably,  it  does  not  follow  necessarily  that  they  belong  to  consec 
utive  periods,  as  has  been  above  explained. 

The  criterion  mentioned,  unless  connected  with  others,  gives  no  aid 
in  comparing  the  rocks  of  distant  or  disconnected  regions.  For  this 
purpose,  other  means  must  be  employed. 


104  LITHOLOGICAL   GEOLOGY. 

(2.)  Color,  texture,  and  mineral  composition. — This  test  may  be 
used  to  advantage  within  limited  districts,  yet  only  with  caution. 
There  were  at  one  time  in  geology  an  "  old  red  sandstone "  and  a 
u  new  red  sandstone ; "  and,  whenever  a  red  sandstone  was  found,  it 
was  referred  at  once  to  one  or  the  other.  But  now  it  is  well  under 
stood  that  color  is  of  little  consequence,  except  within  a  small  geo 
graphical  range. 

The  same  general  remark  holds  with  reference  to  mineral  composi 
tion,  as  explained  on  page  102. 

One  inference  from  the  mineral  constitution  of  a  stratum  is  safe  ; 
that  is,  that  a  stratum  is  more  recent  than  the  rock  from  which  its  mate 
rial  was  derived.  Hence,  an  imbedded  fragment  of  some  known  rock 
may  afford  important  evidence  with  regard  to  the  age  of  the  contain 
ing  stratum. 

The  age  of  metamorphic  and  igneous  rocks  is  sometimes  judged  of  on  lithological 
evidence ;  but,  with  possibly  some  exceptions  among  Archaean  metamorphic  rocks,  the 
criterion  is  worthless. 

(3.)  Fossils.  —  This  criterion  for  determining  the  chronological  order 
of  strata  takes  direct  hold  upon  time,  and,  therefore,  is  very  much  the 
best.  TJie  life  of  the  globe  has  changed  with  the  progress  of  time. 
Each  epoch  has  had  its  peculiar  species.  Moreover,  the  succession  of 
life  has  followed  a  grand  law  of  progress,  involving  under  a  single 
system  a  closer  and  closer  approximation  in  the  species,  as  time  moved 
on,  to  those  which  now  exist.  It  follows,  therefore,  that 

Identity  of  species  of  fossils  proves  approximate  identity  of  age. 

Fossils  are  the  best  means  we  have  for  ascertaining  the  equivalency 
of  strata,  or  their  identity  of  age.  Equivalency  is  sometimes  shown 
in  an  identity  of  species  ;  more  often  in  a  parallel  series  of  nearly  re 
lated  species ;  often  by  an  identity  or  close  relation  in  the  genera  or 
families  ;  often  also  in  some  prominent  peculiarity  of  the  various  species 
under  a  family  or  class. 

The  progress  in  life  has  not  consisted  in  change  of  species  alone 
The  species  of  a  genus  often  present,  in  successive  periods,  some  new 
feature  ;  or  the  higher  groups  under  an  order  or  class  some  modifica 
tion,  or  some  new  range  of  genera,  so  that,  even  when  the  species  dif 
fer,  the  habit  or  general  characters  of  the  species,  or  the  range  of 
genera  or  families  represented,  may  serve  to  determine  the  era  to 
which  a  rock  belongs,  or  at  least  to  check  off  the  eras  to  which  it  does 
not  belong.  Thus  Spirifer,  a  genus  of  mollusks,  which  has  a  narrow 
form  in  the  Silurian,  has  often  a  very  broad  form  in  the  course  of  the 
Devonian  and  the  Carboniferous  ages.  Ganoid  fishes,  which  have  ver- 
tebrated  tails  through  long  ages,  have  their  tails  not  vertebrated  in 


ARRANGEMENT    OF   STRATA.  105 

after  time.     Trilobites  become   wholly  extinct  at  a  certain   epoch   in 
the  history.     And  so  in  multitudes  of  cases. 

This  criterion  based  on  fossils  serves  for  the  comparison  of  the  con 
tinents  with  one  another,  as  to  their  successions  of  rocks.  Had  we  a 
table  containing  a  list  of  the  complete  series  of  rocks,  and  of  the  fam 
ilies,  genera,  and  species  of  fossils  which  each  contains,  it  would  be  a 
key  for  use  over  the  whole  world,  —  South  and  North  America  as  well 
as  the  Orient;  and,  by  comparing  the  fossils  of  any  rock  under  investi 
gation  with  this  key,  the  age  would  be  approximately  ascertained. 
This  is  the  method  now  pursued  in  studying  the  geology  of  the  globe. 
The  key,  is,  in  fact,  already  sufficiently  complete  to  be  constantly  ap 
pealed  to  by  the  geological  observer.  The  list  which  is  made  for  the 
Silurian  and  Devonian  rocks  in  New  York  State  is  used  for  identifying 
the  strata  of  the  Mississippi  basin  ;  and  that  which  has  been  prepared 
in  Europe  is  constantly  employed  to  make  out  the  equivalency  of  the 
rocks  of  the  two  continents. 

By  such  comparison  of  fossils,  it  was  discovered  that  the  Chalk  for 
mation  exists  in  the  Atlantic  border  of  the  United  States,  although 
the  region  contains  no  chalk  ;  that  the  coal  formation  of  North  Amer 
ica  and  that  of  Newcastle,  England,  belong  in  all  probability  to  the 
same  geological  age  ;  and  so  on. 

The  commencement  in  the  preparation  of  such  a  key  was  attended 
with  much  difficulty.  In  New  York  State,  it  was  necessary  —  first  to 
study  all  the  sections  in  the  eastern,  central,  and  western  parts,  and 
determine  carefully  the  fossils  in  each  stratum  ;  then  to  compare  the 
sections  with  one  another  :  when  any  case  of  identity  in  the  fossils 
among  these  strata  of  the  different  sections  was  observed,  it  was  set 
down  as  one  horizon  determined.  By  this  method,  and  other  aid  from 
observing  the  continuity  of  beds,  one  horizon  after  another  was  as 
certained,  and  the  strata  between  were  arranged  according  to  their 
true  order  of  succession. 

By  the  means  explained,  great  progress  has  been  made  in  arranging 
the  rocks  of  the  different  continents  in  a  chronological  series.  North 
America  has  some  large  blanks  in  the  series,  which  in  Europe  are 
filled  ;  and  in  this  way  various  countries  are  contributing  to  its  perfec 
tion. 

But  this  criterion  requires  precaution  in  its  applications,  for  the  fol 
lowing  reasons  :  — 

1.  The  difference  in  species  attending  difference  of  conditions  in  cli 
mate,  soil,  etc.  In  the  same  regions,  during  any  era,  the  species  of  the 
land  differ  from  those  of  the  waters  :  those  of  fresh  water,  from  those 
of  salt ;  those  of  the  surface  or  shallow  ivaters,  from  those  of  deeper, 
and  in  these  deeper  waters  according  to  the  depth  ;  those  of  warm 


106  LITHOLOGICAL    GEOLOGY. 

waters,  from  those  of  cold,  whether  at  the  surface  or  in  the  deep  ocean 
where  oceanic  currents  make  differences  of  temperature ;  those  of 
warm  or  dry  lands,  from  those  of  cold  or  wet ;  those  of  clear  open 
seas,  from  those  of  muddy  waters  or  near  muddy  seashores  ;  those  of 
rocky  bottoms,  from  those  of  muddy  ;  etc.  Hence,  an  ancient  rock 
made  in  a  clear  sea,  as  a  limestone,  will  necessarily  contain  very  dif 
ferent  fossils  from  a  rock  that  was  made  of  mud,  although  they  were 
formed  at  the  very  same  time,  in  the  same  waters,  and  within  a  hun 
dred  miles  of  one  another.  Even  a  hundred  yards  may  be  all  that 
separates  widely  different  groups  of  species.  Again,  a  rock  made  in 
fresh  waters  will  differ  in  its  fossils  still  more  widely  from  that  made 
synchronously  in  salt  waters;  a  rock  made  in  shallow  waters,  from  one 
made  at  great  depths  ;  a  rock  made  in  the  tropics,  from  one  made  in 
the  temperate  zone  or  the  arctic,  provided  the  zones  at  the  time  of  the 
making  differed  as  they  do  now  in  climate.  Hence,  a  very  considerable 
difference  in  the  fossils  of  rocks  is  consistent  with  their  being  contempora 
neous  in  origin. 

2.  The  difference  in  the  time  at  which  species  or  groups  of  species  of 
different  regions  have   become  extinct.     In   one  region,  changes  may 
cause   species  or  genera   (or  higher  groups)  to  disappear,    while,  in 
another,  subjected  to  the  same  conditions  or  causes  of  catastrophe,  the 
same  species,  or  at  least  the  same  genera  (or  higher  groups),  may  con 
tinue   on   through   another  period.     Genera  or  Families  may  become 
extinct  sooner  on   one    continent,   or  part   of  a    continent,  than    on 
another ;  or  in  one  ocean,  or  part  of  an  ocean,  than  in  another. 

Catastrophes  may  affect  the  borders  of  an  ocean  or  shallow  seas, 
that  do  not  reach  the  greater  depths.  Fossils  of  the  group  called 
Cystids  occur  only  in  the  older  rocks  of  the  globe,  and  were  supposed 
to  have  become  extinct  at  the  time  of  their  disappearance  as  fossils  ; 
but  recently  they  have  been  found  in  the  depths  of  the  Atlantic  ocean, 
a  region  not  reached  by  the  agencies  of  extermination  that  swept  from 
time  to  time  over  the  continental  seas.  It  was  formerly  supposed  that 
no  species  that  is  now  alive  existed  anterior  to  the  Tertiary  ;.  but,  in 
the  same  deep*  ocean,  one  living  mollusk  has  been  found  that  is 
supposed  to  date  back  to  the  Cretaceous  or  chalk  era. 

3.  The  difference  in  the  time  at  which  species  or  groups  have  begun 
to  exist  in  different  regions.     The   several  continents  may  not  have 
been  exactly  parallel,  in  all  the  steps  of  progress  in  the  life  of  the 
globe,    certain    families    commencing  a   little    earlier  in  one  than  in 
another.     Again,  one    continental  sea  or  region    may  have  received 
some  of  its  species  by  migration  from  another,  long  after  their  first  ap 
pearance.     Here  is  a  source  of  doubt,  due  on  one  side  to  special  con- 


UXSTRATIFIED    CONDITION.  107 

tinental  idiosyncrasies,  and  on  the  other  to  migratioual  distribution, 
which  is  always  to  be  carefully  considered. 

Such  facts  do  not  lead  to  any  doubt  as  to  conclusions  based  on  the 
general  range  of  types  characterizing  an  era.  Should  a  trilobite  be 
hereafter  discovered  in  any  Cretaceous  rocks  of  the  world,  it  would 
lead  no  one  to  suspect  those  rocks  to  be  Paleozoic ;  because  the  associ 
ated  species  would  unquestionably  be  true  Cretaceous  fossils. 

2.  UNSTRATIFIED  CONDITION. 

The  larger  part  of  the  crystallized  rocks  were  once  fragmental 
rocks,  and  have  been  altered,  that  is,  are  metamorphic  rocks  (p.  66) ; 
and  they  are,  therefore,  not  true  examples  of  unstratified  rocks.  In 
general,  they  still  retain  the  lines  of  deposition  distinct.  When  gneiss 
and  mica  schist  are  found  in  alternations  with  one  another,  it  is  plain 
that  each  layer  corresponds  to  a  separate  layer  in  the  original  de 
posit  ;  and  the  beds,  although  crystalline,  are  still  as  really  stratified 
as  they  ever  were. 

In  some  metamorphic  rocks,  however,  the  appearance  of  stratifica 
tion  is  lost ;  and  such  may  be  properly  said  to  be  un stratified.  Yet  it 
should  be  understood  that  the  name  does  not  imply  that  they  never 
were  stratified,  but  that  this  is  not  now  their  apparent  condition.  Gran 
ite  and  syenyte  are  unstratified  rocks  of  this  kind.  In  much  granite 
there  is  no  lamination,  no  arrangement  of  the  constituent  minerals  in 
parallel  planes,  no  evidence  of  subdivision  into  layers.  But  even  this 
true  granite,  a  few  miles  off,  may  become  gneiss  in  which  a  schistose 
structure  is  very  distinct. 

Examples  of  the  unstratified  condition  are  common  among  true 
igneous  rocks.  The  ridges  of  trap  or  doleryte  which  range  over  many 
districts  —  as  the  Palisades  on  the  Hudson,  Mounts  Tom  and  Holyoke 
and  the  other  trap  ridges  of  the  Connecticut  valley,  the  Giant's  Cause 
way  and  Fiiigal's  Cave  —  are  some  of  these  examples.  The  rocks 
were  melted  when  they  came  up  to  the  light  through  fissures ;  and  they 
now  stand  without  any  marks  of  stratification.  The  sketch  on  p.  108 
represents  a  scene  among  rocks  of  this  kind  in  Australia.  The  dome- 
shaped  masses  of  trachyte,  in  some  regions  of  ancient  volcanoes,  and 
the  interior  mass  of  many  great  volcanoes,  —  sometimes  exposed  to 
view  through  rendings  of  the  mountain  or  denudation  by  water, — 
are  also  examples.  But  the  ordinary  outflows  of  liquid  rock  from  vol 
canoes  usually  produce  layers,  which  are  covered  afterward  by  others 
in  succession  ;  and  volcanic  mountains,  therefore,  have  to  a  great  ex 
tent  a  stratified  arrangement  of  the  rock-material,  and  not  less  per 
fectly  so  than  bluffs  of  stratified  limestone.  Moreover,  tho  same  rock 


108 


LITHOLOGICAL   GEOLOGY. 


which  forms  the  Giants'  Causeway  may  in  other  places  be  interstrati- 
h'ed  among  sandstones  and  shales ;  for  the  layer  of  igneous  outflow, 

Fig.  115. 


Basaltic  columns,  coast  of  Illawarra,  New  South  Wales. 

wherever  it  takes  place,  may  be  followed  afterward  by  deposits  of 
sand  or  other  sediment. 

Another  example  of  unstratified  material  is  found  in  the  loose 
pebbles  and  stones  which  cover  a  large  part  of  the  northern  half  of 
both  the  American  and  European  continents.  Any  ordinary  mode  of 
action  by  water  lays  down  sediments  in  layers.  But  these  accumu 
lations  —  often  called  Drift —  are  of  vast  extent  and  without  layers. 
Wherever  the  same  kind  of  material  is  in  layers,  it  is  then  said  to  be 
stratified  ;  and  thus  it  is  distinguished  from  the  unstratified. 

There  may,  therefore,  be  both  stratified  and  unstratified  fragmental, 
and  stratified  and  unstratified  igneous  rocks ;  and,  from  the  obliteration 
of  the  planes  of  deposition  by  metamorphism,  there  may  be  unstratified 
metamorphic  rocks,  like  granyte,  as  well  as  stratified. 

On  the  subject  of  the  structure  of  these  rocks,  it  is  only  necessary 
to  refer  to  the  ordinary  massive  structure  of  granyte  and  trachyte,  etc., 
arid  to  the  columnar  structure  met  with  among  igneous  rocks.  The 
last  is  represented  in  the  figure  given  above.  There  are  all  shades 
of  perfection  in  this  columnar  structure,  from  prisms  of  great  height 
with  perfectly  plane  sides,  to  a  mere  tendency  to  prismatic  forms ;  and 
also  from  this  less  perfect  prismatic  character,  to  the  massive  structure 
with  no  trace  of  columnar  fracture. 

For  a  continuation  of  this  subject,  see  the  chapter  on  igneous 
operations,  under  Dynamical  Geology. 

(1.)  General  nature  of  veins. —  The  vein  condition.  —  Veins  are 
narrow  plates  of  rock  intersecting  other  rocks.  They  are  the  fillings 
of  cracks  or  fissures ;  and,  as  these  cracks  or  fissures  may  either 
extend  through  the  earth's  crust  and  divide  it  for  long  distances,  or 


UNSTRATIFIED    CONDITION. 


109 


reach  down  only  to  a  limited  depth,  or  be  confined  to  single  strata, 
so  veins  are  exceedingly  various  in  extent.  They  may  be  no  thicker 
than  paper,  or  they  may  be  scores  of  rods  in  width,  like  the  great 
fissures  opened  at  times  to  the  earth's  inner  regions  by  subterranean 
agency.  They  may  be  clustered  so  as  to  make  a  perfect  net-work 
through  a  rock,  or  may  be  few  and  distant.  And,  as  strata  have  been 
faulted,  so  veins  also  may  have  their  faults  or  displacements.  All 
those  subterranean  movements  that  produce  joints  and  fractures  in 
rocks  may  give  origin  and  peculiarities  to  veins. 

(2.)  Subdivisions.  —  Veins  are  divided  into  dikes  and  proper  veins. 

Dikes  are  filled  by  volcanic  rocks,  basalt,  trap,  or  some  other  ig 
neous  rock,  and  have  regular  and  well-defined  walls. 

Veins  are  occupied  by  quartz,  granitic  rocks,  metallic  ores,  calcite, 
fluor  spar,  barite,  etc.,  —  material  which  is  less  obviously  a  liquid 
injection  from  below,  and  probably  is  seldom  of  this  nature.  They 
are  generally  irregular  in  form,  often  indistinct  in  their  walls,  and 
very  varying  in  their  ingredients.  They  abound  in  regions  of  meta- 


Fig.  116. 


Fig.  11' 


morphic   rocks.      Veins   have  been    subdivided  into   kinds  ;    but  the 
divisions  need  not  here  be  considered. 

(3.)  Forms  and    faults  of  veins  and    dikes.  — Fig.  116  reprasents  two 
simple  veins  or  dikes  (a  a  and  b  b)  intersecting  stratified  rocks. 
Fig.  117,  a  net-work  of  small  veins. 


Fig.  118. 


Fig.  119. 


Fig.  118,  small  veins  of  quartz  intersecting  gneiss,  —  the  mass  five  feet  square. 
The  veins  do  not  all  cross  one  another,  and  correspond  to  the  cracks  which  result  from 
contraction,  as  by  sun-drying  or  cooling,  rather  than  to  those  of  any  other  mode  of 
fissuring. 


110 


LITHOLOGICAL    GEOLOGY. 


Fig.  119.  Two  veins  a  a',  presenting  some  of  the  common  irregularities  of  mineral 
veins  in  size,  the  enlarged  parts  containing  mostly  the  ore:  a  is  faulted  by  another 
vein  b,  which  is  therefore  of  subsequent  formation,  but  not  necessarily  long  subsequent. 

Fig.  120. 


Figs.  120,  121,  122.    Examples  of  granitic  veins  of  very  large  size,  in  a  gneissoid 
granite,   showing  their  subdivisions  and  various  irregularities  (taken  by  the  author 


Fig.  122. 


from  granitic  rocks  near  Valparaiso).  The  veins  undergo  constant  changes  of  size, 
and  in  some  places  encircle  masses  of  rock  resembling  the  rock  outside  The  rock  ad 
joining  the  vein  is  more  micaceous  than  that  at  a  distance,  and  the  direction  of  the 
lamination  (as  indicated  in  the  figures)  varies  with  some  reference  to  the  intersecting 
veins,  curving  approximately  parallel  to  the  veins  on  two  opposite  sides,  m  and  n,  and 
not  at  all  so  on  the  other  two,  o  and  p.  The  subdivisions  of  the  veins  in  Fig.  121  cross 
one  another  in  an  alternate  manner,  a  cutting  d  and  e,  but  cut  by  c,  and  b  cut  by  c,  d, 
and  e  ;  in  122,  although  the  veins  are  similar  in  constitution,  one  cuts  the  other  ;  and, 
in  120,  the  two  crossing  veins  are  broken  and  subdivided  at  the  intersection,  so  as  to 
appear  like  one  vein  stretching  off  in  two  directions,like  a  letter  X. 


TNSTRATIFIED    CONDITION. 


111 


Fig.  123.     A  vein  a  faulted  by  b,—  whence  it  is  inferred  that  6  is  subsequent  to  a 
in  age.    Also  a  vein  1  faulted  by  2,  and  again  by  3,  and  3  faulted  by  4;  2  and  3, 

Fig.  123. 


therefore,  were  subsequent  in  age  to  1,  and  4  was  subsequent  to  3.     The  faulting  is 
exhibited  also  in  the  layers  of  the  stratified  rocks  which  the  veins  intersect. 


Fig.  124.        Fig.  125.          Fig.  126. 


Fig.  127. 


Figs.  124,  125,  126.  Veins  much  broken  or  faulted:  in  124,  four  faults  within  a 
length  of  eighteen  inches :  in  125,  six  faults  in  six  feet ;  in  126,  the  broken  parts  of  the 
vein  of  unequal  breadth. 

Fig.  128. 


Figs.  127,  128,  129.  Other  faulted  veins;  127  a  and  b,  six  feet  apart,  and  still 
different  in  their  faults;  128,  129,  other  interrupted  veins.  These  dissimilarities  be 
tween  the  parts  of  one  faulted  vein,  as  in  126,  and  between  the  parts  of  two  parallel 
veins,  as  in  127,  arise  from  an  oblique  shove  of  the  parts,  either  at  the  time  of  the 
fracturing  in  which  the  veins  themselves  originated,  or  at  some  subsequent  fracturing. 

The  points  illustrated  in  the  preceding  figures  are,  — 
The  great  irregularities  of  size  in  veins  along  their  courses,  swell 
ing  out  and   contracting ;   their    occasional   reticulations  ;    their    fre 
quently  embracing  portions    of  the    enclosed    rock  ;  their  numerous 
faultings,  or  breaks  and  displacements. 

(4.)   Structure.  —  Dikes.  —  Dikes  consist  essentially  of  the  same 
kind  of   material    from   side    to  side  and    at  all  heights,  where  not 


112 


LITHOLOGICAL    GEOLOGY. 


Fig.  131. 


altered   by    exposure    to    the    air.       The    structure    may   be    simply 
massive,  or    cracked    irregularly,    as    in    many  volcanic  dikes.      But 

frequently  there  are  transverse  fractures, 
producing  a  columnar  structure,  so  that 
a  dike  is  like  a  pile  of  columns.  For  a 
short  distance  from  the  walls,  the  struc 
ture  is  generally  imperfect  (Fig.  130)  ; 
and  in  many  cases  there  is  an  earthy 
layer  along  the  sides,  or  even  a  laminated 
structure  parallel  with  the  walls  (Fig. 

131),  produced  by  the  friction  of  the  rising  liquid  mass  against  the 
walls  of  the  fissure. 

Dikes  are  sometimes  metalliferous;  and,  when  so,  the  ore  is  com 
monly  found  near  the  walls,  and  often  penetrates  also  the  enclosing 
rock.  Some  of  the  richest  mines  of  the  world  are  connected  with 
dikes,  or  with  igneous  ejections. 

Veins  never  have  the  trarfsverse  columnar  structure  of  dikes.  The 
simplest  consist  of  one  kind  of  material, — as  quartz,  granyte,  heavy 
spar,  —  and  are  alike  from  side  to  side.  But  others  have  a  banded 
structure  not  found  in  dikes,  consisting  in  an  '  arrangement  of  the 
material  parallel  to  the  walls.  Fig.  132  represents  such  a  vein  con 
sisting  of  ten  bands :  1,  3,  and  6  are  bands  of  quartz  ;  2  and  4,  of  a 
gneissoid  granyte  ;  and  5,  of  gneiss.  Of  banded  veins,  the  simplest 
is  a  vein  with  three  bands,  one  central  ;  but  the  number  may  be  a 
score  or  more.  The  bands  may  be  partly  metallic  ores  of  different 
kinds,  and  calcite,  barite,  fluor  spar,  may  .make  the  alternating  bands, 


6  j 

a 

;,!, 

43 

21 

2 

' 

4. 
i.! 

56 

I 

!!•! 

;',', 

1  1 

•, 

/  11 

! 

ii1 

V 

,  '. 

u' 

;•': 

!.'|,' 

' 

, 

i 

||i| 

w 

•j'l, 

, 

I  ' 

''l 

''i1'1, 

i  I' 

'; 

:, 

'; 

ih 

i',i 

'li  1  1 

(  , 

: 

11 

i'i 

Fig    133. 
abbe        C         a  a 


instead  of  granyte  or  gneiss.  In  Fig.  133,  there  are  three  sets  of 
bands :  an  inner,  C,  and  two  outer.  The  left-hand  one  consists  of 
four  bands  or  combs,  a,  b,  b,  c  of  earthy  minerals,  with  ore  along  the 
centre  ;  and  that  to  the  right  of  two  combs,  a,  a,  with  a  central  line 
of  ore  ;  while  C  is  a  simple  band,  and  it  may  be  of  ore.  A  great 


UNSTRATIFIED    CONDITION.  113 

vein  at  Freiberg  consists  of  layers  of  blende,  quartz,  fluor  spar, 
pyrite,  heavy  spar,  calcite,  each  two  or  three  times  repeated,  the 
layers  nearly  corresponding  on  either  side  of  the  middle  seam. 

The  bands  of  a  vein  are  far  from  uniform  at  different  heights,  even 
when  the  width  of  the  vein  is  constant ;  and  they  vary  exceedingly 
through  the  contractions  and  expansions  which  take  place  at  intervals. 
The  expanded  portions  may  alone  be  banded,  or  consist  of  layers 
parallel  to  the  sides,  or  contain  ore. 

The  mineral  or  rock-material  accompanying  the  ore  in  a  vein  is 
called  the  vein-stone,  or  gangue.  The  most  common  kinds  of  vein 
stone  are  quartz,  calcite,  barite,  and  fluorite. 

In  studying  veins,  besides  noting  their  extent,  mineral  character 
and  structure,  it  is  important  to  ascertain  their  strike  and  angle  of 
dip.  There  is  generally  an  approximate  uniformity  of  strike  in  a 
given  region ;  and  frequently  the  direction  is  parallel  to  the  principal 
line  of  elevation  in  the  region.  The  nature  of  the  walls  or  adjoining 
rock,  and  systems  of  faults,  are  other  points  that  should  receive  close 
attention. 

False  veins.  —  False  veins  are  fissures  filled  from  above.  They  are 
usually  distinguished  by  the  sedimentary  nature  of  the  material ;  all 
true  dikes  or  veins  arc  occupied  by  crystalline  rocks  or  minerals.  In 
a  similar  manner,  earth  and  organic  remains  may  be  washed  into 
caverns  or  any  open  spaces  in  rocks,  and  so  make,  in  the  very  body 
of  an  old  record,  a  false  entry. 

Such  openings  may  become  filled,  from  above,  either  with  sand  or  rock,  or  with 
metallic  ores.  The  lead  ore  of  Wisconsin,  Galena  in  Northern  Illinois,  and  Missouri, 
occupies,  according  to  J.  D.  Whitney,  great  irregular  cavities  in  the  rock  of  the  region, 
a  limestone,  and  is  not  in  true  veins.  The  same  is  the  case  with  the  lead  ore  of  Derby 
shire  and  Cumberland,  England:  for,  along  with  the  ore,  and  especially  near  the  lime 
stone  walls  of  the  cavities,  or  so-called  veins,  there  are  sometimes  many  fossils,  partly 
those  of  the  enclosing  limestone,  but  many  those  of  later  rocks,  showing  not  only  that 
the  filling  in  of  the  ore  was  from  above,  but  also  that  it  was  much  subsequent  in  time 
to  the  origin  of  the  limestone  (p.  104). 

Again,  some  of  the  so-called  veins  of  metallic  or  mineral  material  are  only  beds. 
They  have  the  aspect  of  veins,  because  the  rocks  have  been  upturned  so  as  to  make 
the  beds  vertical,  or  nearly  so,  in  position.  The  great  "  veins  "  of  iron  ore  in  northern 
New  York,  and  the  Marquette  region,  Michigan,  and  of  zinc-iron  ore  (franklinite)  in 
New  Jersey,  are  examples.  The  rocks  of  the  region  are  all  metamorphic,  and  so  is  the 
iron  ore,  which  originally  was  a  layer  of  uncrystalline  ore  much  like  those  of  the  Coal 
formation  in  Pennsylvania.  Many  of  the  metallic  "veins"  of  the  world,  even  those 
of  zinc,  copper,  cobalt,  etc.,  are  properly  metalliferous  layers,  somewhat  disguised  by 
upturning  and  metamorphism.  So  also  crystalline  limestone,  in  northern  New  York 
and  Canada,  sometimes  appears  to  be  in  veins,  and  has  been  so  described,  when,  in 
fact,  it  is  strictly  in  layers,  and  is  one  of  the  metamorphic  stratified  rocks  of  the  region. 

In  the  language  of  miners,  — 

A  lode  is  a  vein  containing  ore. 

The  hanging  wall  of  a  vein  is  the  upper  wall  when  the  vein  has  an  oblique  dip ;  and 
the  opposite  is  i\iQ  foot-wall. 


LIFE. 

The  fluccan  is  the  half-decomposed  rock  adjoining  a  vein. 

A  horse  is  a  body  of  rock,  like  the  wall-rock  in  kind,  occurring  in  the  course  of  a 
vein. 

A  comb  is  one  of  the  layers  in  a  banded  vein,  —  so  called  especially  when  its  surface 
is  more  or  less  set  with  crystals.  A  cavity  in  a  vein  set  around  with  crystals  is  called 
a  geode. 

Country,  country-rock,  wall-rock  are  terms  applied  to  the  rock  in  which  a  lode 
occurs. 

A  reef,  in  Australian  gold  mining,  is  a  large  auriferous  quartz  vein. 

Selvage  is  a  thin  band  of  earthy  matter  between  a  lode  and  its  walls,  or  the  sharp 
line  of  demarcation  between  a  lode  and  the  wall-rock. 

A  branch  or  leader  is  a  small  vein  striking  out  from  the  main  lode. 

Fahlbands,m  Germany,  Norway,  etc.,  are  metalliferous  belts  or  zones;  they  some 
times  consist  of  ore-bands  (Erzbander),  and  rock-bands  (Felsbander) ;  or  the  lodes  of 
the  region  may  be  rich  in  ore  only  where  they  intersect  the  Fahlbands. 

On  metallic  veins,  see  further,  WHITNEY'S  "  Metallic  Wealth  of  the  United  States  " 
(Philad.  1854),  and  COTTA'S  excellent  "Treatise  on  Ore  Deposits  "  (New  York,  1869). 


The  progress  of  the  life  of  the  globe  is  one  of  the  two  great  sub 
jects  that  come  before  the  student,  in  the  following  part  of  this  Man 
ual,  treating  of  HISTORICAL  GEOLOGY.  By  way  of  introduction  to 
it,  a  short  chapter  on  its  system  of  structures  is  here  introduced. 

BRIEF    REVIEW  OF    THE    SYSTEM   OF    LIFE. 

1.  GENERAL   CONSIDERATIONS. 

1.  Life.  —  Some  of  the  distinctions  between  a  living  organism  and 
inorganic  or  mineral  substances  have  been  mentioned.  Recapitulating 
them,  with  additions,  they  are :  — 

(1.)  The  living  being  has,  as  the  fundamental  element  of  its  structures, 
visible  cells,  containing  fluids  or  plastic  material ;  instead  of  invisible 
molecules. 

(2.)  It  enlarges  by  means  of  imbibed  nutriment,  through  a  process  of 
evolution ;  and  not  by  mere  accretion  or  crystallization. 

(3.)  It  has  the  faculty  of  converting  the  nutriment  received,  into  the 
various  chemical  compounds  essential  to  its  constitution,  and  of  con 
tinuing  this  process  of  assimilation  as  long  as  the  functions  of  life 
continue  ;  and  it  loses  this  chemical  power  when  life  ceases. 

(4.)  It  passes  through  successive  stages  in  structure,  and  in  chemistry, 
from  the  simple  germ  to  a  more  or  less  complex  adult  state,  and  finally 
evolves  other  germs  for  the  continuance  of  the  species  ;  instead  of 
being  equally  perfect  and  equally  simple  in  all  its  stages,  and  essen 
tially  germless. 

There  is,  therefore,  in  the  living  organism,  something  besides  mere 


LIFE.  115 

physical  forces,  or  the  chemistry  of  dead  nature — something  that 
ceases  to  be  when  life  ceases.  There  is  a  vital  condition,  in  which 
molecules  have  powers  that  lead  to  resulting  seed-bearing  structures, 
widely  different  from  those  of  inorganic  nature,  and  standing  on  alto 
gether  a  higher  level.  There  is  a  power  of  evolution,  an  architectonic 
power,  that  not  only  exalts  chemical  results,  but  evolves  a  diversity  of 
parts  and  structures,  and  a  heritage  of  ancestral  qualities,  of  which 
the  laws  of  material  nature  give  no  explanation. 

2.  Vegetable  and  Animal  Life.  —  The  vegetable  and  animal  king 
doms  are  the  opposite,  but  mutually  dependent,  sides  or  parts  of  one 
system  of  life.  The  following  are  some  of  their  distinctive  character 
istics  :  — 

(1.)  Plants  take  nutriment  into  the  tissues  by  absorption,  and 
assimilate  it  without  the  aid  of  a  stomach,  or  any  digestive  fluid ;  ani 
mals  have  a  mouth,  and  receive  food  into  a  sac  or  stomach.  p]xcep- 
tions  to  this  feature  of  animal  life  occur  only  in  the  lowest  microscopic 
forms  and  certain  parasitic  kinds ;  and  the  most  of  these  extemporize 
a  mouth  and  stomach  whenever  any  particle  of  food  comes  in  contact 
with  the  outer  surface,  so  that  even  here  the  food  is  digested  in  an  inte 
rior  cavity. 

(2.)  Plants  find  nutriment  in  carbonic  acid,  appropriate  the  carbon, 
and  excrete  oxygen,  a  gas  essential  to  animal  life ;  animals  use  oxygen 
in  respiration,  and  excrete  carbonic  acid,  a  gas  essential  to  vegetable 
life. 

(3.)  Plants  take  inorganic  material  as  food,  and  turn  it  into  organic ; 
animals  take  this  organic  material  thus  prepared  (plants),  or  other 
organic  materials  made  from  it  (animals),  finding  no  nutriment  in  inor 
ganic  matter. 

(4.)  The  Vegetable  kingdom  is  a  provision  for  the  storing  away  or 
magazining  of  force  for  the  Animal  kingdom.  This  force  is  acquired 
through  the  sun's  influence  or  forces  acting  on  the  plant,  and  so  pro 
moting  growth ;  mineral  matter  is  thereby  carried  up  to  a  higher  grade 
of  composition,  that  of  starch,  gluten,  and  vegetable  fibre,  and  this  is  a 
state  of  concentrated  or  accumulated  force.  To  this  stored  force  ani 
mals  go  in  order  to  carry  forward  their  development ;  and,  moreover, 
the  grade  of  composition  thus  rises  still  higher,  to  muscle  and  nerve 
(which  contain  much  nitrogen  in  addition  to  the  ordinary  constituents 
of  the  plant)  ;  and  this  is  a  magazining  of  force  in  a  still  more  concen 
trated  or  condensed  state. 

(5.)  Plants  of  some  minute  kinds,  and  the  spores  of  some  larger 
species  (some  Algre),  have  locomotion,  or  a  degree  of  contractility  in 
certain  parts  that  corresponds  to  an  infinitesimal  amount  of  mechanical 
power  ;  but  the  locomotive  spores,  as  they  develop,  become  fixed,  like 


116 


ANIMAL    KINGDOM. 


the  plants  from  ordinary  seeds,  and  no  increase  of  mechanical  power 
ever  accompanies  vegetable  development.  In  animal  development 
from  the  germ,  on  the  contrary,  there  is  always  an  increase  of  power 
-  an  increase,  in  all,  of  muscular  power,  and,  in  the  case  of  species 
above  the  lower  grade,  of  psychical  and  intellectual  power,  —  until  an 
ant,  for  example,  becomes  a  one-ant  power,  a  horse  a  one-horse  power. 
Whence,  an  animal  is  a  self-propagating  piece  of  enginery,  of  various 
power  according  to  the  species. 

(6.)  In  the  plant,  the  root  grows  downward  (or  d«r&-ward)  and  the 
stem  upward  (or  %/^-ward),  and  there  is  thus  the  up-and-down  polar 
ity  of  growth  —  the  higher  developments,  those  connected  with  the 
fruit,  taking  place  above,  or  in  the  light.  In  the  animal,  there  is  an 
antero -posterior  polarity  of  power  as  well  as  growth  —  the  head,  which 
is  the  seat  of  the  chief  nervous  mass  and  of  the  senses,  and  the  .locus 
of  the  mouth,  making  the  anterior  extremity.  Consequently,  there  is 
in  animals  a  connection  between  grade  and  the  greater  or  less  domi 
nance  and  perfection  of  the  head  extremity.  An  animal,  as  its  ordinary 
movements  manifest,  is  preeminently  a  go-ahead  thing.  Even  the  in 
ferior  stationary  species,  like  the  polyp,  show  it  in  the  superior  power 
that  belongs  to  the  mouth  extremity. 

(7.)  Plants  have  no  consciousness  of  self,  or  of  other  existences  , 
animals  are  conscious  of  an  outer  world,  and  even  the  lowest  show  it 
by  avoiding  obstacles. 

From  the  above  diverse  characteristics  of  plants  and  animals,  it  fol 
lows  that,  however  alike  the  germs  of  the  two  are  chemically  (that  is, 
although  containing  the  same  elements  in  the  same  proportions),  they 
must  be  in  their  chemical  nature  fundamentally  different. 

2.  ANIMAL   KINGDOM. 

In  the  Animal  Kingdom,  there  are  Jive  SUB-KINGDOMS,  based  on 
distinct  types  of  structure,  each  having  its  system  of  subdivisions  of 
several  grades  or  ranks.  These  sub-kingdoms  are  as  follow,  beginning 
with  the  lowest :  — 

I.  PROTOZOANS;  II.  RADIATES;  III.  MOLLUSKS  ;  IV.  ARTICU 
LATES  ;  Y.  VERTEBRATES. 

The  Animal  Kingdom  may  also  be  divided  into  INVERTEBRATES, 
and  VERTEBRATES  —  Radiates,  Mollusks,  Articulates,  and  Protozoans 
being  the  Invertebrates. 

I.  Protozoans,  the  lowest  and  simplest  of  animals,  show  their  sim 
plicity  in  their  minuteness  (mostly  between  a  100th  and  a  10,000th  of 
an  inch  in  length)  ;  in  having  no  external  organs  except  a  mouth  and 
minute  cilia  or  thread-like  processes,  and  no  digestive  apparatus  be 
yond  a  stomach ;  in  the  fact  that  the  stomach  and  mouth  are  some- 


ANIMAL   KINGDOM. 


117 


times  wanting,  or  exist  only  when  extemporized  for  the  occasion ;  in 
having  no  heart  or  circulating  system,  beyond  a  palpitating  vesicle  or 
vacuole.  Many  of  the  Infusorians  or  Animalcules  are  here  included. 

II.  Radiates.  —  Having  a  radiate  structure,  like  a  flower,  internally 
as  well  as  externally  ;  that  is,  having  similar  parts  or  organs  repeated 
around  a  vertical  axis.  The  animals  have  a  mouth  and  stomach  for 
eating  and  digestion,  and  hence  they  are  widely  diverse  from  plants, 
although  resembling  them  in  their  radiate  arrangement  of  parts. 

Figs".  137  to  149  represent  examples  of  Radiates  :  137,  an  Actinia, 
or  Polyp;  138,  139,  living  corals,  the  animals  of  which  are  polyps; 
140,  a  Medusa  or  Acaleph,  —  also  called  Jelly-fsh,  —  showing  well 
the  internal  as  well  as  external  radiate  structure,  as  the  animal  is 
nearly  transparent ;  141,  142,  polyp-like  species  of  the  class  of  Aca- 
lephs  ;  143,  an  Echinus,  or  Sea  urchin, — but  not  perfect,  as  the  spines 
which  cover  the  shell  and  give  origin  to  the  name  Echinus  are  re 
moved  from  half  its  surface, to  show  the  shell ;  144,  a  Star-fish;  145, 
146,  Crinoids,  —  animals  like  an  inverted  Star-fish  or  Echinus,  stand- 


Figs.  137-146. 


RADIATES,  Figs.  137-146.  1.  Polyps:  Fig.  137,  an  Actinia  ;  138,  a  coral,  Dendrophy Ilia ;  139.  a 
coral  of  the  genus  Gorgonia.  2.  Acnlephs :  140  a  Medusa,  genus  Tiaropsis  ;  141,  Hydra  (X  S); 
142,  Syncoryna.  3.  Echinodermx :  143,  Echinus,  the  spines  removed  from  half  the  surface. 
(X  K);  144,  Star-fish.  Palaeaster  Niagarensis  ;  145,  Crinoirl,  Encrinus  liliiforniis  ;  146,  Crinoid, 
of  the  family  of  Cystids,  Callocystites  Jewettii. 

ing  on  a  stem  or  pedicel,  like  a  flower.  Fig.  147,  on  the  next  page, 
is  the  shell  of  another  Sea-urchin  ;  and  Fig.  148,  another  Crinoid. 
Figs.  573  to  582  are  additional  examples  of  Radiates. 

The  radiate  feature  exists  not  only  in  the  external  form,  but  also 
in  the  interior  structure.     The  mouth,  when  furnished  with  calcareous 


118 


ANIMAL    KINGDOM. 


jaws  or  mandibles,  has  a  circle  of  five  of  them ;  and  the  nervous  sys 
tem,  when  distinct,  is  circular  in  arrangement. 

III.  Mollusks.  —  The  structure,  essentially :  (1)  a  soft  fleshy  bag, 
containing  the  stomach  and  viscera,  (2)  without  a  radiate  structure, 
and  (3)  without  articulations  or  jointed  appendages.  The  animals  of 
the  Oyster  and  Snail  are  examples.  Similar  parts  are  repeated  on 
the  right  and  left  sides  of  a  median  plane,  as  in  Articulates  and  Ver 
tebrates,  and  not  around  a  vertical  axis,  as  in  Radiates.  They  are 
essentially  simple  in  fundamental  structure,  and  not  multiplicate  iu 
successive  parts,  like  an  Articulate. 

Figs.  147-149. 


RADIATES.— Fig.  147,  an  Echinus  without  its  spines,  — the  Clypeus  Hugi  of  the  Oolyte;  148,  the 
Hying  Pentacrinus  Caput-Medusae  of  the  West  Indies  (X/z) :  «•  b,  c,  c/,  outlines  of  the  stems  of 
different  species  of  Pentacrini :  149,  plates  composing  the  body  of  the  Crinid,  Batocriuus  longi- 
rostris  (wrongly  reversed  in  copying  from  Hall). 

Figs.  150  to  159  represent  some  of  the  kinds  of  Mollusks.  Figs. 
150.  153,  154,  155,  are  shells  of  different  species;  156,  the  shell  of  a 
Snail,  with  its  animal;  158,  another  shell,  the  Nautilus,  with  its 
animal  ;  152,  a  magnified  view  of  a  minute  coral,  with  the  living 
animals  projecting  from  the  cells,  which,  although  apparently  radiated 
like  a  polyp,  are  still  Mollusks,  because  this  radiation  is  only  external, 
as  is  apparent  in  Fig.  152  a.  which  represents  one  of  the  animals 
taken  out  of  the  cell  and  more  magnified.  Fig.  159,  on  the  next 
page,  is  another  Mollusk,  —  a  Cephalopod,  —  having  some  resem 
blance  to  a  Radiate  in  the  position  of  the  arms,  but  none  beyond  this. 
The  name  Mollusk  is  from  the  Latin  mollis,  soft.  The  shells  are  for 
the  protection  of  the  soft,  fleshy  bodies. 

IV.  Articulates.  —  Consisting  (1)  of  a  series  of  joints  or  segments; 
(2)  having  the  legs,  when  any  exist,  jointed  ;  (3)  having  the  viscera 


ANIMAL   KINGDOM. 


119 


and  nervous  cord  in  the  same  general  cavity  ;   (4)  having  no  internal 
skeleton  ;  as  Worms,  Crustaceans,  Insects. 

The  articulations  are  made  in  the  hardened  skin,  and  not,  as  in 
Vertebrates,  in  internal  bones  ;  and  the  principal  nervous  cord  passes 

Figs.  150-158. 
150 


MOLLUSKS,  Figs.  150-158. — 1.  Brachiopods:  150,  Terebratula  impress^,  of  the  Oolyte ;  151,  Liu- 
gula,  on  its  stem.  2.  Eryozoa:  152  (XS),  152  a,genusEschara.  3.  Lamellibranchs (Common 
Bivalves) :  153, 154 ;  155,  the  .  Oyster.  4.  Gasteropods :  156,  Helix.  5-  Pteropods  :  157.  genus 
Cleodora.  6.  Cephalopods:  158,  Nautilus  (X%)- 


Fig.  159. 


The  Calamary  or  Squid,  Loligo  vulgaris  (length  of  body,  6  to  12  inches) ;  i  the  duct  by  which  the 
ink  is  thrown  out;  p,  the  "  pen.'; 

below  the  stomach  and  intestine,  and  has  usually  a  ganglion  for  each 
segment  of  the  body,  —  so  that  the  articulate  structure  is  indicated 
by  the  nervous  system,  as  well  as  by  the  joints  of  the  body  and  its 
members.  The  fundamental  element  of  the  body  is,  hence,  a  segment 
or  ring  containing  a  nervous  ganglion  and  a  portion  of  the  viscera. 
An  Articulate  is  thus  multiplicate  in  structure,  or  consists  of  suc 
cessive  approximately  similar  segments  or  parts,  and  is  thus  unlike 
the  Mollusks. 

Some  of  the  Articulates  are  shown  in  Figs.  160  to  169.      Fig.  160 
is  a  sea-shore  worm;  161,  a  Crab ;  162  to  167,  other   Crustaceans; 


120 


ANIMAL   KINGDOM. 


168,  another  Crustacean,  having  a  shell  like  a  Mollusk,  but  showing 
that  it  is   a  true  Articulate  by  its  jointed  legs  and  antennae,  and  its 


Figs.  160-169. 


ARTICULATES,  Figs.  160-169.  —  1.  Worms:  160.  Arenicola  marina,  or  Lob-worm  (X>g)-  2.  Crus 
taceans:  161,  Crab,  species  of  Cancer  ;  162,  an  Iso pod,  species  of  Porcellio  ;  163,  an  Amphipod, 
species  of  Orchestia  ;  164,  an  Isopod,  species  of  Serolis  (X>a) !  165i  166,  Sapphirina  Iris;  165, 
female,  166,  male  (X6);  167,  Trilobite.  Calymene  Blumenbachii ;  168,  Cy there  Americana,  of 
the  Cypris  family  (x!2) ;  169,  Anatifa,  of  the  Cirriped  tribe. 

jointed  body  within  the  shell;  169,  representing  a  Cirriped,  is  also 
somewhat  like  a  Mollusk  in  its  shell,  —  though  articulate  in  structure, 
as  the  legs  show,  and,  in  fact,  a  Crustacean.  Centipedes,  and  all  In 
sects,  as  well  as  Worms,  are  other  examples  of  Articulates,  the  body 
consisting  of  a  number  of  segments.  The  name  of  the  sub-kingdom 
is  from  articulus,  a  joint. 

V.  Vertebrates.  —  Having  (1)  a  jointed  internal  skeleton,  and 
(2)  a  bone-sheathed  cavity  along  the  back,  for  the  great  nervous  cord, 
distinct  from  the  cavity  for  the  viscera :  as  in  Fishes,  Reptiles,  Birds, 
Quadrupeds. 

The  skeleton  is  made  up  of  vertebras,  or  the  bones  of  the  vertebral 
column,  with  their  appendages  ;  and  a  vertebra  is  the  fundamental 
element  of  the  structure.  The  bone-sheathed  cavity  occupied  by  the 
nervous  cord  is  enclosed  by  processes  from  the  upper  (or  dorsal)  side 
of  the  vertebrae,  and  the  visceral  cavity  by  the  ribs,  which  are  pro 
cesses  from  the  lower  side  of  the  vertebras.  The  legs  and  arms  are 
appendages  to  the  system  of  vertebras  and  ribs. 

Recapitulation.  —  In  Radiates,  the  structure  is  radiate  or  flower- 
like.  In  Mollusks,  it  is  bag-like  and  simple.  In  Articulates,  it  is 
made  of  a  series  of  rings,  and  is  composite  in  the  structure  of  both 
the  skeleton  and  the  nervous  system.  In  Vertebrates,  it  contains  a 
series  of  vertebrae,  and  is  composite  in  the  skeleton ;  and,  besides,  it 
has  separate  cavities  for  the  nervous  cord  and  viscera. 


ANIMAL   KINGDOM.  121 

SUBDIVISIONS    OF    THE    SUBKINGDOMS. 

I.  VERTEBRATES. 

Four  classes  are  generally  recognized  :  — 

1.  MAMMALS. —  Species    suckling   their  young, — a   characteristic 
peculiar  to  this  highest  branch  of  the  animal  kingdom  :  all  are  warm 
blooded  and   air-breathing.     Examples:  ordinary    Quadrupeds,    large 
and  small,  with  Whales  and  Seals. 

2.  BIRDS.  —  Warm-blooded  and  air-breathing  ;  oviparous  ;  covered 
with  feathers,  and  adapted  for  flying. 

3.  REPTILES.  —  Cold  blooded,     air-breathing  ;    oviparous  ;     skin 
naked  or  covered  with  scales.     Two  divisions  are  here  included,  which 
are  often  made  distinct  classes,  —  (1)  Amphibians,  which  have  gills 
when  in  the  young  state,  and  lose  them  on  becoming  adults,  as  Frogs 
and  Salamanders  ;   (2)   True  Reptiles,  which  breath  with  lungs  in  both 
the  young  and  adult  stages,  as  Crocodiles,  Lizards,  Turtles,  Snakes. 

4.  FISHES.  —  Cold-blooded;    breathing    by   means   of  gills;    skin 
naked,  or  covered  with  scales. 

II.  ARTICULATES. 

The  classes  are  three  in  number ;  one  of  them  —  INSECTEANS  (in 
cluding  Insects,  Spiders,  and  Myriopods)  —  aerial  in  respiration ;  the 
other  two,  including  CRUSTACEANS  and  W^ORMS,  breathing  by  means 
of  gills,  and  living  in  water  or  moist  earth. 

A.  Respiration    by  lung-like   cavities,  or    through  breathing-holes 
(spiracles)  along  the  sides  or  posterior  part  of  the   body,  admitting 
air  to  circulate  in  the  interior.     Essentially  land  or  aerial  species. 

1.  INSECTEANS.  —  (1.)  Insects.  —  The  body  in  three  parts,  —  head, 
thorax,  and  abdomen  distinct ;  only  three  pairs  of  legs.     Examples : 
the  Beetle,  Wasp,  Fly,  Butterfly. 

(2.)  Spiders.  —  The  body  in  two  parts  (in  the  lower  division,  only 
one),  the  head  and  thorax  not  distinct ;  four  pairs  of  legs.  Examples: 
the  Spider,  Tick,  Scorpion. 

(3.)  Myriapods. — The  body  worm-like  in  form,  the  abdomen  not 
prominently  distinct  from  the  rest ;  legs  numerous.  Example :  the 
Centipede. 

B.  Respiration  by  means  of  gills,  —  unless  the  species  is  so  minute 
that  the  surface  of  the  body  is  equivalent  to  a  gill  in  its  action.     Es 
sentially  water-species,  living  either  in  water  or  in  moist  places. 

2.  CRUSTACEANS.  —  The  body  in  two  parts,  —  the  anterior  called 
the  cephalothorax,  consisting  of  a  head  and  thorax,  the  posterior  called 
the  abdomen;  locomotion  by  means  of  jointed  organs.      Examples: 
the  Crab,  Lobster,  Shrimp. 


122  ANIMAL   KINGDOM. 

3.  WORMS.  —  Worm-like  in  form,  consisting  of  many  segment*,  with 
out  any  division  into  cephalo-thorax  and  abdomen  ;  the  body  fleshy ; 
no  jointed  legs,  though  often  furnished  with  tubercles,  lamella;,  or  bris 
tles.  Examples :  the  Earth-worm,  Leech,  Serpula,  Intestinal  Worm. 

The  aquatic  species  of  Articulates  commence  in  the  Silurian,  and 
are  here  further  explained. 

Crustaceans.  —  Among  Crustaceans,  there  are  three  orders  :  — 

Thejirst,  or  highest,  ten-footed  species,  or  Decapods  ;  as  Crabs  (Fig. 
1C1)  and  Lobsters. 

The  second,  fourteen-footed  species,  or  Tetradecapods  (Figs.  162, 
163,  164). 

The  third  and  lowest,  irregular  in  number  of  feet,  and  unlike  the 
Tetradecapods,  also,  in  not  having  a  series  of  appendages  to  the  ab 
domen  :  the  species  are  called  JEntomostracans^  from  the  Greek  for 
insects  with  shells. 

(a.)  Among  the  Decapods,  Crabs  are  called  Bracliyurans,  —  from  the  Greek  for  short- 
tailed,  the  abdomen  being  small  and  folded  up  under  the  body  ;  the  Lobsters  and 
Shrimps,  Macrurans, —  from  the  Greek  for  lony-tailed ',  the  abdomen  being  rarely- 
shorter  than  the  rest  of  the  body. 

(b.)  Among  the  Tetradecapods,  Figs.  1G2,  164  represent  species  of  the  tribe  of  fsopods 
(a  word  meaning  equal-footed),  and  Fig.  163,of  that  of  Ampliipods  (feet  of  two  kinds, 
abdominal  as  well  as  thoracic).  Fig.  102  is  the  Sow-bug,  common  under  stones  and 
dead  logs  in  moist  soil.  Fig.  163  is  the  Sand-flea,  abundant  among  the  sea-weed  thrown 
up  on  a  coast.  In  Figs.  162,  164  (Isopods),  the  abdomen  is  abruptly  narrower  than  the 
cephalothorax;  its  appendages  underneath  are  gills.  In  Fig.  163  (Amphipod), the  ab 
domen  is  the  part  of  the  body  following  (usually)  the  eighth  segment;  its  appendages 
are  swimming  legs  and  stylets,  — the  gills  in  Ampliipods  being  attached  to  the  bases 
of  the  true  legs,  and  not  to  the  abdomen. 

(c)  Among  Entomostracans,  the  forms  are  very  various.  The  absence  of  a  series  of 
abdominal  appendages  is  the  most  persistent  characteristic.  The  eyes,  in  a  few  species, 
have  a  prominent  cornea;  but,  in  the  most  of  them,  the  cornea  is  internal,  and  there  is  no 
projection.  In  the  Cyclops  group,  the  species  have  often  a  shrimp-like  form,  as  in  Fig. 
165,  though  usually  minute.  Sometimes  the  male  and  female  differ  much  in  form:  166 
is  male,  and  165  female  of  the  Sapphirina  Iris ;  a  l>  is  the  cephalothorax,  and  b  d  the 
abdomen.  There  are  legs  on  the  under  surface  of  the  anterior  part,  fitted  for  grasping, 
and  others,  behind  these,  for  swimming.  In  the  Cypris  group,  the  animal  is  contained 
in  a  bivalve  shell,  as  in  Fig.  168,  and  they  are  hence  called  Ostracoids.  They  are  sel 
dom  a  quarter  of  an  inch  long.  In  the  Limulus  group,  — containing  the  Horseshoe  of 
the  sea-coasts  of  the  United  States,  — there  is  a  broad,  shield-like  shell,  and  a  number 
of  stout  legs,  the  basal  joints  of  which  serve  for  jaws.  In  the  Phyllupod  group,  the 
form  is  either  shrimp-like,  approaching  Cyclops,  or  like  Daphnia  or  Cypris;  but  the 
appendages  or  legs  are  foliaceous  and  excessively  numerous:  the  name  is  from  the 
Greek  for  leaf-like  feet.  In  the  Cirriped  or  Barnacle  group,  the  animal  has  usually  a 
hard,  calcareous  shell,  and  it  is  permanently  attached  to  some  support,  as  in  the  Anatifa 
(Fig.  169)  and  Barnacle.  The  animal  opens  a  valve  at  the  top  of  the  shell,  and  throws 
out  its  several  pairs  of  jointed  arms  looking  a  little  like  a  curl,  and  thus  takes  its 
food,  —  whence  the  name,  from  the  Latin  cirrus,  a  curl,  and  pes,  foot.  The  Anatifa 
has  a  fleshy  stem,  while  the  ordinary  Barnacle  is  fixed  firmly  by  the  shell  to  its  sup 
port. 

Trilobites.  —  The  TriloUtes  (Fig.  167,  and  also  251,  and  360,448), 


ANIMAL   KINGDOM.  123 

which  occur  only  fossil,  have  resemblances  both  to  the  Entomostracans 
and  to  the  Tetradecapods.  The  similarity  to  Fig.  1G4  (a  Serolis)  among 
the  latter  is  apparent ;  but  they  are  supposed  to  be  still  nearer  the 
Entomostracans,  and  especially  the  group  called  Phyllopods,  in  which 
the  legs  are  thin-foliaceous  and  very  numerous,  — for  no  remains  of 
le^s  are  found  with  any  Trilobites,  which  would  not  be  the  case  if  they 
had  had  the  stout  legs  common  to  Crustaceans  of  the  same  size.  It 
is  possible  that  the  abdomen  (c  d,  in  Fig.  167)  had,  beneath,  a  series 
of  appendages  ;  and,  if  so,  they  differed  from  all  known  Entomostra 
cans,  and  approximated  to  the  Tetradecapods.  The  division  of  the 
body  longitudinally  into  three  lobes,  to  which  the  name  trilobite  refers, 
is  in  some  species  very  indistinct ;  and  there  is  in  no  case  more  than 
a  mere  depression  and  suture. 

In  the  Trilobite,  the  shell  of  the  head-portion  (a  b,  Fig.  167)  is  usually  called  the 
buckler;  the  tail- (or  properly  abdominal)  shield,  when  there  is  one  (Fig.  360),  the 
py(/i<lium.  The  buckler  (a  b)  is  divided  by  a  longitudinal  depression  into  the  cheeks,  or 
lateral  areas,  and  the  ylalella,  or  middle  area  (Fig.  167).  The  cheeks  are  usually 
divided  by  a  suture  extending  from  the  front  margin  by  the  inner  side  of  the  eye  to 
either  the  posterior  or  the  lateral  margin  of  the  shell.  In  Fig.  167  (Ctdymene  Blumen- 
bac/iii),  this  suture  terminates  near  the  posterior  outer  angle.  The  glabella  may  have  a 
plane  surface,  or  be  more  or  less  deeply  transversely  furrowed  (Fig.  167),  and  usually 
with  only  three  pairs  of  furrows. 

Worms.  —  Worms  are  divided  into  Annelids  and  Helminths. 

The  Annelids  include,  1,  the  Chcetopods,  having  setae  for  locomotion;  2,  the  Sipuncu- 
loids.  having  the  body  smooth  and  cylindrical;  3,  the  Bdtlloids,  or  Leeches;  besides 
the  two  groups  of  free -swimming  oceanic  species,  called  Ch&tognaih*  (Sagittai),  and 
Gymnucopa  (Tomopteris). 

The  Cluetopods  embrace  the  groups  — 

(1.)  Dorsibranchs,  or/ree  sea  worms,  having  in  general  short  branchial  appendages 
along  the  back.  Many  swim  free  in  the  open  sea,  and  others  live  in  the  sands  of  sea 
shores  or  the  muddy  bottom.  The  Arenicola  family  includes  species  that  burrow  in 
the  sands  of  sea-shores.  Fig.  160  represents  the  A.  manna,  or  Lob-worm,  which  is 
common  on  European  and  American  shores,  and  grows  to  the  size  of  the  finger.  One 
species  of  Eunice  has  a  length  of  four  feet. 

(2.)  The  Tubicola,  or  Serpula  tribe,  Avhich  live  in  a  calcareous  or  membranous  tube, 
and  have  a  delicate  branchial  flower,  often  of  great  beauty,  near  the  head.  They  are 
confined  to  salt  water.  The  tubes  often  penetrate  corals,  and  the  branchial  flower 
comes  out  as  a  rival  of  the  coral  polyps  around  it. 

(3.)  The  Terricola  (Oligochaeta),  or  Earth  worm  tribe,  destitute  of  branchial  appen 
dages;  as  the  common  Earth-worm. 

Besides  these,  there  are  the  Helminths,  including  various  Intestinal  worms,  and  the 
Turbellaria. 

III.    MOLLUSKS. 

The  three  grand  divisions  of  Mollusks  are  — 

I.  ORDINARY  MOLLUSKS,  having  usually  regular  gills  or  branchice^ 
in  addition  to  an  outer  enveloping  fold  of  the  skin  called  a  pallium, 
from  the  Latin  for  cloak  ;  as  the  oyster,  snail,  and  cuttle-fish. 

II.  ASCIDIAN    MOLLUSKS.     Unlike    Ordinary  Mollusks   in    being 


124  ANIMAL   KINGDOM. 

without  regular  branchiae  ;  and  unlike  the  Brachiate  Mollusks  in  not 
having  a  circle  or  spiral  of  ciliated  tentacles,  or  having  them  only  in 
a  rudimentary  state.  Also  having  a  leathery  or  membranous  exterior, 
without  a  shell. 

III.  BRACHIATE  MOLLUSKS.  Without  regular  branchiae ;  the 
shells,  when  any  exist,  bivalve,  but  transverse  across  the  back  and 
venter,  instead  of  vertical  either  side  of  the  body  ;  the  head  having  a 
fringe  of  slender  organs  arranged  around  the  mouth,  or  in  two  spiral 
groups  either  side  of  the  mouth.  These  Mollusks,  the  earliest  in 
geological  history,  have  some  worm-like  characteristics,  as  shown  by 
Morse ;  but  they  are  true  Mollusks  in  wanting  the  multiplicate  feature 
of  Articulates,  as  well  as  in  other  points. 

I.  ORDINARY  MOLLUSKS. 

The  ORDINARY  Mollusks  are  divided  into  — 

(1.)  The  Acephals,  or  headless  Mollti-sks,  the  head  not  being  distinctly 
defined  in  outline  ;  as  the  Oyster  and  Clam  ; 

(2.)   The  Cephalates,  having  a  defined  head  ;  as  the  Snail ;  and, 

(3.)  The  Cephalopods,  having  the  head  furnished  with  long  arms 
(or  feet)  ;  as  the  Cuttle-fish. 

The  Acephals  have  a  mouth,  but  no  perfect  organs  of  sight ;  the 
Cephalates  have  distinct  eyes  and  a  distinct  head  (Fig.  156)  ;  the 
Cephalopoda  have  the  eyes  large,  and  can  grasp  with  great  power  by 
means  of  their  arms,  which  are  furnished  with  suckers  (Fig.  159). 

The  pallium  starts  from  the  back,  and  often  covers  the  sides  of  the 
body  like  a  cloak,  and  is  either  open  or  closed  along  the  venter  :  it  is 
also  called  a  mantle.  It  lies  against  the  shell  in  the  oyster,  clam  and 
allied  species,  and  secretes  it ;  and,  in  some  univalves  or  Gasteropods, 
it  may  be  extended  out  over  more  or  less  of  the  exterior  of  the 
shell. 

1.  Cephalopods,  or  Cuttle-fishes.  —  There  are  two  orders  of  Ceph- 
alopods ;  one  having  external  shells,  and  four  gills  or  branchiae  ;  a 
second,  having  sometimes  internal  shells  but  no  external,  and  having 
but  two  branchiae.  The  external  shells  are  distinguished  from  those 
of  Gasteropods  (or  ordinary  univalves)  by  having,  with  a  rare  excep 
tion,  transverse  partitions,  —  whence  they  are  called  chambered  shells 
(Fig.  158).  They  may  be  either  straight,  or  coiled;  but  with  few  ex 
ceptions  they  are  coiled  in  a  plane,  instead  of  being  spiral.  A  tube, 
called  a  siphuncle,  passes  through  the  partitions  ;  and  this  siphuncle 
may  either  be  central  or  nearly  so,  as  in  the  genus  Nautilus  (Fig. 
158,  which  represents  a  shell  cut  through  the  middle  plane,  so  as 
to  show  the  partitions  and  the  siphuncle),  or  lie  along  the  inner  or 
ventral  side  of  the  cavity,  or  the  outer  or  dorsal  side,  as  in  Ammonites. 


ANIMAL   KINGDOM.  125 

The  animal  occupies  the  outer  chamber,  as  in  Fig.  158.  These  cham 
bered  shells  containing  Cephalopoda  were  once  extremely  numerous  ; 
but  less  than  half  a  dozen  living  species  are  known,  and  these  are  of 
the  genus  Nautilus. 

Modern  Cephalopods  |re  almost  exclusively  naked  species,  having 
an  internal  shell,  if  any.  In  a  few  species,  as  in  the  genus  Spi/ula, 
the  internal  shell  is  chambered  and  coiled  (the  coils  not  touching)  ;  but 
in  the  rest  it  is  straight,  lying  in  the  mantle  along  the  back,  and  serves 
only  to  stiffen  the  soft  body.  In  the  Cuttle-fish  it  is  spongy-calcareous. 
In  the  Squid,  or  Calamary,  —  a  more  slender  animal,  requiring  some 
flexibility  for  its  movements,  —  it  is  horny,  and  is  called  the  pen  (  p, 
Fig.  159  p.  119).  In  some  cases,  it  has  a  small  conical  cavity  at.  the 
lower  end.  In  the  Belemnites,  a  group  of  fossil  species,  it  was  stout, 
cylindrical  and  calcareous,  with  a  deep  conical  cavity,  and  on  one  side 
the  margin  was  prolonged  into  a  thin  blade  (Figs.  792,  793). 

The  mouth  of  the  Cephalopods  has  often  a  pair  of  horny  mandibles, 
like  the  beak  of  a  hawk  in  form  ;  and  these  beaks,  when  fossilized, 
have  been  called  Rhyncholites. 

2.  Cephalates.  —  The  Cephalates  are  divided  into  two  groups  :  — 

(1.)  The  Gasteropods,  the  group  containing  the  Univalve  shells,  as 
well  as  some  related  species  without  shells,  —  the  animals  of  which 
crawl  on  a  flat  spreading  fleshy  organ  called  the  foot  (Fig.  156)  ;  and 
hence  the  name,  from  the  Greek,  implying  that  they  use  the  venter 
(yao-n/p  in  Greek),  or  under  surface,  for  a  foot. 

(2.)  The  Pteropods,  which  swim  by  means  of  wing-like  appendages 
(Fig.  157),  —  to  which  the  name  refers,  meaning  wing-footed  (from 
wing,  and  TTOVJ,  foot). 


The  Gasteropods,  which  embrace  nearly  all  the  cephalate  Mollusks,  have  usually  a 
spiral  shell,  as  in  the  common  Snail,  Buccinum,  Turbo,  etc.  The  mantle  of  the  animal 
is  sometimes  prolonged  into  a  tube  or  siphon,  to  convey  water  to  the  gills;  and,  in  this 
case,  the  shell  often  has  a  canal  at  the  beak  for  the  passage  of  the  siphon.  The  mod 
ern  marine  univalves  without  a  beak,  the  Natica  group  and  some  others  excepted,  are 
herbivorous,  while  those  having  a  beak  are  as  generally  carnivorous. 

3.  Acephals,  or  Headless  Mollusks.  —  There  is  but  one  group,  the 
Lamellibranchs.  —  These  common  species  are  well  known  as  bivalves. 
Between  the  mantle  or  pallium  and  the  body  of  the  animal  lie  the 
lamellar  branchiae,  or  gills,  as  is  obvious  in  an  oyster  ;  and  hence  the 
name  Lamellibranchs.  In  a  shell  like  Fig.  153,  p.  119,  the  mouth  of 
the  animal  faces  almost  always  (except  in  some  species  of  Nucida  and 
Solemyd)  the  margin  a,  or  the  side  of  the  shorter  slope  ;  and  a  is  there 
fore  the  anterior  side,  b  the  posterior  ;  and,  placing  the  animal  with 
the  short  slope  in  front,  one  valve  is  the  right  and  the  other  the  left. 
The  hinge  is  at  the  back  of  the  Mollusk. 


126  ANIMAL   KINGDOM. 

On  the  lower  margin  of  the  animal,  toward  the  front  part,  there  is,  in  the  Clam  and 
most  other  species, a  tough  portion  which  is  called  the  foot:  it  is  used,  when  large,  for 
locomotion,  as  in  the  fresh-water  Clam;  when  small,  it  sometimes  gives  origin  to  the 
byssus  by  which  shells  like  the  Mussel  are  attached.  It  is  wanting,  or  nearly  so,  in  the 
Oyster. 

The  mantle  is  sometimes  free  at  the  lower  margin,  as  in  the  Oyster;  sometimes  the 
edges  of  the  two  sides  are  united,  making  a  cavity  aboift  the  body,  open  at  the  ends;  in 
other  cases, this  cavity  is  prolonged  into  a  tube  or  siphon,  or  into  two  tubes  projecting 
behind,  one  receiving  water  for  the  gills,  and  the  other  giving  the  water  exit.  The 
shell  is  closed  by  one  muscle  in  the  Oyster,  etc.,  by  two  in  the  Clam,  etc.  The  species 
with  two  muscles  are  called  Dtmi/aries, — from  the  Greek  for  two  muscles;  and  those 
with  one,  Monomyai-ies,  —  from  the  Greek  for  one  muscle. 

These  different  peculiarities  of  the  animal  are  partly  marked  on  the  shell.  In  Figs. 
153,  154,  the  two  muscular  impressions  are  seen  at  1  and  2;  the  impression  of  the 
margin  of  the  mantle  (palli'd  imjwession,  as  it  is  called)  &tpp;  and,  in  Fig.  154,  the 
siphon  is  indicated  by  a  deep  sinus  in  the  pallial  impression  at  s.  In  155,  the  shell  of 
an  oyster,  there  is  only  one  muscular  impression 

2.    ASCIDIANS. 

Ascidians  have  a  leathery  or  membranous  exterior,  bag-like,  with 
two  openings,  one  for  the  admission  of  water  and  food,  the  other  for 
the  exit  of  excretions.  The  name  is  from  the  Greek  do-Kos,  a  leather 
wine-bottle.  Having  no  shell,  they  are  not  yet  known  among  fossils. 
Yet  it  is  probable  that  they  were  among  the  earliest  kinds  of  Mol- 
lusks. 

3.  BRACHIATE  MOLLUSKS. 

1.  Brachiopods.  —  Brachiopods  (Figs.  150,  151,  and  218  to  246, 
pp.  171-173)  have  a  bivalve  shell,  and  in  this  respect  are  like  ordinary 
bivalves.  But  the  shell,  instead  of  covering  the  right  and  left  sides, 
covers  the  dorsal  and  ventral  sides,  or  its  plane  is  at  right  angles  to 
that  of  a  clam.  Moreover,  it  is  symmetrical  in  form,  and  equal,  either 
side  of  a  vertical  line  a  b,  Fig.  150  (p.  119).  The  valves,  moreover, 
are  almost  always  unequal ;  the  larger  is  the  ventral,  and  the  other  the 
dorsal.  There  is  often  an  aperture  at  the  beak  (near  b,  Fig.  150), 
which  gives  exit  to  a  pedicel  by  means  of  which  the  animal  is  fixed  to 
some  support.  In  Fig.  151,  p.  119,  representing  a  species  of  the 
genus  Lingula,  the  fleshy  support  is  a  long  one  implanted  in  the 
sand  by  burrowing. 

These  Brachiopods  are  also  peculiar  in  other  points  of  structure. 
They  have  a  pallium,  but  no  independent  branchial  leaflets.  They 
have  a  pair  of  coiled  fringed  arms,  which  in  some  Brachiopods  may 
be  extruded  (Fig.  226),  —  whence  the  name  Brachiopod,  meaning 
arm-like  foot.  For  the  support  of  these  arms,  there  are  often  bony 
processes  in  the  interior  of  the  shell,  of  diverse  forms  in  different 
genera  (Figs.  218,  222,  and  225.)  These  arms  serve  to  keep  up  a  cur 
rent  of  water  over  or  through  the  brachial  cavity  of  the  animal. 


ANIMAL   KINGDOM.  127 

2.  Bryozoans.  —  Bryozoans,  or  moss-animals  (so  named  with  refer 
ence  to  the  moss-like  corals  they  often  form),  look  like  polyps,  owing 
to  the  series  of  slender  ciliated  organs  surrounding  the  mouth,  as  repre 
sented  in  Figs.  152,  152  a,  p.  119.  152  is  magnified  about  eight  times  ; 
and  152  a  represents  the  animal,  showing  its  stomach  at  s,  and  the 
flexure  in  the  alimentary  canal,  with  its  termination  along  side  of  the 
mouth.  The  corals  consist  of  minute  cells  either  in  branched,  reticu 
lated,  or  incrusting  forms.  They  are  often  cal- 
careous;  and  such  were  common  in  the  Silurian, 
and  still  occur.  Eschara,  Fiustra,  Retepora 
are  names  of  some  of  the  genera. 


Fig.  169  A  represents  a  membranous  species  (called 
Gemellaria  loricata.);  a  is  the  moss-like  coral,  natural 
size;  and  b  a  portion  of  a  branch,  enlarged,  showing  the 
cells.  Bryozoans  are  also  called  Polijzoans.  BRYOZOAX,  Gemellaria  loricata. 

IV.  RADIATES. 

The  sub-kingdom  of  Radiates  contains  three  classes  :  — 

1.  ECHINODERMS. —  Having  the  exterior  more  or  less  calcareous, 
and  often  furnished  with  spines ;  and  having  distinct  nervous  and  res 
piratory  systems  and  intestine,  as  the  Echinus  (Fig.   143),  Star-fish 
(Fig.  144),  Crinoid  (Fig.  145).    The  name  is  from  echinus,  a  hedge 
hog,  in  allusion  to  the  spines. 

2.  ACALEPHS.  —  Having  the   body   usually  nearly   transparent  or 
translucent,  looking  jelly-like  ;  and  internally  a  stomach-cavity,  with 
radiating  branches.     Ex.,  the   Medusa,  or  jelly-fish  (Fig.  140),  which 
generally  floats  free,  when  in  the  adult  stage,  with  the  mouth  down 
ward  ;  the  Hydra  and  allied  species  arc  here  included. 

3o  POLYPS.  —  Fleshy  animals,  like  a  flower  in  form,  having  above, 
as  seen  in  Figs.  137,  138,  a  disk,  with  a  mouth  at  centre,  and  a  margin 
of  tentacles  ;  internally,  a  radiated  arrangement  of  fleshy  plates  ;  and 
living  for  the  most  part  attached  by  the  base  to  some  support.  Ex., 
the  Actinia,  or  Sea-Anemone,  and  the  animals  of  ordinary  corals. 

All  these  classes  commence  in  the  Lower  Silurian  ;  and  some  of 
their  sub-divisions  are  therefore  here  mentioned. 

1.  Echinoderms.     1.  Holothurioids  or  Sea-slugs.  —  Having  the  ex 
terior   soft,    and    throughout    extensile  or  contractile,  and    the    body 
elongated  ;  mouth  at  one  end  surrounded  by  a  wreath  of  branched 
tentacles.     It  includes  the  Biche  de  mar,  or  Sea-cucumber. 

2.  Echinoids   or    Sea-urchins.  —  Having    a  thin    and    firm    hollow 
shell,  covered   externally  with  spines  (Fig.  143)  ;   form,  spheroidal  to 
disk-shape  ;  the  mouth  below,  at  or  near  the  centre,  as  the  Echinus, 
Fig.  143. 


128 


ANIMAL   KINGDOM. 


Fig.  143  represents  an  Echinus  partly  uncovered  of  its  spines,  showing  the  shell  be 
neath,  and  147  another,  wholly  uncovered.  The  shell  consists  of  polygonal  pieces, 
in  twenty  vertical  series,  arranged  in  ten  pairs,  except  in  species  of  the  Paleozoic, 
Five  of  these  ten  pairs  are  perforated  with  minute  holes,  and  are  called  the  am 
bulacral  series  (a  in  Fig.  143  represents  one  pair);  and  the  other  five,  alternating  with 
these,  are  called  the  inter-ambulacral  (b).  The  inter-ambulacral  areas  have  the  sur 
face  covered  with  tubercles,  and  the  tubercles  bear  the  spines,  which  are  all  movable 
by  means  of  muscles.  The  ambulacral  have  few  smaller  tubercles  and  spines,  or  none: 
but  over  each  pore  (or  rather  each  pair  of  pores)  the  animal  extends  out  a  slender 
fleshy  tentacle  or  feeler,  which  has  usually  a  sucker-like  termination  and  is  used  for 
clinging  or  for  locomotion.  In  Fig.  147,  the  inter-ambulacral  areas  are  broad  and  the 
plates  large,  but  the  ambulacral  are  narrow  and  the  plates  indistinct. 

The  mouth-opening  is  situated  below,  at  the  centre  of  radiation  of  the  plates. 

The  anal  opening  in  the  Regular  Echinoids  (Fig.  143)  is  in  the  opposite  or  dorsal 
area  or  centre  of  radiation.  Around  the  dorsal  area  there  are  five  minute  ovarian  open 
ings. 

In  the  Irregular  Echinoids  — constituting  a  large  group  — the  anal  opening  is  to 
one  side  of  this  dorsal  centre  of  radiation,  and  often  on  the  ventral  or  under  surface  of 
the  animal.  In  Fig.  147,  for  example,  the  anal  opening  is  marginal  instead  of  central, 
while  the  ovarian  pores  are  around  the  dorsal  centre,  as  in  the  Reyultr  Echinoids. 

To  one  side  of  the  dorsal  centre  in  the  Regular  Echinoids,  there  is  a  small  porous 
prominence  on  the  shell,  often  called  the  madreporic  body,  from  a  degree  of  resem 
blance  in  structure  to  coral.  In  some  of  the  Irregular  Echinoids,  this  madreporic  body 
is  in  the  centre  of  dorsal  radiation. 

The  ambulacral  areas  are  sometimes  perforated  throughout  their  whole  length.  But 
in  other  cases  only  a  dorsal  portion  is  conspicuously  perforated,  as  in  Fig.  147,  and,  as 
this  portion  has  in  this  case  some  resemblance  to  the  petals  of  a  flower,  the  ambulacra 
are  then  said  to  be  petaloid.  A  large  part  of  Echinoids  have  a  circle  of  five  strong, 
calcareous  jaws  in  the  mouth;  in  a  portion  of  the  Irregular  Echinoids  there  are  no  jaws. 

3.  Asterioids  or  the  Star-fishes,  —  Having  the  exterior  stiffened  with 
articulated  calcareous  granules  or  pieces,  but  still  flexible  ;  form  star- 
shaped  or  polygonal ;  the  viscera  extending  into  the  arms  ;  mouth  be 
low,  at  centre  ;  arms  or  rays  with  a  groove  on  the  lower  side,  along 
which  the  locomotive  suckers  protrude  through  perforated  plates ;  eyes 
at  the  tips  of  the  arms.     Ex.,  the  Star-fish,  Fig.  144. 

4.  Ophiuroids  or  Serpent- Stars.  —  Having  a  disk-like  body  with  a 
star-shaped  mouth  beneath,  and  long,  jointed,   flexible   arms,   which 
sometimes  subdivide  by  forking,  but  never  bear  pinnae,  and  have  no 
grooves    along  the  under  side,  nor  eyes    at    the  slender  tips.     The 
viscera  do  not  extend  into  the  arms  ;  the  ovarial  openings  are  slit-like, 
between  the  bases  of  the  arms  ;  and  there  is  no  anal  orifice. 

5.  Crinoids  (including  Comatulids).  —  Like   ordinary  star-fishes  in 
having  flexible  arms    or  rays;  but   the  calcareous   secretions  of   the 
rays  and  body  constitute  a   series  of  closely-fitting   solid  pieces,  and 
the  viscera  are  confined    to  the  body  portion.     The   rays  are  often 
very  much  subdivided,  and  bear  pinnae,  in  which  the  generative  organs 
are  situated. 

There  are  three  tribes  of  Crinoids:  — 

(1.)  The  Crinidea  or  Encrinites.  —  Having  a  regular  radiate  struc- 


ANIMAL    KINGDOM.  129 

ture,  arid  arms  proceeding  from  the  margin  of  the  disk ;  also  a  stem, 
consisting  of  calcareous  disks,  by  which,  when  alive,  they  are  attached 
to  the  sea-bottom  or  some  support,  so  that  they  stand  in  the  water  and 
spread  their  rays,  like  flowers,  the  mouth  being  at  the  centre  of  the 
flower.  One  of  the  Crinoids  is  represented  in  Fig.  145,  and  another 
in  Fig.  148,  p.  118,  the  upper  part  of  the  figure  in  each  showing  the 
rays  closed  up,  and  the  lower  part  the  stem.  The  rays  open  out,  when 
alive,  and  then  the  animal  has  its  flower-like  aspect.  The  little  pieces 
that  make  up  the  stem,  looking  like  button-moulds,  are  either  circular, 
as  in  Fig.  145  «,  or  five  sided,  as  in  Figs.  148  a,  b,  c,  d.  Under  the 
Crinidea  falls  the  Comatida  family,  the  species  of  which  are  free  when 
adult,  but  have  slender  arms  proceeding  from  the  back  surface  for 
attachment. 

(2.)  The  Blastoidea  or  Petremitids.  —  Having  a  symmetrical  ovoidal 
body,  with  five  petal-like  ambulacra  meeting  at  the  summit,  without 
proper  arms,  and  attached  by  a  stem  like  that  of  the  Crinids. 

(3.)  The  Cyst  idea  (from  the  Greek  for  a  bladder),  Fig.  146.  —  Ar 
rangement  of  the  plates  not  regularly  radiate.  Arms,  when  present, 
proceeding  from  the  centre  of  the  summit  instead  of  the  margin  of  a 
disk  ;  in  some,  only  two  arms  ;  in  others,  replaced  by  radiating  ambu- 
lacral  channels,  which  are  sometimes  fringed  with  pinnules. 

In  ancient  Crinids,  the  arms  are  not  generally  free  down  to  the 
base,  but  there  is  a  union  of  their  lower  part,  either  directly  or  by 
means  of  intermediate  plates,  into  a  cup-shaped  body  or  calyx  (as  in 
Fig.  145,  and  also  Figs.  577,  578,  under  the  Carboniferous  age, p.  298). 

In  Fig.  149,  the  plates  of  one  of  these  cups,  in  the  species  Batocrinus  tongirostris'M.., 
are  spread  out,  the  bottom  plates  of  the  cup  being  at  the  centre.  The  plates,  it  is  seen, 
are  in  five  radiating  series,  corresponding  to  the  five  rays  or  arms  of  the  Crinid,  and 
between  are  intermediate  pieces.  The  three  plates  numbered  1  are  called  the  basal,  as 
the  stem  is  articulated  to  the  piece  composed  of  them ;  3,  3,  3  are  the  radial ;  4,  4, 
supra-radial ;  5,  brachial,  situated  at  the  base  of  the  arms;  7  are  intermediate  plates, 
called  inter-radial;  8,  another  intermediate,  the  inter-supraradial.  Sometimes,  in 
other  Crinids,  there  is  another  series  of  plates,  at  the  junction  of  the  plates  1  and  3, 
called  sub-radial.  Finally,  the  anal  opening  of  a  Crinid  is  situated  toward  one  side  of 
the  disk,  it  being  lateral,  as  in  the  Echinoid  in  Fig.  147 ;  and  the  intermediate  group 
plates  numbered  10  are  called  the  anal. 

In  the  Cystids,  the  aperture  is  generally  lateral  and  remote  from  the  top,  as  iji  Fig. 
146,  while  the  arms  come  out  often  from  the  very  centre.  The,  Cystids  are  also  peculiar 
in  what  are  called  pectinated  rhombs  (see  Fig.  146);  that  is,  rhombic  areas  crossed  by 
fine  bars  and  openings:  the  use  of  them  is  uncertain,  — though  they  are  probably  con 
nected  with  an  aquiferous  system  and  respiration.  The  Cystids  are  the  most  anomalous 
of  Radiates. 

2.  Acalephs.  —  The  free  jelly-like  Acalephs  have  very  rarely  left 

any  traces  in  the  strata.     But,  besides  these,  many  kinds  pass,  in  their 

development,  through  a  polyp-like  state,  and,  as  the  common  Hydra 

of  fresh   waters     is    included    among    them,    the    species   an;   called 

9 


130 


ANIMAL   KINGDOM. 


3.  a,  «',  Sertularia  abietina ;    6,  b',  S. 
rosacea. 


Hydroids.  Many  of  them  make  corals,  and  hence  are  common  as 
fossils.  Fig.  141  represents  a  Hydra  enlarged,  with  a  young  one 
budded  out  from  its  side.  Some  species  of  the  group,  —  those  of  the 
Sertularia  tribe,  —  form  delicate  membranous  corals,  such  as  are  rep 
resented  in  Fig.  169  B,  in  which  each  notch  on  the  little  branchlets 
corresponds  to  the  cup-shaped  cell  from  which  an  animal  protrudes 

its  flower-shaped  head,  (a  is  the 
Sertularia  abietina  ;  b,  S.  rosacea  ; 
and  a',  b',  portions  of  branches 
enlarged).  The  interior  cavities 
°f  each  animal  communicate  free 
ly  with  the  tube  in  the  stem  ;  and 
in  this  they  differ  from  Bryozoans, 
whose  groups  have  no  tubular 
axis.  The  ancient  Graptolites 
(some  of  which  are  represented  on 
page  187)  are  supposed  to  have 
been  of  this  nature.  Others  se 
crete  calcareous  corals  of  large 
size,  and  are  called  Millepores  (be 
cause  the  minute  cells  from  which 

the  animals  protrude  are  like  pin-punctures  in  size,  and  very  numerous 
over  the  surface  of  the  coral).  The  Millepores  are  common  in  the 
West  Indies  and  other  coral  seas.  The  minute  animals  of  a  Millepore 
have  nearly  the  form  represented  in  Fig.  142,  p.  117,  which  represents 
a  species  of  another  genus,  called  Syncoryne. 

There  are  hence  stony  corals  made  by  Polyps,  by  Hydroid  Acalephs, 
and  by  Bryozoan  Mollusks. 

3.  Polyps.  —  There  are  two  groups  of  coral-making  polyps  :  — 

1.  ACTINOID  POLYPS,  illustrated  in  Figs.  137,  138,  which  make  all 
ordinary  corals.     The  rays  or  tentacles  of  the  polyps  are  of  variable 
number,  and  naked  (not  fringed). 

The  coral  is  secreted  within  the  polyps,  as  other  animals  secrete 
their  bones.  It  is  internal,  and  not  external.  It  is  usually  covered 
with  radiate  cells,  each  of  which  corresponds  to  a  separate  polyp  in 
the  group.  The  rays  of  a  cell  correspond  to  the  spaces  between  fleshy 
partitions  in  the  interior  of  the  polyp.  The  material  is  carbonate  of 
lime  (limestone)  ;  and  it  is  taken  by  the  polyp  from  the  water  in 
which  it  lives,  or  from  the  food  it  eats. 

2.  ALCYONOID  POLYPS,  illustrated  in   Fig.   139,  which  make  the 
Gorgonia  and  Alcyonimn  corals.     The  rays  of  the  polyps  are  eight  in 
number,  and  fringed.     The  figure  represents  a  part  of  a  branch  of  a 
Gorgonia   (Sea-Fan),  with  one  of  the  polyps  expanded.     The  branch 


AXLMAL    KINGDOM. 


131 


consists  of  a  black  horny  axis  and  a  fragile  crust.  The  crust  is  partly- 
calcareous,  and  consists  of  the  united  polyps ;  the  axis  of  horn  is 
secreted  by  the  inner  surface  of  the  crust.  The  Precious  Coral  used 
in  jewelry  comes  from  the  shores  of  Sicily  and  some  other  parts  of 
the  Mediterranean,  and  belongs  to  this  Alcyonoid  division.  It  is  re 
lated  to  the  Gorgonias,  but  the  axis  is  red  and  stony  (calcareous) 
instead  of  being  horny ;  and  this  stony  axis  is  the  coral  so  highly  es 
teemed. 

V.  PROTOZOANS. 

The  groups  of  Protozoans  of  special  interest  to  the  geologist  are 
three :  — 

1.  Rhizopods  (Foraminifers).  —  Species  mostly  microscopic,  often 
forming  shells.  The  shells,  with  few  exceptions,  are  very  minute,  — 
much  smaller  than  the  head  of  a  pin.  The  most  common  kinds  have 
calcareous  shells  called  foraminifers  (from  foramen),  and  these  have 
contributed  largely  to  the  formation  of  limestone  strata.  They  con 
sist  of  one  or  more  cells  ;  and  the  compound  kinds  present  various 
shapes,  as  illustrated  in  the  annexed  cut.  The  arrangement  in  a  group 
is  usually  alternate  or  spiral. 


170,- 


178 


Figs.  170-183. 
174 


Figs.  170  to  183.  —RHIZOPODS,  much  enlarged  (excepting  182,  183).  Fig.  170,  Orbulina  uniyersa; 
171,  Globigerina  rubra  ;  172,  Textilaria  globulosa  Ehr. ;  173,  Rotalia  globulosa;  173  a,  Side-view 
of  Rotalia  Boucana;  174,  Grammostomum  phyllodes  Ehr.  ;  175  a,  Frondicularia  annularis  ;  176, 
Triloculina  Josephina  ;  177,  Nodoaaria  vulgaris  ;  178,  Lituola  nautiloides ;  179,  a,  Flabellina 
rugosa  ;  180,  Chrysalidina  gradata  ;  181  a,  Ouneolina  pavonia  ;  182,  Nummulites  nummularia  ; 
183  a,  b,  Fusulina  cylindrica.  All  but  the  last  two  magnified  10  to  20  times. 

Fig.  170  is  a  one-celled  species;  the  others  are  compound,  and  contain  a  number  of 
exceedingly  minute  cells.  A  few  are  comparatively  large  species,  and  have  the  shape 
of  a  disk  or  coin,  as  Fig.  182,  a  Nummulite,  natural  size ;  the  figure  shows  the  interior 
cells  of  one-half :  these  cells  form  a  coil  about  the  centre.  Orbitoides  is  the  name  of 
another  genus  of  coin-like  species.  Fig.  183  a  is  a  species  of  Fusulina,  a  kind  nearly  as 
large  as  a  grain  of  wheat,  related  to  the  Nummulites ;  183  b  is  a  transverse  view  of  the 
same.  This  is  one  of  the  ancient  forms  of  Rhizopods,  occurring  in  the  rocks  of  the  Coal 
formation. 

The  cells  of  Rhizopods  are  each  occupied  by  a  separate  animal  or 


132 


ANIMAL    KINGDOM. 


zooid,  though  each  is  organically  connected  with  the  others  of  the 
same  group  or  shell.  The  animal  is  of  the  simplest  possible  kind, 
having  generally  no  mouth  or  stomach,  and  no  members  except  slen 
der  processes  of  its  own  substance,  which  it  extrudes  through  pores  in 
the  shell  if  it  have  any. 

The  above  are  shell-making  species  of  Rhizopods.  The  name  Rhizopuds  come,s  from 
the  Greek  for  root-like  feet,  —  in  allusion  to  the  root-like  processes  they  throw  out.  The 
name  Foraminifer  alludes  to  the  pores.  Some  of  the  species  not  secreting  shells  (as 
in  the  genus  Amoeba)  have  been  seen  to  extemporize  a  mouth  and  stomach.  When  a 
particle  of  food  touches  the  surface,  the  part  begins  to  be  depressed,  and  finally  the 
sides  of  the  depression  close  over  the  particle,  and  thus  mouth  and  stomach  are  made 
when  needed ;  after  digestion  is  complete,  the  refuse  portion  is  allowed  to  escape. 

The  shells  of  some  Rhizopods  do  not  consist  of  distinct  cells:  the  aggregate  living 
mass  secretes  carbonate  of  lime,  without  retaining  the  distinction  of  the  zooids.  This  is 
the  case,  as  Carpenter  has  observed,  in  the  Nummulite-like  genus  OrbitoUtes.  Some 
species  make  large  coral-like  masses  instead  of  small  shells. 

Other  Rhizopods  make  shell-shaped  coverings  out  of  the  grains  of  sand  or  other  mate 
rial  at  hand,  agglutinating  them. 

Other  forms,  called  Polycystines,  secrete  siliceous  shells;  and  these  shells  are  sym 
metrically  radiate  or  circular.  They  are  common  in  many  seas.  Three  species,  from 

the  Barbadoes,  are  represented  in  Figs. 

Figs.  184-186.  .  184  to  186.      Fig.  184.  Lychnocanium 

185  ^g&5st»L  Lucerna  Ehr.;    Fig.  185,  Eucyrtidium 

Mongolfieri  Ehr. :  Fig.  186,  Halicalyp- 
tra  fimbriata  Ehr.,  the  first  two  mag 
nified  100  diameters,  the  last  about  75. 
From  these  deeply  concave  forms,  there 
are  gradations  in  one  direction  to  disks 
with  concave  centres,  and  to  flat  disks, 
both  with  plain  and  pointed  borders, 
and  in  the  other  direction  to  elongate, 
conical  and  spindle-shaped  forms. 
Others  have  the  shape  of  a  flattened 
cross;  another  is  an  open  diamond, 

with  narrow  diagonals  and  periphery.  The  disks  have  a  concentric,  and  not  a  spiral, 
structure,  and  thus  are  unlike  those  of  Nummulites.  For  figures,  see  Ehrenberg's  "Mi- 
krogeologie,"  and  Bailey  in  "  Amer.  Jour.  Sci.,"  II.  xxii.  pi.  1. 

2.  Sponges.  —  Sponges  are  regarded  as  compound  animals.  The 
animals,  according  to  H.  J.  Clark,  belong  to  the  division  of  flagellate 
Protozoans,  a  kind  (including  the  genus  Monas,  etc.)  in  which  there  is 
a  short  filament  (or  flagellutn}  adjoining  the  mouth.  The  interior  sur 
face  of  the  tubes  of  a  sponge  is  made  up  of  a  closely-packed  layer  of 


184,  Lychnocanium  Lucerna  <x  100);  185,  Eucyr 
tidium  Mongolfieri  (X  100);  186,  Ilalicalyptra 
fimbnata  ( x  75). 


Siliceous  spicula  of  Sponges. 

the  zooids,  their  anterior  or  mouth  extremities  projecting  freely  into 
the  general  cavity.  The  material  of  the  common  sponges  is  ordinarily 
like  horn  in  its  nature  ;  but  in  most  kinds  there  are  minute  siliceous 


VEGETABLE   KINGDOM.  133 

spicula  sticking  out  from  the  sides  of  the  fibres.     Some  of  the  siliceous 
spicula  are  shown  enlarged  in  Figs.  187  a-h.     Many  deep-sea  species 
consist  mainly  of  siliceous  fibres.     They  look  as  if  made  of  spun  glass 
worked  together  into  forms  of  great  delicacy 
and  beauty.     The  annexed  figure  represents,  F'S-  ^88. 

much  enlarged,  a  species  of  sponge  —  a  jelly- 
like  globule  of  minute  size  —  which  some 
times  beclouds  the  sea  in  the  Pacific.  (It  is 
from  the  East  Indian  seas,  and  is  named 
Sphcerozoum  orientale  D.)  It  is  bristled 
with  spicula.  The  death  and  decay  of  such 
sponges  would  add  largely  to  the  silica  of  the 
sea  bottom. 

Some  sponges  secrete  calcareous  spicula  instead  of  siliceous ;  and 
there  are  others  that  are  chiefly  calcareous  in  their  constitution,  and 
consequently  look  like  masses  of  a  compact  coral.  The  large  corals 
referred  to  the  genus  Stromatopora,  and  others  allied,  are  regarded  by 
some  zoologists  as  either  calcareous  sponges  or  foraminifers. 

3.  VEGETABLE  KINGDOM. 

The  vegetable  kingdom  is  not  divisible  into  sub-kingdoms  like  the 
animal ;  for  the  species  all  belong  to  one  grand  type,  the  Radiate,  the 
one  which  is  the  lowest  of  those  in  the  animal  kingdom.  The  follow 
ing  arc  the  higher  subdivisions. 

I.  CRYPTOGAMS.  —  Having  no  distinct  flowers  or  proper  fruit,  the 
so-called  seed  bemg  only  a  spore,  that  is,  a  simple  cellule  without  the 
store  of  nutriment  (albumen  and  starch)  around  it  which  makes  up  a 
true  seed  ;  as  the  Ferns,  Sea-weed.  They  include  — 

1.  Thallogens.  —  Consisting   wholly    of    cellular    tissue ;     growing 
mostly  in  fronds  without  stems,  and  in  other  spreading  forms  ;  as  (1) 
Algae,  or  Sea- weeds  ;  (2)  Lichens;  (3)  Fungi,  or  Mushrooms. 

2.  Anogens.  —  Consisting  wholly  of  cellular  tissue  ;  growing  up  in 
short,  leafy  stems  ;  as  (1)  Musci,  or  Mosses;  (2)  Liverworts. 

3.  Acrogens.  —  Consisting  of  vascular  tissue  in  part,  and  growing 
upward;  as  (1)  Ferns;   (2)  Lycopods  (Ground-Pine);   (3)  Equiseta; 
and  including  many  genera  of  trees  of  the  Coal  period. 

II.  PHENOGAMS.  —  Having  (as  the  name  implies)  distinct  flowers 
and  seed ;  as  the  Pine,  Maple,  and  all  our  shade  and  fruit  trees,  and 
the  plants  of  our  gardens.  They  are  divided  into  — 

1.  Gymnosperms.  —  Exogens,  or  Exogenous  in  growth  :  that  is,  the 
plant  has  a  bark,  and  grows  by  an  addition  annually  to  the  exterior  of  the 
wood,  between  the  wood  and  the  bark,  and  hence  the  wood  shows  in  a 
transverse  section  rings  of  growth,  each  the  formation  of  a  single  year 


134 


VEGETABLE   KINGDOM. 


(Fig.  189).  (This  mode  of  growth  is  in  contrast  to  that  which  char 
acterizes  the  Endogens.)  The  flowers  exceedingly  simple,  and  the  seed 
naked,  —  the  seed  being  ordinarily  on  the  inner  surface  of  the  scales 
of  cones.  Examples  are  the  Pine,  Spruce,  Hemlock,  etc.  The  name 
Gymnosperm  is  from  the  Greek  for  naked  seed.  Gymnosperms  in 
clude  (1)  Conifers;  (2)  Cycads  (p.  408). 

Fig.  189-198. 
191 


PLANTS.  — Fig.  189,  section  of  exogenous  wood;  190,  fibres  of  ordinary  coniferous  wood  (Pinus 
Strobus),  longitudinal  section,  showing  dots,  magnified  300  times ;  191,  same  of  the  Australian 
Conifer,  Araucaria  Cunningham! ;  192,  section  of  endogenous  stem. 

Figs.  193  to  198,  DIATOMS  highly  magnified ;  193,  Pinnularia  peregrina,  Richmond,  Va.  ;  194 
Pleurosigma  angulatum,  id  ;  195,  Actinoptychus  senarius,  id  ;  196,  Melosira  sulcata,  id  ;  a,  trans 
verse  section  of  the  same  ;  197,  Grammatophora  marina,  from  the  salt  water  at  Stonington,  Conn.; 
198,  Bacillaria  paradoxa,  West  Point. 

The  wood  of  the  Conifers  is  simply  woody  fibre  without  ducts,  and, 
in  this  respect,  as  well  as  in  the  flowers  and  seed,  this  tribe  shows  its 
inferiority  to  the  following  subdivision.  The  fibre,  moreover,  may  be 
distinguished,  even  in  petrified  specimens,  by  the  dots  along  the  sur 
face  as  seen  under  a  high  magnifier.  The  dots  look  like  holes,  though 
really  only  thinner  spaces.  Fig.  190  shows  these  dots  in  the  Pinus 
Strobus.  In  other  species,  they  are  less  crowded.  In  one  division  of 
the  Conifers,  called  the  Araucarice,  of  much  geological  interest,  these 
dots  on  a  fibre  are  alternated  (Fig.  191)  ;  and  the  Araucarian  Conifers 
may  thus  be  distinguished. 

2.  Angiosperms. —  Exogens, like  the  Gymnosperms.    Having  regu 
lar  flowers  and   also  covered  seed;  as  the  Maple,  Elm,  Apple,  Rose, 
and  most  of  the  ordinary  shrubs  and  trees.     Called  Angiosperms,  be 
cause  the  seeds  are  in  seed-vessels  ;  and  also  Dicotyledons,  because  the 
seed  has  two  cotyledons  or  lobes. 

3.  Endogens.  —  Regular  flowers  and  seed  ;  but  growth  endogenous, 
the  plants   having  no   bark,  and  showing,  in  a  transverse  section  of  a 
trunk,  the  ends   of  fibres,  and  no  rings  of  growth  (Fig.  192)  :  as  the 
Palms,   Rattan,   Reed,    Grasses,  Indian   Corn,   Lily.,     The  Endogens 
are  Monocotyledons  ;  that   is,  the   seed  is  undivided,  or  consists  of  but 
one  cotyledon. 

Among  Algce,  three  kinds  are  of  prominent  interest  to  the  geol 
ogist  :  — 


VEGETABLE    KINGDOM.  135 

1.  Fucoids,  or  those  related  to  the  tough  leathery  sea-weeds  along 
coasts,  which  are  called  Fuel,  some  of  which,  among  modern  species, 
grow  to  a  great  size,  attaining  a  length  even  of  hundreds  of  feet. 

2.  Plants  having  calcareous  secretions.     Among  these  there  are  (1) 
the  delicate  Corallines,  which  have  generally  a  jointed  stem,  and  are 
only  imperfectly  calcareous ;   (2)   the  Nullipores,  which  are  often  like 
stony  corals  in  form   and  hardness,   making   incrustations,  and    also 
branching  more  or  less  perfectly  :   they  differ  from  corals  in  having 
no  pores  or  cells,  not  even  the  pin-punctures  of  the  Millepores  ;   (3) 
Coccoliths,  lenticular   calcareous   disks,  usually  convexo-concave,  less 
than  a  thousandth  of  an  inch  in  diameter,  occurring  in  many  places 
over  the  ocean's  bottom,  and  also  in  shallow  waters.     Named  from 
KOK/COC,  seed,  and  Ai#o?,  stone. 

3.  Plants   having   siliceous    secretions.      Microscopic,    and    mostly 
unicellular  plants.     The  Diatoms  secrete  a  siliceous  shell ;  and  they 
grow  so  abundantly  in  some  waters,  fresh  or  salt,  as  to  produce  large 
siliceous  accumulations.     A  few  of  these  siliceous  species  are  figured 
above,  in  Figs.  193  to  198. 

There  are  also  microscopic  species  called  Desmids,  that  consist  of 
one  or  a  few  greenish  cells,  and  secrete  little  or  no  silica.  They  do 
not  contribute  largely  to  rock-making,  like  the  Diatoms,  but  are  com 
mon  as  fossils  in  flint  and  other  siliceous  concretions.  Some  are  fig 
ured  on  page  257,  Fig.  484  A. 

The  minute  plants  of  the  waters  are  sometimes  called  Protophytes. 

The  Chares  are  other  Cryptogamous  plants,  having  large  calcareous 
secretions.  They  are  delicate  aquatic  species,  in  some  respects  related 
to  the  Mosses.  The  dried  plant  affords  30  per  cent,  of  ash,  95  per 
cent,  of  which  is  carbonate  of  lime.  Consequently,  when  abundant, 
they  contribute  calcareous  material  to  the  bottoms  of  ponds. 


PART  III. 
HISTORICAL    GEOLOGY. 


GENERAL  DIVISIONS  IN  THE  HISTORY. 

1.  Nature  of  subdivisions  in  history.  —  The  methods  of  ascertain 
ing  the  true  succession  or  chronological  order  of  the  rocks  have  been 
explained  on  pages  101  to  107.  Some  further  explanations  are  neces 
sary,  by  way  of  introduction  to  the  survey  of  geological  history. 

What  are  subdivisions  in  history  ?  —  Many  persons,  in  their  study  of 
geology,  expect  to  find  strongly-drawn  lines  between  the  ages,  or  the 
corresponding  subdivisions  of  the  rocks.  But  geological  history  is 
like  human  history  in  this  respect.  Time  is  one  in  its  course,  and  all 
progress  one  in  plan. 

Some  grand  strokes  there  may  be,  —  as  in  human  history  there  is  a 
beginning  in  man's  creation,  and  a  new  starting-point  in  the  advent  of 
Christ.  But  all  attempts  to  divide  the  course  of  progress  in  man's 
historical  development  into  ages  with  bold  confines  are  fruitless.  "We 
may  trace  out  the  culminant  phases  of  different  periods  in  that  pro 
gress,  and  call  each  culmination  the  centre  of  a  separate  period.  But 
the  germ  of  the  period  was  long  working  onward  in  preceding  time, 
before  it  finally  came  to  its  full  developement  and  stood  forth  as  the 
characteristic  of  a  new  era  of  progress.  It  is  all  one  progress,  while 
successive  phases  stand  forth  in  that  progress. 

In  geological  history,  the  earliest  events  were  simply  physical. 
While  the  inorganic  history  was  still  going  on  (although  finished  in 
its  more  fundamental  ideas),  there  was,  finally,  the  introduction  of 
life,  —  a  new  and  great  step  of  progress.  That  life,  beginning  with 
the  lower  grades  of  species,  was  expanded  and  elevated,  through  the 
appearance  of  new  types,  until  the  introduction  of  Man.  In  this 
organic  history,  there  are  successive  steps  of  progress,  or  a  series  of 
culminations.  As  the  tribes,  in  geological  order,  pass  before  the 
mind,  the  reality  of  one  age  after  another  becomes  strongly  apparent. 
The  age  of  Mammals,  the  age  of  Reptiles,  and  the  age  of  Coal-plants 
come  out  to  view,  like  mountains  in  the  prospect,  —  although,  if  the 


HISTORICAL    GEOLOGY.  137 

mind  should  attempt  to  define  precisely  where  the  slopes  of  the  moun 
tain  end,  as  they  pass  into  the  plain  around,  it  might  be  greatly  em 
barrassed.  It  is  not  in  the  nature  of  history  to  be  divided  off  by 
visible  embankments  ;  and  it  is  a  test  of  the  true  philosopher  to  see 
and  appreciate  the  commencements  and  culminations  of  phases,  or  of 
the  successive  ideas,  in  the  system  of  progress,  amid  the  multitude  of 
events  and  indefinite  blendings  that  bewilder  other  minds. 

We  note  here  the  following  important  principles  :  — • 

First.  The  reality  of  an  age  in  history  is  marked  by  the  develop 
ment  of  some  new  idea  in  the  system  of  progress. 

Secondly.  The  beginning  of  the  characteristics  of  an  age  is  to  be 
looked  for  in  the  midst  of  a  preceding  age  ;  and  the  marks  of  the 
future  coming  out  to  view  are  prophetic  of  that  future. 

Thirdly.  The  end  of  au  era  may  come,  either  after  the  full  culmi 
nation  of  the  idea  or  phase,  or,  earlier,  at  the  commencing  prominence 
of  a  new  and  grander  phase  in  the  history.  It  may  be  as  ill-defined 
as  the  beginning,  although  its  prominent  idea  may  stand  out  boldly  to 
view.  Thus  the  age  of  Coal-plants  was  preceded  by  the  occurrence 
of  related  plants  far  back  in  the  Devonian.  The  age  of  Mammals 
was  foreshadowed  by  the  appearance  of  mammals  long  before,  in  the 
course  of  the  Reptilian  age.  And  the  age  of  Reptiles  was  prophesied 
in  types  that  lived  in  the  earlier  Carboniferous  age.  Such  is  the 
system  in  all  history.  Nature  has  no  sympathy  with  the  art  which 
runs  up  walls  to  divide  off  her  open  fields. 

But  the  question  may  arise,  whether  a  geological  age  is  not,  after 
all,  strongly  marked  off  in  the  rocks.  Rocks  are  but  the  moving 
sands  or  the  accumulations  of  dead  relics  of  the  age  they  represent, 
and  are  local  phenomena,  as  already  explained.  Each  continent  has 
its  special  history  as  regards  rock-making  ;  and  it  is  only  through  the 
fossils  in  the  rocks  that  the  special  histories  can  be  combined  into  a 
general  system.  The  movements  which  have  disturbed  one  continent 
have  not  affected  in  precisely  the  same  manner  the  rest,  although 
there  has  sometimes  been  a  general  parallelism  in  the  changes  of 
level ;  and  hence  there  are  breaks  in  the  succession  of  rocks  on  one 
continent,  or  part  of  a  continent,  that  have  no  representatives  on  an 
other. 

When  an  age  can  be  proved,  through  careful  study,  to  have  been 
closed  by  a  catastrophe  or  a  transition  which  was  universal  in  its 
effects,  the  event  is  accepted  as  a  grand  and  striking  one  in  geological 
history.  But  the  proof  should  be  obtained,  before  the  universality  is 
assumed.  Hence  the  conclusion,  — 

Fourthly.  The  grander  subdivisions  or  ages  in  geological  history, 
based  on  organic  progress,  should  be  laid  down  independently  of  the 


138  HISTORICAL    GEOLOGY. 

rocks.     They  are  universal  ideas  for  the  globe.     The  rocks  are  to  be 
divided  off  as  nearly  as  practicable  in  accordance  with  them. 

Each  continent,  under  these  ages,  then  becomes  a  special  study  ; 
and  its  history  has  its  periods  and  epochs  which  may  or  may  not  cor 
respond  in  their  limits  with  those  of  the  other  continents.  Every 
transition  in  the  strata,  as  from  limestone  to  sandstone,  clay -beds  or 
conglomerate,  or  from  either  one  to  another,  and  especially  where 
there  is  also  a  striking  change  in  the  organic  remains,  indicates  a 
transition  in  the  era  from  one  set  of  circumstances  to  another,  —  it 
may  be  a  change  from  one  level  to  another  in  the  continents,  a  sub 
mergence  or  emergence,  or  some  other  kind  of  catastrophe.  All 
such  transitions  mark  great  events  in  the  history  of  the  continent,  and 
thus  divide  the  era  into  periods,  and  may  further  subdivide  the  periods 
into  epochs.  Hence,  — 

Fifthly.  Through  the  ages,  the  different  continents,  and  often  also 
the  distant  regions  of  the  same  continent,  had  their  special  histories  ; 
and  the  periods  and  epochs  are  indicated  by  changes  or  transitions  in 
the  rock-formations  of  the  region  and  in  their  fossils. 

The  periods  and  epochs  of  America  and  Europe  are  not  in  general 
the  same  in  their  limits,  and  much  less  in  their  rocks.  The  Devonian 
age,  for  example,  has  a  very  different  series  of  periods  and  epochs  in 
North  America  from  what  it  has  in  Europe,  and  there  is  even  con 
siderable  diversity  between  the  subdivisions  in  New  York  and  the 
Atlantic  slope,  and  those  of  the  Mississippi  valley.  It  is  far  from 
certain  that  the  commencement  assigned  to  the  Devonian  in  North 
America  is  synchronous  with  that  for  Europe.  The  Carboniferous, 
Reptilian  and  Mammalian  ages  also  have  their  American  epochs  and 
their  European  differing  from  one  another ;  and  the  differences  be 
tween  the  continents  increase  as  we  come  down  to  more  modern 
times.  We  add,  therefore,  — 

Sixthly.  It  is  an  important  object  in  geology  to  ascertain  as  nearly 
as  possible  the  parallelism  between  the  periods  and  epochs  marked 
off  on  each  continent,  and  to  study  out  the  equivalents  of  the  rocks, 
each  for  each,  that  all  the  special  histories  may  read  as  parts  of  one 
general  history,  and  thus  contribute  to  the  perfection  of  one  geological 
system. 

Subdivisions  based  on  the  progress  of  life.  —  In  accordance  with 
the  principles  explained,  the  following  subdivisions  of  geological  time 
are  here  adopted.1 

1  The  system  of  ages  is  essentially  the  same  with  that  proposed  by  Professor 
Agassiz,  — the  only  difference  consisting  in  calling  the  Silurian  the  age  of  Inverte 
brates,  as  suggested  by  Murchison,  instead  of  considering  both  the  Silurian  and 
Devonian  the  age  of  Fishes. 


HISTOEICAL   GEOLOGY. 


139 


I.  ARCH.EAN  TIME.  —  The   beginning,  including  a  very  long  era 
without  life,   and,  finally,    that  in  which    appeared    the  earliest    and 
simplest  forms  of  plants  and  animals. 

II.  SILURIAN  AGE,  or  AGE  OF  INVERTEBRATES.  —  The  animal  life 
consisting  distinctively  of  Invertebrates. 

III.  DEVONIAN  AGE,  or  AGE  OF  FISHES.  —  Fishes,  a  division  of 
Vertebrates  (the  earliest  of  which  had  appeared  before  the  close  of  the 
Silurian),  the  dominant  race. 

IV.  CARBONIFEROUS  AGE,  or  AGE  OF  ACROGENS,  and  eminently 
also  the  AGE  OF  AMPHIBIANS.  —  Characterized  by  Coal-plants,  which 
were   chiefly  of  the    tribe   of  Acrogens,  —  a   tribe   that  then  had  its 
grandest  exhibition  ;  and  in  animal  life,  by  the  earlier  Reptiles,  be 
longing  mostly  to  the  lower  division,  Amphibians. 

V.  AGE  OF  REPTILES.  —  Reptiles  the  dominant  race. 

VI.  TERTIARY  AGE,  or  AGE  OF  MAMMALS.  —  Mammals  the  domi 
nant  race. 

VII.  QUATERNARY,  or  AGE  OF  MAN. 

The  general  facts  in  the  progress  of  life  on  the  globe  are  illustrated 


in  the  annexed  diagram, — 


Age  of  Man,  or  Quater 
nary. 

Age    of   Mammals,    or 
Tertiary. 


Age  of  Reptiles,  or  Sec 
ondary. 


Carboniferous  Age. 


Age  of  Fishes,  or  De- ) 
vonian. 


Age  of  Invertebrates,  or 
Silurian. 


Archaean  Time 


Fig.  200. 
ANIMALS. 


PLANTS. 


The  horizontal  bands  represent  the  ages,  in  succession ;  the  vertical 
correspond  to  different  groups  of  animals  and  plants.  The  lower  end 
of  each  vertical  band  marks  the  point  in  geological  time  when,  accord 
ing  to  present  knowledge  from  fossils,  the  type  it  represents  began ; 
and  the  varying  width  in  the  same  bands  indicates  the  greater  or  less 
expansion  of  the  type.  The  following  are  accordingly  the  points  the 
diagram  illustrates :  — 


140  HISTORICAL   GEOLOGY. 

Radiates  began  with  the  commencement  of  the  Silurian,  and  have 
continued  till  now,  rather  increasing  throughout  the  ages. 

Mollusks  had  their  beginning  at  the  same  time,  and  continued  in 
creasing  to  the  age  of  Reptiles  :  they  then  passed  their  maximum  (as 
indicated  in  the  figure). 

Articulates  commenced  in  the  Silurian  (as  Crustaceans  and  Worms), 
and  continued  expanding  in  numbers  and  grade  to  the  present  time. 

Fishes  began  near  the  close  of  the  Silurian,  were  very  abundant  in 
the  Devonian,  and  continued  on,  becoming  increasingly  diversified  to 
the  last,  with  some  rise  in  grade. 

Reptiles  began  in  the  Carboniferous,  and  reached  their  maximum 
in  the  Reptilian  age. 

Mammals  began  in  the  Reptilian  age,  and  were  the  highest  race  of 
the  Mammalian  age. 

Sea-weeds  (or  Alga?)  were  the  earliest  plants  of  the  globe,  probably 
preceding  animal  life.  Acrogens  and  Conifers  began  in  the  Upper 
Silurian.  The  Acrogens  had  their  greatest  expansion  in  the  age  of 
Coal-plants,  in  which  they  occurred  with  Conifers.  Cycads  began  in 
the  Carboniferous,  and  had  their  greatest  expansion  in  the  Reptilian 
age.  Dicotyledons  began  in  the  closing  period  of  the  Reptilian  age, 
and  expanded,  along  with  Palms,  through  the  age  of  Mammals. 

The  Silurian,  Devonian,  and  Carboniferous  ages  naturally  stand 
somewhat  apart  from  the  following  ones,  in  the  peculiar  ancient  forms 
of  the  great  portion  of  their  living  tribes ;  and  to  the  whole  collectively 
the  term  PALEOZOIC  era  is  appropriately  applied,  —  the  word  "paleo 
zoic"  being  from  the  Greek  TraAcuos,  ancient,  and  £o>r/.  The  follow 
ing  age,  or  age  of  Reptiles,  is  correspondingly  termed  the  MESOZOIC, 
from  /xeo-og,  middle,  and  £w?j,  it  being  the  mediaeval  era  in  geological 
history.  The  Mammalian  age  is  termed  the  CENOZOIC,  from  KCUVOS, 
recent,  and  £or»j.  (The  words  JZocene,  Miocene,  etc.,  subdivisions  of  the 
age,  are  in  part  from  the  same  root.) 

The  subdivisions  of  geological  time  are,  then,  — 
I.  AHCIIJEAN  TIME,  including  an  Azoic  and  an  Eozoic  era  though 
not  yet  distinguished  in  the  rocks. 

1.  Azoic  Age. 

2.  Eozoic  Age. 

II.  PALEOZOIC  TIME. 

1.  The  Age  of  Invertebrates,  or  Silurian. 

2.  The  Age  of  Fishes,  or  Devonian. 

3.  The  Age  of  Coal-plants,  or  Carboniferous. 

III.  MESOZOIC  TIME. 

The  Age  of  Reptiles. 


HISTORICAL    GEOLOGY.  141 

IV.  CENOZOIC  TIME. 

1.  The  Tertiary,  or  Age  of  Mammals. 

2.  The  Quaternary,  or  Age  of  Man. 

Subdivisions  into  Periods  and  Epochs.  —  The  subdivisions  under  the 
ages,  the  periods  and  epochs,  vary,  as  has  been  said,  in  different  coun 
tries.  The  following  table  (Fig.  201)  presents  a  general  view  of  those 
of  eastern  North  America,  so  far  as  the  Paleozoic  is  concerned, —  the 
Silurian,  Devonian,  and  Carboniferous  being  well  represented  on  the 
North  American  continent.  The  rest  of  the  series  is  from  European 
geology,  in  which  the  later  ages  are  far  better  represented  than  in 
America.  In  this  Manual,  American  geology  is  in  general  first  con 
sidered  ;  and  afterward  such  further  illustrations  are  drawn  from  other 
continents  as  are  necessary  for  comprehensive  views  and  generaliza 
tions.  Where  America  is  deficient  in  its  records,  the  European  are 
taken  as  the  standard. 

The  names  of  the  periods  and  epochs  for  the  Paleozoic  of  America 
are,  in  the  main,  the  same  that  have  been  applied  to  the  rocks  by  the 
New  York  geologists. 


142 


HISTORICAL    GEOLOGY. 
Periods.  Fig.  201.  Epochs. 


15      Permian. 


Archaean. 


14c     Upper  Coal  Measures 


Lower  Coal  Measures 


I4a  ;  Millstone  Grit. 
13b  I  Upper. 
13a    Lower. 

12     Catskill. 

I 

lib  '  Chemung. 

lla  I  Portage. 
ICc  I  Genesee. 

Hamilton. 
^-:T  lOa     Marcellus. 

9c   |  Corniferous. 
Scboharie. 
Cauda-Galli. 
Oriskauy . 

Lower  Helderberg 
Salina. 
Niagara. 
Clinton. 


Medina. 

4c      Cincinnati. 
Utica. 

Trenton. 

Chazy. 

Quebec. 

Calciferous. 

Potsdam. 
Acadian. 
Archaean. 


HISTORICAL    GEOLOGY. 
Fig.  201  (continued). 


143 


Epochs, 


Upper  Cretaceous,   j     Chalk. 


(  Upper    or   White 

Chalk. 
Lower  or  Gray. 

Middle  Cretaceous  (Upper  Green-sand). 
Lower  Cretaceous  (Lower  Green-sand). 


Fnnpr  Oolvte  J  p"rkeck,  Portland,  and 
Oolyte.        Kiinu,eridgc  Clay. 

(  Coral-rag 
I  Oxford  Clav. 


Bunter-sandstein. 


In  the  figures  and  maps  introduced  beyond,  the  numbers  are  used 
as  in  the  above  tables  :  1  standing  for  the  Archiwan  ;  2  for  the  rocks 
of  the  Primordial,  3  for  the  rocks  of  the  Canadian  period ;  3  a,  3  b, 

3  c,  for  its  subdivisions  ;  4  for  rocks  of  the  Trenton  period,  4  a,  4  b, 

4  c,  for  the  epochs  of  this  period  ;  and  so  on. 

The  following  map  of  the  United  States  east  of  the  Rocky  Moun 
tains  exhibits  the  geographical  distribution  of  the  rocks  of  the  several 
ages,  —  that  is,  the  regions  over  which  they  are  severally  the  surface- 
rocks. 

The  Silurian  is  distinguished  by  heavy  horizontal  lining. 

The  Devonian,  by  heavy  vertical  lines. 

The  Carboniferous,  by  light  cross-lines  on  a  black  ground,  or  by  a 
black  surface,  or  by  dots  on  a  black  ground  (the  first  the  Subcar- 
boniferous,  the  second  the  Coal- formation,  the  third  the  Permian). 
The  black  areas  are  the  Coal-areas  of  the  country. 


144 


HISTORICAL    GEOLOGY. 


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HISTORICAL    GEOLOGY.  145 

The  Reptilian,  including  the  Triassic,  Jurassic,  and  Cretaceous,  by 
lines  sloping  from  the  right  to  the  left  (/),  the  Cretaceous  being 
distinguished  by  having  the  lines  broken. 

The  Tertiary,  by  lines  sloping  from  the  left  to  the  right  (  \  ). 

The   surface  without  markings  is  occupied    by  rocks  of  undeter 
mined  asfe ;  that  on  the  east  is  mostly  crystalline. 
o    ~  »'      */ 

In  Xova  Scotia  and  New  Brunswick,  the  Subcarboniferous  is  not  distinguished  from 
the  Carboniferous;  and,  west  of  the  Mississippi,  the  limit  between  the  Carboniferous 
and  Permian  areas  is  partly  conjectural;  and  also  that  in  Arkansas  between  the 
Carboniferous  and  Subcarboniferous.  In  the  lettering, Cr.  stands  for  Cretaceous;  C., 
Charleston,  S.  C.;  Ci.,  for  Cincinnati;  V.,Vicksburg,  Miss.;  B.,  Black  Hills;  0.,  Ozark 
Mountains;  W.,  Witchita  Mountains.  On  rivers,  to  the  west:  w.,  White;  n.,  Niobrara; 
p.,  Platte;  i~p.,  Republican;  s.,  Smoky  Hill;  a.,  Arkansas;  c.,  Canadian;  ?•.,  Red. 

Thickness  of  the  stratified  rocks.  —  The  whole  thickness  of  the 
rocks  in  the  series  has  been  stated  at  twenty  miles  or  more.  But 
this  includes  the  sum  of  the  whole,  grouped  in  one  pile.  As  the  series 
is  nowhere  complete,  this  cannot  be  said  to  be  the  thickness  observed 
in  any  one  region.  The  rocks  of  New  York,  down  to  the  Archasan, 
counting  all  as  one  series,  are  about  13,000  feet  in  thickness.  They 
include  only  the  Silurian  and  Devonian  (excepting  the  Triassic  in  the 
southeast).  They  thin  out  to  a  few  feet  in  the  northern  part  of  the 
State,  and  have  their  greatest  thickness  toward  Pennsylvania.  In 
Pennsylvania,  the  rocks  include  the  Carboniferous ;  and  the  whole 
thickness  is  at  least  40,000  feet.  This  is  exclusive  of  the  Triassic, 
which  may  add  a  few  thousands  to  the  amount.  In  Virginia,  the  thick 
ness  is  still  greater ;  but  no  exact  estimate  has  been  made.  In  Indi 
ana  and  the  other  States  west,  it  is  only  4,000  feet,  although  extending, 
as  in  Pennsylvania,  to  the  top  of  the  Carboniferous.  The  greater 
part  of  the  continent  of  North  America  east  of  the  Mississippi  is  des 
titute  of  rocks  above  the  Carboniferous. 

In  Great  Britain  and  Europe,  the  series  of  rocks  is  more  complete 
than  in  eastern  North  America.  In  Great  Britain,  the  thickness  to 
the  top  of  the  Silurian  is  over  60,000  feet ;  to  the  top  of  the  Car 
boniferous,  or  the  Paleozoic,  85,000  feet;  then  to  the  close  of  the 
series,  100,000.  This  amount  is  the  sum  of  the  thickest  deposits  of 
the  several  formations,  and  not  the  thickness  observed  in  any  par 
ticular  place.  On  the  Continent,  there  are  at  least  25,000  feet  of 
strata  above  the  Paleozoic. 

Subdivision  of  the  North  American  continent  into  regions  of 
partially  independent  progress-  —  It  is  a  remarkable  fact,  illustrated 
through  all  American  geological  history,  that  the  grand  features  of 
the  continent  were  early  denned  ;  and  that,  through  all  time,  from 
the  close  of  the  Archaean,  if  not  also  before,  the  ranges  of  land  which 
are  now  the  courses  of  the  mountain  chains,  were  the  boundaries  be- 
10 


146  ARCHAEAN   TIME. 

tween  great  continental  basins  that  were,  in  a  marked  degree,  inde 
pendent  in  the  progress  of  rock-making  and  of  life.  The  positions  of 
the  mountain  chains,  and  of  other  prominent  features  of  the  land,  were 
thus  indicated  long  before  they  had  existence.  It  will  be  convenient, 
therefore,  to  describe  the  rocks,  and  sometimes  the  life,  of  each  such 
region  separately;  and  these  regions  are  therefore  here  enumerated. 

1.  The  Eastern  Border  basin  or  region,  east  and  northeast   of  the 
Green  Mountain  range,  and  including  New  England,  Eastern  Canada, 
New  Brunswick,  western  Nova  Scotia,  the  Gulf  of  St.  Lawrence  and 
Newfoundland. 

2.  The  Appalachian  region,  along  the  course  of  the  Appalachians, 
through  the  Green  Mountains,  to  the  vicinity  of  Quebec. 

3.  The  Interior  Continental  basin,  between  the  Appalachians  (with 
the  Green  Mountains,  properly  the  northern  part  of  them)   and  the 
Rocky  Mountain  chain. 

4.  The    Western    Border    basin,   west    of    the    Rocky   Mountain 
summit. 

A  great  Arctic  Border  region  and  a  Rocky  Mountain  region  may 
hereafter  be  recognized ;  but  the  facts  thus  far  collected  do  not  at 
present  make  it  necessary  to  refer  separately  to  them. 


I.    ARCK/EAN    TIME. 

Archaean  time  includes  strictly,  as  its  commencement,  an  Azoic  age, 
or  the  era  in  which  the  physical  conditions  were  incompatible  with 
the  existence  of  life.  But  this  era,  so  far  as  now  known,  is  with 
out  recognizable  records  ;  for  no  rocks  have  yet  been  shown  to  be 
earlier  in  date  than  those  which  are  now  supposed  to  have  been 
formed  since  the  first  life  began  to  exist.  About  this  early  era  there 
is,  therefore,  little  known.  By  following  the  lead  of  ascertained  law 
in  physics  and  chemistry,  and  the  suggestions  of  astronomy,  and  also 
analogies  from  later  geological  history,  some  probable  conclusions  may 
be  reached.  But  this  is  not  the  place  for  their  discussion,  except  so 
for  as  to  state  the  principal  steps  of  progress.  There  must  have 
been,  — 

I.  A.  first  era,  after  that  of  the  original  nebula,  if  such  there  was, 
—  in  which  the  earth  was  a  globe  of  molten  rock,  like   the  sun   in 
brightness    and  nature,   enveloped  in  an  atmosphere  containing  the 
dissociated  elements  of  the  future  waters  and  whatever  else  the  heat 
at  the  surface  could  throw  into  a  state  of  vapor. 

II.  A  second  era,  in  which  cooling  went  forward  until,  in  the  first 
place,  the  earth  became  solid  at  centre,  pressure  causing  the  solidifica- 


ARCKLEAX    TIME.  147 

tion  ;  and  then,  in  the  second  place,  and  probably  long  afterward,  a 
crust  was  formed  outside  from  cooling  ;  and  until  finally,  in  the  third 
place,  the  vapors  of  the  atmosphere  were  mostly  condensed,  and  an 
envelope  of  waters,  nearly  or  quite  universal,  was  thus  made.  De 
pressions  for  special  oceanic  basins  would  have  been  early  begun,  over 
the  cooling  and  contracting  sphere  ;  and  it  is  probable,  as  elsewhere 
shown  (pp.  160,  728),  that  the  existing  continental  areas  were  defined 
in  general  contour  in  this  first-formed  crust,  and  that  within  their  con 
fines  appeared  the  first  dry  land.  This  crust  has  since,  through  all 
time,  continued  cooling  and  increasing  in  thickness. 

III.  A  third  era,  or  a  continuation  of  the  preceding,  carrying  for 
ward  the  cooling  to  80°  or  100°  C,  (175°  to  212°  F.),  or  to  a  tempera 
ture  admitting  of  the  existence  of  the  simplest  forms  of  vegetable  life. 
Through  this  era,  the  crust,  by  its  contraction  from  cooling,  which 
was  in  unceasing  progress,  must  have  been  slowly  varying  and  aug 
menting  its  surface  reliefs. 

At  the  same  time,  the  wear  of  the  rocks  of  the  crust,  wherever  they 
were  exposed  to  the  ocean's  waves  or  currents,  aided  by  their  disinte 
gration  where  above  the  waters,  would  have  resulted  in  the  formation 
of  stratified  deposits  out  of  the  detritus  ;  and  so  have  begun  the  series 
of  formations  over  the  surface  that  makes  up  the  earth's  supercrust 
—  the  only  part  of  the  earth's  structure  which  is  within  the  reach  of 
direct  investigation. 

At  first,  the  beds  of  detritus  formed  in  the  hot  waters  (a  powerful 
chemical  agent  through  their  heat,  and  the  silica  and  other  materials  in 
solution)  would  have  been  consolidating  and  crystallizing  beneath, 
while  accumulation  was  going  on  above ;  and  this  may  have  continued 
to  be  true  throughout  the  age,  and  in  fact  long  after  the  waters  had 
passed  the  temperature-limit  of  100°  C.  The  rocks  of  this  era  should 
therefore  be  much  like  those  that  resulted  from  the  original  cooling, 
because  made  chiefly  out  of  the  latter  by  reconsolidation  and  recrystal- 
lization,  except  that  schistose  and  quartzose  rocks  would  have  been 
more  common  in  the  new  formations. 

These  Archaean  rocks  are  the  only  universal  formation.  They  ex 
tend  over  the  whole  globe,  and  were  the  floor  of  the  ocean  and  the 
material  of  all  emerged  land,  when  life  first  began  to  exist.  The 
thickness  which  they  acquired  during  the  long  era  from  the  time  of  the 
first-formed  crust  can  never  be  known. 

Professor  Helmholtz  has  calculated,  from  the  rate  of  cooling  of  lavas, 
that  the  earth,  in  passing  from  2,000°  to  200°  F.,  must  have  taken  three 
hundred  and  fifty  millions  of  years  ;  and  the  estimate  of  another 
author  is  four  times  this.  If  either  be  true,  it  was  in  fact  a  long 
era. 


148 


ARCELEAN   TIME. 


IV.  A  fourth  era,  commencing  with  the  beginning  of  life  on  the 
globe,  —  which  beginning  was  possible,  judging  from  known  facts, 
when  the  temperature  of  the  waters  had  cooled  down  at  least  to 
200°  F.  It  has  been  supposed  that  all  the  Archaean  rocks  open  to 
view  over  the  earth's  surface  are  those  of  this  last  era.  But  more  in 
vestigation  is  required,  before  it  can  be  regarded  as  an  established  fact 
that  none  of  earlier  time  are  open  to  investigation.  From  these  rocks 
in  America,  two  principal  periods  have  been  indicated,  with  other  sub 
divisions. 

I.  Distribution  of  Archaean  Regions. 

The  Archrcan  rocks  of  North  America  are  mostly  crystalline  or 
metamorphic  rocks,  and  their  beds  stand  at  all  angles,  owing  to  the 
uplifting  and  flexing  which  they  have  undergone.  Where  the  Silurian 
strata  overlie  them,  the  two  are  unconformable,  the  latter  being  often 
spread  out  in  horizontal  beds  over  the  upturned  edges  of  the  Archaean 
rocks.  This  position  of  these  rocks  is  illustrated  in  the  following  cuts. 
In  each,  the  Archasan,  numbered  1,  in  its  usual  disturbed  condition,  is 
overlaid  nearly  horizontally  by  the  Silurian  beds  of  the  Potsdam  and 
other  periods,  numbered  2  to  4  ;  2  being  the  Potsdam  sandstone,  3 
the  Calciferous  sandrock,  4  a  the  Trenton  limestone,  4  b  the  Utica 
shale. 


Fig.  203. 


Fig.  204. 


la 


Fig.  205. 


Fig.  203,  by  Emmons,  from  Essex  County,  N.  Y.  ;  1  is  hypersthene  rock,  or  hypersthenyte.  —Fig. 
204,  by  Owen,  from  Black  River,  south  of  Lake  Superior  ;  1  is  a  granytic  rock,  1  a,  chloritic  and 
ferruginous  slates.  —  Fig.  205,  by  Logan,  from  the  south  side  of  the  St.  Lawrence  in  Canada, 
between  Cascade  Point  and  St.  Louis  Rapids  ;  1,  gneiss. 

•This  formation  in  Xorth  America  was  first  distinctly  recognized  in  its  true  importance 
in  the  Report  of  Foster  and  Whitney  on  the  Lake  Superior  region,  in  which  it  was 
named  the  Azmc  system.  Dawson,  after  his  announcement  of  the  animal  nature  of  the 
Eozoon,  suggested  the  name  Eoznic  (from  »jc5?,  dawn,  and  t<»-n,  life)-  As  the  supposed 
Eozoon  may  be  of  mineral  nature,  its  use  here  is  objectionable. 

The  areas  of  the  earth's  crust  over  which  the  Archaaan  rocks  are 
now  exposed  are,  — 

1.  Those  which  have  always  remained  uncovered. 

2.  Those  which  have  been  covered  by  later  strata,  but  from  which 
these  superimposed  beds  have  been  simply  washed  away,  without  much 
disturbance. 


ARCHAEAN   TIME. 


149 


3.  Those  once  covered,  like  the  last,  but  which,  in  the  course  of  the 
uptiirnings  of  mountain-making,  have  been  pushed  upward  among  the 
displaced  strata,  and  in  this  way  have  been  brought  out  to  the  light. 

In  cases  like  those  of  figures  203,  204,  in  which  the  Silurian  rocks  are 
spread  in  nearly  horizontal  layers  over  the  borders  of  an  area  made  up 
of  tilted  Archaean  rocks,  the  Archaean  area  either  has  been  always 
uncovered,  or  has  become  so  from  denudation ;  but,  in  mountain- 
regions,  where  the  Silurian  rocks  have  been  folded  up  in  the  mountain- 
making,  the  Archaean  below  may  have  been  brought  to  view  in  the 
uptiirnings.  Moreover,  tho  Archaean,  if  it  had  not  undergone  flex 
ures  before  the  Silurian  beds  were  laid  down,  would  partake  of  the 
Silurian  flexures,  or,  in  other  words,  be  conformable  to  the  Silurian 
strata.  But,  if  it  had  been  flexed  or  tilted  in  some  previous  period  of 
disturbance,  then  the  Archaean  would  be  uncomfoi'inable  to  the  Silurian, 
although  both  were  finally  upthrown  together,  in  the  making  of  the 
mountains. 

In  the  study  of  Archaean  regions,  these  points  require  special  inves 
tigation. 


Archaean  Map  of  North  America, 

In  the  map,  Fig.  206,  the  chief  Archaean  regions  are  the  white 
areas,  while  the  dark-lined  portion  represents  the  rest  of  the  continent 
submerged  beneath  the  continental  sea. 


150  ARCHAEAN   TIME. 

The  principal  of  the  areas  is  The  great  northern,  nucleal  to  the  con 
tinent,  B  B  C  C  on  the  map,  lying  mostly  in  British  America,  and  hav 
ing  the  shape  of  the  letter  V,  one  arm  reaching  northeastward  to 
Labrador,  and  the  other  northwestward  from  Lake  Superior  to  the 
Arctic.  The  region  appears  to  have  been,  for  the  most  part,  out  of 
water,  ever  since  the  Archaean  era.  To  this  area  properly  belong  the 
Adirondack  area,  covering  the  larger  part  of  northern  New  York,  and 
a  Michigan  area  south  of  Lake  Superior,  each  of  which  was  probably 
an  island  in  the  continental  sea  before  the  Silurian  age  began. 

Besides  this  nucleal  area,  there  are  border-mountain  lines  of  Ar- 
chaean  rocks :  a  long  Appalachian  line,  including  the  Highland  Ridge  of 
Dutchess  County,  N.  Y.,  and  New  Jersey,  and  the  Blue  Ridge  of  Penn 
sylvania  and  Virginia ;  a  long  Rocky  Mountain  series,  embracing  the 
Wind  River  mountains,  the  Laramie  range,  and  other  summit  ridges 
of  the  Rocky  Mountains.  In  addition,  in  the  Eastern  Border  region, 
there  is  an  Atlantic  Coast  range,  consisting  of  areas  in  Newfoundland, 
Nova  Scotia,  and  eastern  New  England ;  in  the  Western  Border  region, 
a  Pacific  Coast  range  in  Mexico  ;  and  several  more  or  less  isolated 
areas  in  the  Mississippi  basin,  west  of  the  Mississippi,  as  in  Missouri, 
Arkansas,  Texas,  and  the  Black  Hills  of  Dakota. 

The  Adirondack  area  in  Northern  New  York  covers  for  the  most  part  Essex,  Clinton, 
Franklin,  St.  Lawrence,  Hamilton,  and  Warren  counties,  and  parts  of  Saratoga,  Fulton, 
Herkimer,  Lewis,  and  Jefferson  counties. 

In  the  Eastern  Border  region,  Archaean  rocks  occur  in  Nova  Scotia  (near  Arisaig); 
in  New  Brunswick  (near  Portland);  probably  in  part  of  Maine,  on  the  Island  of  Mount 
Desert  (according  to  Yerrill);  and  along  a  range  of  country  running  northeastward  to 
New  Brunswick  :  in  northeastern  Massachusetts,  about  Newburyport,  Chelmsford,  and 
Bolton;  and  in  northeastern  Rhode  Island. 

In  central  and  western  New  England,  there  are  areas  in  the  White  Mountain  region, 
New  Hampshire  (first  announced  by  C.  H.  Hitchcock)  as  at  Waterville;  and  west  of 
the  Connecticut,  about  Winchester,  Connecticut  (Hall),  and  the  emery  region  of  Ches 
ter,  Massachusetts,  —  the  titanic  iron  vein  of  Winchester  and  the  emery  and  iron  vein 
of  Chester  lying  nearly  in  the  same  line. 

The  Appalachian  areas  commence  in  Dutchess  County,  New  York,  west  of  Connecti 
cut,  and  extend  south  westward  to  West  Point,  and  thence  along  the  Highlands  of  New 
Jersey,  the  Durham  Hills  of  eastern  Pennsylvania  and  their  continuation  in  South 
Mountain,  and  beyond  in  the  Blue  Ridge,  through  western  Virginia  and  North  Carolina, 
into  South  Carolina,  Tennessee,  and  Georgia. 

The  map  of  New  York  and  Canada,  in  the  chapter  on  the  Silurian,  shows  more  pre- 
ciselv  the  form  of  the  New  York  Archaean  and  that  north  of  the  St.  Lawrence.  It 
represents  also  the  Silurian  and  Devonian  strata  of  the  State,  as  they  become  succes 
sively  the  surface-rocks,  on  going  from  the  Archaean  southward.  Adjoining  the  Archaean 
(numbered  1),  is  the  earliest  Silurian,  No.  2.  which  outcrops  where  it  is  represented,  but 
is  supposed  to  underlie  the  strata  numbered  3,  4.  5,  etc.  So  No.  3  is  the  next  formation 
which  outcrops,  while  it  probably  underlies  all  the  beds  4.  5,  etc.  The  Archaean  is  thus 
the  lowest;  and  eacli  successive  stratum  was  a  new  deposit  over  it,  in  the  seas  that 
bordered  at  the  time  the  Archaean  dry  land. 

In  the  Rocky  Mountain  ret/ion^  there  are  long  narrow  ranges  whose  limits  are  not  well 
determined.  On  the  Mexican  area,  see  Am.  Jour.  Sci.,  II.  xxxix.  309,  1865. 


ARCHJEAX   TIME.  151 

In  Europe,  the  Archrcan  system  has  been  distinctly  recognized  in 
northwestern  Scotland ;  in  Finland,  Norway,  and  Sweden  ;  Bohemia 
(formations  A  and  B  of  Barrande)  ;  Bavaria  (Hercynian  and  Bojie 
Gneiss).  The  great  iron-regions  of  Sweden  are  of  this  age. 

II.  Periods  of  the  Archaean  Era. 

In  Canada,  where  these  rocks  in  North  America  are  most  fully 
represented,  two  periods  have  been  recognized :  1,  The  LAURENTIAN, 
the  older,  so  named  from  the  river  St.  Lawrence  ;  and  2,  the  HURON- 
IAN.  The  estimated  thickness  of  the  rocks  of  the  Laurentian  period 
is  30,000  feet ;  of  the  Huronian,  from  10,000  to  20,000  feet. 

1.  LAURENTIAN  PERIOD. 
I.  Rocks :  Kinds  and  Distribution. 

Geographical  Distribution.  —  The  regions  of  Laurentian  rocks  com 
prise  all  the  Archaean  above  mentioned,  excepting  the  areas  described 
beyond  as  Huronian. 

A  small  part  of  the  Canada  Laurentian  has  been  announced  as  probably  unconform- 
able  on  the  rest;  and  Logan  has  suggested  for  it  the  name  of  the  Upper  Laurentian,  or 
Labrador  beds.  One  area  covers  part  of  Montcahn  and  Terre-bonne ;  another  lies  west 
of  Lake  St.  John ;  others  northeast  of  Montmorency  Falls,  and  near  St.  Paul's  Bay. 

Kinds  of  Rocks.  —  The  rocks, with  few  exceptions,  are  metamorphio 
or  crystalline  rocks.  They  include  granite  and  gneiss  and  some  mica 
schist ;  also,  very  prominently,  rocks  of  the  hornblende  (and  pyroxene) 
series,  as  syenyte,  hornblendic  gneiss,  and  other  kinds  ;  also  extensive 
beds  of  crystalline  limestone.  Besides  these,  there  are  quartzyte  and 
conglomerate.  The  lime-and-soda  feldspar  called  labradorite  —  often 
characterized  by  a  beautiful  play  of  colors  —  is  common  in  Archaean 
terranes,  forming,  with  a  lamellar  mineral  related  to  pyroxene  or  horn 
blende,  the  rock  hypersthenyte. 

Chrysolite,  a  silicate  of  magnesia  and  iron,  is  a  constituent  of  some 
hypersthenyte,  and  also  forms,  with  labradorite,  a  rock  called  ossipyte, 
occurring  in  the  White  Mountain  region. 

Abundance  of  iron-bearing  minerals  is  a  striking  characteristic  of 
the  Archasan  rocks.  It  is  the  cause  of  the  frequent  reddish  color  of 
the  feldspar  of  the  granytic  rocks.  It  is  apparent  in  the  prevalence  of 
rocks  of  the  hornblendic  series,  the  black  variety  of  hornblende  and 
pyroxene,  present  in  them,  containing  much  iron.  It  is  especially  man 
ifested  in  the  existence  of  immense  beds  of  iron  ore,  which  consist 
either  of  magnetite  (Fe304),  or  of  hematite  (Fe203)  or  of  titanic 
iron  (the  last  differing  from  the  others  in  having  part  of  the  iron  re 
placed  by  titanium).  The  beds  are  occasionally  one  or  more  hundred 
feet  thick,  as  in  the  Missouri  Iron  Mountain,  the  Adirondack  region 
of  New  York,  the  Marquette  region  of  the  northern  peninsula  of 


152  ARCILEAN   TIME. 

Michigan,  in  Sweden,  etc;  and  they  occur  interstratified  with  the 
Archaean  schists  and  quartzyte.  They  far  exceed  in  thickness  the  iron 
ore  beds  of  later  ages.  In  Sussex  County,  N.  Y.,  near  Franklin  and 
Stirling,  the  ore  of  the  great  bed  is  a  zinc-iron  ore  called  franklinite. 

Another  very  common  material  is  graphite  (or  plumbago),  a  form  of 
carbon.  It  occurs  disseminated  through  the  rocks,  especially  the  lime 
stones,  constituting  20  to  30  per  cent,  of  some  layers  (which  therefore 
are  worked  for  the  graphite.)  It  is  often  met  with  in  scales  through 
the  iron  ores  ;  also  in  veins  which  afford  it  in  a  purer  state,  and  often 
crystallized. 

There  are,  in  addition,  dioryte,  epidotic  gneiss  and  schist;  massive  hornblende  rock 
and  hornblende  schist;  garnet-euphotide  (eclogyte)  and  a  feldspar-euphotide ;  soapstone 
(rensselaerite,  p.  72) ;  serpentine,  ophiolytes  or  verd -antique  marble  of  different  varieties. 

Part  of  the  feldspar  related  to  labradorite  has  the  composition  of  andesite  or  anor- 
thite ;  and  oligoclase  exists  in  the  Swedish  rocks.  Part  of  the  hypersthenyte  contains 
ordinary  hornblende  instead  of  hypersthene,  and  some  kinds,  mica  or  epidote.  Good 
localities  for  the  opalescent  labradorite  are  the  streams  of  the  Adirondack,  —  especially, 
says  Professor  Emmons,  the  beaches  of  East  River;  also  Avalanche  Lake,  near  the  foot 
of  the  great  slide  from  Mount  McMartin. 

The  potstone  or  soapstone  called  rensselaerite  covers  considerable  areas  in  the  towns 
of  Fowler,  Canton,  Edwards,  Hermon,  etc.,  St.  Lawrence  County,  and  at  Green 
ville,  in  Canada,  and  is  cut  into  slabs  for  tables,  chimney-pieces,  and  furnace-linings, 
or  made  into  inkstands.  The  paropliyte  or  aluminous  potstone  of  Diana,  Lewis  County, 
X.  Y.,  is  used  for  inkstands,  etc. 

Beautiful  red  and  green  porphyry  and  a  buhrstone  are  found  at  Grenville,  Canada. 

Among  the  minerals  of  the  Laurentian  rocks,  the  most  common  are  —  Orthoclase, 
scapolite,  nephelite,  pyroxene,  hornblende,  epidote,  mica  of  different  kinds,  garnet, 
tourmaline,  zircon,  idocrase,  sphene,  wollastonite,  chrondrodite,  among  silicates;  rutile, 
hematite,  magnetite,  franklinite,  titanic  iron,  corundum,  among  oxvds;  apatite,  a  phos 
phate;  graphite.  The  apatite  is  in  some  places  abundant,  and  is  mined  for  fertilizing 
soils.  The  franklinite  of  New  Jersey  is  associated  with  zincite  or  oxyd  of  zinc,  and 
willemite,  a  silicate  of  zinc.  lolite  is  a  common  mineral  in  Bavaria. 

Lead  veins  occur  in  Canada,  and  near  Rossie,  New  York,  affording  galenite,  blende, 
and  iron  and  copper  pyrites,  with  calcite  and  some  barite  and  fluor;  but  Hunt  concludes, 
from  the  fact  that  the  vein  at  Ramsay,  Canada,  traverses  also  Silurian  rocks,  and  the 
latter  contain  similar  veins  elsewhere,  that  all  probably  belong  to  a  later  date,  instead 
of  being  Archaean. 

Arrangement  of  the  rocks.  —  Although  the  Archaean  rocks  are 
mostly  crystalline,  they  follow  one  another  in  various  alternations, 
like  the  sedimentary  beds  of  later  date.  In  the  sections  which  have 
been  given,  there  are  alternations  of  granite,  gneiss,  schists,  lime 
stone,  etc. ;  and  the  dip  and  strike  may  be  studied  in  the  same 
manner  as  in  the  case  of  any  tilted  sandstones  or  shales.  The  follow 
ing  sections  represent  other  examples ;  and  in  them  there  are  beds 
of  iron -ore,  fifty  feet  and  upward  in  thickness,  which  are  banded 
with  siliceous  layers  and  chlorite  schist,  showing  thereby  a  distinctly 
stratified  character.  Where  most  flexed  or  folded,  there  is  still  a 
distinction  of  layers  ;  and  it  is  owing  to  this  fact  that  the  rocks  may 
be  described  as  folded ;  for  folds  can  be  identified  only  where  the 


ARCHAEAN   TIME. 


153 


rocks    are  in   sheets.     This  grand  fact   is,  then,  evident,  —  that  the 
Archaean  rocks  are  stratified,  as  much  as  the  rocks  of  any  later  age. 

In  the  series  in  the  region  of  Ottawa,  there  are  three  great  limestone  strata,  separated 
by  gneissoid  rocks,  in  all  not  less  than  3,500  feet  in  thickness.  The  upper  of  these 
limestones  is  about  1,500  feet  thick;  but  nearly  half  consists  of  intercalated  layers  of 
gneiss,  and  the  limestone  of  each  stratum  is  often  associated  with,  or  passes  into,  rocks 
consisting  largely  of  pyroxene  or  hornblende;  and  these  portions  often  abound  in 
minerals,  the  most  common  of  which  are  graphite,  orthoclase,  mica,  scapolite,  wol- 
lastonite,  sphene,  serpentine. 

The  following  section  by  Logan  (real  in  its  general  truths,  although  pai'tly  ideal) 
exhibits  well  the  fact  and  condition  of  the  stratification.  It  presents  to  view  a  stratum 


of  (n-)  white  granular  or  crystalline  limestone,  many  times  folded,  and  interstratitied 
with  gneiss  and  quartz  rock  (b)-   and  the  limestone  has  been  traced  over  the  same 
region  (Grenville  and  adjacent  country,  Canada),  in  linear  and  curving  bands  corre 
sponding  to  a  series  of  folds. 
The  following  figures  represent  iron-ore   beds   alternating   with  other  strata.     In 


Fig.  208. 


Fig.  210. 


N.  Y.,  Emmons),  the 


Fig.  208  (from  the  Michigan  region,  Foster  and  Whitney),  the  iron-ore,  in  extensive 
beds  (i,  i),  occurs  between  chlorite  slate  (a,  a)  and  dioryte  (i);  and  the  iron-ore  in  i 
is  banded  with  jasper.     In  Figs.  209  and  210  (Essex  County, 
iron-ore,  in  beds  several  yards  wide,  is  associated 
with  gneiss  and  quartz  i-ock,  and  is  interlaminated 
with  quartz,  the  whole  dipping  together  in  a  com 
mon  direction,  like  beds  of  sandstone,  shale  and 
iron-ore,    in   many   regions   of  sedimentary  rocks. 
At  the  Adirondack  mines,  in  Essex  County,  N.  Y., 
one  bed,  according  to  Emmons,  is  150  feet  thick. 

In    Fig.    211    (Penokie   Range,    south   of    Lake 
Superior,  C.  Whittlesey),  h  is  hornblende  rock  and 


slaty  quartz;  </,  quartzyte,  30  feet  thick;  i,  a  bed  of  iron-ore,  25  to  50  feet  thick. 

In  the  Missouri  region,  at  Pilot  Knob,  — a  hill  662  feet  high  above  its  base,  —  there 
is  a  bed  of  hematite,  46  feet  thick,  overlaid  by  140  feet  of  porphyry -conglomerate,  and 
underlaid  by  a  red  jaspery  porphyry  and  other  porphyritic  rocks ;  and  the  ore-bed  is 
divided  into  two  parts  by  a  layer  of  slate  ten  inches  to  three  feet  thick.  The  pebbles 
of  the  porphyry-conglomerate  are  cemented  by  iron-ore.  The  rocks  of  the  region 
also  include  granyte.  (Pumpelly.)  When  the  region  was  first  visited,  the  surface  of 
the  hill  was  covered  mostly  with  huge  blocks  of  the  ore. 

The  iron-ore,  which  is  found  so  very  abundantly  in  each  of  these  regions,  is  partly 


154  ARCILEAN   TIME. 

magnetic  and  partly  specular  ore,  or  hematite,  —  that  of  Lake  Superior  and  Missouri 
mostly  the  latter,  and  that  of  New  York  mainly  the  former. 

In  western  North  Carolina,  great  beds  of  magnetite,  and  also  of.  hematite  and  titanic 
iron,  occur  between  layers  of  hornblende  schist  and  mica  schist,  with  intercalated  lay 
ers  at  times  of  jaspery  quartz;  one  of  the  beds  is  over  300  yards  thick  (Genth). 

In  Canada,  at  Bay  St.  Paul's,  there  is  a  bed  of  titanic  iron,  90  feet  wide,  exposed  for 
200  or  300  feet,  occurring  in  syenyte,  with  rutile  or  oxyd  of  titanium.  The  ore  does 
not  differ  from  ordinary  specular  iron  in  appearance;  but  the  powder  is  not  red. 

In  Sweden  and  Norway,  the  iron-ores  are  interstratiried  in  the  same  manner  with 
crystalline  rocks,  — mainly  gneiss,  hornblende  rocks,  chlorite  slate,  clay  slate,  quartzyte 
and  granular  limestone,  with  which  they  are  more  or  less  laminated.  At  Dannemora, 
the  stratum  containing  iron  is  600  feet  in  width;  and  it  occurs  with  granular  limestone, 
chlorite  slate  and  gneiss.  At  Uto,  Sweden,  red,  jaspery  quartz  bands  the  ore,  in  the 
same  way  as  in  Michigan:  the  ore  — hematite  mixed  with  magnetite  —  occurs  in  mica 
schist  and  quartzyte,  in  an  irregularly-shaped  mass,  about  120  feet  in  its  widest  part. 
At  Gellivara  there  is  an  iron  mountain  three  or  four  miles  long  and  one  and  a  half 
wide,  consisting  mostly  of  magnetite,  with  some  hematite.  In  each  of  these  regions 
the  beds  dip  with  the  enclosing  rock,  — showing  that  all  have  had  a  common  history. 

In  the  annexed  sections  (St.  Lawrence  County,  N.  Y.,  Emmons),  granular  limestoi^e 
is  represented  in  connection  with  granite  and  other  rocks.  In  Fig.  212,  /  is  limestone, 
without  any  appearance  of  stratification;  and  the  containing  rock  is  granite.  In 
Fig.  213,  a  a  are  gneiss,  b  steatyte,  I  unstratitied  limestone.  Although  a  and  b  are  not 

Fig.  212.  Fig.  213. 


evenly  stratified,  yet  thev  are  sufficiently  so  to  show  that  the   limestone,  while  it  has 
lost  its   division   into   layers  in    the  crystallizing  process,  is  probably  a  conformable 
stratum. 
The  quartzyte  of  Sank  County,  Wisconsin,  is  referred  to  the  Archa?an  (Irving). 

1  The  order  of  stratification  among  the  Archaean  rocks  is  as  various 
as  among  the  rocks  of  other  ages.  As  sandstones,  shales,  argilla 
ceous  sandstones,  conglomerates,  follow  one  another  in  any  succession, 
so  granite  or  gneiss  may  lie  between  layers  of  slate  or  schist,  and 
quartz  rock  or  limestone  may  have  any  place  in  the  series.  It  is 
common,  however,  to  find  the  different  hornblendic  rocks  associated 
together ;  and  both  these  and  the  chloritic  often  abound  in  the  iron- 
regions,  since  hornblende  and  chlorite  are  ferriferous  minerals.  The 
association  of  pyroxene  and  hornblendic  rocks  with  the  limestones 
has  been  mentioned  above. 

Original  condition  of  the  Laurentian  beds.  —  The  alternations  of 
hornblendic  and  other  schists  with  quartzyte,  limestone,  gneiss,  and 
the  other  rocks,  prove  that  all  were  once  sedimentary  beds,  —  beds 
formed  by  the  action  of  moving  water,  like  the  sandstones,  argilla 
ceous  beds,  and  limestones  of  later  times.  They  have  no  resemblance 
to  lavas  or  igneous  ejections.  The  schists  graduate  into  true  slates,  and 
the  quartzytes  into  unmistakable  sandstones  and  conglomerates  ;  so  that 


ARCJLEAN   TIME.  155 

there  is  direct  proof  in  the  gradations  as  well  as  in  the  arrangement 
in  alternating  layers,  that  all  the  schists  and  limestone  rocks  are  parts 
of  one  series  of  sedimentary  beds,  which  by  some  process  have  been 
hardened  and  crystallized.  Moreover,  there  is  as  direct  a  passage 
from  the  gneiss  to  the  gneissoid  granite,  and  thence  to  true  granyte 
and  syenyte ;  so  that  even  the  most  highly  crystalline  rocks  cannot, 
as  a  general  thing,  if  at  all,  be  separated  from  this  series.  These 
Laurentian  rocks,  therefore,  are  made  out  of  the  ruins  of  older 
Laurentian,  or  of  still  older  Archa3an  rocks,  —  that  is,  of  the  sands,' 
clays  and  stones  made  and  distributed  by  the  ocean,  as  it  washed 
over  the  earliest-formed  crust  of  the  globe.  The  loose  material 
transported  by  the  currents  and  waves  was  piled  into  layers,  as  in 
the  following  ages,  and  vast  accumulations  were  formed ;  for  no 
one  estimates  the  thickness  of  the  recognized  Laurentian  beds  as 
below  thirty  thousand  feet.  Limestone  strata  occurred  among  the 
alternations  ;  and  argillaceous  iron-ores,  like  the  beds  of  the  Coal- 
measures,  though  vastly  more  extensive ;  and  beds  of  earthy  ores  of 
zinc  were  a  part  of  the  formations  in  the  deposits. 

The  beds,  moreover,  were  spread  out  horizontally,  or  nearly  so  ; 
for  this  is  the  usual  condition  with  sediments  and  limestones,  when 
first  accumulated.  The  original  condition,  then,  of  the  rocks  was  the 
same  as  that  of  ordinary  modern  sediments  —  in  horizontal  beds  and 
strata. 

Disturbances  and  Foldings.  —  But,  from  the  sections  and  de 
scriptions  on  the  preceding  pages,  it  is  apparent  that  horizontal  Lau 
rentian  rocks  are  now  exceedingly  uncommon.  The  whole  series  has 
been  upturned  and  flexed,  broken  and  displaced,  until  little,  if  any,  of 
it  remains  as  it  was  when  accumulated. 

This  upturning,  moreover,  is  not  confined  to  small  areas,  nor  has 
it  been  done  in  patchwork -style ;  for  regions  of  vast  extent  have 
undergone  in  common  a  profound  heaving  and  displacement.  This 
community  of  action  or  history  is  evident  in  the  fact  that  the  rocks 
have  nearly  a  common  strike  over  wide  regions,  —  the  strike  being  at 
right  angles,  or  nearly  so,  to  the  action  of  the  force  causing  the  uplift. 

The  strike  in  the  New  York,  Canada,  Michigan,  and  Lake  Superior  Archaean  is 
generally  northeastward,  or  nearly  parallel  to  the  course  of  the  Appalachians  and 
Green  Mountains,  but  varies  to  north,  and  also  to  east. 

In  the  New  York  region,  according  to  Emmons,  the  course  of  the  line  of  limestone 
from  Johnsburg  to  Port  Henry,  on  Lake  Champlain,  is  nearly  northeast;  that  of 
another,  along  by  Rossie  (between  Black  Lake  and  Pitcairn,  and  from  Theresa  nearly 
to  Lisbon  and  Madrid),  north-north  en st ;  another,  parallel  to  this,  extends  from  Ant 
werp  to  Fowler  and  Edwards.  These  outcrops  of  limestone  follow  the  line  of  strike. 
The  dip  varies  from  10°  to  90°,  either  side  of  the  perpendicular.  The  iron-ore  beds 
have  the  same  strike;  for  all  together  constitute  one  system. 

In  Canada,  the  limestone  ranges   of  the  township  of  Grenville  have  a  course,  ac- 


156  ARCHAEAN   TIME. 

cording  to  Logan,  between  northeast  and  north-northeast,  and  mostly  the  latter;  and 
the  strike  of  the  gneiss  and  schists  has  the  same  general  course. 

The  usual  strike  of  the  Archaean  rocks  of  Scandinavia  is  also  to  the  northeastward, 
—  a  fact  to  be  expected  where  this  is  the  general  trend  of  the  mountain  range. 

The  beds  were  laid  down  as  sediments  over  immense  continental 
areas  ;  and  then  followed  an  epoch  of  uplift,  when  the  horizontal 
layers  were  pressed  into  folds  and  displaced,  on  the  grand  scale  ex 
plained.  Many  such  periods  of  uplift  may  have  previously  occurred. 
But  it  is  evident  that  uplifting  and  disturbance  were  not  the  prevail 
ing  condition  of  Laurentian  times,  any  more  than  they  were  of  later 
ages.  This  is  proved  by  the  conformability  of  the  various  beds  to 
one  another  in  this  system  of  foldings.  An  age  of  comparative  quiet, 
allowing  of  vast  accumulations  of  horizontal  strata,  even  to  a  thick 
ness  of  30,000  feet,  must  have  preceded  the  epoch  of  disturbance. 

In  these  primeval  times,  the  ocean  worked  almost  alone  at  rock- 
making,  without  the  aid  of  great  rivers  to  wear  off  and  bring  material 
for  its  use,  as  in  the  later  ages ;  and  consequently  rock-making  went 
forward  then  with  extreme  slowness.  It  is  obvious,  therefore,  that 
the  period  of  comparative  quiet,  in  which  the  30,000  feet  of  rock  were 
deposited,  was  long.  It  had  the  aid  of  an  excessive  proportion  of 
carbonic  acid  in  the  atmosphere  to  be  carried  down  with  the  rains,  so 
that  this  most  efficient  of  all  agents  in  rock-destruction  (p.  689  )  must 
have  worked  with  an  energy  unknown  in  later  time.  (Hunt.) 

Alterations  :  Solidification  and  Crystallization.  —  Besides  the  dis 
placements,  there  was  an  almost  universal  crystallization  of  the  old 
sedimentary  beds  and  limestones  ;  and  now,  in  place  of  the  sands  and 
clays  and  earthy  limestone  layers,  the  rocks,  through  this  metamor- 
phism,  are  granite,  gneiss,  syenyte,  granular  limestone,  etc.  .The 
once  massive  and  earthy  limestones  now  contain  in  many  places 
crystals  of  mica,  scapolite.  apatite,  spinel,  etc.  ;  and  the  limestone  itself 
is  in  part  a  white  or  variegated  architectural  marble.  The  argil 
laceous  iron-ore  has  become  the  bright  hematite  or  magnetite  ;  and  it 
is  banded  by,  or  alternates  with,  schist  and  quartz,  etc.,  which  were 
once  accompanying  clay  and  sand  layers.  The  franklinite  (zinc-iron 
ore)  and  its  associated  ores  of  zinc,  often  in  regular  crystallizations, 
were  made  from  the  stratified  beds  containing  impure  zinc  and  iron 
ores,  and  were  in  part  limestone  strata,  like  those  which  afford  such 
earthy  ores  in  Belgium  and  Carinthia,  and  near  Bethlehem  in  Penn 
sylvania. 

Some  of  the  Archaean  rocks  have  experienced  a  second  or  third  alteration  during 
the  later  ages.  The  potstone  or  rensselaerite,  gieseckite,  and  part  of  the  serpentine, 
with  some  of  the  associated  minerals,  are  among  these  later  products.  The  renssel 
aerite  has  been  observed  under  the  crystalline  form  of  pyroxene,  showing  that  in  part, 
at  least,  it  has  been  made  out  of  pyroxene;  and  the  gieseckite  exists  under  the  crys- 


ARCILEAN    TIME.  157 

talline  form  of  nephelite,  evincing  that  it  was  made  out  of  preexisting  nephelite 
crystals,  like  the  gieseckite  of  Greenland,  which  it  resembles  in  aspect  and  com 
position.  Another  species,  loganite,  has  the  forms  of  pyroxene.  Other  evidences  of 
alteration  subsequent  to  the  original  crystaflization  are  the  rounded  crystals  of  quartz 
and  apatite  of  Gouverneur,  and  the  soft  spinels  of  St.  Lawrence  County,  called  houghite 
or  hydrotalcite.  In  view  of  the  remoteness  of  the  Archaean  era,  and  also  of  the 
chemical  powers  of  water,  especially  when  charged  with  heat  and  therefore  with  alkalies 
and  silica,  such  changes  are  not  a  source  of  wonder. 

Igneous  or  eruptive  rocks —  There  are  few  examples  of  dikes  of  igneous 
rocks,  through  the  Laurentian  of  Canada;  and  these  are  mostly  confined  to  the  county 
of  Grenville.  The  dikes  there  are  of  four  different  periods  of  eruption.  The  oldest, 
as  Hunt  observes,  consist  of  greenish-gray  doleryte.  These  are  intersected  by  dikes 
of  red  syenyte,  in  part  granitic;  these  again  by  others  of  a  quartz-bearing  porphyry 
(orthophyre),  greenish,  reddish  or  black,  with  the  crystals  of  feldspar  red;  and, 
finally,  there  is  a  fourth  series,  consisting  of  grayish-black  doleryte,  containing  some 
mica,  sphene  and  titanic  iron,  besides  occasionally  large  crystals  of  augite.  These 
last  resemble  the  dikes  intersecting  the  Silurian,  and  are  regarded  as  of  Silurian 
eruption.  The  others  occur  where  the  Laurentian  is  overlaid  by  the  lowest  Silurian, 
and  hence  must  be  of  pre-Silurian  age.  (Logan's  Rep.  1863,  p.  652.) 

II.  Life. 

1.  Plants.  —  No  distinct  remains  of  plants  have  been  observed. 

The  occurrence  of  graphite  in  the  rocks,  and  its  making  20  per 
cent,  of  some  layers,  is  strong  evidence  that  plants  of  some  kind,  if 
not  also  animals,  were  abundant.  For  graphite  is  carbon,  one  of  the 
constituents  of  wood  and  animal  matters  ;  and  mineral  coal,  whose 
vegetable  origin  is  beyond  question,  has  been  observed,  in  the  Carbon 
iferous  rocks  of  Rhode  Island,  changed  to  graphite  ;  and  even  coal- 
plants,  as  ferns,  occur  at  St.  John,  New  Brunswick,  in  the  state  of 
graphite.  Further,  the  amount  of  graphite  in  the  Laurentian  rocks 
is  enormous.  Dawson  observes  (taking  his  facts  from  Logan)  that 
it  is  scarcely  an  exaggeration  to  maintain  that  the  quantity  of  carbon 
in  the  Laurentian  is  equal  to  that  in  similar  areas  of  t1^  Carbon 
iferous  system. 

In  Europe,  graphite  occurs  in  the  Archaean  rocks  of  Bavaria;  anthracite  has  been 
observed  in  the  iron-bearing  rocks  of  this  age  at  Arendal,  Norway;  and  carbonaceous 
(partly  anthracite)  and  bituminous  substances  are  distributed  through  layers  of 
Archaean  gneiss  and  mica  schist  at  Nullaberg,  in  Wermland,  Sweden,  constituting 
5  to  10  per  cent:  facts  pointing  clearly  to  the  existence  of  life  before  the  close  of 
this  era. 

Animal  life,  as  Hunt  observes,  may  have  afforded  part  of  the  carbonaceous  material, 
and,  perhaps,  as  large  a  part  as  vegetable  life. 

The  plants  must  have  been  the  lowest  of  Cryptogams,  or  flowerless 
species,  and  mainly,  at  least,  marine  Alga  or  Sea-weeds  ;  for  the  Lower 
Silurian,  the  next  succeeding  era,  has  remains  of  nothing  higher  in 
its  beds.  This  argument,  from  the  Silurian,  excludes  all  Mosses  and 
the  ordinary  terrestrial  plants  ;  but  not  necessarily  Lichens,  since  these 
grow  in  dry  places,  and  could  not  have  contributed  to  marine  deposits 


158 


ARCILEAN   TIME. 


Fig.  214. 


if  they  had  existed.  It  is  hence  possible  that,  besides  seaweeds  in  the 
water,  there  were  Lichens  over  the  bare  rocks.  The  easily  destructi 
ble  Fungi  may  also  have  lived  in  damp  places. 

2.  Animals.  —  Animals  of  the  lowest  division  of  animal  life,  that  of 
Rhizopods  among  Protozoans,  were  probably  abundant.  The  existence 
of  strata  of  limestone,  alternating  with  metamorphic  schists,  affords  a 
strong  presumption  in  favor  of  the  existence  of  some  living  species,  since 
all  newer  limestones  of  much  extent  intercalated  among  stratified  rocks 
have  been  made  mainly  of  the  calcareous  relics  of  such  species ;  and 
the  Rhizopods  are  those  animals  which  should  have  first  appeared, 
and  which  should  have  contributed  most  largely  to  the  making  of  the 
limestones.  These  limestones  may,  however,  have  proceeded  from  the 
calcareous  secretions  of  the  lowest  forms  of  vegetable  life  —  that  is, 
from  kinds  related  toNullipores  and Coccoliths  (p.  135). 

The  existence  of  Rhizopods  is  believed  by  many  to  have  been  dem 
onstrated  by  the  discovery  of  their  fossils  in  serpentine  associated 
with  the  limestone,  and  later  in  the  limestone  itself.  Dawson,  who 
made  the  earliest  investigations  of  them,  named  the  species  (one  found 

in  Canada)  Eozoon  Canadense.  It  is  pro 
nounced  a  kind  of  coral-making  Rhizopod. 
The  coral-like  masses  attributed  to  them 
are  sometimes  several  feet  in  diameter. 

Fig.  214  represents,  natural  size,  a  sec 
tion  of  a  specimen  of  this  fossil,  from 
Grenville.  The  white  bands  are  the  cal 
careous  layers  supposed  to  have  been  se 
creted  by  a  layer  of  the  Rhizopods,  while 
the  dark  bands  correspond  in  position  to 
the  layer  of  Rhizopods,  and  are  made  up 
of  mineral  material  (serpentine  generally, 
sometimes  pyroxene,  loganite,  etc.,  accord 
ing  to  Hunt)  that,  after  the  death  of  the 
animals,  filled  the  cells.  Dilute  muriatic 
acid  removes  the  limestone,and  opens  the  rest  to  examination. 

The  Eozoon  >\is  been  compared  by  Carpenter  to  the  small  forms  made  by  Rhizopods 
of  the  genus  Cnlcarina. 

The  specimens  of  Eozoon  were  first  supposed  to  be  Polyp-corais  (Logan's  Rep.  Geol. 
Can.,  1863,  p.  48),  and  afterward  announced  as  Rhizopods  by  Dr.  Dawson  (Logan's 
Rep.  Geol.  Canada,  for  1866;  Am.  J.  Sci.,  II.  xxxvii.  272,  431,' 1864,  xl.  344,  1865). 

They  occur  in  the  third  or  Grenville  stratum  of  limestone  of  the  Laurentiau,  near 
Grenville,  and  in  the  Petite  Nation  Seignory;  also  in  Burgess  (where  the  calcareous 
part  is  dolomite  according  to  Hunt),  and  at  the  Grand  Calumet,  in  a  limestone  whose 
place  in  the  series  is  not  determined;  but  whether  or  not  anywhere  in  the  first  and 
second  limestones  is  not  known;  also  in  Nova  Scotia,  in  New  Brunswick,  and  in 
^Massachusetts,  at  Newburyport,  Chelmsford  and  Bolton,  where  the  spaces  are  filled 


ARCILEAN    TIME.  159 

with  serpentine.  Eozoon  has  also  been  observed  in  Archaean  rocks  in  Bavaria  (named 
E.  Bavaricum),  in  Saxony,  Bohemia,  Hungary,  and  at  Pargas  in  Finland. 

Profs.  Win.  King  and  J.  H.  Rowney,  of  Dublin,  hold  that  Eozoon  is  of  mineral  and 
not  of  animal  origin  (Proc.  Roy.  Irish  Acad.  for  1869  and  1871);  and  others  have  urged 
the  same  opinion.  Doubts  are  excited  by  the  fact  that  the  Eozoonic  structure  has  been 
found  by  Dawson  in  a  spinel ;  by  the  unequal  thickness  of  the  calcareous  layers  and  the 
interspaces;  and  by  the  fact  that  serpentine  of  later  formations  has  afforded  similar 
forms.  H.  J.  Carter,  in  his  research,  in  1874,  found  no  Rhiznpod-like  structure  whatever. 

Forms  resembling  Annelid  tubes  have  been  stated  by  Dr.  Fritsch  to  occur  in  the 
Laurentian  of  Bohemia;  and  Dr.  Dawson,  from  some  obscure  indications,  has  sug 
gested  the  "  possible  existence  "  of  sea-worms  or  Annelids  in  the  Canada  Laurentian. 
Whatever  may  be  the  final  decision  with  regard  to  Eozoon,  there  can  be  little  doubt  that 
Rhizopods  existed  in  Archaean  time. 

2.  IIURONIAN  PERIOD. 

Geographical  Distribution,  and  Rocks.  —  The  rocks  first  distin 
guished  as  Huronian  lie  over  a  region  on  the  north  coast  of  Lake 
Huron,  extending  from  a  point  a  few  miles  west  of  French  River 
nearly  to  Sault  Ste.  Marie.  The  width  is  undetermined,  but  probably 
it  does  not  exceed  ten  or  fifteen  miles.  They  lie  unconfqrmably  upon 
the  Laurentian  rocks,  showing  that  they  are  of  subsequent  origin  ; 
but  they  contain  no  fossils  to  fix  precisely  their  age.  Other  smaller 
areas  occur  on  the  north  shore  of  Lake  Superior. 

The  rocks  of  the  Lake  Huron  region  include  greenish  siliceous 
slates  and  conglomerates  ;  quartzytes  ;  layers  of  jasper  and  chert ; 
hard  quartz  and  jasper  conglomerates ;  thin  layers  of  grayish  or  blue- 
ish  limestone  ;  and  also  beds  of  dioryte,  which  in  some  places  graduate 
into  syenyte,  and  in  others  contain  epidote.  The  strata  of  quartzyte 
and  conglomerates  are  from  1,000  to  2,500  feet  thick.  The  latter  con 
tain  stones  (some  a  foot  in  diameter)  that  were  derived  from  the 
Laurentian.  Some  of  the  sandstone  layers  are  ripple-marked.  The 
limestones  contain  none  of  the  minerals  common  in  this  rock  in  the 
Laurentian. 

The  strata  are  much  intersected  by  dikes  of  dioryte  ;  and  it  has 
been  questioned  whether  the  beds  of  dioryte  were  not  injected  beds. 
There  are  also  large  numbers  of  veins  bearing  copper  ores  (sulphids 
chiefly),  which  intersect  the  dikes  of  dioryte,  and  are  therefore  the 
later  in  origin. 

Beside*  the  above-mentioned  regions  of  Huronian  rocks,  there  are  others  which  are 
referred  to  this  period  mainly  on  lithological  grounds,  —  chloritic  rocks,  dioryte,  felsitic 
(porphyroid)  rocks  and  epidotic  rocks  being  regarded  as  especially  characteristic  of 
the  Huronian. 

Of  these  are:  (1)  In  Michigan,  the  large  area,  south  of  Lake  Superior,  in  which  lie 
the  immense  iron-ore  beds  of  Marquotte,  already  mentioned  (p.  151).  The  rocks  are  in 
part  dioryte,  chlorite  schist,  beds  of  jasper  and  chert.  As  it  is  not  certain  that  such  an 
association  of  rocks  may  not  have  been  formed  in  other  eras,  and  even  in  the  Lauren 
tian,  the  evidence  as  to  age  is  far  from  conclusive.  The  extent  of  the  beds  of  iron-ore 
affords  some  reason  for  believing,  as  shown  by  Whitney,  that  they  are  true  Laurentian. 


160  ARCHAEAN   TIME. 

The  iron-ore,  unlike  that  of  northern  New  York,  is  specular  iron-ore  (Fe208).  But  it 
contains  in  many  places  octahedral  crystals,  which  appear  to  indicate  that  it  was  once 
magnetic  iron-ore,  and  therefore  that  originally  the  ore  of  the  two  regions  was  alike. 
H.  Credner  refers  part  of  the  region  to  the  Laurentian,  but  retains  the  Marquette  por 
tion  in  the  Huronian.  He  states,  that  he  observed  an  example  of  unconformability  be 
tween  the  two  systems  of  beds.  They  are  also  stated  to  be  unconformable  by  Brooks 
and  Puvnpelly. 

(2.)  Other  regions  of  rocks  supposed  to  be  Huronian  occur  in  Newfoundland,  New 
Brunswick  and  some  parts  of  New  England;  in  most  cases  they  have  been  determined 
onlv  by  the  valueless  test  —  the  nature  of  the  rocks.  Credner  refers  to  the  Huronian, 
with  no  better  reason,  a  range  of  rocks  along  the  whole  course  of  the  Appalachians, 
from  Canada  to  South  Carolina;  and  he  so  calls  certain  auriferous  rocks  of  Montgomery 
County,  North  Carolina,  which  Emmons  refers  to  the  Taconic  system,  including  hydro- 
mica  schist,  quartzytes,  itacolumyte  or  flexible  sandstone,  etc.  Emmons  found  in  one 
of  the  beds  a  fossil-like  form,  which  he  pronounced  a  silicified  coral  and  named  Pakeo- 
trochis(Am.  Jour.  Sci.,  II.  xxii.  389);  but,  according  to  Hall  and  Marsh,  it  is  probably 
only  a  concretion. 

As  the  original  Huronian  has  no  fossils,  there  is  no  basis  for  a  satisfactory  determina 
tion  of  its  equivalents.  It  is  quite  possible  that  it  is  Cambrian  or  Primordial. 

3.  GENERAL  CONCLUSIONS. 

Relations  of  the  North  American  Archaean  areas  to  the  Conti 
nent. —  On  the  map,  p.  149,  the  striking  fact  is  shown  that  the  great 
northern  V-shaped  Archrean  area  of  the  continent  has  (1)  its  longer 
arm.  B  B,  parallel  approximately  to  the  Rocky  Mountain  chain  and 
the  Pacific  border  ;  and  (2)  its  shorter,  C  C,  parallel  to  the  smaller 
Appalachian  chain  and  the  Atlantic  border.  Further :  Of  the  other 
ranges  of  Archasan  lands,  (1)  there  is  one  near  the  Atlantic  border, 
in  Newfoundland,  Nova  Scotia,  and  New  England  ;  (2)  another  along 
the  eastern  side  of  the  Appalachian  chain  ;  (3)  two  or  more,  of  great 
length,  along  the  Rocky  Mountain  chain  ;  and  (4)  others,  not  included 
in  the  above,  lie  in  ranges  parallel  to  these  main  courses.  Moreover, 
the  Archaean  rocks  of  these  regions  were  upturned  and  crystallized 
before  the  Silurian  age,  and  probably  at  two  or  more  different  epochs ; 
and  some,  if  not  all,  were  thus  early  raised  into  ridges,  standing  not 
far  below  the  water's  surface,  if  not  above  it. 

Hence,  in  the  very  inception  of  the  continent,  not  only  was  its  gen 
eral  topography  foreshadowed,  but  its  main  mountain  chains  appear  to 
have  been  begun,  and  its  great  intermediate  basins  to  have  been  de 
nned  —  the  basin  of  New  England  and  New  Brunswick  on  the  east ; 
that  between  the  Appalachians  and  the  Rocky  Mountains  over  the 
great  interior  ;  that  of  Hudson's  Bay  between  the  arms  of  the  north 
ern  Y.  The  evolution  of  the  grand  structure-lines  of  the  continent 
was  hence  early  commenced,  and  the  system  thus  initiated  was  the 
system  to  the  end.  Here  is  one  strong  reason  for  concluding:  that  the 
continents  have  always  been  continents ;  that,  while  portions  may 
have  at  times  been  submerged  some  thousands  of  feet,  the  continents 


ARCHAEAN   TIME.  161 

have  never  changed  places  with  the  oceans.  Tracing  out  the  develop 
ment  of  the  American  continent,  from  these  Archaean  beginnings,  is 
one  of  the  main  purposes  of  geological  history. 

Source  of  the  material  of  later  fragmental  rocks.  —  The  Archaean 
rocks,  and  rocks  made  from  them,  are  the  main  source  of  the  material 
of  subsequent  non-calcareous  fragmental  rocks.  Volcanic  eruptions 
have  added  a  little  to  the  supply ;  chemical  depositions  also  a  little ; 
and  the  siliceous  secretions  of  the  lowest  orders  of  plants  and  animals 
have  contributed  silica  to  some  extent;  but  all  these  sources  are  small 
compared  with  those  of  the  Archaean  terranes.  From  the  fact  pointed 
out,  that  these  most  ancient  of  rocks 'were  distributed,  as  the  Silurian 
era  opened,  in  insular  areas  all  along  the  Atlantic  border  —  from  Lab 
rador,  through  New  England,  southwestward  (and  other  areas  may 
have  existed,  which  are  now  at  shallow  depths  under  other  rocks  or  the 
sea-border)  —  it  is  seen,  as  Hunt  has  urged,  that  they  were  well  situ 
ated  for  supplying,  through  the  help  of  the  ocean,  mud,  sand  and  gravel, 
for  the  deposits  that  were  in  progress  as  the  next  era  opened.  And 
their  contributions  have  continued  ever  since  to  be  used  in  rock  mak 
ing,  both  directly  and  through  the  strata  which  had  been  made  from 
them. 

Life.  —  The  earliest  representatives  of  animal  life  on  the  earth  had 
no  special  organs,  either  of  sense ;  of  motion,  excepting  minute  hairs, 
or  hair-like  processes ;  or  of  nutrition,  beyond,  at  the  best,  a  mouth 
and  a  stomach.  It  was  life  in  its  simplest  or  most  elemental  condi 
tion  —  systemless  life  —  since  neither  of  the  four  grand  systems  of 
the  animal  kingdom  was  distinctly  indicated.  Such  was  the  beginning. 

Indications  of  plants  occur  in  earlier  Archaean  beds  than  those  of 
animals ;  yet  the  absence  of  animal  remains  may  be  owing  to  the  met- 
amorphism  of  the  rocks.  That  plants  preceded  animal  life  on  the 
globe  is  altogether  probable,  because  they  may  live  and  reproduce  in 
hotter  waters ;  and,  therefore,  a  temperature  admitting  of  the  existence 
of  plants  would  have  been  reached,  in  the  progressing  refrigeration, 
before  that  favorable  to  animal  life.  The  fact,  also,  that  animals  need 
plants  for  food  (page  115),  affords  a  strong  presumption  in  favor  of 
the  view  that  plants  were  first  in  existence. 


11 


162  PALEOZOIC   TIME. 

II.   PALEOZOIC   TIME. 

I.   AGE   OF   INVERTEBRATES,    OR    SILURIAN   AGE. 

The  term  Silurian  was  first  applied  to  the  rocks  of  the  Silurian  age 
by  Murchison.  It  is  derived  from  the  ancient  name  Silures,  the  desig 
nation  of  a  tribe  inhabiting  a  portion  of  England  and  Wales  where 
the  rocks  abound. 

The  subdivisions  of  the  Silurian  are  not  only  widely  different  on 
two  continents,  as  America  and  Europe,  but  also  on  different  parts  of 
the  same  continent.  In  American  geological  history,  it  has  been  found 
most  convenient  to  recognize  in  the  main  that  subdivision  into  periods 
and  epochs  which  is  derived  from  the  succession  of  rocks  in  the  State 
of  New  York,  where  most  of  the  strata  are  well  displayed  and  have 
been  carefully  studied. 

Some  standard  for  the  division  of  time  must  be  adopted ;  and,  whatever  that  stand 
ard,  it  is  afterward  easy  to  compare  with  it,  and  bring  into  parallelism,  the  successive 
strata,  or  events,  of  other  regions.  The  State  of  New  York  lies  on  the  northeastern 
border  of  the  great  interior,  —  a  vast  region  stretching  southward  and  westward  from 
the  Appalachians  to  the  Rocky  Mountains,  and  beyond  the  head-waters  of  the  Missis 
sippi  to  the  Arctic  Ocean,  over  which  there  were  many  common  changes;  and,  owing 
apparently  to  this  situation  on  the  north  against  the  Archaean,  and  near  the  head  of  the 
Appalachian  range,  there  are  indicated  a  greater  number  of  subordinate  subdivisions  in 
the  rocks,  or  of  epochs  in  time,  than  are  recognized  to  the  west.  It  is,  therefore,  a 
more  detailed  indicator  than  other  regions,  of  the  great  series  of  changes  and  epochs  in 
the  Paleozoic  era. 

On  pages  375  to  379,  sections  are  presented  of  the  Paleozoic  strata  in  different  parts 
of  the  United  States.;  and,  by  means  of  them,  the  diversities  between  the  regions  may 
be  studied.  The  general  truth,  above  stated,  is  well  exhibited,  that  the  geological 
structure  of  the  great  Interior  basin  is  more  simple  than  that  of  New  York  and  the 
Appalachian  region. 

The  order  of  succession  in  the  Silurian  periods  and  rocks  is  shown 
in  the  section  on  page  142  (Fig.  201).  The  numbers  affixed  to  the 
subdivisions  of  the  section  are  used  for  the  same  formations  through 
out  the  work. 

The  Silurian  age  is  divided  into  the  Lower  Silurian  and  Upper  Si 
lurian.  In  North  America,  the  transition  in  the  rocks  and  life  of  the 
two  eras  is  comparatively  abrupt.  In  Great  Britain,  the  two  are 
generally  unconformable  in  stratification  ;  but  as  regards  life  there  is  a 
gradual  transition  between  them.  In  Bohemia,  there  is  no  break  in 
the  rocks,  but  a  somewhat  abrupt  change  in  the  life.  Thus,  even  the 
grander  divisions  in  Geological  history  are  not  set  forth  alike  in  all 
countries  ;  each  great  region  has  carried  forward  independently  its 
making  of  rocks,  and  had  often  its  independent  disturbances. 


LOWER   SILURIAN.  163 

SUBDIVISIONS   OF   THE   SILURIAN. 

A.  LOWER  SILURIAN. 
I.  PRIMORDIAL  OR  CAMBRIAN  PERIOD  (2). 

1.  ACADIAN  EPOCH  (2  «).     Shale  and  sandstone  at  St.  John, 
New  Brunswick,  the  St.  John  group  of  Matthew  and  Logan,  the 
Acadian  group  of  Dawson  ;  beds  at  St.  Johns  and  elsewhere,  in 
Newfoundland  ;  clay-slate  and  siliceous  slate  of  Braintree,  Mass. ; 
Ocoee  conglomerate   and   slates   of  East   Tennessee  and  North 
Carolina. 

2.  POTSDAM  EPOCH  (26).     Sandstone  of  Potsdam  and  other 
places  in  northern  and  northeastern  New  York,  western  Vermont 
and  Canada  ;  sandstone  and  limestone  of  Troy,  N.  Y. ;  slate  and 
limestone  of  northwestern  Vermont,  including  the  Georgia  shales ; 
limestone  and  sandstone  of  shores  of  the  Straits   of  Belle  Isle ; 
Chilhowee  sandstone  of  East  Tennessee  ;  sandstone  with  some 
limestone  in  Wisconsin  and  Minnesota. 

In  Great  Britain,  the  Cambrian,  including  beds  in  the  Longmynd,  in  Xorth 
Wales,  the  Harlech  beds  in  Pembrokeshire,  and  the  overlying  Menevian  beds, 
and  also,  higher  in  the  series  but  conformable,  the  Lingula  flags.  In  Bohemia, 
Barrande's  Stage  C,  and  perhaps  his  B,  or  part  of  it.  In  Sweden,  Angelin's  A 
and  B,  the  Alum  slate  and  Fucoidal  sandstone. 

II.  CANADIAN  PERIOD  (3). 

1.  CALCIFEROUS  EPOCH  (3  a).     Calciferous  sandrock  in  New 
York.     Lower  Magnesian  limestone  of  the  Mississippi  valley ;  St. 
Peters  sandstone   of  Wisconsin   and  Illinois;   Knox  sandstone, 
East  Tennessee  ;  thick  limestones  (part  of  the  so  called  Quebec 
group)  of  Newfoundland. 

2.  QUEBEC  EPOCH  (3  b).    Levis  formation,  Canada,  near  Que 
bec  ;  Taconic  slates  of  Green  Mountains  ;  shales,  limestones,  and 
sandstones,  Newfoundland.    Part  of  the  Knox  group,  Tennessee. 

3.  CHAZY  EPOCH  (3  c).    Chazy  limestone  of  New  York,  Can 
ada,  etc.     Part  of  the  crystalline  limestone  of  the  Green  Moun 
tains  in  Vermont  and  to  the  south. 

Tremadoc  slates  of  North  Wales*;  Skiddaw  slates  of  northern  England ;  Arenig 
or  Stiper  stones  group  (the  Lower  Llandeilo  of  Murchison).  Angelin's  group 
B  C  in  Sweden.  The  Pleta  of  Russia,  according  to  Billings,  and  the  Ungulite 
grit  of  Pander. 

III.  TRENTON  PERIOD  (4). 

1.  TRENTON  EPOCH  (4  a)  :  (1)  Birdseye  limestone,  (2)  Black 
River  limestone,  (3)  Trenton  limestone  ;  Galena  limestone  of  Illi 
nois,  etc. ;  Lebanon  limestone  of  Middle  Tennessee. 

In  Great  Britain,  Llandeilo  group.  In  Bohemia,  Barrande's  formation  D.  In 
Sweden,  Angelin's  C,  Orthoceratite  limestone. 


164  PALEOZOIC   TIME. 

2.  UTICA  EPOCH  (4  b).     Utica  shale. 

3.  CINCINNATI   EPOCH  (4  c).     (Hudson  River  epoch  of  last 
edition  of  this  work.)     Part  of  Hudson  River  shales,  Lorraine 
shales,  of  New  York  ;  limestone  of  Cincinnati ;  Nashville  group 
of  Tennessee. 

In  Great  Britain,  Bala  limestone  and  Caradoc  sandstone;  upper  part  of  Llan- 
deilo  flags;  Lower  Llaiulovery  sandstone.  In  Bohemia,  Barrande's  formation  D1. 
In  Sweden,  Graptolitic  slate;  Angelin's  Region  D.  In  Russia,  the  Wesenberg, 
Lyckholm.  and  Boniholm  groups. 

B.  UPPER  SILURIAN. 
I.  NIAGARA  PERIOD  (5). 

1.  MEDINA   EPOCH  (5  a)  :    Oneida  conglomerate  and  Medina 
sandstone. 

2.  CLINTON  EPOCH  (5  b)  :  Clinton  group. 

3.  NIAGARA    EPOCH    (5  c) :    Niagara   shale    and    limestone ; 
Guelph  limestone. 

In  Great  Britain,  the  Upper  Llandovery  or  May  Hill  sandstone  has  been 
referred  to  the  Clinton  and  Medina,  and  the  Wenlock  shale  and  limestone  to  the 
Niagara.  Tn  Sweden,  part  of  Region  E  of  Angelin,  and,  in  Bohemia,  Stage  E  of 
Barrande  are  probably  equivalents  of  the  Medina,  Clinton,  and  Niagara.  The 
Pentamerus  group  of  Esthland  and  Livland  in  Russia,  and  the  Lower  Malmij  of 
Norway  are  referred  to  the  Medina  and  Clinton,  and  the  middle  Malmu  to  the 
Niagara. 

II.  SALINA  PERIOD  (6).     Onondaga  Salt  group. 

III.  LOWER  HELDERBERG  PERIOD  (7). 

Lower  Helderberg  limestones,  including,  in  New  York,  (1)  the 
Water-lime  group ;  (2)  the  Lower  Pen tamerns limestone;  (3)  the 
Delthyris  shaly  limestone  ;  (4)  the  Upper  Pentamerus  limestone. 

IV.  ORISKANY  PERIOD  (8).  —  Oriskany  sandstone. 

In  Great  Britain,  the  equivalents  of  the  Lower  Helderberg  and  Oriskany  groups  are 
approximately  the  Ludlow  beds,  including  the  Lower  Ludlow  rock,  the  Aymestry  lime 
stone,  the  Upper  Ludlow  rock  and  the  Tilestones.  In  Norway,  Upper  Malmb  limestones 
and  schists.  Part  of  E  of  Angelin,  in  Gothland,  Sweden, the  Coral  limestone.  In  Bohe 
mia,  Barrande's  formations  E  to  H,  consisting  of  schists,  part  graptolitic,  and  limestones, 
are  referred  to  the  Upper  Silurian. 

Explanation  of  the  Section  and  Geological  Map. 
The  annexed  map  of  New  York  and  a  part  of  Canada  exhibits  the 
surface-rocks  of  the  region.  As  is  shown  in  the  section,  p.  166,  the 
strata  of  the  Silurian  and  Devonian  outcrop  in  succession,  on  going  from 
the  Archaean  (No.  1)  southward.  The  numbers  on  the  areas  render  easy 
a  comparison  with  the  section  and  with  the  tables  beyond.  The  Si 
lurian  strata  are  lined  horizontally  ;  the  Devonian,  vertically ;  and  the 
Subcarboniferous  beds,  which  appear  at  the  southern  margin  of  New 
York  State  (No.  13),  are  cross-lined.  The  area  very  coarsely  cross- 
lined  horizontally  includes  the  Chazy  and  Trenton  limestones  ;  the 
Chazy  (3  c)  is  separated  from  the  Trenton  by  a  dotted  line. 


SILURIAN   AGE. 


165 


The  area  5  (Niagara  period)  is  divided  into  a,  b,  c,  corresponding  to  5  a,  5  b,  5  c,  in 
the  preceding  table.     Other  areas  are  similarly  divided.     The  areas  of  Nos.  7  and  8  in 


il ik^r^S^v  - -1  '*'  - r&J 


the  series  (the  Lower  Helderberg  and  the  Oriskany)  are  not  distinguished  on  the  map 
from  No.  9. 


166  PALEOZOIC   TIME. 

Fig.  216  is  an  ideal  section  of  the  rocks  of  New  York,  along  a  line 
running  southwestward  from  the  Archaean  on  the  north  across  the  State 


Fig.  210. 


Carbonif-  Devonian. 


to  Pennsylvania.  It  shows  the  relative  positions  of  the  successive 
strata,  —  bringing  out  to  view  the  fact  that  the  areas  on  the  preceding 
map  are  only  the  outcrops  of  the  successive  formations.  This  is  all  the 
section  is  intended  to  teach  ;  for  the  uniformity  of  dip  and  its  amount 
are  very  much  exaggerated,  and  the  relative  thickness  is  disregarded. 

A.  LOWER  SILURIAN. 

I.   PRIMORDIAL   PERIOD  (2). 
1.  AMERICAN. 

The  Primordial  or  Cambrian  Period  in  North  America  includes  two 
subdivisions,  distinct  in  their  fossils,  according  to  present  knowledge. 

(1.)  The  Acadian  Epoch,  including  the  St.  John  group  of  Matthew 
(Acadian  group  of  Dawson),  of  St.  John,  New  Brunswick,  and  other 
rocks  of  eastern  Newfoundland. 

(2.)  The  Potsdam  Epoch,  or  that  of  the  Potsdam  sandstone,  of 
Potsdam,  in  the  northern  part  of  St.  Lawrence  county,  N.  Y.,  and  its 
equivalents  elsewhere  ;  and  also  of  the  Georgia  and  Swanton  slates 
and  Winooski  limestone  of  western  Vermont,  and  sandstone  and  lime 
stone  near  Troy,  N.  Y.  The  Acadian  beds  in  Newfoundland  lie  un- 
conformably  beneath  those  of  the  second  epoch. 

I.  Rocks  :  kinds  and  distribution. 

Primordial  rocks  have  been  observed  over  various  parts  of  the 
North  American  continent,  both  adjoining  the  Archaean  regions  of 
New  York,  Canada,  and  elsewhere  (where  they  bear  every  evidence 
that  they  were  formed  on  the  shores  of  the  Archaean  lands),  and  also 
distant  from  them,  where  in  some  places  they  were  made  in  the  deeper 
continental  seas.  They  occur  on  the  eastern  border  of  the  continent, 
in  Newfoundland,  Nova  Scotia,  New  Brunswick,  and  eastern  Massa- 


LOWER   SILURIAN.  167 

chusetts  ;  in  northern  Vermont,  northern  New  York,  and  Canada  ; 
along  the  Appalachians,  from  New  Jersey  southwestward  ;  at  many 
points  in  the  Mississippi  basin,  in  Wisconsin,  Minnesota,  Missouri, 
Arkansas,  and  Texas  ;  also  farther  west,  over  the  Rocky  Mountain 
slopes,  about  the  Black  Hills  of  Dakota,  etc. 

All  the  various  kinds  of  sedimentary  rocks  occur  in  the  Primordial. 
Sandstones,  shaly  sandstones,  and  shales  are  the  prevailing  kinds. 
Limestones  cover  only  small  areas.  There  are  also,  through  meta- 
morphism,  various  crystalline  rocks ;  and  among  them  the  gold-bear 
ing  rocks  of  Nova  Scotia. 

O 

1.  ACADIAN  EPOCH.  —  The  rocks  are  exposed  to  view  in  a  number  of  valleys  in 
southern  New  Brunswick,  and  especially  at  St.  John,  where  they  were   first  proved 
to  be  Primordial  by  G.  F.  Matthew.     The  name  Acadian  was  given  to  the  period  by 
Dawson.     The  rocks  here  are  gray  and  black  shales,  with  some  sandstones,  and  have  a 
thickness,  allowing  for  a  fold,  of  2,000  feet.     There  are  fossiliferous  rocks  of  this  era 
also  in  southeastern  Newfoundland.     In  the  same  region,  underlying  beds,  that  have 
been  pronounced  Huronian,  have  afforded  two  fossils  (see  Billings,  Amer.  Jour.  Sci., 
III.  iii.  223).     At  Braintree,  Mass.,  not  far  from  Boston,  the  rock  is  siliceous  slate  and 
clay  slate.     In  both  regions,  the  beds  are  much  upturned.     The  lowest  beds  of  the  Wis 
consin  Primordial  may  belong  to  this  division,  as  stated  beyond. 

2.  POTSDAM  OR  GEORGIA  DIVISION. 

a.  Eastern-Border  Region.  —  On  the  Labrador  side,  and  parts  of  the  Newfoundland, 
of  the  Straits  of  Belle  Isle,  there  are  strata  of  limestone,  sandstones,  and  shales  of  this 
era.    They  stretch  across  the  north  peninsula  of  Newfoundland  to  Canada  Bay,  where 
the  thickness,  according  to  Murray,  is  5,000  feet. 

b.  Neio  York,  Vermont,  and  Canada.  —  The  rocks  occur  adjoining  the  Archaean  of 
New  York  and  Canada.     They  are  here  mainly  hard  sandstones,  often  gritty,  some 
times  pebbly  (especially  the  lower  beds),  and  only  occasionally  friable.     The  sand 
stone  is  generally  laminated,  and  sometimes  thinly  so;   and  of  gray,  drab,  yellowish, 
brownish  and  red  colors.     Much  of  it  is  a  good  building  stone,  as  at  Potsdam,  Malone, 
Keeseville,  etc.     North  of  the  Archaean,  in  the  northwest  part  of  Clinton  County,  in 
part  of  St.  Lawrence  County,  near  De  Kalb,  and  also  in  Franklin  County,  N.  Y.,  the 
conglomerate  is  in  places  300  feet  thick.     The  rock  bears  evidence  of  being  mainly  of 
shallow-water  or  beach  origin. 

In  St.  Lawrence  County,  N.  Y.,  there  are,  according  to  Brooks,  conformable  beneath 
the  Potsdam  sandstone,  strata  of  sandstone,  metamorphic  schist,  limestone,  and  hema 
tite  iron  ore  (the  Caledonian  or  Parish  ore-bed  included),  having  in  all  a  thickness  of  at 
least  200  feet.  See  Amer.  Jour.  Sci.,  III.  iv.  22. 

The  formation  is  represented  in  western  Vermont  by  the  "  Red  Sandrock  "  ;  the 
Winooski  limestone  extending  from  Addison,  through  Burlington  to  St.  Albans;  also, 
apparently  over  the  latter,  the  black  and  gray  shales  or  slates  of  Georgia,  St.  Albans, 
and  Swanton  (referred  by  Emmons  to  the  Taconic),  which  continue  into  Missisquoi 
County,  in  Canada,  lying  to  the  west  of  other  slates  of  the  Quebec  period.  There  are 
Primordial  black  shales  in  Bald  Mountain,  Greenwich,  Washington  County,  N.  Y.,  de 
scribed  as  Taconic  by  Emmons;  and  shales  and  sandstone, with  beds  of  limestone  and 
limestone-conglomerate,  near  Troy,  N.  Y.,  recently  made  known  by  S.  W.  Ford  (Am. 
Jour.  Sci., III.  ii.  to  vi.).  The  Troy  beds,  and  also  the  Winooski  marble  and  Georgia 
slates,  are  believed  to  be  inferior  to  the  Potsdam  sandstone. 

c.  Region  of  the  Appalachians. — Along  the  Appalachian  chain,  the  great  thickness 
of  the  accumulations,  and  especially  of  the  slates,  is  the  striking  peculiarity.     Part  of 
the  slates,  however,  belong  to  the  next  period. 

In  New  Jersey,  the  rocks  supposed  to  be  Potsdam  are  sandstone,  either  soft  or  hard; 


168  PALEOZOIC    TIME. 

or  a  red  crumbling  shale,  as  in  the  Green  Pond  Mountain  Range ;  or  a  firm  conglom 
erate.  Near  Flanders,  a  kind  crumbles  easily  to  sand. 

In  Pennsylvania,  there  are,  in  the  Primal  series  of  Rogers,  2,000  feet  of  lower  slates, 
overlaid  by  90  feet  of  sandstone,  and  this  by  200  to  1,000  feet  of  upper  slates  (H.  D. 
Rogers).  In  Virginia,  there  are  1,200  feet  of  lower  slate,  300  of  sandstone,  and  700  of 
upper  slates  (W.  B.  Rogers). 

In  East  Tennessee,  J.  M.  Safford  has  described,  as  of  this  age,  the  "Chilhowee  " 
sandstones  and  shales,  several  thousand  feet  in  thickness  (consisting  of  sandy  shales, 
sandstones,  and  light  gray  quartzyte),  resting  on  the  Ocoee  conglomerates,  sandstones, 
and  micaceous,  talcose,  and  chloritic  slates. 

d.  Interior   Continental  basin. —  The   sandstone    rocks   in  New  York   and  Canada, 
above  mentioned,  properly  lie  in  the  northeastern  border  of  this  basin. 

In  Wisconsin  (as  first  announced  by  D.  D.  Owen),  a  broad  band  of  the  Potsdam 
sandstone  borders  the  east,  south,  and  west  sides  of  the  Archaean,  south  of  Lake 
Superior,  crosses  the  Mississippi,  about  the  Falls  of  St.  Croix,  into  Minnesota,  and  then 
stretches  northward  and  southward,  passing  in  the  latter  direction  toward  Iowa.  The 
rock  over  the  interior  of  Wisconsin  and  Minnesota  is,  for  the  most  part,  a  very 
crumbling  and  imperfectly  coherent  mass  of  sand.  It  includes  much  green  sand  in 
its  lower  part,  similar  in  general  character  to  the  green  sand  of  the  Cretaceous  form 
ation  (Hall).  It  forms  bluffs  on  the  Mississippi,  in  Iowa,  below  the  Upper  Iowa 
River.  This  loose  condition  of  one  of  the  most  ancient  of  rocks,  in  Wisconsin  and 
Minnesota,  shows  how  ineffectual  are  ordinary  waters,  even  through  the  lapse  of  ages, 
in  causing  solidification.  The  sands  are  often  wholly  siliceous,  with  only  1  or  2  per 
cent,  of  impurity,  and,  when  crumbling,  make  a  good  material  for  glass. 

Hall  (Regents'  Rep.  18G3)  makes  out  three  divisions  of  the  Wisconsin  beds:  1,  the 
lower,  containing  species  of  Conocoryphe  and  no  Dicellocephali ;  2,  the  middle,  charac 
terized  by  species  of  Conocoryphe,  Dicellocejihalus,  Ayraulos,  Ptychaspis,  Agnostus, 
with  the  earliest  Graptolites ;  and  3,  an  upper,  clearly  separated  from  the  great  central 
mass,  and  containing  species  of  Dicelloceplialus,  Triarthrella,  Aylaapis,  Linyula.,  Serpu- 
lites,  Euomphalus. 

The  Pictured  Rocks,  forming  bluffs  50  to  200  feet  high,  on  the  south  shore  of  Lake 
Superior,  in  Michigan,  and  the  Pillared  Rocks,  at  the  west  end  of  the  lake,  have  been 
considered  as  of  the  Potsdam  era,  but  are  now  referred  to  the  next  period. 

The  Potsdam  beds  of  Texas  occur  in  Burnet  County,  Texas,  where  they  consist  of 
sandstones  covered  by  limestone.  (B.  F.  Shumard.) 

Beds  of  sandstone  and  conglomerate,  according  to  Dr.  Hay  den,  skirt  the  Black 
Hills  of  Dakota  (lat.  43°-45°  N.,  long.  103°-104°  W.),  overlying  the  Archaean,  and 
containing  characteristic  fossils. 

e.  Summit  and  western  slopes  of  the  Rocky  Mountains.  —  Primordial   rocks  occur  in 
the  Big  Horn  Mts.,  at  the  head  of  Powder  River,  long.  107°;  as  quartzytes  (probably 
of  this  age),  near  long.  112°  W.,  along  the  Wahsatch,  Teton,  Madison,  and  Gallatin 
ranges,  resting  unconformably  upon  the  upturned  Archaean  gneisses  and  granytes;  also 
in  Nevada,  long.  116°  W.,  as  announced  by  J.  D.  Whitney. 

The  Potsdam  formation  is  60  to  70  feet  thick  in  St.  Lawrence  County,  N.  Y.:  in 
Warren  and  Essex  Counties,  100  feet;  in  the  St.  Lawrence  valley,  300  to  600  feet,  or 
more;  about  250  feet  on  Lake  Superior;  700  feet,  according  to  Owen,  on  the  St.  Croix, 
Wisconsin;  50  to  80  feet  in  the  Black  Hills,  Dakota;  500  feet  in  Burnet  County,  Texas. 

Markings  in  the  rocks.  —  In  the  Acadian  rocks,  near  St.  John, 
N.  B.,  the  coarser  layers  are  frequently  covered  with  ripple-marks 
and  shrinkage  cracks,  and  also  with  scratches  that  appear  to  be  the 
tracks  of  some  water-animal ;  and,  besides,  there  are  worm-burrows. 
(SeeScolithus<p.  177.)  The  facts,  as  G.  F.  Matthew  states,  are  evi 
dence  that  the  beds  are  of  seashore  origin.  The  shales  of  Georgia, 


LOWER   SILURIAN.  169 

i 

Vermont,  are  in  some  places  marked  with  ripples,  and  have  the 
tracks  of  worms  as  well  as  their  borings.  In  the  Potsdam  rocks  of 
northern  New  York  and  Canada,  and  those  of  Wisconsin,  there  are 
similar  evidences  of  littoral  deposition.  Ripple-marks  and  worm- 
borings  are  common  ;  and,  in  some  places  in  Canada,  there  are  tracks 
of  Crustaceans,  as  well  as  worms  (p.  176 ).  In  Wisconsin,  also, 
ripple-marks  and  mud-cracks  occur ;  and,  on  some  layers,  broken  shells 
and  other  appearances  afford  the  most  positive  evidence  of  sea-beach 
formation.  (Hall.)  The  beds,  though  of  great  thickness,  are  often 
diagonally  laminated,  showing  the  action  of  tidal  currents  over  the 
bottom  of  a  shallow  sea.  The  Tennessee  and  Pennsylvania  sand 
stones  also  are,  in  many  places,  penetrated  by  worm-borings,  and 
covered  with  ripple-marks. 

Economical  products.  —  The  Primordial  rocks  afford  much  good  stone  for  building, 
and  for  the  hearths  of  furnaces,  and,  in  many  localities,  sand  for  glass-making.  There 
are  gold-bearing  quartz  veins  in  the  Ocoee  series,  in  Tennessee. 

II.  Life. 

The  Primordial  rocks  have  afforded  evidence  only  of  marine  life. 

1.  Plants.     Alga?  or  seaweeds,  of  the  kind  called  Fucoids,  are  the 
only  forms  observed.     The  slabs  of  sandstone  are  sometimes  covered 
throughout  with  vermiform  casts  of  what  appear  to  be  stems  of  this 
leathery  kind  of  seaweed.     Some  of  the  fossils  formerly  regarded  as 
indications  of  plants,  are  now  believed  to  be  worm-tracks  or  borings. 
But  others  show  by  their  branching  forms  that  they  are  true  Fucoids. 

2.  Animals.    The  species  observed  are  all  invertebrates ;  they  per 
tain  to  the  four  sub-kingdoms,  PROTOZOANS,  RADIATES,  MOLLUSKS, 
and  ARTICULATES. 

The  Radiates  were  represented  by  Crinoids ;  the  Mollusks,  by 
Brachiopods?  Pteropods,  Gasteropods,  and  Cephalopods  ;  and  the  Ar- 

1  As  Bracliiopods  are  the  most  abundant  fossils  of  the  Silurian,  their  distinguishing 
characteristics  and  the  more  important  genera  are  here  mentioned,  —  taken  principally 
from  Davidson  (Paleontographical  Society  publications). 

1.  Animal.  — As  stated  on  page  126,  the  living  animal,  unlike  all  other  Mollusks,  has 
a  pair  of  fringed  spiral  arms,  as  shown  in  Figs.  222,  225 ;  and  to  this  the  name  Brachio- 
pod  alludes,  from  the  Greek  for  arm  and  foot. 

2.  Shell.  — The  characteristics  of  most  importance  are  as  follow:  — 

0.  The  large  valve  (see  Fig.  221  and  others)  is  the  ventral. 

1.  The  form  of  the  internal  supports  connected  with  the  spiral  arms  varies  much :  and 
often  they  are  wanting.     The  loop-form  is  seen  in  Figs.  218,  219,  220;  the  spiral,  in 
Figs.  222,  225;  the  short  process,  in  Fig.  227;  and  they  are  wanting  in  Figs.  230,  231. 

c.  The  general  form  and  exterior  markings  of  the  shell  afford  important  characters ; 
the  nearly  equal  convexity  of  the  two  valves,  or  a  median  depression  on  the  ventral 
valve,  Avith  a  corresponding  elevation  on  the  dorsal,  Figs.  221,  223. 

d.  The  beak  of  the  shell  may  be  very  large  and  full  (Figs.  221,  238),  or  very  small 
and  little  prominent  (Figs.  229,  230);  may  have  an  aperture  or  foramen  at  apex  (Fit>;s. 
150.  223,  224),  or  not. 


1TO  PALEOZOIC    TIME. 

ticulates  by  Worms  and  Crustaceans.  No  evidence  has  been  yet  found 
of  the  existence  of  Polyps  (corals),  among  Radiates;  or,  in  the  earlier 
epoch,  of  Lamellibranchs  (ordinary  bivalves),  among  Mollusks. 

e.  The  hinge-line  maybe  straight,  or  not;  as  long  as  the  greatest  breadth  of  the  shell 
(221,  229,  232),  or  shorter  (227,  228). 

/.  A  cardinal  area  (hinge-area)  may  exist, or  not;  there  is  a  large  one  in  Fig.  221,  and 
none  in  Fig.  238. 

g.  There  may  be  a  deltidium, — composed  of  one  or  two  accessory  pieces  occupying 
a  triangular  opening  under  the  beaks,  as  seen  in  Fig.  224.  Sometimes  a  similar  open 
ing  at  the  middle  of  the  hinge  is  partly  or  entirely  closed  by  the  growth  of  the  shell, 
so  as  to  leave  a  triangular  prominence,  called  a  pseudo-deltidium,  as  in  Cyrtia,  Strepto- 
rhynckvs,  etc. 

h.  The  markings  on  the  inner  surfaces  of  the  valves  are  of  special  importance,  and 
particularly  the  muscular  impressions,  usually  situated  near  the  median  line,  not  far  from 
the  hinge:  on  the  dorsal  (or  smaller)  valve  there  are,  in  the  articulated  genera,  two  pairs 
(a  and  a'  in  Figs.  227,  230,  234,  236),  sometimes  coalescing  so  as  to  be  one  pair,  for  the 
attachment  of  the  adductor  muscle  (closing  the  shell):  one  is  usually  in  advance  of  the 
other,  but  in  Figs.  230  and  233  they  are  side  by  side ;  on  the  ventral  (or  larger)  valve, 
there  is  a  single  impression  on  the  median  line  between  two  others  (Figs.  228,  234); 
the  single  impression  is  the  insertion  of  the  adductor  muscle  (a,  Figs.  228,  231,  234, 
237),  and  the  pair  are  the  insertions  of  the  cardinal  muscle;  the  latter  muscle  terminates 
on  the  dorsal  valve,  usually  in  a  small  process. 

Families  of  BracMopods. 

Terebratula  Family  (Figs.  150,  218-220).  —  Having  arm-supports  of  the  form  of  a 
loop,  attached  to  the  smaller  or  dorsal  valve,  and  a  foramen  at  the  apex  of  the  beak. 
Shell-structure  punctate. 

Spiiifer  Family  (Figs.  221-225). — Having  spiral  supports,  shell  usually  with  a 
median  fold;  hinge-line  commonly  long  and  straight  (sometimes short);  beak  large  and 
full. 

Rliynclionella  Family  (Figs.  226-228).  — Having  the  arm-supports  short  curved  pro 
cesses;  beak  usually  full,  but  narrow,  having  a  foramen;  shell  seldom  wider  than 
high. 

Orthis  Family  (Figs.  229-237).  —  Arm-supports  wanting;  shell  rarely  with  a  median 
fold;  shell  varying  between  orbicular  and  D-shape;  beak  usually  very  small,  but  some 
times  produced. 

Prodttctus  Family  (Figs.  238-240).  — Arm-supports  wanting;  shell  without  a  median 
fold,  or  almost  wholly  so ;  hinge-line  straight,  often  as  long  as  the  breadth  of  the  shell, 
or  nearly  so,  and  without  a  cardinal  area,  or  with  only  a  narrow  one  (excepting  Stro- 
])lialosi'i  and  Aulosteges) ;  surface  often  tubular-spinous ;  form  usually  D-shaped,  with  the 
dorsal  valve  very  concave;  beak  often  very  large  and  full. 

Discina  Family  (Figs.  243-245).  —  Thin  and  small  disk-shaped  shells;  orbicular  or 
ovate :  a  slit  or  foramen  through  the  ventral  valve :  no  articulation  between  the  valves. 

Linr/ula  Family  (Figs.  151  and  246).  — Thin  and  small  shells;  orbicular  or  subovate; 
no  foramen;  no  articulation. 

Besides  these,  there  are  also  the  Crania  and  Tlieddium  families. 

GENERA  OF  BHACHIOPODS.  —  1.  Terebratula  Family.  —  Genus  Terebratula.  like 
Figs.  150  and  218:  the  loop  small,  as  in  Fig.  219.  Genus  Waldheimia,  the  same;  the 
loop  large,  Fig.  218. 

Besides  these  genera,  Terebrntulina  has  the  side  (or  "crural")  processes  near  the 
base  of  the  loop  united  (Fig.  220).  Another  genus,  Tercbratella,  has  the  sides  of  the 
loop  united  at  middle  by  a  cross-piece,  and  this  piece  soldered  to  the  shell.  Terebri- 
rosfra  has  the  beak  extravagantly  prolonged,  so  as  to  be  longer  than  the  dorsal  valve. 
Rensselaeria  has,  instead  of  a  loop,  a  peculiar  hastate  brachial  support,  projecting  far 


LOWER    SILURIAN. 


171 


The  fossils  thus  far  obtained  from  the  rocks  of  the  Acadian  epoch 
differ  in  species  from  those  of  the  Potsdam.     They  include  species  of 

within  the  dorsal  valve.  Stricklamlinia  of  Billings  may  be  the  same  genus,  and,  if  so, 
it  antedates  Rensselaeria.  Centronella  seems  to  be  intermediate  between  Terebratula 
and  Waldheimia.  Other  genera,  rarely  met  with,  are  Triycncsemus,  Meyerlia,  Mayas, 

Figs.  218-225. 


Fig.  218,  Waldheimia  flavescens  ;  219,  loop  of  Terebratula  vitrea  ;  220  id.  Terebratulina  caput- 
serpentis  ;  221,  Spirifer  striatus  ;  222,  same. interior  of  dorsal  valve;  223,  Athyris  concentrica  ; 
224,  225,  Atrypa  reticularis,  the  latter  dorsal  valve. 

Aryiqpe,  appearing  first  in  the  Cretaceous,  and  Kraussia,  Souchardia,  and  Morrisia, 
known  only  in  recent  seas,  with  a  possible  exception  of  the  last.  Sfoingocephahu  is 
another  genus,  probably  constituting  a  sub-family,  occurring  in  the  Devonian. 

2.  Spirifer  Family.  —  The  genus  Spirifer  includes  the  common  species,  having  usually 
a  long  hinge-line  and  distinct  cardinal  area  (Figs.  221,  222).  In  Athyris  (Fig.  223), 
the  hinge-line  is  much  shorter,  the  hinge-area  small  or  none,  the  beak  contracted  and 
having  a  small  round  aperture.  This  genus  is  like  Terebratula,  in  its  narrow  form  and 
beak  without  cardinal  area,  but  has  the  spires  of  the  Spirifers.  Uneites  has  the  beak 
extravagantly  prolonged,  and  a  large  opening  beneath  it.  Cyrtia  has  nearly  the  same 
extravagant  prolongation  of  the  beak,  but  with  a  large  hinge-area,  and  a  very  small 
opening  left  at  the  top  of  the  pseudo-dcltidium.  Koninckina  is  an  imperfectly  deter 
mined  genus,  resembling  Product-its  in  form,  but  differing  internally. 

Among  other  genera  and  subgenera  of  this  family  may  be  mentioned  Cyrtina,  Rttzia, 
Meritta,  Nucleospira,  Trematuspira,  Rhynckvqnrtt,  Charionella,  etc. 

•3.  Rliynclionella  Family.  —  The  genus  Rynchonella  (Figs.  226-228)  contains  plump- 
ovoid  or  subtrigonal  shells,  usually  narrower  than  high,  and  narrowing  to  the  beak, 
having  usually  a  foramen  and  no  hinge-area;  generally  a  U-shaped  flexure  in  the  an 
terior  margin  of  the  shell.  Pentamerus  has  a  much  fuller  and  more  incurved  beak,  and. 
no  area  or  deltidium,  though  there  is  a  triangular  opening  at  the  middle  of  the  hinge, 
which  usually  becomes  closed  in  adult  shells  by  the  incurving  of  the  beak.  Camaro- 
phoria  is  a  rare  genus  of  the  Carboniferous  and  Permian.  Porambonites,  a  very  plump 
shell  of  the  Lower  Silurian,  near  Rhynchonella.  Camerella  of  Billings  is  another  genus 
of  this  family,  found  in  the  Lower  Silurian.  Lcptoccelia  and  Eatonia  probably  belong 
to  this  family.  Atrypa,  Figs.  224,  225,  which  is  referred  to  this  family  by  Woodward, 
on  account  of  the  arrangement  of  its  spiral  arms,  narrows  to  the  beak,  where  there  is 
no  hinge-area  or  onlv  a  small  one. 


172 


PALEOZOIC   TIME. 


Trilobites  of  the  genus  Paradoxides  (Fig.  251),  none  of  which  are 
known  afterward. 


4.  Orthis  Family.  —  In  the  genus  Orthis  (Figs.  235-237)  the  species  are  usually  rather 
thin;  often  orbicular,  at  times  a  little  wider  than  high:  both  valves  in  general  nearly 
equally  convex;  the  hinge-line  usually  not  long,  with  a  small  cardinal  area;  a  few 
species  resemble  a  narrow  Spirifer,  and  have  a  median  fold  and  long  hinge-line.  Or- 

Figs.  220-237. 

228  /^^        227 


Fig.  226,  Rhynchonella  psittacea,  showing  the  spiral  arms  of  the  animal,  227,  id  dorsal  valve  ; 
228,  id.  ventral  :  229,  Strophomena  planumbona;  230,  id.  dorsal  valve;  231,  id.  ventral;  232} 
Lepteena  transversalis  ;  233,  id.  dorsal  valve  ;  234,  id.  ventral ;  235,  Orthis  striatula  ;  236,  id. 
dorsal  valve  ;  237,  id.  ventral. 

thisinu  has  the  hinge-area  very  large  and  reversed-triangular,  with  a  convex  deltidium, 
and  the  shell  subquadrate.  Strophomena  contains  thin  D-shaped  species  (Figs.  229- 
231),  with  a  straight  hinge-line  about  as  long  as  the  width  of  the  shell,  a  very  nar 
row  hinge- area,  the  dorsal  valve  often  very  concave,  with  the  ventral  bending  to  cor 
respond,  and  the  four  adductor  muscular  impressions  in  the  same  transverse  line. 
Leptasna  is  similar  (Figs.  232-234),  but  has  the  four  muscular  impressions  of  different 
character,  as  seen  in  Fig.  233,  while  in  Strophomena  they  are  as  in  Fig.  230. 

5.  Productus  Family.  —  In  the  genus  Product  us  (Figs.  238,  239)  the  beak  is  very  full, 
hinge-line  usually  a  little  shorter  than  the  width  of  shell;  no  true  hinge-area,  and  no 
beak-aperture;  the  smaller  valve  concave;  the  surface  of  the  shell  spinous,  the  spines 
tubular;  spiral  arms  present,  but  without  calcareous  supports  The  margin  of  the 
shell  is  prolonged  downward,  often  to  a  great  length,  and  sometimes  closes  around 
into  a  tube-  CJionetes  (Fig.  240)  has  a  straight  hinge-line,  commonly  as  long  as  the 
width  of  the  shell,  the  form  rather  thin,  with  the  beaks  net  full  and  prominent, 
resembling  Leptaena;  smaller  valve  concave;  hinge-edge  of  larger  valve  furnished 
with  a  few  spines.  Strophalosia  is  much  like  Productus  in  form  and  spines,  but 


LOWER    SILURIAN. 


173 


Among  the  Acadian  fossils,  no  remains  of  Crinoids  have  yet  been 
found.     The    Brachiopods  include  species  of   Lingulella  (Fig.  248), 

is  more  circular,  and  the  shells  have  a  hinge-area,  and  a  regular  hinge  with  teeth ; 
it  also  differs  in  being  attached  by  the  beak  of  the  ventral  valve.  Aulosteycs  is  also 
similar  to  Productus  in  general  form  and  spines;  but  there  is  a  broad  triangular  hinge- 
area,  and  the  beak  is  twisted  somewhat  to  one  side. 


23* 


Fig.  238,  Productus  aculeatus,  dorsal  view  ;  239,  Productus  semireticulatus,  ventral  view  :  239  a, 
section  of  Productus,  showing  the  curvature  of  the  valves  ;  240,  Chonetes  lata,  opposite  views  ; 
241,  Calceola  sandalina  :  242,  Crania  antiqua  ;  243,  Discina  lamellosa,  side-view  ;  244,  id.  showing 
foramen  ;  245  a,  b.  Siphonotreta  unguiculata,  opposite  views  ;  246  a,  b,  Obolus  Appollinis. 

Koninckina  is  like  Productus  in  form,  but  has  about  the  same  relation  to  the  Produc 
tus  family  as  Atrypa  to  the  Rhynchonella  family. 

6.  Discina  Family.  —In  Discina  (Figs.  243,  244)  the  form  is  orbicular  or  oval,  and  the 
valves  low-conical ;  there  is  a  slit  through  the  ventral  valve,  beginning  at  or  near  the 
highest  point.     The  genus   Orbicula  is  here    included.     Trematis  is  similar;  but  one 
valve  has  the  umbo  or  prominent  point  marginal,   or  the  slit  reaches  nearly  to  the 
margin.     In  Siphonotreta  (Fig.  245),the  form  is  ovate;  the  beak  projects  at  the  margin, 
is  somewhat  pointed,  and  has  a  small  aperture.     Acrotreta  has  the  perforate  valve 
elevated  into  a  high  oblique  cone. 

7.  Linyula  Family.  — Linyula,  (Fig.  151)  is  narrower  than  high,  and  pointed  at  the 
beak;  valves  equal,  thin.     Obolus  (Fig.  246)  is  rotund  or  rotund-ovate ;  valves  a  little 
unequal,  the  dorsal  valve  being  the  smaller  and  least  convex,  as  in  most  Brachiopods ; 
muscular  impressions,  six,  —  two  median,  two  lateral,  and  two  very  near  the  umbos 
(Fig.  246  b),  — having  some  approximation  to  the  Cranice.     Oboletta  of  Billings  h^s  still 
different  muscular  impressions,  as  shown  in  Fig.  273. 

8.  Crania  Family.  — The  genus  Crania  has  internal  markings  as  in  Fig.  242;  and  the 
shell  was  attached  when  living,by  the  substance  of  one  valve  to  a  rock  or  other  support. 

9.  Thecidium  Family.  —  Thecidium  contains  thick-shelled  species,  higher  than  wide, 
having  a  pointed  beak,  very  large  triangular  hinge-area,  and  internally  digitate  mus 
cular  impressions;  commenced  in  the  Trias,  and  has  a  single  living  species. 

Davidsonia  is  a  genus  of  rare  occurrence  and  undetermined  relations.  There  is  some 
resemblance  to  Leptcena  ;  but  it  has  a  pair  of  low  and  faint  spiral  cones  on  the  inner 
surface  of  the  larger  valve. 

The  following  genera  have  species  in  the  existing  seas ;  and  those  having  an  asterisk 
are  known  only  as  recent.  In  the  Terebratula  family,  the  genera  Terebratula,  Wald- 


174 


PALEOZOIC   TIME. 


Fig.  247,  Bryozoan  (?). 
248-250,  BR.VCHIOPODS  : 
248,  Lingulella  Mat- 
thewi :  249,  Disciua 
Acadica;  250,  Orthis 
Billingsii. 


a  genus  eminently  characteristic  of  the  Primordial,  containing  species 
related  to  the  modern  Linqula  ;  of  Discina  (Fig. 

Fio-s    917_9 "iO 

249     949),  disk-shaped    shells ;    and    others   of  Orthis 
(Fig.  250)  and  Obolella. 

Among  Articulates,  the  Worms  are  fleshy  spe 
cies  ;  and  only  their  borings  or  tracks  remain  in 
the  rocks.  The  borings  or  burrows  are  vertical 
in  the  beds,  and  generally  in  pairs,  in  accordance 
with  the  habit  of  the  boring  sea-worm,  of  sandy 
or  muddy  sea-shores.  The  genus  to  which  the 
common  kind  is  referred  is  called  Scolithus  (from 
the  Greek  for  worm  stone).  Some  of  these  bur 
rows,  of  a  kind  common  in  the  Potsdam  sand 
stone,  are  represented  in  Fig.  265.  The  species 
of  the  St.  John  beds  have  not  been  particularly  described. 

Trilobites l  are  very  numerous  in   rocks  of  the  Acadian   epoch,  as 

hcimia,  Terebratella,  MegerHa,  Kraussia.*  Bouchardia,*  Morrisia,  Argiope;  in  the 
TJteddiiim  family,  Thecidium;  in  the  Rliynclwndla  family,  Rhynchonella;  in  the 
Crania  family,  Crania;  in  the  Disdna  family,  Discina;  in  the  Linyula  family ,  Lingula. 
There  are  no  living  species  of  the  Orthis,  Productus,  and  Spiriftr  families.  Calceola 
(Fig.  242)  is  not  now  regarded  as  a  Brachiopod. 

1  The  genera  are  distinguished  mainly  by  the  form  and  markings  of  the  head  and 
tail  portions,  and  the  form  and  position  of  the  eyes.    The  large  anterior  segment  is  the 
head  or  buckler;  the  posterior,  when  shield-shaped  and  combining  two  or  more  seg 
ments,  the  pyrjidium.     The  middle  area  of  the  head,  which  is  often  very  convex,  is  the 
glabetiti  ;  the  parts  of  the  head  either  side  of  the  glabella,  the  cheeks;  a  suture  running 
from  the  anterior  side  of  the  eye  forward  or  outward,  and  from  the  posterior  side  of  the 
eye    outward    (s  s  in   the   figure),  the  facial  suture;   a 
Fig.  254.  prominent  piece  on  the  under  surface  of  the  head,  cover 

ing  the  mouth,  the  hypostome.  The  eyes  may  be  very 
large,  as  in  Dalmanitts  (Fig.  254),  Phacops,  and  Asaphus 
(Fig.  360),  or  small,  as  in  Homalonotus ;  or  not  at  all  pro 
jecting,  as  in  Tiinucleus  (Fig.  363);  and  may  also  differ 
in  position  in  different  genera. 

The  glabella  may  be  broader  anteriorly,  as  in  Phacops, 
Dalmanites,  Trinuchus;  or  broader  posteriorly,  as  in  Caly- 
mene  (Fig.  361),  Batliyums  (Fig.  301);  and  it  may  vary 
otherwise  in  form ;  or  it  may  be  ill  denned,  as  in  Asaphus 
(Fig.  360)  and  Ilkenus  (Fig.  393).  It  may  have  no  fur 
rows  across  its  surface,  or  one  or  more  up  to  four  (or 
Dalmanites  Haunnanni.  rarely  five).  The  four  may  be  numbered,  beginning  be 

hind,  No.  1,   2,   3,  4  (Fig.  254).      These  furrows  may 

extend  entirely  across,  or  be  divided  at  middle  as  Nos.  2,  3,  4.  Asaphus  (Fig.  360)  and 
Ilknus  (Fig  393)  have  none  of  these  furrows;  Trinudeus  (Fig.  363)  has  No.  1  faint  or 
obsolete;  Asaphus  (Fis?.  360),  Homalonotus,  and  Bathyurus  have  No.  1  entire;  Dteet 
ctphalus  (Fig.  268)  has  Nos.  1  and  2  entire,  and  3  divided;  Calymene  (Figs.  167,  d61), 
Dalmanites,  Cryphem,  O<,yc,ia,  Ceraurus,  Proetm,  have  No.  1  entire,  and  2,  3.  4  divided, 
but  4  is  sometimes  obsolete.  Sao  (Fig.  281)  has  No.  1  entire,  and  2,  3,  4  divided;  but 
there  is  a  median  longitudinal  depression  in  which  2,  3,  4  from  either  side  coalesce.  In 
one  group,  the  genus  Lidias,  the  glabella  has,  on  either  side,  one  or  two  longitudinal  or 


LOWER   SILURIAN. 


175 


Figs.  251-253. 


well  as  in  the  following.  Fig.  251  represents  one  of  the  largest  kinds, 
a  species  of  Paradoxides,  that  at  times 
exceeded  twenty  inches  in  length.  It 
is  from  the  beds  near  Braintree,Mass. 
Fig.  252  represents  the  cephalic 
shield  of  another  Trilobite,  of  the 
genus  Conocoryphe,  from  St.  John ; 
and  Fig.  253,  the  cephalic  and  caudal 
(head  and  tail)  portions  of  another 
genus,  Agnostus.  These  three  gen 
era  of  Trilobites  have  many  species 
in  Primordial  rocks,  and  mark  this 
era  in  the  history  of  life. 

In  the  rocks  of  the  Potsdam  epoch, 
various  fossil  sponges  are  found  (Fig. 
261,  p.  177);  remains  of  Crinoids  ; 
Brachiopods  of  the  genera  Lingu- 
lella  (Figs.  262,  263,  264),  Orthis, 
etc.;  and  various  Trilobites  (Figs.  266 
-269),  but  among  them  none  that 
were  alive  in  the  Acadian  epoch,  and 
none  of  the  genus  Paradoxides. 
Nearly  100  species  of  Trilobites  have 
been  described  from  the  American 
Primordial  rocks. 

There  are  also  the  first  of  Grapto- 
lites,  delicate  plume-like  fossils,  so 
named  from  the  Greek  ypac/xo,  T  write. 
They  are  described  as  Hydroid  Aca- 
lephs  on  page  130.  Fig.  270  repre 
sents  one  species,  natural  size,  and 
.  Fig.  271,  a  portion  of  a  branch  en 
larged  :  it  is  from  the  Wisconsin  beds. 


TRILOBITES.  Fig.  251,  Paradoxides  Harlani 
(X>i);  252,  Conocoryphe  Matthewi ; 
253,  Agnostus  Acadica  — a,  head,  6,  cau 
dal  part. 


oblique  lobes  (Figs.  362,  449).  The  furrows,  as  shown  in  the  genus  Paradoxides,  cor 
respond  to  articulations  of  the  body.  They  are  mostly  obliterated  in  the  higher  Trilo 
bites  where  the  head-shield  is  most  compact,  and  are  most  distinct  in  the  lowest,  like 
Paradoxides,  being  a  part  of  that  general  looseness  of  body  that  marks  inferior  grade. 

The  position  of  the  facial  suture  (see  p.  174  and  s  s  in  Fig.  254)  affords  characters  for 
distinguishing  genera;  also  the  number  of  segments  of  the  body  (in  Aynostiis,  Fig.  279, 
the  number  is  very  small,  and  the  head  and  pygidium  are  almost  in  contact);  the  con 
tinuation  of  the  free  movable  segments  to  the  posterior  extremity,  or  the  union  of  the 
posterior  into  a  shield  (called  the  pygidium);  in  some  cases  the  breadth  of  the  middle 
lobe  of  the  body  as  compared  with  the  lateral,  it  being  very  broad  in  Homalonotus  (Fig. 
450);  the  form  of  the  fold  of  the  shell  beneath  the  head  at  its  anterior  margin-,  the 
shape  of  the  hypostome ;  the  capability  of  folding  into  a  ball  by  bringing  the  abdomen 
to  the  head,  as  in  Calymene,  Isotelus,  Pliacops. 


176 


PALEOZOIC   TIME. 


Besides  the  remains  of  Crustaceans,  there  are,  at  Beauharnois,  in 
Canada,  and  elsewhere,  tracks  called   Protichnites   (Fig.  258),  which 
Fig.  258.  Fig.  259. 


Protichnites  7-notatus  (  x  % 


Track  of  a  Trilobite  (  X  %  )• 


are  supposed  to  have  been  made  by  large  Crustaceans  having  stout 
legs  like  the  modern  Limulus  :  they  need  further  explanation.  A 
very  different  kind  of  track,  also  first  made  known  by  Logan  (Fig. 
259),  occurs  in  the  same  Canada  rocks.  It  is  six  and  three-quarter 
inches  wide  ;  and  one  trail  is  continuous  for  thirteen  feet.  It  was 
probably  made  by  the  clusters  of  foliaceous  swimming  or  crawling 
organs  of  one  of  the  great  Trilobites. 

Characteristic  Species. 

1.  ACADIAN  EPOCH. 

1.  Plants. 

Algae.  —  Several  Fucoids;  also  Eophyton  Linnceanum  (a  fossil  of  doubtful  character, 
first  described  in  Sweden),  from  near  Quebec,  and  in  the  auriferous  rocks  of  Nova 
Scotia. 

2.  Animals. 

1.  Radiates  —  None  yet  described. 

2.  Mollusks  --  a.  Bryozoans.  —  None  are  known. 

b.  Brachiopods.  —  Fig.  248,  Linguletta  Matthewi  Hartt.,  St.  John,  N.  B.;  L.  -  ? 
ib.  ;  Obolella  transversa  Htt.,  ib.  ;  249,  Discina  Acadica  Htt.,  ib.  :  250,  Orthis  Billinysii 
Htt,  ib. 

c.  Of  undetei*mined  relations.  —  Aspidella  Terranovica  B.,  from  supposed  Huronian 
in  S.  E.  Newfoundland. 

3.  Articulates.  _  «.  Worms.    ScolitJms     -  ?;   Arenicolites  spiralis?  Lovell, 
from  S.  E.  Newfoundland,  with  Eophyton. 

b.  Crustaceans:  all  thus  far  known  are  Trilobites.  —  Fig.  252,  Conocoryphe  (Cono- 
cephalites}  Matthem  Htt.,  besides  14  other  species  of  the  genus,  from  St.  John,  N.  B.  ; 
253,  Agnostus  Acadicus  Htt.,  and  also  another  species,  ib.;  Paradoxides  Imnellatus 
Htt.,  with  four  other  species,  from  St.  John  :  P.  Bennettii  Salter,  St.  Mary's  Bay, 
Newfoundland;  251,  Pciradnxides  Harlani  Green,  Braintree,  Mass.;  Bathyurus  f/rec/a- 
rius  B.,  St.  Mary's  Bay,  Newf. 

2.  POTSDAM  EPOCH. 

Some  of  the  Vermont  fossils  of  this  epoch  are  identical  with  those  from  Anse  au 
Loup,  on  the  north  shore  of  the  Straits  of  Belle  Isle,  Newfoundland. 


LOWER   SILURIAN. 


177 


Fig.  261. 


1.  Plants. 

Two  species  of  the  genus  of  Fucoids,  Palceophycus,  from  Straits  of  Belle  Isle,  have 
been  described  by  Billings,  as  P.  incipiens  and  P.  conyreyatas ;  and  the  first  of  these 
occurs  also  near  S wanton,  Vt. 

2.  Animals. 

Protozoans.  —  Sponyes.—  Fig.  2G1,  Archceocyatkus  Atlanticus  B.,  from  the  Straits 
of  Belle  Isle:  a,  external  form,  diminished  one- 
half;  b,  a  polished  transverse  section,  natural 
size,  showing  an  irregularity  of  structure, 
like  that  of  a  sponge;  Archceocyathellus  Rens- 
selaencus  Ford,  at  Troy. 

The  Green  Sand  of  the  Wisconsin  and  Ten 
nessee  beds  suggests  the  probable  existence  of 
Rhizopods,  since  the  shells  of  these  Protozoans 
have  been  found  to  be  connected  with  the 
origin  of  this  material  in  the  Silurian  rocks  of 
Europe,  as  well  as  in  those  of  the  Cretaceous 
in  Europe  and  America. 

Radiates.  — a.  Polyps.  — None  are  known. 

b.  Acalejrfis. —  Figs.  270,  271,  Dendroyraptus  Hallianus,  from  St.  Croix,  Minnesota. 

Figs.  202-271. 
265  ^^~ 


Archaeocyathus  Atlanticus. 


Figs.  262,  263,  Lingulella  prima ;  264,  L    antiqua;  265,  Scolithus  linearis  ;  266,  267,  Conocoryphe 

minuta,    head    and   tail  shields   (X4);    268,  Dicellocephalus  Minnesotensis  (X%)  ;    269,    C. 

lowensis;  270,  271,  Dendrograptus  Hallianus. 

c.  Echinoderms.  —  Stems  of  Crinoids,  at  La  Grange,  Minnesota  (probably  Cysti- 
dean);  and  a  single  disk  at  Keeseville,  N.  Y. 

Mollusks —  a.  Bryozonns.  —  None  are  known. 

b.  Brachiopods.  —  Fig.  262,  Linyulella  (formerly  Lingula)  prima  Conrad,  from 
Keeseville,  N.  Y. ;  263,  same,  from  Lake  Superior  (Tequamenon  Bay),  and  from  St. 
Croix,  Wis. ;  264,  L.  antiqua  H.  (or  L.  acuminata  Conrad),  from  St.  Croix,  — a  much 
larger  specimen  than  those  of  New  York,  but  varying  much  in  size  and  form.  It  is 
common  also  in  Canada.  Other  Linf/ulte  occur  in 

Wisconsin  and  Canada.     ObokUa  t  polita.  Hall  (Obolus  Fi£s-  272>  273' 

Apollinis  Otven)  from  near  the  mouth  of  Black  River 
in  Iowa.  Species  of  Obolella  have  been  described 
from  Troy,  N.  Y.,  and  Wisconsin,  and  one  (0.  nana, 
Figs.  272,  273),  from  the  Black  Hills  of  Dakota; 
Obolus  Labradoricus  B,  Straits  Belle  Isle;  Obolella 
chromitica  B.,  ib. ;  Oboklla  (Kutoryina)  cingulnta  B. 
(recently  shown  to  be  0.  PhilUpsil  Salter,  of  mid-  Obolella  nana. 

die    Lingula   flags    of    Great    Britain);     0.    desqua- 

mata   Hall,   and  other  species,  Troy;    Camerelki  antiquata   B.,    S  wanton ;    Orthisina 
12 


ITS  PALEOZOIC   TIME. 

festinata  B.,  1^  m.  E.  of  Swanton,  Vt. ;  also,  at  same  locality,  another  Orthisina  and 
an  Orthis,  and  at  the  Straits  of  Belle  Isle,  two  different  species  of  Ortku  and  another 
Orthisina;  on  the  St.  Croix,  Orthis  Pepina  Hall. 

c.  Lamdlibranchs.  —  An  undetermined  one  is  reported  from  Troy. 

d.  Pteropods.—'Fig.   274,  Hyolites    (Thtca)  yreyariux  M.  &   H., 

ffrom  the  Big  Horn  Mountains,  lat.  43°  N.,  long.  107°  W.,  where 
they  are  crowded  together  in  great  numbers  on  the  slabs.  //.  i/n- 
par  Ford  and  H.  Americanus  Ford  occur  near  Troy.  A  species  has 
also  been  found  at  Keeseville,  N.  Y. 

e.  Gasteropods. —  Imperfect   specimens   of    a    Pleurotomaria  and 
Ilj-olites  gre"urius.  OphUeta  compacta,  in  Canada,  and   the  former  also  at  Keeseville, 

N.  Y. ;  a  Gasteropod  of  the  form  of  a  Capulus.  in  Texas  (B.  F.  Shu- 
mard);  Platyceras  primordiale  H.,  at  Trempaleau,  Wis. ;  liuontphalus?  vaticinus  H., 
Lagrange  Mt.,  Minn. 

/.  Cephalopods.  —  Two  species  of  •  Orthoceras  occur  in  the  Potsdam  of  Canada,  in 
the  top  lavers,  with  the  Linyula,  antiqwt  (or  acuminata). 

Articulates. —a.  Worms.  —  Fig.  205,  casts  of  worm-holes  of  Scolitlim  Unearis 
H.,  common  in  New  York,  Canada,  Pennsylvania,  Tennessee,  and  occurring  also  at 
the  Straits  of  Belle  Isle.  The  Fucoides  ?  duplex  H.  (Foster  &  WhitnYy's  Lake  Superior 
Report,  pi.  23)  probably  belongs  to  another  species  of  worm.  Serpulites  Murchisoni  H. 
occurs  in  Wisconsin.  Salterella  rugosa  B.,  and  S.  pulchella,  B.,  slender  conical  shells, 
one  half  inch,  or  so,  long,  from  Straits  of  Belle  Isle,  are  regarded  by  Billings  as  allied 
to  Serpulites  among  Worms,  but  brothers  as  shells  of  Pteropods.  The  S.  pulchella 
occurs  in  the  Winooski  Limestone  in  Vermont. 

b.  Crustaceans.  —  (1.)  Phyllopods. — No  Phyllopods  have  been  found,  although  they 
occur  in  the  British  Primordial.  (2.)  Ostracoids.  — Leperditia  Trojensis  Ford,  at  Troy. 
(3.)  Trilobites.  —Figs.  266,  267,  Conocoryphe  minuta  Bradley,  from  Keeseville,  N.  Y., 
and  also  from  Wisconsin ,  266,  the  head-shield  or  buckler,  with  the  side-pieces  wanting, 
none  having  been  found  united  to  the  head;  267,  the  pygidium;  C.  Adamsii  B.,  and 
C.  Vulcanm  B.,  at  Highgate,  Vt.,  and  the  former  in  Newfoundland;  C.  (Atops)  tri- 
lineata  Emmons,  at  Troy  and  Bald  Mountain,  N.  Y. ;  C.  Ttucer  B.,  in  Swanton,  Vt. ; 
C.  Towensis  Shum.  (Fig.  269),  from  near  the  mouth  of  Black  River,  Iowa.  Fig.  268, 
DiceUocephalus  Minncsotensis  D.  D.  Owen,  a  trilobite  six  inches  long,  from  the  upper 
beds,  Lake  St.  Croix,  Minnesota.  The  name  of  this  genus  is  from  Si.Ke\\rt,  a  shovel, 
and  Ke^aXri,  head  (whence  the  spelling  above).  The  same  region  in  Wisconsin  affords 
species  of  Aynostus,  Agraulos,  Ptychaspis,  Chariocephalus,  Aylaspis,  and  Jllcemtrus,  the 
last  two  only  in  the  upper  beds.  Species  of  Aynostus,  Agrattlos,  Dicellocephahts,  and 
Conocoryphe,  in  Texas.  Agraulos  ?  Oiceni  M.  &  H.  is  from  the  Black  Hills,  Dakota, 
and  the  Big  Horn  Mountains;  also,  Olenellus  (Elliptocephahis)  asnphoides  Emmons, 
Bald  Mountain  and  Troy,  N.  Y.,  a  very  large  species;  Olenellus  Thompsoni  Hall, 
Swanton,  also  Straits  of  Belle  Isle  and  East  arm  of  Bonne  Bay,  Newfoundland,  and 
Bradore  and  Forteau  Bays,  Labrador;  0.  Vermont-ana,  Swanton  and  Straits  of  Belle 
Isle,  and  also  Bradore  and  Forteau  Bays,  Labrador;  Peltura  holopyya  Hall,  Vermont 
shales;  Aynostus  nobilis  Ford,  Troy,  N.  Y. ;  BitJiynrus  senectus  B.,  B.  parvulits  B., 
Straits  of  Belle  Isle;  B.  vetustus  and  B. perj)lexus  B.,  from  East  arm  of  Bonne  Bay, 
Newfoundland. 

Fig.  259  represents  a  track,  probably  of  a  large  trilobite,  from  near  Perth,  Canada, 
described  by  Logan,  who  names  it  CUmactichnites  Wilsoni.  Fig.  258,  track,  supposed 
to  be  Crustacean,  called  Protichnites  7-notatus  Owen. 

The  following  are  the  genera  of  Trilobites  represented  in  American  Primordial  rocks : 
1.  Those  peculiar  to  the  Primordial:  Paradoxides,  Olenellus,  Aglaspis,  Chariocephalus, 
IllaMiurus,  Pemphigaspis,  Triarthrella.  2.  Those  occurring  also  in  the  following  or 
Canadian  period:  Agnostus,  Amphion,  Agraulos,  Bathyurus,  Conocoryphe,  Dicello- 
cephalus,  Menocephalus,  Crepicephalus,  Ptychaspis,  Bathynotus  (Billings).  The  genus 
most  abundant  in  species  is  Conocoryphe.  Of  all,  only  Bathyurus  continues  into  the 
Trenton  period.  Triarthrella  is  very  near  Triarthrus  of  the  Trenton. 


LOWER    SILURIAN. 


179 


2.  EUROPEAN. 

The  Primordial  or  Cambrian  rocks  of  Great  Britain  outcrop  in 
North  and  South  Wales,  and  in  Shropshire  (or  Salop),  just  east  of 
Wales.  The  lowest  rocks  of  the  series  are  the  shales  and  sandstones 
of  the  Longmynd,  in  Shropshire,  and  of  northern  Wales,  the  maxi 
mum  thickness  of  which  has  been  estimated  at  28,000  feet.  The 
Penrhyn  and  Llanberis  slates  are  in  the  upper  part  of  the  series  in 
north  Wales,  near  the  Menai  Straits.  In  southwest  Wales,  there  are 
(1)  the  Harlech  grits,  overlaid  by  (2)  the  Menevian  group.  Similar 
rocks  occur  in  County  Wicklow  and  County  Dublin,  in  Ireland, 
which  are  supposed  to  be  of  the  same  age.  The  Longmynd  rocks 
are  the  Lower  Cambrian  of  Sedgwick.  In  northwest.  Scotland,  beds 
referred  to  the  Cambrian,  consisting  of  red  and  purple  sandstones  and 
conglomerates,  overlie  unconformably  the  Archaean. 

The  Cambrian  rocks  of  the  Longmynd  and  north  Wales  are  over 
laid  conformably  by  the  Lingula  flags,  a  series  of  beds  of  shale,  grit, 
and  sandstone,  3,000  to  4,000  feet  thick.  The  three  British  divisions 
of  the  Primordial  are,  1,  Lower  Cambrian ;  2,  Menevian,  or  Upper 
Cambrian,  corresponding  to  the  American  Acadian  group,  and  con 
taining  species  of  Paradoxides  ;  3,  the  Lingula  flags,  or  upper  part 
of  them,  affording,  like  the  American  rocks  of  the  Potsdam  period, 
no  Paradoxides. 

In  Lapland,  Norway,  and  Sweden,  there  is  a  Primordial  sandstone  overlaid  by 
schists,  the  lowest  beds  passing  at  times  into  a  conglomerate ;  the  regions  A,  B  of  the 
geologist  Angelin.  In  Bohemia,  the  lowest  Primordial  beds  are  schists  1,200  feet 
thick,  called  by  Barrande  Protozoic  schists,  or  the  Primordial  Zone,  and  numbered  C 
in  his  series,  — his  A,  B  consisting  of  schists  and  conglomerates  conformable  to  C. 
Until  recently,  B  was  thought  to  contain  no  trace  of  life,  and  therefore  to  be  below  the 
Primordial ;  but  worm-burrows  have  been  reported  to  occur  in  some  of  these  inferior 
beds.  South  of  Hof,  in  Bavaria,  there  are  other  rocks  of  the  Primordial  zone. 

1.  Life — 1.  Cambrian.  —  The  Longmynd  rocks  have  afforded  worm-burrows,  the 
species  named  Arcnicolites  dichjma.  From  the  Harlech  beds  of  the  Upper  Cambrian, 

Figs.  27G-282. 
281 


Fig.  276,  Oldhamia  antiqua;  277,  0.  radiata  ;  278,  Lingulella  Davisii  :  279,  Agnostus  Rex;  280, 
Olenus  micrurus;    281,  Sao  hirsuta  (XK);  282,  Hymenocaris  vermicauda  (  XK)- 


many  species  have   been  described,   including  Ptempods,    Brnchiopods,    Pliyllopods, 
Trilobites  and  Annelid  tracks.    And  from  the  Menevian,    a  larger  number,  among 


180  PALEOZOIC   TIME. 

them  species  of  Paradoocides  (one,  two  feet  long),  Conocoryphe,  Aynostus,  Leperditia, 
and  Theca  ;  also,  the  Oldhamia  antiqua,  Fig.  276,  a  species,  probably  vegetable,  found 
with  0.  radiata,  Fig.  277,  at  Bray  Head,  in  Wicklow,  Ireland. 

From  the  Harlech  grits  have  been  obtained  species  of  Paradoxides,  ConocephaUtes 
(Conocoryphe),  Microdiscus,  and  Plutonia  Sedytcickii,  among  Trilobites;  a  species  of 
Theca  among  Pteropods:  and  a  number  of  kinds  of  worm-burrows ;  also  the  Pahi-»jnir,- 
Ramsay  i  S.,  a  supposed  trilobite. 

In  the  Menevian  beds  have  been  found:  Among  PROTOZOANS,  Protosponyia  fene- 
strata  S. ;  among  MOLLUSKS,  Theca  corruyata  S. ;  among  TRILOBITES,  Paradoxides 
Davidis  S.,  P.  Aurora  S.,  Apopolenus  (near  Pafadoxides)  Iletmci  S.,  A.  Salteri  Hicks, 
Conocoryphe  (Conocephalites)  variolaria  S.,  C.  bufo,  Hicks.  C.  (?)  humerosci  S.,  C. 
applaiKtfa  S.,  Aynostus  princeps  S.,  Erynnis  renulosa  S.,  Mlcrodiscus  punctatus  S.; 
among  OSTRACOIDS,  Leperditia  Solrensis  Jones,  with  other  species  of  this  group: 
among  WORMS,  at  Bray  Head,  Histioderma  Hibernicum  Kinahan. 

The  Lingula  flags,  as  restricted,  contain  the  Brachiopod  Lmguletta  Darisii  McCoy, 
Fig.  278,  Olenus  micrums  S.,  Fig.  280,  species  of  Conocoryphe,  DiceHocephalus,  etc., 
Hymenocaris  reiinicauda,  Salter,  Fig.  282,  etc. 

Some  of  the  Bohemian  Primordial  species  are:  Aynostus  Rex  Barr.,  Fig.  279;  A. 
integer  Barr.,  from  Skrey,  Paradoxides  Bohemicus  Barr.,  Sao  hirsuta  Barr.,  Fig.  281: 
ElUptocephalus  dejwessus  S.,  Conocoryphe  inrita  S.,  C.  striata  Barr.,  some  species  of 
Cystids.  Bavarian  serpentine,  of  Primordial  age,  has  afforded  Giimbel  the  Eozoon 
Bavaricum.  Sweden  has  afforded  the  British  species.  Paradoxidts  Hicksii  S.,  besides 
other  fossils. 

No  Polyp  corals  have  been  found  in  any  Primordial  beds.  Over  seventy  species  of 
Primordial  Trilobites  have  been  discovered  in  Scandinavia,  and  nearly  thirty  in  Bohe 
mia.  The  Eopkyton  Sandstone  at  Lugnas,  in  Sweden,  which  has  been  referred  to  the 
Cambrian,  and  is  of  the  "  Fucoid  region  "  of  the  Swedish  geologists,  has  afforded  a 
Linyula,  besides  species  of  a  genus  of  plants  called  Eophyton,  which  have  been  consid 
ered  terrestrial  plants,  and  are  placed  by  Linnarson  near  the  genus  Rhachiopteris  of 
Unger.  The  absence  of  the  successors  to  these  species  in  the  later  Lower  Silurian 
throws  doubt  on  this  reference  of  them. 

TV.  General  Observations. 

1.  North  American  Geography. —  On  p.  149  a  map  is  given,  pur 
porting  to  represent  the  general  outline  of  North  America  at  the  close 
of  the  Archoean  or  during  the  earlier  part  of  the  Silurian.  It  is  there 
stated  that  there  may  have  been  other  lands  above  the  water,  large  and 
small,  in  the  great  continental  sea  ;  but  that  the  continent,  in  a  gen 
eral  way  already  denned  as  to  its  ultimate  outline,  lay  at  no  great 
depth  beneath  the  surface.  The  facts  gathered  from  the  rocks  of  the 
Primordial  era  throw  additional  light  on  early  American  geography. 

The  fact  that  the  depositions  of  the  Acadian  period  occur  only  on 
the  border  of  the  continent  —  alonff  eastern  Newfoundland,  New 

D 

Brunswick,  and  Massachusetts  —  and  nowhere  over  the  interior,  should 
it  be  sustained  by  future  observations,  would  show  that,  as  the  Silurian 
age  opened,  the  continent,  on  the  east  at  least,  was  raised  nearly  to  its 
present  limits  above  the  sea.  The  beds  of  St.  John,  New  Brunswick, 
bear  evident  marks,  as  Matthew  observes,  of  sea-shore  origin.  The 
eastern  sea-coast  of  Acadian  time  was  therefore  not  far  from  the  pres 
ent  line ;  and  the  dry  land  of  North  America  for  a  while  may  have 
approximated  in  extent  to  that  now  existing. 


LOWER   SILURIAN.  181 

In  the  next  or  Potsdam  epoch,  there  were  beach  deposits  of  sand  in 
progress  about  the  shores  of  the  Archaean  dry  land,  but  in  Vermont 
mostly  shales,  with  some  limestones,  indicating  deeper  waters  off  the 
Archrean  coasts.  West  of  Vermont,  this  coast  line  bent  around  the 
Adirondack  region  of  northern  New  York  and  Canada,  as  marked 
out  by  the  distribution  of  the  Potsdam.  The  Potsdam  rocks  of  New 
York  and  Canada  indicate  their  beach  or  shallow-water  origin,  by  their 
foot-prints,  worm-borings,  ripple-marks  and  mud-cracks  (p.  169).  Simi 
lar  evidences  of  shallow  water  are  observed  also  in  the  Potsdam  rocks 
of  Pennsylvania  and  Tennessee.  Thus  we  are  enabled  to  run  a  line 
of  soundings  along  the  continental  sea  of  the  Potsdam  era.  The  ma 
terials  of  the  sandstones  were  the  moving  sands  and  pebbles  of  the 
shores  and  shallow  seas ;  and  the  animals  which  had  living  places  over 
these  flats  and  sea  bottoms  found  in  them  also  a  burial  place,  to  remain 
as  fossils  and  become  testimony  as  to  the  early  life  of  the  world. 

2.  Climate.  —  No  marked  difference  between  the  life  of  the  Pri 
mordial  period  in  warm   and  cold  latitudes   has  been  observed  ;  and 
there  is  wanting,  therefore,  all  evidence  of  a  diversity  of  climate  and 
of  oceanic  temperature  over  the  earth's  surface.     With  a  warm  and 
equable  climate,  the  atmosphere  would  have  been  moist  and  the  skies 
much  clouded ;  but  storms  would  have  been  less  frequent  or  violent 
than  now.     The  eyes  of  the  Trilobite,  as  Buckland  observes,  indicate 
that  there  was  the  full  light  of  day,  and  therefore  that  sunshine  alter 
nated  with  the  clouds  as  now. 

So  far  as  has  been  deciphered  in  the  history  of  the  Primordial 
period,  there  was  no  green  herbage  over  the  exposed  hills;  and  no 
sounds  were  in  the  air  save  those  of  lifeless  nature,  —  the  movin^ 

O 

waters,  the  tempest  and  the  earthquake. 

3.  Exterminations  of  life.  —  The    life    of    the    Primordial     period 
changed  much  during  its  course ;  and,  at  one  time  —  the  close  of  the 
Acadian  epoch  —  there  was   a  general  extermination  of   the  species 
about  the  eastern  portion  of  the  continent ;  for  no  species  of  this  epoch 
have  yet  been  found  in  the  higher  rocks.     Among  the  Trilobites,  the 
genus  Paradoxides,  some  of  whose  species  were  the  largest  of  known 
Crustaceans,  became  extinct ;  most  of  the  other  genera  remained,  but 
were  represented  by  new  species.     No  Trilobites  of  the  Primordial 
extend  up,  so  far  as  known,  into  the  beds  of  the  next  period. 

V.  Disturbances  during  the  progress  of  the  Primordial  period. 

In  Newfoundland,  the  beds  of  the  Potsdam  division  lie  unconform- 
ably  over  those  of  the  Acadian,  indicating  an  epoch  of  disturbance 
between.  No  direct  evidence  of  a  similar  disturbance  over  the  rest  of 
North  America  has  yet  been  made  known,  beyond  the  fact  of  the  de- 


182  PALEOZOIC    TIME. 

struction  of  the  Acadian  life  above  mentioned,  and  the  additional 
observation,  by  F.  H.  Bradley,  that  at  Henry's  Lake,  Idaho,  a  quartz- 
yte  (probably  Potsdam)  underlies  unconformably  the  beds  of  the 
Quebec  group.  The  fact,  stated  by  Emmons,  that  pebbles  of  the  Pots 
dam  sandstone  are  included  in  a  conglomerate  at  the  base  of  the  Cal 
ciferous,  seems  to  show  that  the  consolidation  of  the  Potsdam  had 
taken  place  before  the  Calciferous  era. 

2.  CANADIAN  PERIOD. 

1.  AMERICAN. 

Epochs.  —  1.  The  CALCIFEROUS,  or  that  of  the  Calciferous  sand 
stone  of  New  York,  etc.  2.  The  QUEBEC,  or  that  of  the  Quebec 
group  in  Canada.  3.  The  CHAZY,  or  that  of  the  Chazy  limestone. 

The  rocks  of  the  extensive  Quebec  group  were  first  distinguished 
and  described  in  Canada  by  Canadian  geologists,  and  all  the  subdivi 
sions  are  well  represented  there ;  and  hence  the  period  is  named  the 
Canadian. 

I.  Rocks  :  their  kinds  and  distribution. 

The  rocks  of  the  earlier  section  of  this  period  —  the  Calciferous  — 
are  a  calcareous  sandstone  and  magnesian  limestone  in  Canada  and 
northern  New  York,  adjoining  the  region  of  the  Potsdam  sandstone  : 
and  the  same,  more  purely  limestone,  with  some  shales,  along  the  Ap 
palachians  ;  but,  in  the  Mississippi  basin,  mainly  magnesian  limestones, 
with  some  small  intervening  sandstone  beds,  excepting  to  the  north, 
where  sandstone  prevails.  Those  of  the  second  section  —  the  Que 
bec —  consist  of  shales,  with  some  sandstone  and  thin  limestone  strata 
near  Quebec  ;  limestone  chiefly  in  the  Appalachian  region  of  East 
Tennessee,  and  also  in  the  Rocky  Mountain  region,  in  Utah,  Idaho, 
and  also  "Wyoming  Territories.  Those  of  the  third  —  the  Chazy.  so 
named  from  a  locality  in  Northern  New  York  —  are  limestone  in  New 
York  and  Western  Canada,  outcropping  near  the  Calciferous  out 
crops  ;  and  magnesian  limestone  in  part  of  the  Mississippi  basin ;  the 
same,  but  of  greater  thickness,  to  the  southwestward  along  the  Ap 
palachian  region  in  Pennsylvania  and  Virginia  —  though  the  beds  are 
not  wholly  distinguished  from  the  limestone  of  the  Trenton  period. 

Through  the  discovery  of  fossils  near  Rutland,  in  Vermont,  it  has 
been  shown  by  Billings,  that  part  of  the  great  crystalline  limestone  of 
the  Green  Mountain  region  is  of  the  Chazy  epoch. 

The  St.  Peter's  sandstone,  overlying  the  Lower  Magnesian  lime 
stone  of  Wisconsin  and  Iowa,  is  referred  to  the  Chazy  epoch ;  and  the 
sandstone  along  the  southern  and  part  of  the  northern  shores  of  Lake 
Superior,  including  the  4>  Pictured  rocks."  is  regarded  by  Hall  as  rep- 


LOWER   SILURIAN. 


183 


resenting  the  whole  Canadian  period,  from  the  St.  Peter's  sandstone 
to  the  Calciferous.  In  the  vicinity  of  Carp  River,  Whitney  observed 
tliis  sandstone  resting  unconformably  on  the  Archaean,  as  represented 

Fie.  283. 


Unconformability  at  Carp  River,  Michigan. 

in  the  preceding  sketch  (Fig.  283)  by  him.  The  Archaean  rocks  evi 
dently  stood  there  as  a  seashore  ledge,  when  the  sands  of  the  sand 
stone  were  deposited. 

1.  Calciferous  epoch.  —  a.  Interior  Continental  basin.  —  In  New  York  and  Can 
ada,  the  Calciferous  formation  often  consists  below  of  impure  magnesian  limestone  of  a 
dark  gray  color.  In  many  places  in  northern  New  York,  the  layers  are  very  hard  and 
siliceous," and  contain  geodes  of  quartz  crystals,  as  at  Diamond  Rock,  Lake  George,  and 
at  Middleville  and  elsewhere  in  Herkimer  County,  etc.  The  mixture  of  calcareous  with 
hard  siliceous  characteristics  is  a  striking  peculiarity  of  the  rock.  Owing  to  the  lime 
present,  much  of  it  becomes  rough  from  weathering.  Besides  quartz  and  calcite, 
barite,  celestite,  gypsum  and  occasionally  blende  and  anthracite,  are  found  in  its 
cavities.  The  limestone  often  contains  chert  or  hornstone. 

The  "Lower  Magnesian  Limestone"  of  Missouri,  mostly  unfossiliferous,  is  referred 
by  Swallow  to  the  Calciferous  epoch.  He  makes  it  to  consist  of  four  limestone  strata, 
190  to  350  feet  thick,  which  he  numbers,  beginning  above,  1  to  4,  and,  between  these, 
thinner  strata  of  sandstone,  50  to  125  feet  thick.  Shumard  has  described  fossils  from 
the  third  which  are  regarded  as  Calciferous.  In  the  other  strata,  above,  the  rest  of  the 
Canadian  period  may  be  represented.  In  Wisconsin,  according  to  Hall,  the  Lower 
Magnesian  limestone  is  in  all  only  200  to  250  feet  thick ;  and  at  top  there  is  the  St. 
Peter's  sandstone,  mostly  60  to  100  feet  thick,  referred  to  the  Chazy.  Farther  north, 
near  Lake  Pepin,  there  are,  beneath  the  Magnesian  limestones, several  hundred  feet  of 
sandstone,  probably  Calciferous  in  age.  Along  the  south  shore  of  Lake  Superior,  on 
Keweenaw  Point  and  elsewhere,  there  is  sandstone  only.  On  Keweenaw  Point,  it  under 
lies  at  one  or  two  places  a  thin,  fossiliferous  limestone  of  the  Black  River  and  Trenton 
age,  showing  that  it  is  older.  The  rocks  on  KeAveenaw  Point  include  8.000  to  10,000 


184  PALEOZOIC    TIME. 

feet  of  sandstone  and  conglomerate  (Whitney),  along  with  intersecting  trap  rocks  and 
some  intercalated  scoria-conglomerate.  East  of  this  point,  there  are  in  the  same  sand 
stone  formation  the  Pictured  Rocks  of  the  coast— fine  sandstones  blotched  or  mottled 
with  red  or  light  gray.  Westward,  the  sandstone  extends  to  the  west  end  of  the  lake, 
and  then  nortliward  and  eastward  to  Thunder  Bay  and  Neepigon  Bay.  The  rocks  of 
Isle  Royale  and  Michipicoten  Island  are  of  the  same  age.  The  formation  is  remark 
able  for  its  copper  mines.  In  Canada,  the  Calciferous  sandrock  has  a  thickness  of  50 
to  300  feet. 

b.  Appalachian  Reyion.  —  The  Auroral  series  of  Rogers,  in  Pennsylvania,  corre 
sponds,  according  to  him,  to  the  Calciferous,  Chazy,  and  Black  River  beds,  and  con 
sists  mainly  of  magnesian  limestone;  it  is  from  2,500  to  5,000  or  6,000  feet  in  thick 
ness. 

In  eastern  Tennessee,  near  Knoxville,  the  Calciferous  includes  the  "  Knox  sand 
stone  "  of  Safford,  the  lower  member  of  the  Knox  Group  (F.  H.  Bradley). 

2.  Quebec  epoch — Near  Quebec,  the  beds  are  largely  developed  on  the  island  of 
Orleans  and  in  the  district  around  Point  Levis.     From  the  Levis  beds,  Logan  separates 
the  upper  part,  occurring  more  to  the  southward  and  southeastward,  which  is  destitute 
of  fossils  and  consists  mainly  ot  copper-bearing  metamorphic  schists,  and  designates 
it  the  Lnuzon  division.     He  also  adds  to  the  series- the  "  Sillery  Sandstone  "  (so  called 
from  a  place  near  Quebec)  as  an  upper  member,  the  actual  connection  of  which  with  the 
system  is  not  clear. 

In  the  vicinity  of  Quebec,  the  thickness  of  the  Levis  beds  is  said  to  be  5,000  feet; 
4,000  feet  of  the  whole  are  gray  and  green  shales,  155  feet  intercalated  beds  of  lime 
stone  (half  of  it  limestone-conglomerate),  and  700  feet  gray  sandstones  partly  shaly. 
The  shales  are  either  calcareo-magnesian,  argillaceous  or  arenaceous.  Many  of  the 
beds  abound  in  fossils. 

The  extension  of  the  Quebec  group  southward,  along  the  west  side  of  the  Green 
Mountain  range,  covers,  according  to  Logan,  a  considerable  part  of  New  York  east  of 
the  Hudson,  the  rock  being  part  of  the  non-fossiliferous  clay-slate  (formerly  called 
Hudson  River  slate)  which  outcrops  near  Poughkeepsie,  etc.  The  area  is  divided  on 
the  west  from  that  of  the  true  fossiliferous  Hudson  River  beds  (or  Cincinnati  series,  as 
now  called),  by  a  great  fault,  which,  beginning  near  Quebec,  crosses  the  Hudson  near 
Rhinebeck,  15  miles  north  of  Poughkeepsie.  As  these  rocks  have  afforded  no  fossils, 
the  age  is  still  doubtful. 

In  northwestern  Newfoundland,  the  thickness  of  the  Quebec  series  is  6,600  feet,  — 
the  lower  3,200  feet  mostly  limestones,  and  the  rest  sandstones  and  shales,  with  some 
conglomerate  limestone.  The  upper  2,000  feet  are  separated  by  Logan  and  Billings  as 
"  Sillery;  "  the  next  1,400,  of  sandstones  and  shales  and  some  limestones,  as  "Levis,  " 
and  the  lower  beds,  1,839  feet  thick,  of  limestones,  as  Cnlciferous.  Between  these 
Calciferous  beds  and  those  referred  on  paleontological  evidence  to  the  Levis,  there  are 
2,061  feet  of  fossiliferous  limestone,  which  have  no  equivalents  in  Canada,  and  arc  called 
Upper  Calciferous,  in  distinction  from  the  New  York  beds  which  are  hence  made 
Lower  Calciferous.  "It  thus  appears  that  the  'Levis'  formation  not  only  lies  :ibove 
the  Calciferous,  but  more  than  2,000  feet  above  it."  (Billings.) 

The  Quebec  group  in  Tennessee,  about  Knoxville,  includes  the  shale  and  dolomite  of 
the  "  Knox  group  "  of  Safford  (F.  H.  Bradley):  the  base  of  the  dolomite  abounds  in  trilo- 
bites  characteristic  of  the  group.  In  Idaho,  Bradley  found  the  group  on  the  east  side 
of  Malade  valley,  six  miles  south  of  Malade  city,  2,000  feet  thick,  mostly  of  limestone, 
underlaid  and  overlaid  by  quartzyte;  and  in  the  Teton  range,  at  the  base  of  the  lime 
stones  over  the  granytes  of  the  range  (Am.  Jour.  Sci.,  III.  iv.,  vi.),  and  separated 
from  the  latter  by  only  a  few  feet  of  quartzyte  referred  to  the  Potsdam  epoch. 

3.  Chazy   epoch.  — (a.)  Interior  Continental  basin.  —  The  Chazy  limestone  out 
crops  at    different   places   in   northern   New  York,    in   the   vicinity   of   the   Archaean 
(though  not    along  its   more  southern  border);    also  in    Canada,  around  the  Trenton 
limestone  of  the  Ottawa  basin.     The  thickness  in  some  parts  of  New  York  is  100  to 
150  feet.    Occasionally,  it  graduates  into  the  next  rock  below,  the  Calciferous  sandrock, 
so  that  the  two  are  separated  with  difficulty. 


LOWER   SILURIAN.  185 

The  reference  of  part,  at  least,  of  the  Stockbridge  limestone  formation  of  the  Green 
Mountain  region,  to  the  Chazy.  is  based  on  the  discovery  of  fossils  in  West  Rutland, 
by  Rev.  A.  Wing,  as  described  by  Billings.  The  latter  states  that  he  identified  a  Cri- 
noidal  plate  as  pertaining  to  Palceocystites  tenuiradiat-us,  a  characteristic  Chazy  species, 
and  a  Mollusk  as  Pleurotomaria  stamineaDn. 

The  rocks  supposed  to  be  equivalents  of  the  Chazy  in  the  Mississippi  basin  are 
mentioned  on  the  preceding  page.  A  limestone  of  the  age  has  been  stated  to  occur  in 
the  Winnipeg  region,  west  of  the  Archaean. 

(c.~)  Appalachian  region.  —  The  Chazy  has  not  been  distinguished  from  the  Trenton 
in  the  Green  Mountains,  or  in  Pennsylvania;  in  the  latter  State,  there  is  a  magnesian 
limestone,  according  to  H.  D.  Rogers. 

In  East  Tennessee,  it  is  represented  by  from  50  to  600  feet  of  blue  and  drab,  more 
or  less  concretionary, argillaceous  limestone  ("Maclurea  limestone  "  of  Safford). 

(d.)  Arctic  region.  —  Limestone  strata,  containing  Chazy  fossils,  have  been  observed 
in  the  Arctic,  on  King  William's  Island,  North  Devon,  and  at  Depot  Bay  in  Bellot's 
Strait  (lat.  72°,  long.  94°).  The  species  Orthoceras  moniliforme  Hall  and  a  Maclurea 
(If.  Arctica  Haughton,  near  J/.  mayn(t),  have  been  observed.  The  limestone  is  in 
part  a  cream-colored  dolomyte. 

Igneous  or  Intrusive  Rocks. 

Through  New  York  and  the  States  directly  West,  no  evidences  of 
disturbance  have  been  observed  that  can  be  traced  to  this  period. 
The  rocks  are  for  the  most  part  nearly  horizontal,  and  in  general 
little  altered  ;  and  the  tilting  which  is  observed  appears  to  have  taken 
place  at  a  later  period.  But,  on  Keweenaw  Point,  the  famous  copper- 
region  of  Lake  Superior,  the  sandstones  of  this  period  are  associated 
with  trap,  —  an  igneous  rock, that  was  ejected  through  fissures  opened 
in  the  earth's  crust ;  and  these  trap  ejections  have  added  much  to 
the  accumulations.  Some  of  the  conglomerate  (according  to  Foster 
and  Whitney,  and  Owen)  seems  to  be  made  of  volcanic  scoria,  like 
the  tufa  of  modern  volcanoes,  as  if  the  ejections  had  been  submarine, 
and  the  cool  waters  had  shattered  the  hot  rock  to  fragments,  and  so 
made  the  material  of  the  conglomerate  ;  and,  as  many  of  the  masses 
are  not  rounded,  these  authors  infer  that  it  was  piled  up  rapidly 
during  the  igneous  action.  Dr.  D.  I).  Owen  represents  the  trap  as 
often  in  layers,  alternating  with  shale  and  other  rocks,  indicating 
eruptions  at  different  times.  The  trap  rocks  of  Lake  Superior  present 
many  scenes  of  basaltic  columns  of  remarkable  grandeur.  Some  of 
them  are  represented  and  described  in  the  Geological  Report  on  Wis 
consin,  Iowa,  and  Minnesota,  by  Dr.  Owen.  The  native  copper  of 
the  Lake  Superior  region  is  intimately  connected  in  origin  with  the 
history  of  the  trap  and  sandstone. 

II.  Economical  Products. 

Copper  mines  are  numerous  in  the  rocks  referred  to  this  period, 
and  many  of  them  are  highly  productive.  Those  of  Keweenaw  Point, 
on  the  southern  border  of  Lake  Superior,  are  among  the  most  remark- 


186  PALEOZOIC   TIME. 

able  in  the  world.  The  copper  is  mostly  in  the  native  state,  or  pure 
copper,  and  occurs  in  great  masses  or  sheets,  as  well  as  in  strings 
and  grains.  The  strings  are  really  made  up  of  imperfect  crystals. 
One  great  sheet  of  copper,  opened  to  view  in  the  course  of  the 
mining,  was  forty  feet  long,  and  weighed,  by  estimate,  two  hundred 
tons.  Much  of  the  copper  contains  native  silver,  in  imbedded  grains, 
often  large  enough  to  be  visible,  and  sometimes  an  inch  or  more 
across  ;  some  specimens  are  spotted  white  with  the  more  precious 
metal. 

In  addition  to  copper,  the  rocks  contain  the  usual  trap  minerals,  — 
zeolites,  datolite,  calcite,  quartz ;  and  some  calcite,  datolite,  and  anal- 
cite  crystals  arc  implanted  on  or  about  threads  of  copper,  showing 
that  they  are  of  subsequent  origin.  The  copper  occurs  in  irregular 
veins  in  both  the  trap  and  the  sandstone,  near  their  junction  ;  and, 
whenever  the  trap  was  thrown  out  as  a  melted  rock,  the  copper  prob 
ably  came  up,  having  apparently  been  derived  from  copper-ores  in 
some  inferior  Archaean  rocks,  through  which  the  liquid  trap  passed 
on  its  way  upward.  The  extent  to  which  the  rock  and  its  cavities 
are  penetrated  and  filled  with  copper  shows  that  the  metal  must  have 
been  introduced  by  some  process  before  the  rock  had  cooled. 

There  are  also  rich  silver  mines.  "  Silver  Islet,"  adjoining  the 
north  shore  of  Lake  Superior,  is  already  a  noted  mining  region j  the 
ore  deposits  have  been  found  to  be  continued  over  the  country  to  the 
north. 

In  Eastern  Canada,  copper  ores  have  been  observed  in  upward  of  500  localities  in 
rocks  of  the  Quebec  group.  The  ores  are  the  yellow  sulphid  or  chalcopyrite,  chalco- 
cite  (vitreous  copper)  and  bornite.  There  are  also  many  localities  along  the  north 
shore  of  Lake  Superior. 

The  Quebec  group  also  affords,  in  Canada,  magnetic  and  specular  iron;  chromic  iron, 
in  serpentine,  of  workable  value,  one  bed,  in  Ham,  three  to  four  feet  thick;  native 
antimony  and  other  ores  of  this  metal,  in  Ham. 

The  lead  mines  in  Washington,  Jefferson,  and  Madison  Counties,  Missouri,  and  in 
Arkansas,  occur  in  the  Lower  Magnesian  limestone.  In  Jefferson  County,  Missouri, 
as  also  in  Tennessee  and  southwestern  Virginia,  the  ores  of  zinc,  calamine,  and  smith- 
sonite,  as  well  as  blende,  occur  with  the  lead  ore  or  galenite. 

Quartz  crystals  occur  in  great  abundance  in  cavities  in  the  Calciferous  sandrock 
of  central  New  York  and  East  Tennessee,  and  fissures  are  often  lined  with  them.  A 
kind  of  mineral  coal,  in  small  lumps,  usually  concretionary  in  structure,  is  found  in 
some  of  the  beds ;  and  fragments  are  often  imbedded  in  the  crystals  of  quartz,  or  lie 
loose  in  the  cavities  that  afford  the  crystals. 

III.  Life. 

The  living  species  of  this  period  belonged  to  the  same  grand 
divisions  as  those  of  the  Primordial.  The  plants  thus  far  discovered 
were  all  Alga?  or  sea-weeds ;  and  the  animals  wrere  all  marine  Inverte 
brates,  they  belonging  to  the  four  sub-kingdoms,  Protozoans,  Radiates, 
Mollusks,  and  Articulates. 


LOWER    SILURIAN. 


187 


The  Protozoans  were  represented  by  Rhizopods  and  Sponges ;  the 
Radiates,  by  Graptolites  and  Crinoids,  but  very  sparingly  by  true 
Polyp  corals  ;  the  Mollusks,  by  species  of  all  the  grand  divisions,  from 
the  lowest,  that  of  Bryozoans,  to  the  highest,  that  of  Cephalopoda  ; 
the  Articulates  by  Worms  and  Crustaceans,  and,  among  Crustaceans, 
by  a  great  number  and  diversity  of  Trilobites. 

Graptolites,  of  which  some  of  the  forms  are  represented  in  the 
following  figures,  were  exceedingly  numerous ;  over  fifty  species  have 

Figs.  283-288. 
»  285  283 


Fic-s.  233,  284,  285,  Gruptolithus    Logani ;   28*5,  287,  Phyllograptus    typus  ;   288,    the    j  ouug   of 

a  Graptolite. 

been  found  in  the  Quebec  group.  These  feathery  species  appear  to 
have  grown  in  immense  numbers  over  the  muddy  sea-bottom,  and, 
probably,  as  observed  by  Hall,  in  the  still  waters  at  considerable 
depths  (probably  some  hundreds  of  feet),  for  they  are  especially 
abundant  in  the  fine-grained  shales  and  slates  of  the  era.  Each 
branchlet  or  stem,  as  explained  on  p.  130,  was  margined  with  little 
flower-like  animals,  looking  like  polyps. 

Among  the  Mollusks,  Gasteropods  (Univalves)  were  rather  com 
mon.  Figures  290,  291,  292  are  some  examples.  Lamellibranchs 
(Bivalves)  were  of  several  species.  Pteropods  were  numerous  and 
large,  vastly  larger  than  any  living  species  of  this  group.  Cephalopoda 
appeared  under  the  form  of  the  straight  Orthoceras  (Figs.  293,  294, 
and  295)  — a  long,  tapering  shell,  chambered  like  that  of  the  Nautilus. 
Fig.  295  is  a  specimen  with  the  extremity  broken.  The  name  is  from 
6/o(9o?,  straight,  and  itcpas,  horn,  and  alludes  to  the  form  of  the  shell. 
Besides  these  "  straight  horns,"  there  were  also  some  curved  species, 
and  others  that  were  coiled  up  like  the  Nautilus  of  the  present  day. 

But  the  most  common  of  all  species  of  Mollusks,  by  a  hundred 
fold,  were  the  Brachiopods,  the  characteristic  species  of  the  Paleozoic 
world.  Some  shells  of  Lingidellce  are  two  inches  or  more  in  length, 
and  resemble  much  in  shape  the  largest  species  of  Lingula  of  the 
present  day,  though  still  different.  Shells  of  species  of  Orthis  are 
very  abundant ;  one  species  is  represented  in  Fig.  289. 


188 


PALEOZOIC    TIME. 


Among  Trilobites,  there  were  no  Paradoxides,  but  large  numbers 
of   species  of  Bathyurtts,  Dicettocephahis,   Ayuostus,   Olenus,  Conoco- 


294 


s.  280-2  8. 


Fig.  289,  Orthis  (Orthisina?)  grandaeva;  290,  Helicotoma  uniangulata ;  291,  Ophileta  levata  ; 
292,  Holopea  dilucula ;  293,  295,  Orthoceras  primigenium  ;  294,  0.  laqueatimi ;  296,  297,  Le- 
perditia  Anna;  298,  several  shells  of  the  same,  natural  size. 

ryphe,  etc.,  genera  that  began  in  the  Primordial,  and  some  also  of 
the  genera  Asaphus,  Ill-anus  and  others,  which  became  prominent  in 
the  succeeding  period.  Fig.  300  represents  the  pygidium,  and  299, 


Figs.  299,  300.  Bathyurus  Saffordi  ;  301,  Bathyurellus  nitidus  ;  302,  Amphiou  Burrandei. 

part  of  the   cephalic  shield  of  a   Bathyurus  ;  Fig.  301,  a   species  of 
Bathyurellus  ;  302,  the  pygidium  of  an  Amphion. 

The  Ostracoids,  small  Crustaceans  that  have  the  body  concealed  in 
side  of  a  bivalve  shell,  in  form  somewhat  like  that  of  a  clam,  were 
abundant.  Fig.  298  represents  several  of  one  of  the  species  ;  and 


296,  a  side  view   of  the   same,  enlar 


In    the   existing  seas,  the 


species  are  from  a-  twentieth  to  a  fourth  of  an  inch  in  length  ;  while 
many  of  those  of  the  Silurian  rocks  are  between  a  third  and  half  an 
inch.  The  shells  are  so  abundant,  in  the  shale  of  some  localities,  as 
completely  to  cover  the  surfaces  of  the  thin  laminae. 

Characteristic  Species. 
1.  CALCIFEROUS  EPOCH. 

Protozoans.  —  a.  Sponges.  Archceocyathus  Jrinyanensis  B.  occurs  at  the  Min- 
gan  Islajids,  in  the  lower  part  of  the  Calciferous  ;  also  Trickospongia  sericea  B.  ;  both 
of  these  species  appear  to  contain  siliceous  spicules. 


LOWER   SILURIAN.  189 

b.  Rhizopods.  —  The  Green  sand  of  some  Calciferous  beds  is  good  evidence  of  the  ex 
istence  of  Rhizopods  (p.  177).  Receptaculites  Calciferus  B.,  Mingan  Ids.,  is  sup 
posed  by  some  to  be  related  to  the  Rhizopods;  it  looks  like  a  coral  pitted  closely  with 
small  squarish  depressions.  Dawson  suggests  that  Archceocyathus  and  Stromatopora 
may  be  Rhizopods  and  related  to  Eozoon.  The  Stromatopora  are  massive  corals,  very 
finely  porous;  species  of  this  era  occurs  at  Phillipsburg,  Canada. 

Radiates.  —  a.  Polyps.  —  No  Polyp-corals  have  been  found.  The  genus  Stenopora 
is  represented  among  the  Canada  beds  and  at  the  Mingan  Islands ;  but  it  is  probably 
a  genus  of  Acaleph-corals,  —  that  is,  the  stony  secretion  of  Hydroid  Acalephs  (see 
p.  130). 

b.  Acalephs.  The  Stenopora,  just  alluded  to.  Also  Graptolites,  a  tribe  very  nu 
merously  represented  in  the  Quebec  group. 

Ecliinoderms.  — Crinoidal  remains  are  not  common.  Among  them,  Billings  has  dis 
tinguished  some  stems  that  probably  belong  to  the  genus  Glyptocrinus  (see  Fig.  373 
for  a  species  of  this  genus). 

Mollusks.  —  a.  Bryozoans.  —  Some  authors  place  the  Stromatopora  here. 

b.  Brachiopods. — Fig.  289.   Orthis  (Orthisina?)  grandceva  B. ;  Linyulella  acuminata 
Con  ,  Orthis parva  ?  Pander,   Camarella  calcifera  B.,  a  species  of  Leptcena,  and  one  of 
Stropliomena. 

c.  Lamellibranchs.  —  One  of  the  earliest  of  this  group  is  the  Conocardium  Blumen- 
bachii  B.,  found  on  the  coast  of  Newfoundland  in  limestone  (p.  184),  a  shell  related 
to  Cardium,  and  having  a  siphonal  tube.     This  division,  the  sinupallial,  was  far  less 
common  in  the  Silurian  than  the  Jntegripallial  or  that  in  which  the  tube  was  wanting; 
and  it  is  therefore  the  more  remarkable  that  one  of  the  earliest  of  species  should  have 
this  high  characteristic. 

d.  Gasteropods. — Many  genera  of   Gasteropods  are  represented  in  the  Calciferous 
rocks;  and,  in  all,  the  aperture  of  the  shell  is  without  a  beak.    These  genera  are  in  part 
of  the  Trochus  family. 

The  following  are  characteristic  species:  Fig.  290,  Helicotoma  (Euomplialus  formerly) 
uniangulata  II. ;  291,  Ophileta  levata  V. ;  0.  complanata  V. ;  0.  compacta  S.,  a  fine  species 
from  Canada,  1J  inches  across;  292,  Ilolopea  dilucula  H. ;  Pleurotomaria  Calcifera  B., 
from  near  Beauharnois,  Canada;  P.  yreyaria  B.,  from  St.  Ann's,  Canada,  extremely 
abundant;  Maclurea  matutina  H.,  from  New  York  and  Canada;  Murchisonia  Anna  B. 
(a  long  turreted  shell,  approaching  the  M.  bellicincta,  Fig.  346),  from  St.  Ann's  on  the 
island  of  Montreal,  and  also  the  Mingan  Islands,  in  the  White  limestone  and  the  sand- 
rock  below.  Species  of  Straparollus,  Murchisonia  and  Eaphistoma  occcur  in  the  third 
bed  of  the  Magnesian  limestone  of  Missouri  (Shumard). 

e.  Pteropods.  —  Ecculiomplialiis  Canadensis  B.  (a  shell  three  inches  long,  having  the 
form  of  a  curved  horn, without  transverse  partitions  within);   E.  intortus  B.,  a  smaller 
species. 

/.  Cephalojwds.  —  Figs.  293,  295,  Or'thoceras  primiyenium  V.,  a  species  having  the 
septa  or  partitions  very  closely  crowded ;  294,  0.  laqueatum  H.  Other  species  are  0. 
Lomarcki  B. ;  0.  Ozarlcense  Shum.,  from  third  bed  of  Magnesian  limestone,  Ozark 
County,  Missouri;  Lituites  Farnsworthi  B.,  a  large  species  partially  coiled,  and  nearly 
five  inches  in  its  longer  diameter;  L.  imperator  B.,  a  still  larger  species,  10|  inches 
across,  having  the  first  three  whorls  coiled  in  contact;  these  Lituites  are  from  the 
upper  part  of  the  Calciferous  sandrock  of  Phillipsburg,  Canada  East.  Nautilus  Pom- 
ponius  B.,  about  3  in.  across,  from  Phillipsburg;  N.ferox  B.,  Mingan  Ids. 

Articulates.  —  Crustaceans:  Trilobitcs.  —  Over  100  American  species  of  Trilo- 
bites  of  the  Canadian  Period  have  been  described;  and  14  of  these  occur  in  the  Calcif 
erous.  Among  these  14,  there  are  2  species  of  Amphion  and  6  of  Bathyurus,  both 
Primordial  genera;  and  1  of  Asaphus  (A.  canalis),  a  genus  more  fully  represented  in 
the  Trenton  period.  Species  of  Ayraulos  and  Conocoryphe  occur  in  the  third  mag- 
nesian  limestone  of  Missouri  (Shumard).  The  Ostracoid  Leperditia  Anna  Jones  (Figs. 
296,  297,  298)  occurs  at  St.  Ann's,  Island  of  Montreal. 


190 


PALEOZOIC   TIME. 


2.  QUEBEC  EPOCH. 

Over  two  hundred  and  twenty  species  of  fossils  have  been  observed  by  Mr.  Billing 
in  the  rocks  of  the  Quebec  group;  twelve  of  them  are  also  Calciferous  species,  and  live 
Chazy. 

1.  Protozoans Sponges.     Calathium  (?)  pannosum  B.,  C.  Anstedi  B.  (?),  both 

from  Point  Levis  and  Newfoundland.    Trachium  cyathiforme  B.,  from  Newfoundland. 
The  genus  Calathium  commences  in  the  Calciferous.     Strotnatopora  compacta  B.  and 
S.  rugosa  H. 

2.  Radiates — a.  Acalephs;  Stenopora  fbrosn  Goldf.     Graptolites.    Figs.  283-285 
represent  the  Graptolithus  Loyani  H.,  showing,  in  Fig.  283,  the  centre  of  the  group,  and 
the  furcating  mode  of  branching;  in  Fig.  284,  a  portion  of  a  branchlet,  and  285,  same 
enlarged.     Figs.  286  and  287  are  of  a  leaf-shaped  species,  the  Phylloyraptus  typus  H. 
Fig.  288  represents  a  form  common  on  the  graptolitic  shales,  which  Prof.  Hall,  to  whose 
investigations  we  owe  our  knowledge  of  the  Quebec  graptolites,  regards  as  a  young 
graptolite.      b.  Echinoderms.     The   Star-tish,  Stenaster  Huxleyi  B.,  from  Newfound 
land.     Portions  of  crinoidal  columns. 

3.  Mollusks.  —  Nearly  a  hundred  species  of  Mollusks  have  been  described,  twenty- 
eight  of  which  are  Brachiopods,  forty-two  Gasteropods,  twenty  Cephalopods  and  only 
three   Lamellibranchs.     Among  the  Brachiopods,  besides  many  species  of  Linyula  and 
Orthis,  there  are  others  of  Oboletta,  Discina,  Camerella,  Lept&na,  Strophomena,  Rliyn- 
chonella,   Stricklandinia,  Acrotreta.     Among  the  Lamellibranchs  are  the  Conocardium 
(or  Euchasma)  Blamenbachii  B.,  Eoptena  typica  B.  (near  Pterinea  in  form),  Ctenodonta 
Angela  B. 

4.  Articulates.  —  Over  a  hundred  species  of  Trilobites  have  been  described,  and 
nearly  all  by  Billings.     Of  the  genera,  as  he  observes,  Aynostus,  Amphion,  Bathyurus, 
Conocoryphe,  DicettocepkaUtt,  Menocephalus,   Crepicephalus,  Ptychaspis  and  Bathynotus 
(very  close  to  Ptychaspis)  occur  also  in  the  Primordial.     Besides  these,  there  are  the 
genera  Bathyurellus  and  LoganeBui  (Primordial  in  type);  also  Ampyx,   Cerauiiis,  Har- 
pides,  Harpes,  Nileus,  Remopleurides,  Shumardia,  Ilksnus,  Asaphus.    The  Levis  formation 
contains  four  Calciferous  species,  viz.,  Batltyurm  Cordai  B.,  B.   conicus  B.,  Amphion 
Salteri  B.,  Asaphus  canalis  B. ;  two  Chazy  species  Cerawus  (Cheirwm)  prolificus  B. 
and  Asaphus  canalis. 

Figs.  299,  300  represent  Bathyurus  Saffordi  B.,  a  common  species  in  Canada,  and 
occurring  also  in  Newfoundland  and  Idaho  —  299,  the  glabella,  300,  the  pygidium;  301 
Bathyurellus  nitidus  B.,  from  Cow  Head,  Newfoundland;  302,  pygidium  of  Amphion 
Barrandei  B.,  id. 

Only  one  trilobite  (Asaphus  pl/itycephalus  Stokes)  of  the  Quebec  group  occurs  in  the 
Trenton,  and  this  is  doubtfully  determined  (Billings). 

A  part  of  the  "Quebec  group"  of  Newfoundland,  called  Upper  Calciferous  by 
Logan,  contains  the  Ostracoids,  Leperditia  condnnula  B.,  L.  ventralis  B.,  Beyriclna 
Atlantica  B. 

3.  CHAZY  EPOCH. 

1.  Protozoans.  —  Sponges.  —  Eosponnia  Raemeri  and  E.  varians  B.  occur  at  the 
Mingan  Islands.  Many  undescribed  species,  of  several  genera,  including  Recepfacidites, 
occur  in  East  Tennessee  (Bradley). 

2  Radiates.  —  (<•/..)  Polyps.  — Species  of  Columnaria  have  been  described,  (b.) 
Acalephs.  —  Stenopora  fibrosa  of  Goldf uss. 

(c.)  Echinoderms.  — The  Crinoids  include  as  many  known  Cystids  as  Crinids.  The 
following  are  a  few  of  them:  (1.)  Crinlds. — Pnkeocrinus  striatus  (Fig.  304),  the  body, 
showing  the  radiating  ambulacral  grooves  (five)  at  top;  Blastoidocrimiscarchari(edens 
B.,  —  the  genus  apparently  of  the  Pentremite  family,  a  family  which  makes  its  next 
appearance  near  the  top  of  the  Upper  Silurian,  and  abounds  in  the  Subcarboniferous.  — 
(2.)  Cystids.  —  Malocystites  Miirchisoni  B.  (Fig.  305),  the  body  nearly  spherical  (whence 


LOWER   SILURIAN. 


191 


the  name,  from  the  Latin  malum,  an  apple;,  and  having  no  arms,  and  the  ambulacral 
grooves  irregularly  radiating;  another  species  is  the  Pakeocystites  tenuiradiatus  B. 
(Hall's  Actlnocrlnus  tenuiradiatus),  which  is  common,  and  has  been  detected  in  the 
granular  limestone  of  West  Rutland  (Am.  Jour.  Sci.,  III.  iv.  133.) 

3.  Mollusks.  —  (a.)  Bryozoans.—V'ig.  306  represents  the  Retepora  Incepta  H.,  a 
thin, reticulate  coral,  the  surface  of  which,  magnified,  is  shown  in  Fig.  306  a;  Fig.  307, 

Figs.  304-316. 
310  _  307-^    ,5*  306 


RADIATES.  —  Fig.  304,  Palaeocrinus  striatus  ;  305,  Malocystis  Murchisoni.  MOLUTSKS.  —  3%,  Rete 
pora  incepta ;  307,  Ptilodictya  fenestrata ;  308,  Orthis  costalis  ;  309,  Leptscna  plicifera  ;  310, 
Khynchonella  plena;  311,  Maclurea  magna ;  312,  M.  Logani(xK);  313,  operculum  of  same ; 
3U,  Scalites  angulatus  ;  315,  Bellerophon  rotundatus.  ARTICULATES.  —  316,  Leperditia  Canaden- 
sis,  vnr.  nana. 

Ptilodictya  fenestrata  H.,  a  small  branching  species,  covered  with  minute  cells,  and  Fig. 
307  a.,  the  surface  magnified. 

(b.)  Brachiopods.  —  Yig.  308,  OrtJiis  costalis  H. ;  Fig.  309,  Leptce.no,  plicifera  H. ;  L. 
Incrassata  H.;  Fig.  310,  Rhynchanelln  plena  H.  (a  fide-view),  a  very  common  species,  it 
almost  constituting  some  beds  of  the  limestone.  There  are  also  several  Lingulellre  (L. 
Lyelli  B.,  L.  Huronensis  B.,  etc.):  Orlliis  imperator  B.,  a  species  nearly  1J  in.  across,  be 
sides  several  other  species  of  the  genus. 

(c.)  Lamettibranchs. — Vanuxemia  Montrealensls  B.,  a  species  nearly  1J  in.  long,  re 
lated  to  Avlcula. 

(d.)  Gasteropoda.  —  Fig.  311,  Maclurea  magna,  which  is  very  abundant,and  sometimes 
has  a  diameter  of  eight  inches;  Fig.  312,  Maclurea  Lor/ani,  showing  the  shell  closed  by 
its  operculum;  Fig.  313,  the  operculum,  inside-view;  Fig  314,  Sc-iUte»  anf/ulatus  Con.; 
Fig.  315,  Bellernphon  (Bucania)  rotundatus  H. ;  Pleurotomarla  Calyx  B.,  near  Montreal. 

(e.)  Cephnlopods  —  Orthocera*  rectl-annulatum  H  ;  0.  temiiseptum  H.,  a  large  species, 
with  the  septa  thin  and  rather  crowded;  0.  velox  B.,  Montreal,  Mingan  Ids.;  0.  dif^ 
fidens  5.,  Mingnn  Ids. 

4.  Articulates.  —  (n.)  Trilobites.  —  Among  the  species  there  are  Illcenus  Arcturus 


192  PALEOZOIC  TIME. 

II.;  /.  Bayjieldi  B.  V  ;  Asaphus  obtusus  H. ;  Bathyurus  Anyelini  B. ;  Amphion  Caniden- 
sisB. 

b.  Ostracoids. —  Fig.  310,  Leperditla  Ccinadensis  Jones,  from  Grenville,  Huntlev  and 
elsewhere  in  Canada;  L.  amyyduUna  B.,  from  near  L' Original,  Canada. 

The  Mollusks  common  to  the  Calciferous  and  Levis,  according  to  Billings,  are  Linfjuli 
Mantelli,  Camerella  Calcifera  and  Pleurotomaria  Cakifera  (and  possibhT  also  Ophileta 
uniunyulata,  Maclurea  matutina,  M.  sordida,  Holopea  dilucula).  Only  the  Cumerdla 
varians  is  common  to  the  Chazy  and  Levis.  In  the  lower  part  of  the  beds  underlying 
the  true  Levis  beds  of  Cow  Head,  Newfoundland,  which  have  been  called  Upper  Cal 
ciferous  by  Logan,  there  are  seven  trilobites,  of  which  Amphion  Barrandei  and  Asaphus 
canalis  occur  in  the  Levis.  Ortliis  Electro,  is  also  common  to  these  beds  and  the  Levis; 
but  the  other  fossils  are  either  new  species,  or  species  that  occur  in  the  Chazy  and  Cal 
ciferous.  Above  these  beds,  there  are  277  feet  of  rock  with  still  another  fauna :  and 
then  follow  700  feet  of  sandstone,  and  then  the  true  Levis  formation,  at  Cow  Head. 

EUROPEAN. 

Although  in  North  America  the  rocks  of  this  period  have  an  aggre 
gate  thickness  of  more  than  7,000  feet,  with  3,000  feet  of  them  lime 
stones,  and  some  of  them  abound  in  fossils,  their  precise  equivalents 
in  Europe  are  not  well  understood.  This  is  part  of  the  proof  that 
geological  changes  over  the  different  continents  have  to  a  large  extent 
gone  forward  independently.  All  that  can  be  positively  said  is,  that 
the  American  strata  correspond  to  the  lower  part  of  the  Lower  Silu 
rian,  above  the  Primordial,  in  Europe  —  and  probably  to  (1)  the  Tre- 
madoc  slates,  and  (2)  the  Areuig  or  Stiper  Stones  group  (Lower  Llan- 
deilo)  in  England;  the  lower  part  of  Barrande's  stage  D,  in  Bohemia, 
and  Angelin's  group  BC  in  Sweden. 

Among  the  fossils  of  the  Tremadoc  slates,  there  occur  Trilobites  of  the  genera  Dice l- 
locephalus,  Conocoryphe,  Olenus,  Cheirurus,  Angelina,  Asaphus;  also  the  Linyulella  Da- 
visii  M'Coy,  a  Lingula-flags  species.  The  Stiper  Stones,  quartzose  strata  in  Shropshire, 
contain  the  burrows  of  Annelids  (like  Arenicolites  linearis  H.),  which,  however,  are  an 
uncertain  mark  of  age.  But  beds  in  Arenig  Mountain  in  Merionethshire,  and  the  Skid- 
daw  slates  in  the  lake  district  of  Cumberland,  which  are  of  the  same  age,  have  afforded 
over  sixty  species  of  fossils — among  them,  Obolella  plumbea  S.,  Didymoffrapttu  yemi- 
nus  Hisinger,  D.  liirundo  Hisinger,  Oyyyiii  Selicynii  S.,  jEgKna  binodosa  S.  and  other 
species  that  are  not  Primordial,  and  are  distinct  from  the  species  of  the  overlying  Llan- 
deilo  flags  (Lvell).  H.  A.  Nicholson  has  announced  that  fourteen  species  of  Grapto- 
lites,  from  the  thirty-one  in  the  Skiddaw  slates,  are  species  which  Hall  has  described 
from  the  Quebec  group  of  Canada  (Q.  J.  G.  Soc.,  xxviii.  217). 

3.  General  Observations. 

While  the  rocks  of  the  Primordial  era,  over  the  larger  part  of  North 
America,  are  chiefly  sandstones,  and  but  sparingly  limestones,  and 
bear  evidence,  in  most  places,  of  shallow  waters  and  of  currents  bear 
ing  sediments,  —  those  of  this  second  period  of  the  Lower  Silurian 
are  as  prominently  limestones,  and  over  large  regions  are  indications 
of  clear  seas.  But,  while  limestones  are  the  prevailing  rock,  all 
regions  over  the  continent  were  not  contemporaneously  making  lime- 


LOWER    SILURIAN.  193 

stones.  This  is  evident  from  the  nature  and  distribution  of  the  rocks. 
The  sandy  limestones  of  the  Calciferous  appear  to  mark  in  New 
York  the  transition  from  the  Primordial  (with  its  beach  and  sand-flat 
formations)  to  the  second  or  Canadian  period,  while  the  limestone, 
along  the  Green  Mountain  range,  if  this  is  partly  of  the  Chazy  series, 
shows  that  the  water  deepened  in  that  direction.  In  Newfoundland, 
on  the  other  side  of  the  same  border  region,  the  Calciferous  epoch 
was  a  time  of  immense  limestone  accumulations,  their  thickness 
amounting  to  3,200  feet ;  while,  in  the  later  part  of  the  period,  there 
were  made  as  many  feet  of  sandstones  and  shales,  with  little  limestone. 
Again,  over  the  Mississippi  basin,  —  a  region  of  deeper  waters 
through  a  large  part  of  geological  history,  and  much  of  the  time  the 
southern  half  of  an  open  "Mediterranean  sea,"  connecting  the  At 
lantic  (or  Mexican  Gulf)  and  the  Arctic  Ocean,  —  the  rocks  are  very 
largely  limestones.  Yet,  even  here,  in  some  parts,  sand-beds  alter 
nate  at  intervals  with  the  limestones,  showing  changes  during  the 
period  in  the  level  of  the  sea-bottom  or  in  the  marine  currents. 
Toward  the  head  of  the  basin,  and  about  Lake  Superior,  the  prev 
alence  of  sandstones  proves  that  the  waters  were  there  shallow,  as 
Hall  has  remarked,  and  partly  those  of  sea-shore  flats  and  wind 
drifts.  The  events  prove  that  no  one  kind  of  rock  was  formed 
simultaneously  over  a  continent ;  but  that  ,the  several  parts  of  the 
continental  seas  were  giving  origin  to  different  kinds,  according  to  the 
depth  of  water,  nearness  to  sea-shores,  the  character  of  the  currents, 
and  other  circumstances. 

Billings  has  observed,  with  regard  to  the  Quebec  formation,  that 
the  limestones  of  the  era  contain  different  fossils  from  the  intervening 
.shales  ;  and  yet  both  are  essentially  of  the  same  age.  The  species 
of  clear  waters  are  often  wholly  unlike  the  contemporaneous  species 
of  muddy  bottoms  ;  and  hence  a  change  of  condition,  from  that 
requisite  for  making  limestones  to  that  for  shales,  would  naturally 
be  accompanied  by  a  change  of  species,  and  then  be  followed  by  a 
return  of  the  former  species,  whenever  (through  some  rising  or  sink 
ing  of  the  sea-bottom  or  land)  the  seas  returned  to  their  former  clear 
condition. 

Origin  of  the  limestones.  —  The  limestones  of  New  York  and 
Canada  contain  various  fossils,  and  may  have  resulted  from  the  trit- 
uration  of  shells,  crinoids,  etc.  If  so,  the  species  must  have  lived 
in  comparatively  shallow  water,  like  those  making  the  shell  banks  or 
coral  reefs  of  the  Pacific ;  for  the  waves  and  currents  are  the  pul 
verizing  agents,  and  these,  at  great  depths,  are  too  feeble  for  such 
work. 

The  Lower  Magnesian  limestones  of  the  Mississippi  basin  contain 
13 


194  PALEOZOIC    TIME. 

very  few  fossils.  It  is  possible  that  these  limestones  were  largely 
made  from  the  minute  shells  of  Rhizopods ;  and,  if  so,  they  may  have 
been  accumulated  in  deep  water. 

3.  TRENTON  PERIOD  (4). 

1.  AMERICAN. 

Epochs.  —  1.  TRENTON  epoch  (4  a),  or  that  of  the  Black  River 
and  Trenton  limestones.  2.  UTICA  (4  b),  or  that  of  the  Utica  shale. 
3.  CINCINNATI  (4c),  or  that  of  the  Hudson  River  group  and  the 
Cincinnati  limestones  and  shales. 

o 

I.   Rocks:  kinds  and  distribution. 

The  rocks  of  the  Trenton  series  over  the  United  States  are  almost 
solely  limestones.  They  occur  extensively  along  the  range  of  the 
Appalachians,  in  New  York  arid  Canada ;  probably  in  western  New 
England,  as  part  of  the  Stockbridge  or  great  Green  Mountain  lime 
stone  ;  in  Ohio  and  Indiana,  in  Illinois  and  other  States  over  the 
wide  Mississippi  basin  (where  it  includes  the  '*  Galena  limestone  "  of 
Wisconsin  and  the  adjoining  States)  ;  and  in  a  broad  band  stretching 
northwest  from  Lake  Superior,  by  Winnipeg  Lake,  west  of  -the 
Archaean. 

In  the  State  of  New  York,  the  formation  is  exposed  to  view  on  the 
eastern  border  of  the  Chazy  area,  not  far  from  the  border  of  the 
Archaean  peninsula,  and  also  south  of  the  Archaean,  resting  on  the 
Calciferous.  It  constitutes  the  high  bluffs  of  the  gorge  at  Trenton  Falls, 
on  West  Canada  Creek,  and  thence  derived  its  name.  It  occurs  in 
the  Ottawa  region  in  Canada,  and  extends  northeastward  to  Quebec. 

The  formation  in  New  York  is  divided  into  the  Black  River  and 
Trenton  limestones,  the  latter  being  the  upper;  and  these  divisions  are 
recognized  in  Canada  and  some  parts  of  the  States  west  of  New 
York.  The  lower  part  of  the  Black  River  limestone  is  distinguished 
by  the  New  York  geologists  as  the  Birdseye  limestone,  from  crystal 
line  points  scattered  through  the  rock. 

The  thickness  of  the  series  in  northern  New  York  and  Canada, 
where  probably  lay  the  ocean's  border,  is  generally  from  100  to  300 
feet ;  yet,  in  the  region  of  Ottawa  —  a  great  St.  Lawrence  Bay  in  the 
earlier  Silurian  era  (see  map,  p.  165)  —  it  is  about  800  feet.  West  of 
the  Appalachians,  the  thickness  averages  about  300  feet.  Along  the 
Appalachian  region  in  Pennsylvania,  it  is  made  2,000  feet  by  Rogers. 

The  Utica  shale,  or  the  rock  of  the  Utica  epoch,  is  the  surface-rock 
along  a  narrow  region  in  the  Mohawk  valley.  New  York  (see  4  b  on 
map,  p.  165),  following  a  course  nearly  parallel  with  the  outline  of 


LOWER    SILURIAN.  195 

the  Archa?an  farther  north.  The  shale  is  in  some  places  three  hundred 
feet,  or  more,  thick.  It  extends  westward  through  Canada,  and 
beyond,  probably  into  Wisconsin  and  Iowa,  though  a  very  thin  de 
posit  at  the  west ;  and  also  southward  along  the  Appalachians,  being, 
in  Pennsylvania,  from  three  hundred  to  seven  hundred  feet  thick. 

The  rock  is  a  crumbling  shale,  mostly  of  a  dark  blue-black  or 
brownish-black  color,  and  frequently  bituminous  or  carbonaceous,  — 
so  much  so,  in  certain  places,  as  to  serve  as  a  black  pigment.  It 
sometimes  contains  thin  coaly  seams ;  and  much  money  has  been 
foolishly  spent  in  searching  for  coal  in  this  deposit.  Thin  layers  of 
limestone  are  occasionally  interpolated,  especially  in  the  lower  part. 

The  rocks  of  the  Cincinnati  epoch  (called  formerly  the  Hudson 
River),  are  shales  in  New  York  and  Canada,  but  become  calcareous  to 
the  west,  and  consist  of  limestone,  largely  mingled  with  shale,  about 
Cincinnati,  in  Ohio,  and  farther  west.  The  shales  in  New  York 
(called  Hudson  River  and  Lorraine  shales)  cover  a  narrow  area 
through  the  centre  of  the  State,  near  the  Mohawk,  which  widens  to 
ward  the  Hudson.  West  of  New  York,  the  shales  extend  through 
western  Canada,  and  southward  of  the  State,  along  the  Appalachians. 
The  greatest  thickness  in  New  York  is  1,000  feet. 

The  Cincinnati  limestone  continues  from  Ohio  westward,  outcrop 
ping  in  several  of  the  States  of  the  Mississippi  valley.  There  is 
limestone  of  this  epoch  also  in  the  Island  of  Anticosti,  in  the  Gulf  of 
St.  Lawrence,  about  1,000  feet  thick. 

In  the  Green  Mountains,  there  are  strata  of  mica  schist,  gneiss 
and  quartzyte,  overlying  the  great  Stockbridge  limestone  ;  and,  since 
they  are  quite  certainly  Lower  Silurian,  and  at  the  same  time  newer 
than  this  limestone,  they  probably  belong  to  the  Cincinnati  epoch. 
Some  of  the  higher  summits  in  southern  Vermont  are  reported  to 
consist  mainly  of  this  quartzyte  ;  the  elevation  of  Bald  Mountain,  m 
Bennington,  for  example,  is  3,124  feet  above  the  sea,  and  of  Mount 
Prospect,  in  Woodford,  2,690  feet. 

1.  Trenton  Epoch.  _  («.)  New  York  and  to  the  Eastward. —In  New  York,  the 
Trenton  limestone  is  grayish-black  to  black.  It  is  sometimes  bituminous,  especially  in 
its  upper  portions.  Its  layers  are  often  thin,  and  beds  of  shale  in  many  places  inter 
vene.  The  black  color  is  due  to  carbon  or  carbonaceous  substances,  as  is  shown  by  its 
burning  white.  The  crystalline  points  of  the  Birdseye  are  not  always  present,  and  occur 
in  other  limestones.  The  color  of  this  rock  is  drab  or  dove-colored  and  brownish,  and 
not  so  dark  as  that  of  the  overlying  beds.  The  Black  River  limestone  is  named  from 
Black  River,  N.  Y.,  east  of  Lake  Ontario.  The  color  is  generally  dark,  nearly  black. 

In  Canada,  the  Trenton  outcrops  over  a  large  area  about  Ottawa,  and  also  over  an 
other  of  less  width  along  the  north  side  of  the  St.  Lawrence,  from  Montreal  eastward 
nearly  to  Quebec,  and  at  intervals  beyond  to  Murray  Bay ;  and  a  branch  passes  south 
ward  from  Montreal  to  Lake  Champlain.  Near  Montreal,  the  whole  thickness  is  530 
feet,  and  that  of  the  lower  part,  including  the  Black  River  limestone  and  Birdseye 
limestone,  38  feet  (Logan). 


196  PALEOZOIC    TIME. 

The  Stockbridge  limestone  formation  (Eolian  limestone  of  Hitchcock)  varies  in  thick 
ness  from  1,000  to  probably  3,000  feet.  In  Mt.  Eolus,  East  Dorset,  Vt.,  the  thickness 
is  2,000  feet.  The  upper  part  of  this  formation  is  doubtless  Trenton,  though  its  lower 
portion  is  referred  to  the  Chazy  epoch  of  the  Canadian  period. 

(b.)  Inferior  Continental  basin.  —  The  Galena  or  lead-bearing  limestone,  of  Wisconsin 
and  the  adjoining  States  in  the  West,  constitutes  the  upper  portion  of  the  Trenton 
series,  and  often  alternates  with  layers  of  the  Trenton  limestone.  Its  color  is  light  gray 
or  yellowish.  It  is  generally  magnesian  limestone.  It  is  100  to  200  feet  thick  in  north 
ern  Illinois;  about  250  feet  thick  near  Dubuque,  Iowa,  and  the  underlying  Trenton  20 
to  100  feet  (Hall).  There  is  usually  at  base  a  buff-colored  limestone,  equivalent  to  the 
Black  River  group. 

In  Missouri,  there  are  350  feet  of  limestone,  the  upper  100  called  Receptaculite  lime 
stone  by  Shumard. 

In  East  Tennessee,  the  formation  includes  blue  limestone,  with  many  fossils,  200  to 
600  feet  thick ;  and,  above,  380  feet  of  red  and  gray  marble,  400  of  bluish  shale,  and 
250  of  iron-limestone  containing  the  Asaplms  Platycephalus.  In  Middle  Tennessee, 
where  the  beds  are  horizontal,  there  are  from  400  to  450  feet  of  blue  limestone  (Safford). 

(c.)  Arctic  reyion.  —  The  Trenton  limestone  has  been  identified  upon  King  William's 
Island,  .North  Somerset  and  Boothia. 

2.  Utica  Epoch.  —  (a.)  Interior  Confine ntul  basin.  —  The  Utica  shale  is  15  to  35 
feet  thick  at  Glenn's  Falls,  in   New  York;  250  feet  in  Montgomery  County;  300  in 
Lewis  County;  300  near  Quebec. 

(b.)  Appalachian  reyion.  —  In  Pennsylvania,  the  rock  is  a  black  shale,  and  in  some 
parts  it  is  fossiliferous.  The  thickness,  given  by  Professor  Rogers,  in  the  Kittatinny, 
Nippenose,  and  Nittany  valleys  is  300  feet,  and  in  the  Kishacoquillas  valley  400  feet. 

3.  Cincinnati  Epoch.  — The   Hudson  River  shales  cover  the  region  north  of 
Lake  Champlain,  in  Canada,  reaching  to  Quebec,  and  northeastward  to  Montmorency 
and  beyond.    They  also  lie  over  a  small  area  near  the  centre  of  the  Trenton  limestone 
region  of  the  Ottawa  basin. 

In  New  York,  the  Hudson  River  beds  include  shales  and  sandstones.  They  are  the 
Lorraine  shales  of  Jefferson  County  (the  Pulaski  shales  of  the  New  York  Annual  Re 
ports),  containing  some  thin  beds  of  limestone.  The  slates  along  the  Hudson  River,  to 
which  the  name  was  especially  applied,  have  been  proved  to  be  in  part  Primordial,  and 
part,  probably,  of  the  Quebec  series,  (q.  v.) 

In  the  Green  Mountain  region,  there  are  2.000  to  3,000  feet  or  more  of  mica  schist 
and  slate,  hydromica  slate,  gneiss,  quartzyte,  and  conglomerate,  overlying  the  Stock- 
bridge  limestone,  which  are  probably  of  the  Cincinnati  series.  They  constitute  Mount 
Washington  and  part  or  all  the  Taconic  range,  Graylock,  Tom  Ball,  Monument  Moun 
tain  and  other  elevations  in  Berkshire  County,  Mass.  The  quartzyte  in  many  places 
graduates  rather  abruptly,  in  a  horizontal  direction,  into  mica  schist  or  slate,  or  hydro- 
mica  slate  or  gneiss,  showing  that  its  sands  were  often,  when  accumulating,  a  local 

Fig.  316  A. 


Section  in  eastern  part  of  Great  Barrington. 

deposition  along  shores  or  shallow  flats,  while  off  these  shores  there  were  mud  deposits 
—  the  sands  making  the  quartzyte,  and  the  mud  the  other  rocks,  these  differing  accord 
ing  to  differences  in  the  mud  and  differences  in  the  degree  of  metamorphism  afterward 
undergone.  Some  sections  are  given  on  page  213;  in  them,  the  dotted  portions  repre- 


LOWER    SILURIAN.  197 

sent  quartzyte,  the  blocked,  limestone,  and  the  others  the  schist,  slate,  or  gneiss. 
While,  in  Monument  Mountain  (Fig.  395  A),  there  are,  over  the  limestone,  two  strata  of 
schist  (or  gneiss)  alternating  with  two  of  quartzyte,  in  other  sections  the  lower  quartz- 
yte,  or  the  lower  schist,  is  absent,  and,  in  the  more  western  hills  (Tom  Ball,  and  the 
Taconic)  all  the  quartzyte  is  wanting.  In  the  annexed  section,  toward  the  right  or  east 
end,  the  quartzyte,  limestone,  and  gneiss  (or  mica  schist)  alternate;  while  on  the  west 
side  of  the  same  valley  (left  end  of  section)  there  is  quartzyte,  with  a  narrow  band  of 
mica  schist  in  it, which  becomes  quartzyte  a  hundred  feet  to  the  south ;  and  above  the 
quartzyte,  gneiss. 

The  thickness  of  the  shales,  in  Schoharie  County,  N.  Y.,  is  700  feet;  near  Quebec, 
2,000  feet;  in  western  Canada,  700  feet;  on  Lake  Huron,  180  feet;  in  the  Michigan 
Peninsula,  18  feet;  in  Iowa,  25  to  100  feet.  In  Missouri,  there  are  alternations  of  shale 
and  sandstone,  with  some  limestone,  100  to  200  feet  in  total  thickness;  at  Cincinnati, 
shales  and  limestones,  700  feet  thick.  In  Middle  Tennessee,  the  Cincinnati  series  in 
cludes  the  Nashville  group  of  Safforcl,  and  consists  of  argillaceous  limestone,  with 
many  shaly  layers,  about  500  feet  thick.  In  East  Tennessee,  the  beds  (corresponding 
to  both  the  Utica  and  Hudson  River  epochs)  are  of  great  extent,  and  consist  of  blue 
calcareous  and  more  or  less  sandy  shales,  with  some  thin  layers  of  calcareous  sand 
stone.  They  also  occur  of  great  thickness  in  Virginia,  and  reach  down  to  Alabama. 

In  Pennsylvania,  in  the  Kishicoquillas  valley,  the  rock  is  a  blue  shale  and  slate,  with 
some  thin  layers  of  calcareous  sandstone,  and  the  thickness  is  1,200  feet;  in  the  Nittany 
valley,  700  feet;  in  the  Nippenose  valley,  a  little  less.  (Rogers.) 

The  limestone  formation  on  the  island  of  Anticosti  has  a  total  thickness  of  nearly 
2,400  feet,  and  is  divided  by  Logan  into  five  parts  — the  Jirst,  or  lowest,  959  feet  thick; 
the  second,  about  300  feet  thick;  the  third,  about  450  feet;  the  fourth,  about  550  feet; 
the  fifth,  70  feet.  The  first  two  are  referred  to  the  Trenton  period,  and  the  rest  to  the 
Upper  Silurian.  There  are  thin  beds  of  shales  in  the  series.  The  rocks  are  nearly 
horizontal. 

II.  Economical  Products. 

The  Galena  limestone,  of  Wisconsin  and  the  adjoining  portions  of 
Illinois  and  Iowa,  is  noted  for  its  yield  of  lead  ore.  The  ore  is  the 
ordinary  sulphid  of  lead,  or  Gahnite.  It  occupies  vast  cavities,  rather 
than  veins,  in  the  limestone,  which  cavities  were  filled  from  above. 

The  lead-region  of  Wisconsin  and  Illinois,  according  to  Owen,  is  87  miles  from  east 
to  west,  and  54  from  north  to  south ;  and  throughout  much  of  this  region  traces  of  lead 
maybe  found.  The  beds  resemble  in  position  the  lead-mines  of  Missouri;  but  the 
latter  occur  in  a  limestone  of  the  Calciferous  epoch.  These  mines  of  the  Upper  Missis 
sippi  have  been  the  subject  of  a  report  (1854)  by  J.  I).  Whitney.  The  galenite  is  often 
in  large  crystals,  and  is  associated  with  sphalerite  (zinc  blende  or  "black  jack"), 
Smithsonite  (carbonate  of  zinc),  pyrite,  and  marcasite,  and  occasionally  barite  (heavy 
spar),  anglesite  (sulphate  of  lead),  chalcopyrite,  azurite  and  zinc  bloom.  The  Smith 
sonite  (dry-bone  of  the  miners)  constitutes  pseudomorphs  at  Mineral  Point,  Shullsburg, 
etc.,  in  Wisconsin,  after  sphalerite  and  calcite.  Beautiful  stalactites  of  marcasite  occur 
near  Galena,  at  Marsden's  Diggings. 

Both  the  Trenton  limestone  and  the  Utica  and  Hudson  River  shales 
afford  in  some  places  mineral  oil.  It  occurs  sparingly  in  the  Tren 
ton,  at  Riviere  a  la  Rosa  (Montmorenci),  in  Canada  ;  at  Pakenham, 
Canada,  in  large  Orthocerata ;  at  Watertown,  N.  Y.,  in  drops  in 
fossil  coral.  In  Kentucky,  the  blue  limestone  yields  oil  very  abun 
dantly.  On  Grand  Manitoulin  Island,  Canada,  a  spring  rises  from  the 


198 


PALEOZOIC    TIME. 


Utica  shale ;  and  another  from  the  Hudson  River  beds  at  Guildeiiand, 
near  Albany,  N.  Y. 

The  black  Utica  shale  abounds  in  combustible  material,  although 
containing  no  coal.  Whitney  found  about  21  per  cent,  in  the  shale  of 
Savannah,  111. ;  11  to  16  per  cent,  in  that  of  Dubuque  ;  and  12  to 
14  per  cent,  in  that  of  Herkimer  County,  N.  Y. 

The  Trenton  formation  in  East  Tennessee  affords  a  reddish  varie 
gated  marble  of  great  beauty,  and  also  a  grayish-white  variety,  which 
are  extensively  worked  and  exported. 

III.  Life. 
1.  Plants. 

Sea-weeds  are  the  only  known  fossil  plants,  and  specimens  are  rare. 
Two  of  the  species  are  represented  in  Figs.  316  B,  C. 

Fig.  316  B  is  the  Suthotrephis  gracilis  H.,  and  Fig.  316  C,  B.  succulosus  H.    The  figures 
represent  only  portions  of  these  plants. 


Fig.  316  B. 


Fig.  316  C. 


Fig.  316  B,  Buthotrephis  gracilis  ;  316  C,  B.  succulosus. 

2.  Animals. 
1.  TRENTON  EPOCH. 

The  seas  of  the  Trenton  period  were  densely  populated  with  animal 
life.  Many  of  the  beds  are  made  of  the  shells,  corals,  and  crinoids, 
packed  down  in  bulk  ;  and  most  of  the  less  fossiliferous  compact  kinds 
have  probably  the  same  origin,  and  differ  only  in  that  the  shells  and 
other  relics  were  pulverized  by  the  action  of  the  sea,  and  reduced  to  a 
calcareous  sand  or  mud  before  consolidation  ;  while  others  may  be  of 
Rhizopod  origin. 

The  same  four  sub-kingdoms  of  invertebrate  animal  life  were  repre 
sented  as  in  the  preceding  period,  and  only  by  marine  species.  All 
the  grander  subdivisions  of  the  Radiate  as  well  as  the  Molluscan  sub- 
kingdom  had  their  species.  The  Articulates  were  still  confined  to  the 
inferior  aquatic  classes  of  Worms  and  Crustaceans. 


LOWER    SILURIAN. 


199 


Among  RADIATES,  there  were  now  undoubted  Corals  (Figs.  317, 
318),  of  the  class  of  Polyps,  as  well  as  Crinoids  (Figs.  324,  325),  in 
creasing  much  the  diversity  and  beauty  of  the  flowers  of  the  seas  — 
the  only  flowers  of  the  Paleozoic  world.  There  were,  however,  but 
few  Polyp-corals,  compared  with  the  number  in  later  periods.  Single 
masses  of  the  coral  Columnaria  alveolata  H.  (Fig.  318)  occur  in  the 

Figs.  317-325. 


RADIATES.  —  Fig.  317,  Petraia  corniculum  ;  318  a.  Columnaria  alveolata  ;  319,  320,  Cheetetes  lyco- 
perdon  ;  321  a,  Graptolithus  amplexicaulis  ;  322,  Palaeaster  matutiua  ;  323,  Taeniaster  spinosa  ; 
324,  Lecanocrinus  elegans  ;  325,  Pleurocystis  filitextus. 

Black  River  limestone,  weighing  between  two  and  three  thousand 
pounds.  Cystids  (Fig.  325)  were  the  most  characteristic  kind  of  Cri 
noids.  They  belong  in  geological  history  eminently  to  this  early  era, 
reaching  in  it  their  greatest  expansion.  The  delicate  plume-like 
forms  of  life  called  Graptolites  were  common  (Fig.  321). 

Brachiopods  (Figs.  326-340),  were  yet  the  most  abundant  of 
MOLLUSKS,  their  shells  outweighing  and  outnumbering  those  of  all 
other  species.  But  with  these  there  were  large  numbers  of  each  of 
the  other  classes,  the  Bryozoans,  Pteropods,  Lamellibranchs  (Figs. 
341-343),  Gasteropods  (Figs.  344-352)  and  Cephalopods. 

Multitudes  of  delicate  corals,  made  by  Bryozoans,  occur  in  the 
limestone  rocks. 

The  Trenton  species  of  Brachiopods  were  mostly  of  the  Orthis 
family  (the  genera  Orthis,  Orthisina,  Leptcena,  and  Strophomend)  ;  and 
with  these  there  were  species  of  the  Lingula,  Discina,  and  Rhyrwho- 


200 


PALEOZOIC    TIME. 


nella  groups,  —  the  same  families  that  were  represented  in  the  early 
Calciferous  epoch.     The  genera  Rhynchonella,  which  began  in  the  era 

Figs.  320-340. 


BRACHIOPODS  —Figs.  326,  327,  Orthis  lynx;  328,0.  occidentals  ;  329,  0.  testudinaria ;  330,0. 
tricenaria;  331,  Leptaena  sericea;  332,  Strophomena  (Leptaena)  ru^osa ;  333,  Stroph.  alternata ; 
334,  335,  336,  Rhynckonella  capax  ;  337,  333,  Rhynchonella  (?)  bisulcata;  339,  Obolus  filosus  ;  340, 
Lingula  quadrata. 

of  the  Quebec  group,  and    Crania  (Fig.  242),  of  the  Trenton,  have 
representatives  in  modern  seas. 

Orthocerata   (Figs.  353—355),  of  the   tribe   of  Cephalopods,  were 
very  numerous,  and  some  were  ten  to  fifteen  feet  long.     Fig.  353  rep- 


LAMELLIBRAXCHS.  —  Fig.  341,  Avicula(?)  Trentonensis  ;  342,  Ambonychia  bellistriata ;  343,  Telli- 

nomya  nasuta. 

resents  a  portion  of  one  of  these  long  conical  (or  straight  horn- 
shaped,  as  the  name  signifies,  p.  187)  shells,  and  exhibits  the  parti 
tions  dividing  it  interiorly  into  chambers  ;  and,  in  Fig.  353  a,  one  of 


LOWER    SILURIAN. 


201 


the  partitions  is  figured  separately,  so  as  to  show  the  position   and 
size  of  the  siphuncle.     Fig.  355  is  a  transverse  section  of  another 


346 


Figs    344-352. 
344 


GASTEROPODS.  —  Fig.  344,  Pleurotomaria  lenticularis  ;  345,  Murchisonia  bicincta;  346,  M.  belli- 
cincta;  347,  Helicotoma  planulata ;  348,  349,  Bellerophon  bilobatus ;  350,  Cyrtolites  com- 
pressus  ;  351,  C.  (?)  Trentonensis  ;  352,  id.,  dorsal  view. 

species,  in  which  the    siphuncle  is   very  large.     These  Orthocerata 
occupied  the  place  of  Fishes  in  the  seas;  yet,  with  their  long  unwieldy 


Figs.  353-358. 


CEPHALOPODS.  —  Fig.  353,  a,  Orthoceras  junceum  ;  354.  0.  vertebrate  ;  355,  Ormoceras  tenuifilum  ; 
356,  «,  Cyrtoceras  annulatum  ;  357,  Cryptoceras  undatum  ;  358,  Trocholites  Ammonius. 

shells,  they  must  have  been  sluggish  animals.     Other  related  Cephal- 
opods  had  the  shells  coiled  (Figs.  357,  358),  a  much  more  convenient 


202 


PALEOZOIC    TIME. 


form ;  arid  these,  although   smaller  species,  were  probably  of  superior 
rank  to  the  Orthocerata. 

TriloUtes  (Figs.  3GO-3GG),  continued  to  be  the  most  common  and 


Figs.  360-367. 
3ol 


CRUSTACEANS. —Fig.  360,  Asaphus  gigas  (XK);  361,  a,  Calymenc  Blumenbachii ;  362,  Lichas 
Trentonensis ;  363,  Trinucleus  concentricus ;  364,  365,  Agnostus  lobatus  (x4);366,  same, 
natural  size  ;  367,  a,  b,  Leperditia  fabulites  (natural  size). 

largest  of  ARTICULATES.  Besides,  there  were  many  of  the  little 
bivalve  Crustaceans  or  Ostracoids,  the  shell  of  one  species  of  which 
is  shown  in  Fig.  367. 

Characteristic  Species. 
1.  TRENTON  EPOCH. 

1.  Protozoans.  — Sponf/es.  —  Astylospon  yia  parvula   B.  from  the  Trenton,  near 
Ottawa  City,  Canada.     Perhaps  related  to  the  Sponges,   Stromntocerium  ruyosum  H.*, 
Black  River  limestone;  and  Receptaculites  ylobularis  H  ,  ft.  Oweni  H.,  from  the  Galena 
limestone  of  Wisconsin  and  Illinois. 

2.  Radiates.  — (rr.)  Polyps. —Tig.  317,  Petraia  cornicitlum   H.,  a   coral  of   the 
Cyathophyllum  family,  P.profunda  H.,  Trenton  limestone;  P.  aperta  B.,  Black  River 
limestone.     Fig.  318,  Columnana  alveolata  H.,  Black  River  limestone,  but  occurring 
elsewhere  in  the  Trenton,  — a  section  of  one  of  the  columnar  cells  shows  the  tables  or 
partitions  of  the  interior;  Fig.  318  a,  top-view,  showing  the  radiate  cells;  Fig.  319, 
Chcetetes  lycoperdon  of  the  Trenton,  a  solid  coral  of  a  conoidal  or  hemispherical  form, 
having  a  fibrous  or  fine  columnar  structure,  as  shown  in  the  sectional  view.  Fig.  320. 
Stenopora  Jibrosa   Goldf .,  is  a  common  species ;  it  began  in  the  Calciferous,  and  con 
tinued  into  the  Upper  Silurian.     The  chain-coral  (genus  HaJysites,  a  species  of  which 
is  shown  in  Fig.  370)  is  occasionally  found  in  the  Trenton  rocks,    as  in  the  Galena 
limestone,  and  in  Canada.     Fig.  372,  Tetradium  fbrosum  Saff.,  Tennessee,  Canada,  a 
tine  columnar  coral  with  tubular  quadrate  cells;   T.  columnare  H.,  Tenn. ;  Aurora 
arachnoidea  H. 

(b.)  Acalephs.  —  Fig.  321,  GraptoKthw  amplexicaulis  H.  of  the  Trenton,  of  New  York 
and  Tennessee;  321  a,  an  enlarged  view.  The  genera  Chcetetes  (Fig.  319)  and  Steno 
pora  have  been  referred  to  the  Acalephs. 

(c  )  Echinoderms. — Fig.  322,  the  Star-fish  Pukeaster  matutina  H.,  of  the  Trenton; 


LOWER    SILURIAN.  203 

323,  Tceniuster  spinosa  B. ;  Fig.  324,  the  Criniol  Lecanocrimis  elegant  B. ;  Comarocystites 
Shumardi  M.  &  W.,  from  Missouri;  Fig.  325,  the  two-armed  Cystid  Pleurocystis  squa- 
mosus  B.,  of  the  Trenton,  in  Ottawa,  Canada;  also,  Ayelacrinites  Billinysii,  Chapman. 

The  number  of  Cystids  described  by  E.  Billings  from  the  Lower  Silurian  of  Canada 
is  21;  making  in  all,  for  this  era  in  North  America,  thus  far  known,  22;  the  Crinids  of 
the  same  era  amount  to  50  species,  and  the  Star-fishes  to  11;  13  of  the  Crinids  and 
8  of  the  Star-fishes  are  Trenton  species. 

3.  Mollusks.  —  (a,)  Bryozoans. —  Species  of  JRetejwra  and  Ptilodictya  (related  to 
Figs.  300,  307)  are  common;  Clathropora  flabellata  II. 

(b.)  Brachiopods.  —  Y\gs.  326,  327,  Orthis  lynx  Eich.;  328,  0.  occidentals  H. ;  329, 
0.  testudinaria  Dalm. ;  330,  0.  tncenaria  Con. ;  331,  Leptmna  sericea  Sow. ;  332,  Stro- 
phomena  ruyosa  H.  (formerly  Leptcena  depressn  Sow. ;  333,  Stroph.  altemata  Con. ;  334- 
336,  Rhynchonella  capax  Con.;  337,  338,  Rlnjnchonella  (?)  bisukata  Emm. ;  339,  Obolus 
filosus  (  Orbicula  ?  flosa  H.);  340,  Linyula  yuadrataB..,  and  other  Linyulelke  ;  species  of 
Discina,  Trematis,  Camerella,  etc. 

(c.)  Lamellibranchs. —  Fig.  341,  Avicula  (? )  Trentonensis  Con.;  342,  Ambonychia  belli- 
striata  II. ;  343,  Tellinomya  nasuta  H. ;  also  Conocardium  immaturum  B.,  of  Black 
River  limestone,  Ottawa;  species  of  Modiolopsis,  Cyrtodonta. 

(d.)  Gasteropoda.  — Fig.  344,  Pleurotomaria  lenticularis  Con.,  very  common  in  the 
Trenton;  also  several  other  species  of  the  genus;  345,  Murchisonia,  bicincta  McCoy; 
346,  M.  bellicincta  H.,  often  four  inches  long;  347,  Helicotoma  planulata  Salter,  from 
Canada;  Ophileta  Owenana,  M.  &  W.,  from  the  Galena  limestone;  348,  Bdleropkon 
bilobatus  Sow. — very  common;  349,  same,  side-view;  350,  Cyrtulites  compressus  H.; 
351,  352,  Cyrtolites  (?)  Trentonensis  H.  The  genus  Cyrtolites  is  like  a  partly  uncoiled 
Bellerophon,  and  is  not  chambered.  The  genera  Btllerophon  anjtl  Cyrtolites  are  sup 
posed  to  belong  to  the  group  of  Ileteropods.  There  are  also  several  Patella-like  species 
of  Metoptoma  (formerly  Cctpulus  and  Patella),  a  genus  which  began  in  the  Calciferous 
beds;  species  of  Ilolopen,  Cyclonemn,  Trochonema,  Eunemo,  Raphistoma,  Subulitett, 
etc.  Maclurea  mayna,  a  Chazy  species  (Fig.  311,  p.  191),  occurs  in  the  Trenton,  in 
Middle  Tennessee  (Safford);  Chiton  Canadensis  B.  occurs  in  the  Black  River  limestone, 
in  Ottawa. 

(e.)  Pteropods.  —  Fig.  368  represents  Conularia  Trentonensis  H.,  a  delicate  four-sided 
pyramid,  apparently  admitting  of  some  motion  at  the  angles,  but 
having  septa  within  in  the  smaller  extremity  («);  it  is  supposed 
therefore  to  be  the  shell  of  a  Pteropod  by  Barrande ;   b  is  an  en 
larged  view  of  the  surface. 

(/•)  Cephalopofls. — Fig.  353,  Orihoceras  junceum  H.,  a  small 
Trenton  species;  354,  0.  vertebrate  II.,  also  Trenton,  the  figure 
reduced  to  one-third;  355,  part  of  an  Ormoceras  tenulfilum  II., 
common  in  the  Black  River  limestone,  and  sometimes  over  two 
feet  long:  the  genus  Ormoceras  is  peculiar  in  the  beaded  form  of 
the  siphuncle.  Other  common  species  of  the  Orthoceras  family 
are  the  Endoceras  proteiforme  H.,  and  the  Gonioceras  anceps  H. 
The  Endoceras  was  in  some  cases  fifteen  feet  long,  and  nearly  one 

foot  through.     In  this  genus  (named  from  the  Greek  /ce'pa?,  horn, 

i    „  f  .,7  >   \     ,1  .  £  .,,  •       Conulariu, Trentonensis. 

and  ei/Sov,  within),  there  is  a  concentric  structure  ot  cone  within 

cone.  In  Gonioceras,  the  partitions  are  much  crowded  and  have  a  double  curvature, 
and  the  siphuncle  is  central. 

Among  the  curved  species,  Fig.  356  is  Cyrtoceras  annulatum  H. ;  a,  a  transverse 
section;  Fig.  357,  Cryptoceras  undatum  (Lituites  undatus  H.),  abundant  in  the  Black 
River  limestone;  Fig.  358,  Trocholites  Ammonius  Con.,  of  the  Trenton;  358  a,  trans 
verse  section.  In  Cryptoceras,  the  spiral  is  open  at  the  outer  extremity,  and  the 
siphuncle  is  dorsal;  while,  in  Trocholites,  it  is  closed  and  tightly  coiled  throughout. 
Lituites,  which  first  appeared  in  the  Calciferous,  differs  from  Cryptoceras  in  having 
the  siphuncle  sub-central.  The  genus  Phraymocertix  has  the  mouth  of  the  shell  very 
much  contracted,  by  a  bending  inward  of  the  sides;  P.  immaturum  B.,  is  from  the 
Black  River  limestone  of  Canada. 


204 


PALEOZOIC    TIME. 


4.  Articulates.  — («.)  Worms.  —  Serpulites  dissolutus  B.,  Trenton,  of  Montreal, 
etc.,  Canada;  Salterella  Billinysii  Saff.,  Tennessee,  (b.)  Trilobites.  —  Fig.  360,  Asaphus 
platycephalus  (Isotelus  yiyas};  the  species  is  sometimes  ten  inches  or  a  foot  long; 
Fig.  361,  Calymene  Bhimenbachii  Brongt. :  Fig.  361  a,  same  rolled  up,  by  bringing 
the  tail  to  the  head,  common;  Fig.  362,  Lich'is  Trentonensis  B. ;  L.  cucullus  M.  &  W., 
from  Illinois;  Fig.  363,  Trinucleus  concentricus  Eaton;  Figs.  364,  365,  Aynostus  lobatus 
H.,  head  and  tail  portions  magnified;  366,  natural  size;  Illcenus  crassicauda  Wahl., 
New  York  and  Illinois.  Among  the  other  species,  occur  the  Genera  Bathyurus,  Triar- 
thrus,  Cheiritrus,  Bronteus,  Acidaspis,  Dalmanites,  Encrinurus,  Haiyes,  Proetus,  Pha- 
cops ;  of  which,  the  first  only  is  represented  in  the  Primordial  rocks.  Asaphus  platy- 
cephalusSt.  is  the  only  trilobite  common  to  the  Chazy  and  Trenton  (Billings). 

(b.)  Ostracouls.  —  Fig.  367,  Leperditia  fabulites?  Con.,  natural  size,  from  New  York, 
Tennessee,  etc. ;  a,  b,  transverse  and  vertical  sections,  the  specimen  from  Canada  (L. 
Josephiann  Jones, who  refers  the  species  with  a  query  to  the  fabulites  of  Conrad). 


2.  UTICA  AND  CINCINNATI  EPOCHS. 

1.  Radiates.  —  («..)  Polyps. — No  corals  have  been  described  from  the  Utica 
shale.  In  the  Hudson  River  beds  in  New  York,  there  are  species  of  Cltcetetes  related 
to  those  of  the  Trenton,  and  rarely  specimens  of  the  Favistella  stellata  H.  (Fig.  369),  a 
colunmiform  coral  related  to  the  Coltonnarife,  having  stellate  cells.  This  species  is  more 
abundant  in  the  West.  Cyathophyllids  of  the  genus  Petraia  occur,  as  in  the  Trenton; 
also  of  the  genus  Zaphrentis,  Z.  Canadensis  B. ;  also  a  species  of  the  Chain-coral,  or 
ffalysites,  II.  yradlis  H.,  Fig.  370,  from  Green  Bay,  Wisconsin;  also  Syrinyopora 
obsoleta  II.  (Fig.  371);  and  species  of  the  genus  Tetradium,  as  Tetradium  Jibrosum 
Saff.,  Figs.  372,  372  a;  Aulopora  arachnoidea  H. 


373 


Figs.  369-373. 
370 


Fig.  369,  Favistella  stellata ;  370,  Halysites  gracilis  ;  371,  Syringopora  obsoleta  ;  372,  a, 
Tetradium  fibrosum  ;  373,  Glyptocrinus  decadactylus. 


(b.)  Accdephs.  —  Y\g.  374  represents  the  Graptolitlms  jmstis  H.,  a  species  occurring 
abundantly  in  the  Hudson  River  and  Utica  shales  at  many  localities.  Several  other 
species  have  been  described  by  Hall. 

(c.)  EcMnoderms.  —  Crimd*,  Cystids,  and  Star-fishes  occur  in  the  rocks  of  the  period. 

Among  Crinids,  the  Glyptocnnus  de- 
Fig.  374.  cadftctylus  H.  (Fig.  373)  is  not  un- 

Graptolithus  pristis.  •, 


crinus,  Palaocrinus,  Heterocrinus,  ffybocrinus,  Porocrinu*,  etc.  Fig.  375  represents  a 
large  Star-fish  from  the  Blue  limestone  of  Cincinnati,  as  figured  by  U.  P.  James,  the 
original  of  which  was  four  inches  across. 


LOWER   SILURIAN. 


205 


2.  Mollusks.  —  The  Trenton  Brachiopods  Leptcena  sericea  Sow.,  Fig.  331;  Stro- 
phomena  alternate  Con.,  Fig.  333;  Orthis  testudinaria  Dalm.,  Fig.  329;  Orthis  lynx 
Eichw.,  Fig.  326;  Orthis  occidentalis  H.,  Fig.  328;  Rhynchvnttllii  capax  Con.,  Figs.  334- 
336;  and  some  others,  are  continued  in  the  Cincinnati  epoch;  also  the  Heteropod 
Beilerophon  bilobatus,  Figs.  348,  349;  the  Gasteropod,  Murchisonm  bidncta  H. ;  the 


ECHINODERM  —  Palasterina  (?)  Jamesii. 


Cephalopods,  Trocholites  Ammonius  Con.,  Fig.  358,  and  species  of  the  Orthoceras  family 
etc.    The  following  are  characteristic  species:  Lamellibranchs,  Pterinea  demissa  M'Coy 


LAMELUBRANCUS.  — Fig.  376,  Pterinea  demissa  ;  377,  Ambonychia  radiata  ;  378,  Modiolopsis 
modiolaris  (X%) ',  379,  OrthonoU  parallela. 

Fig.  376;  Ambonychia   radiata   H.,   Fig.  377;   Modiolopsis  modiolaris  Con.,  Fig.  378; 
Ortlionota  parallela  H.,  Fig.  379;   Cyrtodontti  Hindi  B. ;  Dolabra  Sterlinyensis  M.  &  W., 


206  PALEOZOIC   TIME. 

from  the  Cincinnati  group.  Among  Gasteropods,  occur  Cyrtolites  ornatus  Con.,  near 
Fig.  350;  C.  imbricatus  M.  &  W.,  Illinois;  Cyclonema  bilix  Con.,  Pleurotomaria  Amer 
icana  B. 

Among  Pteropods,  there  are  species  of  Tentaculites,  T.  tenuistriatus  M.  &  W.,  and 
T.  Osweyoensis  M.  &  W.,  from  Illinois,  in  the  Cincinnati  group. 

3.  Articulates.  — Among  Trilobites,  Asaphus  platyceplialus  (Fig.  3QQ),C(ilymtne 
Blumenbachii  Brngt.  and  Trinucltus  concentricus  (Fig.  363)  continue  on  from  the  Tren 
ton  period ;  but  A.  platycephalus  is  rivalled  both  as  to  abundance  and  size  by  A.  meyistos, 
already  referred  to,  found  in  Ohio  and  other  States  west.  A.  Canadensin  Chapm.  is  a  species 
from  the  Utica  shale.  Triarthrus  Beckii  is  common  in  the  Utica  shale,  and  occasionally 
seen  in  the  Trenton  beds.  The  head-shield  generally  occurs  without  the  body :  Fig.  380 

Fig.  381. 


Triarthrus  Beckii. 

represents  its  usual  form,  and  Fig.  381  the  same  entire.    The  body  is  much  like  that  of 
a  Calymene  (Fig.  361):  it  has  a  row  of  minute  spines  along  the  middle  of  the  back. 

The  Anticosti  limestone  is  supposed  to  range  in  time  from  the  Trenton  period  through 
the  Niagara,  and  probably  through  the  Lower  Helderberg.  Some  of  the  characteristic 
fossils  of  its  upper  four  divisions  (p.  197)  are  the  following. 

I.  Leptcena    sericea,  Strophomena  rhomboidalis,  S.  pecten  Sharpe,    Orthis  lynx,   0. 
Salteri  B.,  Pentamerus  reverses  B. ,  Bellerophon  bilobatus,  B.   acutus  Sharpe,  Pleuroto- 
maria  Americana  B.,  Ambonychia  racliata  ;  and,  with  these,  Halysites  catemdata,  Fa 
vosites  Gothlandica  Linn,  Petraia   yracilis  B.,  a  Ileliolites;  also   Strophomena  subtenta 
Con.,  a  species  occurring  in  the  Cincinnati  limestone,  and  S.  recta  Con.,  a  Wisconsin 
(Mineral  Point)  species. 

II.  Favosites  Gotldandica,  Halysites  catenulata,  Stromatopora  concentrica,  a  species  of 
Aulopora,   species  of    Cyathophyttum,    Orthis   Salt  en,   Strophomena  Leda,  S.  pecten, 
Pentamerus  Barrandei  B.,  Atrypa  conyesta  Con.,  A.  reticularis  Linn.,  Calymene  Blu- 
menbachii,  etc. 

III.  The  same  species  as  in  II.  of  Favosites,  Halysites,  Stromatopora,  Strophomena, 
Atrypa,  Orthis,  Calymene,  with  Orthis  eleyantula  Dalm.,  Stricklandinia  lens  Sow.,  Pen 
tamerus  oblonyus  Sow.  (a  species  characteristic  of  the  Clinton  group  in  the  Xiagara 
period),  Phacops  orestes  B.,  Favosites  favosa  H.  Xiagara  species),  Zaphrentis  Stokesi  B., 
Aheoliies  Labechii  M'Edw.,  etc. 

IV.  The  same  species  as  in  III.  of  Favosites,  Halysites,  Stromatopora,  Zaphrenti*, 
Alveolites,  Strophomena,  Atrypa,  Orthis,    Calymene,  Phacops,  with  species  of   Cyatho- 
pliyllum,  Ptychophyllum,  etc. 

2.  EUROPEAN. 

In  Great  Britain,  the  beds  of  the  whole  Lower  Silurian  from  the 
bottom  of  the  Primordial  make  a  single  conformable  series.  Those 
which  appear  to  be  equivalents  of  the  beds  of  the  Trenton  period 
are  the  Llandeilo  flags,  5,000  feet  thick ;  the  Bala  beds,  or  Caradoc 
rocks,  6,000  feet,  and  the  Lower  Llandovery,  1,000  feet.  The  Llan 
deilo  flags  of  South  Wales  include  thin  laminated  sandstones  or  flags, 
and  dark  earthy  slates  often  gritty,  with  some  beds  of  limestone. 
These  pass  up,  without  any  definite  line  of  demarcation,  into  the  Bala 


LOWER   SILURIAN. 


207 


rocks,  which  also  include  flags  and  slates,  but  the  latter  in  general 
more  sandy,  with  beds  of  limestone.  In  the  whole  thickness  of  G,000 
feet,  there  are  two  beds  of  limestone,  one,  of  little  persistency,  the  Hir- 
nant  limestone,  of  10  feet,  and  the  other  the  Bala,  of  2o  feet ;  and  be 
sides,  1,400  feet  below  the  latter,  there  is  a  Bala  "  ash-bed  "of  15  feet 
thickness.  Many  beds  of  igneous  rocks  are  intercalated  in  some 
regions.  In  Shropshire,  corresponding  beds  are  sandstones,  with  occa 
sional  calcareous  layers  —  the  Caradoc  sandstone  of  Murchison. 

Near  the  town  of  Llandovery  in  South  Wales,  there  is  a  series  of 
beds  of  sandstone  and  shale,  called  the  Lower  Llandovery,  which  are 
referred  to  the  Lower  Silurian. 

In  Bohemia  and  Bavaria,  the  Lower  Silurian  rocks  are  schists, 
quartzytes,  and  conglomerates,  the  lower  part  of  Stage  D  of  Barrande; 
in  Scandinavia,  there  are  limestones  overlaid  by  slates  and  flags ;  in 
Russia,  in  the  Baltic  provinces,  mainly  limestones  ;  in  Spain,  schists 
and  limestones,  with  some  sandstones. 

The  following  list  of  characteristic  fossils  of  the  Lower  Silurian  of  Great  Britain 
serves  to  show  the  close  parallelism  in  the  life  of  this  era  between  Europe  and  America. 

The  names  of  species  that  occur  also  in  North  America  are  printed  in  small  capitals. 

PROTOZOANS. —  Sponyes,  species  of  Acanthosponyia  and  Clione;  Stromatopora  striatclla 
D'Orb. 

RADIATES.  (1)  Polyp-corals:  Farosites  alveolnris  Goldf.,  F.  GOTHLANDICA,  two 
species  of  Ileliolites,  HALYSITES  CATENULATA,  Petraia  subduplicata  M'Coy,  Syrinyo- 
plitjlhim  (Sarcinula)  oryanum  Linn.  (2)  Acahphs  :  ALVEOLITES  (STENOPORA)  FIBROSA, 
same,  variety  LYCOPERDON,  Ptilodictya  dichotoma  Portl.,  various  Graptolites,  of  the 
genera  D!ploffrapf.us,Phylloy)'ciptus,  etc.  (3)  Eclrinoderms:  Glyptocrinus  basalts  M'Coy, 
two  species  of  Palceaster,  id.  of  SpJiteronites  and  Echtnotpkcarites,  Ayelacrinites  Bucli- 
ianus  Forbes. 

MOLLUSKS.  —  (1)  Bryozoans:  Fenestelki  antiqua,  PTILODICTYA  ACUTA  H.,  P.  dicho- 
toma,  Retepora  Hisingeri.  —  (2)  Brachiopods:  Linguist,  Davisii,  ORTHIS  TESTUDINARIA, 

0.  VESPERTILIO  SOW.,   0.  FLABELLULUM  SOW.,  Fig.  388.       O.   CALLIGRAM31A  Dallll.,  0. 


Figs.  388-394. 

390,; 


Fig.  388,  Orthis  flabellulum  :  389,  0.  elegantula  :  390,  Crania  divaricata  ;  391,  Conocardium 
dipterum  ;  392,  Asaphus  Powisif;  393,  Illfeuus  Davisii ;  394,  Ampyx  nudus. 

ELEGANTULA,  Dalm.  (Fig.  389),  O.  BIFORATA  (or  LYNX,  Fig.  326),  O.  STRIATULA  Con., 
O.  PORCATA,  Stroplwmena  complanata  Sow.,  LEPT^ENA  SERICEA  (Fig.  331),  Crania 
divaricata  M'Coy  (Fig.  390),  Dlsdna  (Trematis) punctata  Sow.  (near  T.  cancellata  Sow., 
of  the  Trenton).  —  (3)  Lamellibranchs :  MODIOLOPSIS  MODIOLARIS,  J/.  expansa  Portl., 


208  PALEOZOIC    TIME. 

Ctenodonta  varicosn.  ORTHONOTA  NASUTA  Con.,  Conocardium  dipterum  S.  (Fig.  391), 
Ambonychia  Triton.  —  (4)  Pteropods  and  Heteropods:  THECA  TRIANGULARIS  Portl.,  T. 
vayinuki  S.,  Ecculiomjtlialus  Bucklandi  Portl.,  Bellerophon  carinatus  Sow. — (5)  Gaster- 
opods:  MACLUREA  LOGANI  S.?  (Scotland),  Murchisvnia  simplex  M'Coy,  Holopea  con- 
cinna  M'Cov.  —  (6)  Ctphalopods :  Orthoceras  vnffatu8.$  JAtuites  Hibernicus  S. ;  Cyrto- 
ceras  incequiseptum  Portl.,  C.  MULTICAMEHATUM  H.  ? 

ARTICULATES. — (1)  Worms:  Nereites  Sedytrickii  Murch.,  Tentaculites  Anylicus  S. 
(2)  Trilobites:  Oyyyii  Bucli'd  Brngt.,  Asaphau  tyrannus  Angelin,  A.  Poicisii  Sharpe 
(Fig.  392),  TRINUCLEUS  CONCENTRICUS,  CALYMEXE  BLUMEXBACHII,  Illcenus  Darisii 
S.  (Fig.  393),  Ampyx  nmlus  Murch.  (Fig.  394),  Lid  as  Hibernicus  Portl..  Aynostus 
pisiformis  (also  Primordial),  and  also  species  of  Il'trpts,  Phacops,  Cheirurus,  Cybele, 
etc.  —  (3)  Ostracoidt:  Beyrichin  complicata. 

The  Lower  Llandovery  rocks  contain  STRICKLAXDINIA  (Pentamerus)  LENS*,  and 
rarely  PENTAMERUS  OBLONGUS*,  both  species  occurring  in  the  Anticosti  beds,  also 
Pentinnerus  undatus  Sow.,  Meristella  anyustifrons  M'Coy,  ^f.  ?  crassa  Sow.,  ATRYPA 
RETICULARIS*,  A.  crassa,  Orthis  CdlUyramina.*^ ,  O.  ELEGANTULA*!,  0.  virgata,  STRO- 

PIIOMEXA    DEl'HESSA*f,     LEPT.ENA     SERICEA*|.     L.    TKAXSVERSALIS*f,    Murchlsonitt 

simplex,  JStUerophon  dilitatus  Sow.*f,  Petraia  subduplicata* ^  ;  Jllienus  Bowmanni  S.f, 
CALYMEKE  BLUMKNBACHII*!,  Lichns  laxatus  M'Coyt,  Homalonotus  sulcatus^.  FA- 

VOSITES     GOTHLANl)ICA*f,     HELIOLITES     IXTERSTIXCTA*f,      HALYSITES     CATENULA- 

TA*f-  The  species  whose  names  are  marked  with  a  t  occur  also  in  the  formations 
beloAv;  and  those  with  an  *  are  found  also  in  the  Upper  Silurian.  A  species  of  Eozoon 
has  been  reported  from  the  green  serpentine  marble  of  Conneinara,  of  the  age  of  the 
Lower  Silurian  according  to  Murchison,  it  underlying  the  Lower  Llandovery  beds. 

Rhizopods  have  been  found  by  Ehrenberg  in  the  Obolus  or  Ungulite  grit  of  Russia. 
The  rock  is  in  part  a  very  soft  green-sand  ;  and  the  connection  of  the  microscopic 
Rhizopod  shells  with  the  green  grains  shows,  as  Ehrenberg  states,  that  it  is  of  the  same 
nature  with  the  Green-sand  of  the  Cretaceous.  Among  these  fossils,  occur  the  three 
modern  genera  Textulnrid,  Rotalia,  and  Guttulinn.  Ehrenberg  has  also  detected  in  this 
rock  great  numbers  of  Pteropods  (related  to  HyoKtet),  and  made  out  ten  new  species 
and  four  genera.  The  rock  derives  its  name  from  its  most  common  fossil,  Obulus  Apal- 
linis  (Fig.  246,  p.  173 ),  which  is  about  as  large  as  a  small  ringer-nail.  The  Siphono- 
treta  unyuiculnta  (Fig.  245)  is  another  of  its  fossils.  It  has  also  afforded  minute  teeth, 
not  larger  than  pins'  heads,  which  Pander  regarded  as  those  of  Ganoids,  but  which 
have  since  been  shown  to  be  from  the  dental  apparatus  of  Mollusks.  The  age  of  the 
beds  is  either  that  of  the  Trenton  or  earlier.  They  underlie  a  dark -colored  schist  con 
taining  graptolites.  and  over  this  occurs  the  Orthoceratite  limestone  or  Pitta. 

General  Observations. 

North  American  Geography.  —  The  era  of  limestone-making,  — 
and,  therefore,  of  continental  seas  largely  free  from  sediments,  —  which 
made  progress  in  the  Canadian  period,  reached  its  culmination  in  the 
earlier  division  of  the  Trenton  period,  when  limestones  were  almost 
the  only  kind  of  rock  being  deposited  over  the  breadth  of  the  conti 
nent.  The  absence  of  sediments  from  a  large  part  of  the  continental 
region  must  have  been  owing  to  the  absence  of  the  conditions  on 
which  their  distribution  depends.  The  currents  of  the  ocean  which 
ordinarily  swept  over  the  land  (the  Labrador  current  from  the  north, 
along  the  eastern  border,  and  the  Gulf  Stream  from  the  south,  over 
the  interior),  must  have  had  their  action  partly  suspended.  This  may 
have  been  caused  by  a  barrier  outside  of  the  limestone  area,  near  or 
outside  of  the  present  Atlantic  coast  line.  If  the  land,  in  the  shallow 


LOWER   SILURIAN.  209 

region  outside  of  the  present  Atlantic  border  of  the  continent,  were 
above  tide-level  at  the  time  (see  p.  418),  it  would  have  been  a  conti 
nental  barrier  against  both  waves  and  currents. 

With  the  opening  of  the  Cincinnati  era,  sediments  again  were  de 
posited  over  New  York  and  the  Appalachians,  and  some  change  of 
level  had,  therefore,  taken  place.  But,  as  the  formation  of  lime 
stones  was  continued  in  the  Mississippi  basin,  and  also  in  the  St. 
Lawrence  bay  (at  Anticosti),  the  change  did  not  affect  essentially 
these  regions.  If  the  Atlantic  barrier,  above  alluded  to,  were  a  fact 
in  the  Trenton  era,  an  oscillation  of  level  submerging  it,  and  raising 
toward  the  surface  another  parallel  region  more  to  the  west,  where 
the  Appalachians  now  stand,  would  have  opened  again  the  New 
York  and  Appalachian  area  to  the  ocean,  and  so  might  have  occasioned 
the  transition  to  sedimentary  accumulations. 

Climate.  —  No  proof  that  a  diversity  of  zones  of  climate  prevailed 
over  the  globe  is  observable  in  the  fossils  of  the  Trenton  period,  or 
of  any  part  of  the  Lower  Silurian  era,  so  far  as  yet  studied.  The  fol 
lowing  species,  common  in  the  United  Stages,  and  occurring  at  least  as 
far  south  as  Tennessee  and  Alabama,  have  been  found  in  the  strata  of 
northern  North  America,  near  Lake  Winnipeg  :  Strophomena  alter- 
nata,  Leptcena  sericea  ?,  Maclurea  magna,  Pleurotomaria  lenticularis  ?, 
Calymene  senaria,  Ghcetetes  JLycoperdon,  Receptaculites  Neptuni. 

The  mild  temperature  of  the  Arctic  regions  is  further  evident  from 
the  occurrence  of  the  following  United  States  and  European  species 
on  King  William's  Island,  North  Devon,  and  at  Depot  Bay,  in  Bel- 
lot's  S trait  (lat.  72°,  long.  94°), — Ghcetetes  lycoperdon,  Orthoceras 
moniliforme  IL,  Receptaculites  Neptuni  De  France,  Ormoceras  crebri- 
septum  II.,  Huronia  vertebralt's  Stokes ;  besides  Maclurea  Arctica 
Haughton,  near  the  Chazy  species  M~.  magna.  Moreover,  the  forma 
tion  of  thick  strata  of  limestone  shows  that  life  like  that  of  lower 
latitudes  not  only  existed  there,  but  flourished  in  profusion. 

Life.  —  Exterminations.  —  At  the  close  of  the  Chazy  epoch,  its 
species,  with  few  exceptions,  disappeared,  for  the  rocks  of  the  Trenton 
epoch  contain  a  different  range  of  species.  No  facts  have  been  ob 
served  to  explain  the  nature  of  the  catastrophe  that  intervened 
between  the  two  epochs.  Such  a  fact  as  this  —  that  sinking  the 
coral  islands  of  the  Pacific  three  hundred  feet  would  destroy  the  reef- 
forming  Corals  of  those  islands  —  may  have  some  bearing  on  the 
subject.  The  geographical  changes  introducing  the  Cincinnati  epoch 
appear  to  have  had  some  connection  with  the  partial  destruction  of 
the  Trenton  species  that  then  occurred.  A  large  number  of  species 
are  continued  on  from  the  Trenton  into  the  Cincinnati  group,  wherever 
the  rocks  of  the  latter,  like  those  of  the  former,  are  limestones.  But, 
14 


210  PALEOZOIC   TIME. 

where  the  latter  are  shales,  —  in  other  words,  where  the  seas  after 
ward  had  a  muddy  bottom,  —  there  the  species  were  almost  wholly 
different,  and  the  new  fauna  was  one  fitted  for  the  muddy  bottom, 
including,  therefore,  many  Lamellibranchs  with  the  Brachiopods,  and 
but  few  Crinoids. 

4.  GENERAL    OBSERVATIONS    ON    THE    LOWER    SILURIAN. 

Thus  far  in  American  Geology,  no  evidence  has  been  detected  of 
(1)  fresh- water  lakes  or  deposits,  or  (2)  of  terrestrial  or  fresh- water 
life.  The  animals  were  mainly  Protozoan,  Molluscan,  and  Radiate, ' 
because  these  are  the  aquatic  divisions  of  the  Animal  kingdom  ;  and 
with  them  were  associated  the  aquatic  Articulates,  —  Worms  and 
Crustaceans  ;  but  not  yet  the  aquatic  section  of  Vertebrates,  —  Fishes. 
Whatever  terrestrial  life  may  have  existed,  no  trace  of  it  has  yet 
been  discovered.  The  continent  was  already  outlined,  and,  in  its 
heavings  and  progressing  changes,  its  coming  features  were  shadowed 
forth,  —  even  its  mountain  chains,  the  wide  interior  basin  and  the 
great  lakes, —  although  the  mountains  had  yet  but  small  parts  above 
tho  seas,  and  the  lakes  only  the  beginnings  of  their  depressions. 

1.  Differences  in  the  conditions  of  the  several  continental 
regions  of  North  America.  —  (a.)  Reality  of  the  Eastern  Border 
region  in  American  geological  history. — In  the  Primordial  era,  the 
thickness  of  the  limestone  strata  made  in  the  Newfoundland  seas  was 
far  greater  than  that  over  the  Continental  Interior.  The  same  was 
true  again  in  the  Quebec  period.  And,  finally,  in  the  Cincinnati 
epoch,  when,  after  the  deposition  of  the  Trenton  limestones,  frag- 
mental  rocks  were  again  forming  over  New  York,  a  great  limestone 
formation  commenced  in  Anticosti,  which  continued  in  progress  to  the 
close  of  the  Lower  Silurian,  and  so  on  to,  and  through  a  large  part  of, 
the  Upper  Silurian.  No  trace  of  unconformability,  and  no  striking 
interruption  in  the  beds,  mark  the  transition  from  the  Lower  to  the 
Upper  Silurian.  Such  facts  sustain  the  statement,  on  page  145,  that, 
in  North  American  geological  progress,  the  Eastern  Border  region  — 
including  central  and  eastern  New  England,  and  the  British  posses 
sions  on  the  north  to  Labrador  and  Newfoundland  —  was  an  area  of 
progress  independent  of  that  of  the  great  mass  of  the  continent. 

(i.)  The  formations  thicker  in  the  Appalachian  region  than  over 
the  Continental  Interior.  —  The  whole  thickness  of  the  Lower  Silurian 
in  Missouri  was  2,000  feet ;  in  Iowa,  1,200 ;  in  Illinois,  but  700  ;  in 
Middle  Tennessee,  1,000  feet,  where  the  outcrops,  however,  expose 
nothing  below  the  top  rocks  of  the  Canadian  period.  On  the  con 
trary,  in  the  Appalachian  region  (which  includes  the  whole  mountain 
region  from  Quebec  to  Alabama),  the  thickness  in  Pennsylvania  was 


LOWER   SILURIAN.  211 

12,000  feet  (Rogers);  in  the  Green  Mountains,  not  less;  in  Canada, 
north  of  Lake  Champlain  and  Vermont,  at  least  7,000  feet ;  in  East 
Tennessee.  15,000  feet,  or  more. 

(c.)  Proportion  of  limestones  to  the  sandstones  and  shales  less  in  the 
Appalachian  region  and  to  the  north,  than  over  the  Interior  basin.  — 
Out  of  the  whole  thickness  of  the  rocks  in  Missouri  and  Illinois, 
five-sixths  are  limestone,  and  in  Iowa,  one-half.  In  the  Appalachian 
region,  out  of  the  12,000  feet,  5,000  feet,  or  five-twelfths,  are  lime 
stone,  according  to  Rogers ;  in  Tennessee,  at  least  one-third ;  in 
Canada,  about  Quebec,  not  one-twentieth. 

(d.)  The  Appalachian  region,  the  Green  Mountains  included,  from 
the  period  of  the  earliest  Silurian,  a  region  of  comparatively  shallow 
waters.  —  Along  its  course,  there  were  Archsean  islands  and  reefs, 
when  the  Silurian  era  opened,  —  portions  of  the  Blue  Ridge  to  the 
south,  the  Highlands  of  New  Jersey  and  Orange  and  Dutchess  Coun 
ties,  N.  Y.,  and  the  patches  of  Archaean  rocks  in  New  England  being 
some  of  these  areas.  It  was  hence  a  barrier  region  to  the  continent, 
over  which  the  Atlantic  currents  flowed  and  waves  broke  ;  and  here, 
therefore,  fragmental  rocks,  —  rocks  of  sand,  pebbles,  mud,  and  clay 
—  ought  to  have  abounded.  The  interior  basin,  under  the  protection 
of  this  barrier,  was  occupied  by  relatively  quiet  seas,  and  fitted  there 
by  for  the  growth  of  Crinoids,  Corals  and  Mollusks,  whose  calcareous 
relics  were  the  material  of  the  limestones.  This  point  is  illustrated 
by  nearly  all  the  successive  formations. 

(e.)  The  Appalachian  region  experienced  through  the  Lower  Silurian 
greater  changes  of  level  than  the  Continental  Interior.  —  If  the  Appal 
achian  region  was  an  area  of  comparatively  shallow  waters,  or  the 
course  of  a  great,  though  mostly  submerged, continental  barrier,  as  just 
stated,  it  follows  that  there  must  have  been  a  gradual  sinking  of  the 
bottom,  in  order  that  the  depositions  should  have  reached  the  great 
thickness,  in  different  parts,  of  10,000  to  20,000  feet.  For  only  by 
such  a  subsidence  could  the  accumulations  have  exceeded  in  thickness 
the  actual  depth.  It  must  have  been  an  extremely  slow  subsidence, 
not  faster,  on  the  average,  than  the  rate  of  progress  in  the  deposi 
tions.  The  succession  of  different  kinds  of  rocks,  —  sandstones, 
shales,  conglomerates,  limestones,  —  shows  that  the  sinking  went  on 
interruptedly,  or  was  the  resultant  after  a  long  series  of  oscillations, 
in  which  the  surface  was  here  and  there  at  times  emerged. 

2.  General  quiet  of  the  Lower  Silurian  era;  Limited  disturb 
ances.  —  The  strata  of  the  Lower  Silurian  in  North  America  appear 
to  have  been  spread  out  over  the  Interior  Continental  basin  in  hori 
zontal  beds  of  great  extent,  and  to  have  followed  one  another  without 
much  disturbance  of  the  formations.  There  were  extended  oscillations 


212  PALEOZOIC   TIME. 

of  the  surface  of  the  continent ;  for  this  is  indicated  in  the  varying  lim 
its  of  the  formations,  as  well  as  the  alternations  in  the  kinds  of  rocks. 
One  marked  exception  to  the  general  quiet  occurred  during  some 
part  of  the  Canadian  period,  in  the  region  of  Lake  Superior,  where 
there  were  extensive  igneous  ejections  (p.  185),  —  events  probably 
connected  with  the  deepening  of  the  Lake  Superior  basin.  Another 
case  of  disturbance  has  been  noted  in  Newfoundland  (p.  181).  It 
occurred  in  the  course  of  the  Primordial,  the  lower  beds  of  this 
period  having  been  upturned  before  those  following  were  laid  down  ; 
in  other  words,  those  of  the  two  being  unconformable.  Indications 
of  probable  disturbances  in  the  Rocky  Mountains  are  mentioned  on 
page  182;  and  the  wide  extermination  of  species  that  several  times 
took  place  show  that  there  was  change  and  catastrophe.  But  still  it 
remains  a  fact  that  the  Lower  Silurian  was  an  era  of  comparative 
quiet.  This  quiet,  moreover,  was  a  very  long  one,  —  probably  two 
thirds  as  long  as  all  of  the  time  that  has  since  elapsed. 

5.  DISTURBANCES    AT   THE  CLOSE  OF   THE  LOWER   SILURIAN. 

The  rocks  of  the  Lower  Silurian  having  been  laid  down  over  the 
New  England  and  other  North  American  areas,  the  long  quiet  was 
finally  interrupted,  in  some  parts  of  the  continent,  by  subterranean 
movements  and  metamorphism,  —  not  by  sudden  catastrophe,  but, 
after  the  ordinary  style  in  geological  progress,  by  slow  and  gradual 
change.  The  principal  regions  of  this  change,  now  known,  are  that 
of  the  Green  Mountains,  the  northern  extremity  of  the  Appalachian 
region,  and  that  of  the  "  Cincinnati  uplift,"  from  Lake  Erie,  over  the 
Cincinnati  region,  into  Tennessee. 

Previous  to  the  epoch  of  revolution,  the  Green  Mountain  area  had 
been  a  region  of  accumulating  limestones,  through  the  Canadian  and 
Trenton  periods,  and  of  beds  of  quartzose  sands  and  mud,  and  prob 
ably  some  limestone,  through  the  Cincinnati  era.  But  here  the  rock- 
making  over  the  region  ended ;  next  came  the  upturning,  in  which 
the  same  rocks  were  lifted  and  folded  and  crystallized,  and  the  Green 
Mountain  region  made  dry  laud. 

1.  The  fact  of  the  Green  Mountain  revolution  is  manifested  in.  — 
(a.)  The  present  position  of  the  rocks.  —  The  strata  were  originally 
horizontal.  They  are  now  upturned  over,  the  whole  of  the  wide  region 
described,  some  portions  standing  vertical,  the  larger  part  inclined 
30°  to  60°,  yet  varying,  occasionally  at  short  intervals,  from  10°  to 
90° ;  the  beds  rising  and  descending  in  great  folds.  Moreover,  the 
whole  series  of  beds,  to  the  very  bottom  of  the  Silurian,  if  not  to 
lower  depths,  were  involved  together  in  the  upturning. 


LOWER   SILURIAN. 


213 


The  following  section,  of  a  region  about  two  miles  in  length,  represents  the  rocks  of 
Monument  Mountain,  situated  half  way  between  Stockbridge  and  Great  Barrington,  in 
Berkshire  Co.,  Massachusetts.  Below,  to  the  west  (left,  near  the  Housatonic  river),  the 

Fig.  395  A. 


Section  across  Housatonic  Valley  and  Monument  Mountain. 


Stockbridge  limestone  (Chazy  or  Trenton),  is  seen  bent  into  a  low  fold.  Over  it,  there 
is  a  bed  of  mica  schist  and  gneiss  (once  a  bed  of  sediment),  bent  in  the  same  manner; 
then,  to  the  east  of  this,  there  is  a  great  stratum  of  quartzyte  (once  a  bed  of  quartz 
sand),  200  to  250  feet  thick,  dipping  southeastward;  this  quartzyte,  going  eastward, 
is  overlaid  by  a  second  stratum  of  gneiss  and  mica  schist,  300  to  400  feet  thick,  and 
by  a  second  of  quartzyte,  200  feet,  or  so,  thick. 

The  limestone,  to  the  west  of  the  section,  dips  under  a  ridge  of  mica  slate,  called 
Tom  Ball,  and  comes  up  on  the  west  side  in  nearly  vertical  beds.  Tom  Ball,  a  ridge 
800  or  900  feet  high  above  the  Housatonic  river,  is  a  portion  of  the  overlying  slate, 
that  was  squeezed  up  in  a  deep  downward  flexure,  or  synclinal,  of  the  underlying 
limestone;  and  to  this  the  slate  constituting  it  owes  its  existence  in  a  ridge;  for,  where 
the  limestone  raised  its  back  in  anticlinal  folds,  the  rocks  above  were  broken  from  top 
to  bottom,  and  so  became  an  easy  prey  to  denuding  agencies.  The  Tom  Ball  synclinal 
is  a  shallow  one  at  the  north  end  (V4,  Fig.  395  B),  where  the  limestone  may  be  seen 
(near  W),  dipping  under  the  slate;  but,  at  the  south  end,  a  very  steep  and  deep  one, 
with  the  axial  plane  inclined  eastward  (V4,  Fig.  395  C),  both  the  slates  and  the  lime 
stone  beds  east  and  west  of  them  having  a  high  easterly  dip.  The  limestone  region  of 

Fig.  395  B. 


Y4  V4  V3  A3  V*     A*     Vi     Ai    G 

Section  from  Glendale  westward,  through  north  end  of  Tom  Ball.     (G,  Glendale  ;  V*,  Tom  Ball.) 

Fig.  395  C. 


\V 


H 

Alluvial  plain  S.  of  Mon.  Mt. 


Section  across  Long  Pond  Valley  through  Southern  half  of  Tom  Ball. 

the  Green  Mountains  is  full  of  examples  of  such  folds.  The  eastern  (right)  part  of  the 
section  in  Fig.  395  B  exhibits  their  character  directly  north  of  Monument  Mountain, 
where  there  are  two  narrow  synclinals  (V1,  V2),  with  anticlinals  of  limestone  (A2,  A1), 
m  place  of  the  gently  inclined  strata  of  the  mountain ;  and  the  synclinals  are  so  narrow 
that  only  a  small  part  of  the  overlying  schist  is  pinched  in,  and  no  quartzyte.  The 
culminating  range  of  the  Green  Mountains,  south  of  Vermont,  stands  along  the 
western  boundary  of  Massachusetts,  and  is  called  the  Taconic  range.  Mount  Wash- 


214  PALEOZOIC    TIME. 

ington,  in  the  southwestern  corner  of  the  State,  is  2,634  feet  above  the  sea.  Graylock, 
in  the  northwestern,  3,600  feet  high,  belongs  properly  to  the  range,  though  situated 
six  miles  to  the  east  of  it.  The  limestone  may  be  seen  for  a  distance  of  four  to  nve 
'miles,  dipping  under  Mount  Washington,  showing  that  this  part,  at  least,  of  the  Taconic 
range  is  a  synclinal;  and  Graylock  was  long  since  shown  to  be  a  synclinal  by  Em- 
mons.  Each  is  a  great  mass  of  mica  slate,  or  hydromica  slate,  partly  chloride,  held 
up  in  a  very  broad  trough  of  limestone.  In  other  parts,  the  range  is  a  narrow  and  steep 
synclinal,  like  the  south  end  of  Tom  Ball.  For  other  sections  of  this  broken,  upturned 
and  crystallized  region  of  Green  Mountain  rocks,  see  a  Memoir  by  the  Author  in  Vols. 
IV.,  vl,  and  VI  of  the  American  Journal  of  Science  (1872,  1873).  Between  this 
region  and  the  Hudson  River,  the  slates  and  limestones  all  dip  eastward ;  and  the  rocks 
are  probably,  for  the  most  part,  of  the  Quebec  group  (Logan).  What  faults  there  may 
be  over  the  region  has  not  yet  been  ascertained. 

(b.)  Crystallization  of  the  rod's.  —  The  strata,  as  already  implied, 
were  once  beds  of  sand,  mud,  clay,  or  pebbles  —  or  sandstones,  argilla 
ceous  sandstones,  shales,  and  conglomerates  —  besides  limestones,  and 
all  may  have  contained  fossils,  while  some  were  unquestionably  full  of 
them.  They  are  now  crystalline  or  metamorphic  rocks,  —  gneiss, 
granyte,  mica  schist,  hydromica  slate,  chlorite  slate,  quartzyte,  crystal 
line  limestone,  etc.  The  sandstones,  shales,  etc.,  were  made  out  of 
older  gneiss,  mica  schist,  etc. ;  and  in  this  era  of  metamorphism  they 
were  turned  again  into  gneiss,  mica  schist,  etc. 

The  degree  of  crystallization  over  the  Green  Mountain  region 
diminishes  west  of  Connecticut  and  Massachusetts,  the  limestone  out 
cropping  west  of  the  New  England  boundary  being  generally  little 
crystalline,  and  the  schists  mostly  ordinary  argillyte.  It  diminishes 
also  northward,  along  the  Green  Mountains,  toward  Canada. 

(c.)  Extensive  fractures  and  faults.  —  The  most  remarkable  of  all 
the  fractures  and  faults  is  that  which  occurred  near  the  western  bound 
ary  of  the  region  of  disturbance,  and  brought  up  the  Quebec  rocks  on 
the  east  side  of  the  fracture  to  a  level  with  the  Hudson  river  shales 
or  Trenton  limestone  on  the  west,  as  made  out  by  Logan.  From 
Quebec,  it  extends  west  of  south,  along  western  Vermont  (passing  from 
Weybridge  by  southern  Sudbury),  crosses  Washington  County,  X.  Y., 
approaches  the  Hudson  River  near  Albany,  crosses  the  river  not  far 
from  Rhinebeck,  fifteen  miles  north  of  Poughkeepsie,  and  continues 
on  southward  into  New  Jersey.  There  may  have  been  many  inter 
ruptions  and  shifts  along  the  course  of  this  fault ;  but  the  fact  of  its 
essential  continuation  throughout  all  this  distance  is  wrell  substantiated 
by  observed  facts.  The  line  of  it  apparently  runs  into  another  series, 
which  extends  through  Pennsylvania  and  Virginia  (according  to 
Rogers  and  Lesley),  and  through  eastern  Tennessee  (Safford)  and 
northern  Georgia,  to  Alabama.  But  the  principal  part  of  this  latter 
series  dates  from  the  epoch  of  the  Appalachian  disturbance,  following 
the  Carboniferous  period ;  for  the  Coal-measures  in  some  places  make 
one  side  of  the  fault. 


LOWER    SILURIAN.  215 

The  following  section  (Fig.  395  D)  has  been  published  by  Logan,  in  illustration  of  the 
fault  in  the  vicinity  of  the  Falls  of  Montmorency,  just  east  of  Quebec.  It  extends  from 
the  Montmorency  side  of  the  St.  Lawrence  across  the  north  channel  and  the  upper  end 
of  the  island  of  Orleans. 

Fig.  395  D. 


F  is  the  fault;  1,  Archrcan  gneiss  (Laurentian  of  Logan) ;  4  a,  Trenton  limestone  over 
lying  the  Archaean;  46,  Utica  shale,  and  4  c,  Hudson  River  shale;  3,  the  Quebec  group; 
S,  S,  the  level  of  the  sea;  M,  the  position  of  Montmorency;  C,  the  North  Channel;  0, 
Orleans  Island.  The  horizontal  and  vertical  scale  is  one  inch  to  a  mile.  "The  chan 
nel  of  the  Montmorency  is  cut  through  the  black  beds  of  the  Trenton  formation  to  the 
Laurentian  gneiss  on  which  they  rest ;  and  the  water,  at  and  below  the  bridge,  floAvs 
down  and  across  the  gneiss,  and  leaps  at  one  bound  to  the  foot  of  the  precipice,  which, 
immediately  behind  the  water,  is  composed  of  this  rock."  The  Trenton  limestone,  at 
the  top  of  the  precipice,  is  fifty  feet  thick  and  nearly  horizontal ;  at  the  foot  of  the  preci 
pice,  it  lies  against  the  gneiss,  of  nearly  the  same  thickness,  but  dippping  at  an  angle  of 
57°,  and  is  overlaid  by  shales  with  some  sandstone  of  the  Utica  formation.  The  Que 
bec  group  and  the  beds  of  the  Trenton  and  Hudson  River  groups  are  represented  as 
having  been  originally  laid  down  in  conformable  strata,  and  as  having  been  involved 
together  in  the  folding  and  faulting  here  illustrated. 

2.  Evidence  as  to  the  time  of  the  Epoch  of  Disturbance.  —  This 
epoch  is  proved  to  have  been  between  the  Lower  and  Upper  Silurian 
eras,  as  Logan  first  observed,  by  the  fact  that  unaltered  and  uncon- 
formable  Upper  Silurian  formations  overlie  in  some  places  the   up 
turned  Lower  Silurian  beds.     This  is  the  case,  as  Logan  states,  near 
Gaspe,  on   the    Bay  of  St.  Lawrence ;    also   near   Montreal,  on   St. 
Helen's  Island  and  Belceil  Mountain,  and  at  Becraft's  Mountain,  near 
Hudson,  west  of  the  Hudson  River,  in  each  of  which  cases  the  Lower 
Helderberg  beds  overlie  unconformably  Lower  Silurian  slates ;   and 
near  Lake  Memphremagog,  where  the  Niagara  limestone  occurs  with 
its  characteristic  fossils,  and  also  beds  of  Devonian  corals.     Again,  on 
the  eastern  side  of  the  mountains,  in  the  Connecticut  valley,  there  are 
unconformable   Lower  or   Upper    Helderberg   beds    at    Bernardston, 
Mass.,  and  Littleton,  N.  H.     It  is  therefore  certain  that  the  upturning 
antedated  the  Lower  Helderberg,  and  almost  equally  so  that  it  closed 
the  Lower  Silurian  era.    The  earlier  formations  of  the  Upper  Silurian 
are  scarcely  represented,  or  are  very  thin,  in  the  eastern  part  of  New 
York  State,  and  this  is  apparently  owing  to  the  previous  elevation  of 
the  Green  Mountain  region.     After  this  epoch,  this  region  was  part  of 
the  solid  continent,  like  the  older  Laurentian  hills,  yet  of  less  elevation 
than  now  above  the  ocean,  and  still  undergoing  some  oscillations  of 
level. 

3.  Other  effects   of  the   Disturbance.  —  Lake    Champlain   valley 


216  PALEOZOIC    TIME. 

was  probably  defined  before  the  Silurian  era  began,  by  Archaean  up 
lifts  along  the  Green  Mountain  area ;  but,  if  not,  it  dates  from  this 
epoch,  as  suggested  by  Logan.  It  lies  where  unstable  or  oscillating 
New  England,  through  Lower  Silurian  time,  hinged  on  to  the  stable 
Archaean  ;  or,  just  where  the  heavy  pressure  during  the  era  of  disturb 
ance  operated  against  the  stable  Archaean,  as  it  folded  up  the  thick 
series  of  rocks  to  their  bottom. 

Moreover,  the  great  St.  Lawrence  gulf  about  Ottawa,  where  the 
Trenton  and  Cincinnati  formations  had  been  accumulated,  was  prob 
ably  nearly  obliterated  at  this  time ;  for  no  rocks  of  more  recent  date 
occur  there,  to  prove  the  presence  of  the  sea,  until  the  Quaternary 
age,  just  before  Man,  excepting  the  small  patches  of  Lower  Helder- 
berg  near  Montreal.  This  region  of  dry  land  spread  eastward  from 
Montreal  to  the  Green  Mountain  region  in  western  New  England. 
Thus,  the  St.  Lawrence  channel,  which  was  first  a  short  strait  between 
the  Archaean  areas  of  Canada  and  New  York,  had  become  much  nar 
rowed  and  lengthened  by  the  close  of  the  lower  Silurian  ;  but  it  still 
opened  into  a  broad  oceanic  basin  near  the  longitude  of  Quebec ;  for 
both  Upper  Silurian  and  Devonian  strata,  as  has  been  stated,  were 
formed  over  eastern  Canada  and  part  of  New  England. 

4.  Some  characteristics  of  the  force  engaged. — The  cause  of 
the  extensive  uplifts  and  flexures  of  the  Lower  Silurian  rocks  had  the 
following  characteristics  :  — 

1.  The  force  acted  at  right  angles  to  the  course  of  the  flexures,  and, 
therefore,  approximately  to   the  general  direction   of  the  eastern  New 
England  coast.  —  It  is  obvious,  without  explanation,  that  only  force 
from  this  direction  could  have  produced  the  result. 

2.  The  force  acted  from  the  direction  of  the  ocean. —  For  the  effects 
are  most  intense  to  the  eastward  ;  they  diminish  toward  the  interior. 

3.  The  force  was  slow  in  action  and  long  continued.  —  That   the 
movement  must*  have  been  slow  in  progress,  the  flexures  a  gradual  re 
sult  of  a  movement  not  exceeding  a  few  feet  or  yards  in  a  century, 
continued  through,  a  very  long   time,  is   evident  from   the  regularity 
which  the  stratification  now  presents,  notwithstanding  the  upturning ; 
for  there  is  no  chaos :  the  beds  remain  in  their  old  order,  only  bent 
into  arches  and  bold  flexures.     The  brittle  rock  experienced  the  force 
so  gradually  that  it  yielded  with  little  fracture,  except  in  the  neighbor 
hood  of  the  axes  of  the  folds,  where  the  strain  was  greatest.     There 
may  have  been  sudden  starts,  and  earthquakes  beyond  modern  experi 
ence  ;  but  the  general  course  of  progress  must  have  been  quiet. 

While  all  this  upturning  and  crystallizing  of  strata  was  going  for 
ward  in  western  New  England,  and  displacements  to  the  eastward  even 


LOWER   SILURIAN.  217 

at  Gaspe,  there  was  apparent  quiet  north  of  Gaspe  in  the  St.  Law 
rence  Gulf;  or,  if  interruptions  occurred,  through  the  earthquake 
waves  that  must  at  intervals  have  swept  destructively  up  the  bays  and 
over  the  land,  still  there  was  no  profound  disturbance.  This  is  proved 
by  the  fact  already  mentioned,  that  the  great  limestone  formation  of 
Anticosti,  which  was  begun  in  the  lower  Silurian,  continued  its  un 
broken  progress  through  the  whole  prolonged  era  of  revolution,  and 
afterward  far  into  the  Upper  Silurian  era. 

What  happened  in  Nova  Scotia  during  this  disturbance  is  not  yet 
definitely  known. 

The  making  of  the  Appalachians  from  New  Jersey  southwestward 
took  place  later,  and  mainly  at  the  close  of  the  Paleozoic.  But,  at 
this  same  epoch,  according  to  Safford,  Newberry,  and  Orton,  the  region 
from  Lake  Erie  over  Cincinnati  into  Tennessee,  where  rocks  of  the 
Cincinnati  and  Trenton  eras  are  exposed  to  view,  was  lifted  into  a 
geanticlinal  (p.  730),  so  as  to  stand  for  the  remainder  of  the  Silurian 
age  and  part  of  the  Devonian  as  an  island  in  the  continental  seas. 
The  axis  of  the  uplifted  region  is  parallel  to  that  of  the  Appalachians. 
That  this  was  the  time  of  the  uplift  is  proved  by  the  absence  of  Up 
per  Silurian  and  Lower  Devonian  beds  over  the  region,  these  for 
mations  thinning  out  toward  the  axis  ;  and,  in  Tennessee,  as  Safford 
states,  by  the  Devonian  black  slate  resting  directly  on  the  Lower  Silu 
rian  beds. 

This  epoch  of  revolution  closing  the  Lower  Silurian  was  followed, 
if  not  attended,  by  the  formation  of  a  coarse  conglomerate  along  the 
Appalachian  region,  which  is  described  beyond.  There  was  also,  as 
has  been  remarked,  an  extensive  extermination  of  the  living  species, 
over  the  continental  seas. 

In  Europe,  there  was  also  a  period  of  disturbance  at  the  close  of  the 
Lower  Silurian ;  but  the  destruction  of  life  was  less  complete  than 
over  central  North  America,  and  corresponds  nearly  with  that  in  the 
eastern  basin  about  the  Gulf  of  St.  Lawrence. 

There  is  evidence  of  unconformability  between  the  Upper  and 
Lower  Silurian  in  many  parts  of  England ;  and  the  elevation  of  the 
Westmoreland  Hills,  as  first  ascertained  by  Prof.  Sedgwick,  has  been 
referred  to  this  epoch ;  so,  also,  that  of  the  mountains  in  North  Wales, 
and  hills  in  Cornwall,  and  the  range  of  southern  Scotland,  from  St. 
Abb's  Head,  on  the  east  coast,  to  the  Mull  of  Galloway.  Elie  de 
Beaumont  refers  to  this  era  the  elevation  of  the  Hundsruck  Chain 
(now  about  3,000  feet  high)  and  other  ridges  in  Nassau.  The  changes 
of  the  period  are  supposed  to  have  been  attended  in  England  by  meta- 
morphic  action,  in  which  gneiss  and  clay  slates  were  made  out  of  the 
Lower  Silurian  deposits. 


218  PALEOZOIC   TIME. 


B.    UPPER   SILURIAN. 

Marine  life,  large  oceans,  small  lands,  and  uniform  climates  —  the 
features  of  the  Lower  Silurian  —  continued  to  characterize  the  open 
ing  period  of  the  Upper  Silurian. 

The  periods  and  epochs  indicated  in  the  New  York  rocks  have  been 
mentioned  on  p.  164.  The  periods  are  —  the  NIAGARA  (5),  the  SA- 
LINA  (6),  and  the  LOWER  HELDERBERG  (7). 

I.    NORTH     AMERICAN. 

1.  NIAGARA  PERIOD  (5). 

Epochs.  —  1.  MEDINA  epoch,  or  that  of  the  Oneida  conglomerate 
and  Medina  sandstone  (5  «).  2.  CLINTON  epoch,  or  that  of  the  Clin 
ton  group  (5  b).  3.  NIAGARA  epoch,  or  that  of  the  Niagara  shale 
and  limestone  (5  c). 

I.  Rocks  :    kinds  and  distribution. 

The  rocks  of  the  Medina  epoch  in  New  York  are  mainly  sandstones 
and  conglomerates ;  and  much  of  the  sandstone  is  argillaceous.  It  is 
not  known  west  of  the  State  of  New  York,  except  in  Upper  Canada 
and  northern  Michigan.  The  lower  member  is  a  pebbly  sandstone  or 
grit,  called  the  Oneida  conglomerate,  being  so  named  from  its  occur 
rence  in  Oneida  County,  N.  Y.  The  upper  is  called  distinctively  the 
Medina  sandstone,  and  is  usually  a  red  or  mottled  argillaceous  sand 
stone.  Both  are  thin  to  the  north,  the  former  100  to  120  feet  in 
Oneida  County,  and  the  latter  300  to  400  feet  along  the  Niagara 
River.  The  conglomerate  is  500  feet  thick  in  the  Shawangunk  Moun 
tains,  where  it  is  called  the  Shawangunk  grit,  and  700  feet  in  some 
parts  of  Pennsylvania  and  Tennessee.  The  Medina  beds  are  1,800 
feet  thick  in  Pennsylvania  and  500  feet  in  Tennessee. 

In  the  Eastern-border  region,  at  Anticosti,  several  hundred  feet  of 
limestone  represent  this  epoch. 

The  rocks  of  the  Clinton  and  Niagara  epochs  have  a  much  wider 
range  ;  and  both  formations  thin  out  toward  the  Hudson  River.  The 
Clinton  beds  occur  near  Canajoharie,  in  New  York,  and  stretch  on 
west  through  Canada  to  Michigan,  and  along  the  north  side  of  Lake 
Huron  ;  and  also  appear  in  Ohio,  Indiana,  and  Wisconsin  ;  also  south, 
in  Pennsylvania,  Virginia,  and  Tennessee.  The  rocks  in  New  York 
and  along  the  northern  border  of  the  United  States  are  shaly  sand 
stones,  shales,  and  limestone. 

In  the  formation,  there  are  one  or  more  thin  beds  of  red  argillaceous 
iron  ore,  made  up  mostly  of  small  flattened  grains ;  these  outcrop  in 


UPPER   SILURIAN. 


219 


central  and  western  New  York,  Ohio,  and  Wisconsin ;  also  along  the 
Appalachians,  from  Pennsylvania  to  Alabama;  also  in  Nova  Scotia. 

The  rocks  of  the  Niagara  epoch  are  among  the  most  extensive  of 
the  continent,  occurring  over  a  large  part  of  the  Continental  Interior, 
from  New  York  westward  and  southwestward ;  in  the  Eastern  Border 
region,  on  Anticosti ;  and  in  the  Arctic  and  other  parts  of  British 
America.  In  all  these  regions,  they  are  partly  or  wholly  limestone, 
the  Niagara  having  been,  like  the  Trenton,  one  of  the  limestone-making 
epochs  of  North  America.  Near  Niagara  Falls,  there  are  1G5  feet  of 
limestone  resting  on  80  of  shale;  and  directly  at  the  fall,  85  of  lime 
stone  over  the  80  of  shale;  and  the  removal  of  the  shale  by  the 
waters  is  the  occasion  of  the  slow  retrocession  of  the  falls.  Along  the 
Appalachians,  the  rocks  have  a  thickness  of  1,500  feet,  and  extend  to 
Alabama. 

In  Illinois  and  Missouri, there  are  no  shales  or  sandstones  interven 
ing  between  the  limestones  of  the  Cincinnati  and  Niagara  eras  ;  and, 
as  the  two  formations  are  continuous,  it  may  be  that  the  Medina  and 
Clinton  epochs  are  there  represented  by  limestone. 

1.  Medina  Epoch  (5  a). 

The  relation  of  the  Medina  group  to  the 
overlying  Clinton  and  Niagara  groups  is  well 
illustrated  in  one  or  two  sections  from  the 
western  part  of  the  State  of  New  York. 
Fig.  396  represents  the  rocks  at  Genesee 
Falls,  near  Rochester.  The  lower  strata,  1, 
2,  are  the  Medina  sandstone  (5  b);  3,  4,  5, 
6,  the  Clinton  group  (5  c);  and  7,  8,  the 

Section  at  Gem  see  Falls.  Niagara  group  (5  d),  —  2  being  a  grit  rock, 

3  and  5  shales,  4  and  G  limestone,  7  shale, 
and  8  limestone.     The  whole  height  is  about  400  feet. 

The  following  figure  (397)  represents  a  section  of  the  rocks  along  Niagara  River, 
from  the  bluff  at  Lewiston  (L)  to  the  Falls  at  F,  passing  by  the  Whirlpool  at  W,  —  a 
distance  of  seven  miles. 

In  the  beds  at  Lewiston,  there  are  eiyht  strata:  1,  2,  3,  4  belong  to  the  Medina  group, 
and  consist  —  1  and  3,  of  shaly  sandstone ;  2  and  4,  of  hard  sandstone ;  5,  of  shale,  and 


Section  along  the  Niagara,  from  the  Falls  to  Lewiston  Heights. 

6,  limestone,  are  of  the  Clinton  group;  7,  a  shale,  and  8,  limestone,  of  the  Niagara 
group.    The  dip  is  up-stream,  as  in  the  figure,  but  is  only  fifteen  feet  to  a  mile. 


220  PALEOZOIC    TIME. 

Where  fullest  developed  in  New  York,  the  Medina  group  includes  four  divisions,  as 
follow:  — 

4.  Red  marl  or  shale,  and  shaly  sandstone,  resembling  No.  2,  below;  banded,  and 
spotted  with  red  and  green. 

3.  Flagstone,  —  a  gray,  laminated  quartzose  sandstone,  called  "  gray  band." 

2.  Argillaceous  sandstone  and  shale,  red,  or  mottled  with  red  and  gray. 

1.  Argillaceous  sandstone,  graduating  below  into  the  Oneida  conglomerate. 

In  the  Genesee  section  (Fig.  397),  the  strata  1  and  2  correspond  to  2  and  3  of  these 
divisions;  and  the  Niagara  section  contains  2,  3,  and  4. 

The  Oneida  Conglomerate  is  the  surface  rock  in  Oneida  and  Oswego  counties,  N.  Y. 
It  is  here  20  to  120  feet  thick,  but  thins  out  to  the  eastward,  in  Herkimer  County.  The 
Esopus  millstones  are  made  of  it. 

In  East  Tennessee,  the  rock  is  a  hard,  whitish,  thick-bedded  sandstone,  400  feet  thick, 
partly  a  conglomerate,  and  in  many  places  filled  with  Scolithus  (fillings  of  worm-bor 
ings). 

The  Medina  beds  spread  through  western  New  York  west  of  Utica.  In  East  Ten 
nessee,  in  White  Oak  Mountain,  they  are  400  to  500  feet  thick.  In  Canada,  they  occur, 
south  of  the  St.  Lawrence,  over  a  few  areas  east  and  northeast  of  Lake  St.  Peter. 

In  Ohio,  a  few  feet  of  shales,  at  the  top  of  the  Cincinnati  Group,  have  the  red  color 
and  sandy  texture  of  the  Medina,  though  to  a  less  degree  than  at  its  typical  localities; 
but  no  characteristic  fossils  of  that  age  have  yet  been  found  in  them.  (Orton.)  In 
southern  Indiana,  similar  beds  contain  Cincinnati  group  fossils,  up  to  the  very  line  of 
junction  with  the  Clinton.  (Bradley.) 

2.    Clinton  Epoch. 

The  sandstone  of  the  Clinton  epoch  in  New  York  is  often  quite  hard ;  and  much  of  it 
has  the  surface  uneven  from  knobby  and  vermiform  prominences,  some  of  which  are 
due  to  Fucoids. 

a.  Interior  Continental  basin.  —  On  the  Genesee  (see  Fig.  390,  p.  219),  the  Clinton 
group  consists  of,  — 

(1.)  24  feet  of  green  shale,  of  which  the  lower  part  is  shaly  sandstone  and  the  upper 
part  an  iron-ore  bed;  (2.)  14  feet  of  limestone,  called  Pcntamerus  limestone,  from  a 
characteristic  fossil;  (3.)  24  feet  of  green  shale ;  (4.)  18^  feet  of  limestone,  called  the 
upper  limestone. 

On  the  Niagara  (see  section,  Fig.  397,  p.  219),  there  is  only  a  shale  4  feet  thick, 
without  the  iron-ore,  overlaid  by  a  limestone  stratum  25  feet  thick,  —  this  limestone 
corresponding  to  the  three  upper  divisions,  and  its  upper  20  feet  to  the  upper  limestone. 
To  the  eastward,  in  Oneida,  Herkimer,  and  Montgomery  counties,  the  rock  is  100  to 
200  feet  thick,  and  includes  no  limestone,  though  partly  calcareous.  The  group  con 
sists  of  shale  and  hard  grit  or  sandstone, in  two  or  more  alternations,  along  with  two 
beds  of  the  lenticular  iron-ore.  The  flattened  grains  making  up  this  ore  are  concretions 
like  those  of  an  oolite.  Near  Canajoharie  — which  is  not  far  from  its  eastern  limit  — 
the  formation  has  a  thickness  of  50  feet.  In  the  town  of  Starkville,  Herkimer  County, 
the  rock  contains  a  good  bed  of  gypsum.  In  the  southern  part  of  Herkimer  County, 
the  beds  are  separated  from  the  Hudson  River  shales  by  only  a  small  thickness  of  the 
Oneida  conglomerate. 

In  Ohio  and  Southern  Indiana,  the  Clinton  group,  10  to  60  feet  thick,  is  recognized  by 
its  fossils,  overlying  the  shaly  limestone  of  Cincinnati.  In  Wisconsin,  there  is  a  bed  of 
lenticular  iron-ore,  6  to  10  or  even  15  feet  thick,  which  is  referred  to  the  Clinton  epoch. 

North  of  Lake  Huron,  the  Clinton  beds  occur  along  the  Manitoulin  Islands,  Drum- 
mond  Island,  and  20  miles  to  the  westward. 

b.  Appalachian  reyion. — In  Pennsylvania,  Professor  H.  D.  Rogers  divides  the  rocks 
into  (1)  a  lower  slate,  which  at  Bald  Eagle  Mountain  is  700  feet  thick;  (2)  iron -sand 
stone,  80  feet  in  the  Kittatinny  Mountain;  (3)  upper  slate,  100  to  250  feet;  (4)  lower 
shale,  100  to  250  feet;  (5)  ore  sandstone,  25  to  110  feet;  excepting  the  last,  these  strata 


UPPER   SILURIAN.  221 

augment  in  thickness  lo  the  northwest;  (6)  upper  shale,  12!)  to  250  reet,  which  thickens 
to  the  northwest;  and  (7)  red  shale  or  marl,  975  feet  thick,  at  the  Lohigh  Water-Gap. 
The  formation  spreads  across  the  State,  "from  the  northwest  riank  of  the  Kittatinny 
Mountain  to  the  similar  slope  of  the  last  main  ridge  of  the  foot  of  the  Alleghany 
Mountains."  (H.  D.  Rogers.)  In  East  Tennessee,  the  rocks  are  200  to  300  feet  thick, 
and  include  one  or  two  beds  of  argillaceous  lenticular  iron  ore. 

c.  Eastern-border  region.  —  The  relations  of  the  limestones  of  Anticosti  to  this  epoch 
have  been  mentioned  on  p.  206. 

In  Nova  Scotia,  at  Arisaig,  where  the  rocks  are  shales  and  limestone,  and  have  a  thick 
ness  of  about  500  feet,  fossils  occur  throughout  the  formation,  and  are  very  abundant  in 
the  upper  or  more  calcareous  part.  These  rocks  may  be  partly  Lower  Helderberg,  accord 
ing  to  Dawson.  At  the  East  River  of  Pictou,  there  are  also  slates  and  calcareous  bands, 
probably  of  the  same  age.  They  include  a  deposit  of  oolitic  iron-ore,  like  that  of  the 
Clinton  rocks  of  central  New  York,  which  in  some  places  has  a  thickness  of  40  feet. 
Shales  and  sandstone  occur  also  in  New  Brunswick,  northeast  and  southeast  of  Passama- 
q noddy  Bay. 

3.  Niagara  Epoch. 

a.  Interior    Continental  basin. — At  Rochester,  N.  Y.,    there   are   about    80  feet  of 
limestone,  overlying  80  of  shale.     Farther  eastward,  in  Wayne  County,  the  limestone 
is  30  or  40  feet  thick,  and  in  Cayuga  County  still   less.     The  formation  appears  to 
thin  out  in  Herkimer  County.     It  is,  hoAvever,  represented  in  the  Helderbei'g  Moun 
tains,  south  and  west  of  Albany,  by  a  bed  of  limestone  about  25  feet  thick,  called 
the  Coralline  limestone.    From  New  York,  the  formation  extends  westward  into  Canada, 
and  then  northward  around  the  north  side  of  Lake  Huron,  the  north  and  west  sides  of 
Lake  Michigan,  and  thence  westward  through  northern  Illinois  into  Iowa.     In  Ohio, 
it  outcrops,  like  the  Clinton,   around  the  area  of  Cincinnati  limestone.     Throughout 
theso  regions,  the  rock  is  almost  wholly  limestone.     In  the  peninsula  of  Michigan,  the 
thickness  is  about  100  feet;  in  Ohio,  the  lower  part  of  the  Cliff  limestone,  80  feet. 

In  West  Tennessee,  the  Meniscus  limestone,  150  to  200  feet  thick,  noted  for  its  fossil 
sponges,  of  which  one  is  meniscus-shaped,  is  probably  the  equivalent  of  the  Niagara 
limestone. 

The  Gait  or  Guelph  limestone,  well  seen  at  Gait  and  Guelph  in  Western  Canada, 
and  farther  west,  which  was  formerly  supposed  to  be  of  the  age  of  the  Salina  beds, 
is  now  regarded  as  the  upper  part  of  the  Niagara  limestone.  The  Leclaire  limestone 
of  Iowa  has  the  same  position. 

b.  Appalachian  region.  —  In  Pennsylvania,  the   formation  consists    of    two   distinct 
deposits  of  marl  or  fragile  shale.     The  lower  is  about  450  feet  thick,  where  most  de 
veloped,  near  the  middle  belt  of  the  Appalachian  zone,  and  decreases  both  to  the 
southeast  and  northwest.     The  upper  deposit,  including  some  thin  limestone  layers,  is 
1,200  feet  thick  in  the  northwest  belt,  and  declines  to  the  southwest  (H.  D.  Rogers). 
These  strata  may  include,  besides  the  true  Niagara,  strata  of  the  Salina  or  Salt-group 
period. 

c.  Eastern-border    region. — The  Niagara  limestone  is  supposed  to  occur  in  eastern 
Canada,  some  distance  south  of  the  St.  Lawrence.     It  is  part,  according  to  Logan,  of 
an  extensive  formation,  which  stretches  from  northern  Vermont,  eastward  over  a  part 
of  northern  New  Hampshire  and  northern  Maine,  to  Cape  Gaspe  on  St.  Lawrence  Bay, 
being,  in  this  part,  limestone  with  some  massive  and  shaly  sandstone.     The  formation 
embraces  also  the  strata  of  the  Lower  Helderberg,  and  possibly  part  of  those  of  the 
Lower  Devonian.     Niagara  fossils  occur  near  Lake  Memphremagog  and  in  the  lower 
part  of  the  Gaspe  limestone,  as  well  as  at  some  intermediate  points. 

Near  New  Canaan,  in  Nova  Scotia,  there  are  clay  slates  of  the  Niagara  epoch. 

d.  Arctic  regions.  —  In  the  Arctic,  the  Niagara  limestone  has  been  observed  between 
the  parallels  of  72°  and  76°,on  the  shores  of  Wellington  and  Barrow  Straits,  and  on 
King  William's  Island.     The  common  Chain-coral  Halysites  (Catenipora)  catenulata 


222  PALEOZOIC   TIME. 

has  been  foumt  at  several  localities,  along  with  other  Upper  Silurian  species.     (See, 
further,  p.  230. ) 

The  color  of  the  Niagara  limestone  is  commonly  dark  bluish-gray  to  drab.  It  is 
sometimes  quite  impure,  and  good  for  hydraulic  purposes.  A  specimen  from  Mako- 
queta,  Jackson  County,  Iowa,  afforded  J.  D.  Whitney  —  Carbonate  of  lime  52-18, 
carbonate  of  magnesia  42-64, — with  0-35  of  carbonate  of  soda,  traces  of  potash,  car 
bonate  of  iron,  chlorine,  and  sulphuric  acid,  0-63  of  alumina  and  sesquioxyd  of  iron, 
and  4.00  insoluble  in  acid,  — making  it  nearly  a  true  dolomite. 

Structural  peculiarities.  —  The  Medina  beds  bear  evidence  of  having 
been  formed  as  a  sand-flat  or  reef  accumulation.  Besides  the  thin 
lamination  alluded  to,  they  abound  in  ripple-marked  slabs  (Fig.  62, 
p.  83)  ;  mud-cracks  (Figs.  64,  65),  due  to  sun-drying ;  wave-lines  ; 
rill-marks  about  stones  and  shells  (Fig.  63)  ;  and  diagonal  lamination 
(Fig.  61  e),  an  effect  of  tidal  currents.  Fig.  63  is  drawn  from  a  slab 
of  Medina  sandstone.  All  these  peculiarities  evince  that  the  accu 
mulations,  while  forming,  were  partly  in  the  face  of  the  waves  and 
currents,  and  partly  exposed  above  the  waves  to  the  drying  air  or 
sun,  and  to  the  rills  running  down  a  beach  on  the  retreat  of  the  tides 
or  waves. 

The  structure  of  the  Niagara  limestone  is  often  nodular  or  con 
cretionary.  In  Iowa  and  some  other  parts  of  the  West,  the  rock 
abounds  in  chert  or  hornstone,  which  is  usually  in  layers  coincident 
with  the  bedding,  like  flint  in  chalk ;  and  the  fossils  are  all  siliceous. 
At  Lockport,  N.  Y.,  cavities  in  the  limestone  afford  fine  crystalliza 
tions  of  dog-tooth  spar  (calcite)  and  pearl-spar  (dolomite),  with  gyp 
sum,  and  occasionally  celestite,  and  still  more  rarely  a  crystal  of  fluor. 

The  Niagara  limestone  (like  many  others)  sometimes  breaks  ver 
tically  with  smooth  columnar  surfaces ;  and  such  specimens  have  been 
called  Stylolites.  Prof.  O.  C.  Marsh  has  shown  that  the  columns  are 
often  capped  by  a  shell ;  and  that  this  shell  has,  in  some  way,  kept 
the  material  beneath  from  the  compression  which  the  parts  around 
underwent,  and  hence  the  vertical  surfaces.  The  shell  probably 
acted  by  causing  an  earlier  hardening  of  the  material  it  covered. 

Economical  products.  —  The  Ulster  lead  and  copper  mine,  near 
Redbridge,  N.  Y.,  is  situated  in  the  Shawangunk  Grit :  it  has  afforded 
large  masses  of  galena  and  copper  pyrites,  with  blende,  but  is  not 
worked.  The  Ellenville  and  Shawangunk  mines  are  others  of  similar 
character  in  the  grit. 

Mineral  oil  occurs  in  large  quantities  in  the  Niagara  limestone  at 
Chicago,  though  not  capable  of  being  collected  to  advantage,  Worthen 
says,  that  a  portion  of  the  limestone  is  "  completely  saturated  with 
oil." 


UPPER   SILURIAN. 


223 


II.  Life. 

The  rocks  of  the  Medina  epoch  in  New  York,  and  farther  west, 
contain  few  fossils,  while  those  of  the  Clinton  abound  in  them.  The 
Anticosti  beds  of 'the  same  era  show  that  there  was  a  profusion  of 
life  in  the  seas,  through  both  epochs.  The  Niagara  beds  are  generally 
full  of  fossils. 

1.  Plants. 

The  only  fossil  plants  are  Algre  (sea-weeds),  called  Fucvids.  Forms 
referred  to  this  group  are  common  in  the  sandstones  of  the  Medina 
and  Clinton  beds,  but  rare  in  the  limestones  of  the  Niagara  period 
(limestones  seldom  containing  fossil  sea- weeds).  Fig.  398  represents 
portions  of  a  fossil  supposed  to  be  the  cast  of  a  sea-weed.  It  has 
been  suspected  to  be  the  cast  of  the  tracks  of  large  worms.  It  covers 
thickly  some  layers  of  the  Medina  sandstone.  Other  fucoids  of  these 
rocks  are  rounded  branching  stems,  from  the  size  of  a  thread  to  that  of 
a  finger. 

2.   Animals. 

The  sandstones  and  shales  of  the  Medina  and  Clinton  groups  con 
tain,  besides  great  numbers  of  Brachiopods,  many  Lamellibranchs, 
with  few  Corals  or  Crinoids ;  while  the  limestones  of  the  Clinton 


Figs.  398-403. 


Fig    398,  Arthrophycas  Harlani  ;  399,  Lingulella  cuneata  ;  400,  Modiolopsis  orthonota ;  401,  M.  (?) 
primigenia  ;   402,   Pleurotomaria  litorea  ;  403,  Eucanella  trilobata. 

group,  and  especially  those  of  the  Niagara,  abound  in  Brachiopods, 
Corals,  Crinoids,  and  Trilobites,  and  contain  few  Lamellibranchs  or 
muddy-bottom  species.  Some  of  the  limestone  beds  were  originally 
coral  reefs.  No  evidences  of  fishes  or  freshwater  life  have  been 
observed.  One  of  the  most  common  Medina  species  is  a  wedge- 


224 


PALEOZOIC   TIME. 


shaped  Lingulella,  L.  cuneata  (Fig.  399).  Two  of  the  Lamellibranchs 
of  the  same  beds  are  represented  in  Figs.  400,  401,  and  two  Gastero- 
pods  in  Figs.  402,  403.  A  considerable  number  of  the  Medina  species 
are  identical  with  the  Clinton. 

The  following   figures    represent   fossils  of  the  Clinton  group.  — 


Figs.  405-409. 


3|  408       409 
•1 


409  a 


'.(     :       -,,    -,V>- 


~       -li:. 


RADIATES.  —  Figs.  405,  406,  Zaphrentis  bilateralis  ;  4C7,  407,  Palaeocyclus  rotuloides  :  408,  a,  Case- 
tetes  ;  409,  a,  Graptolithus  Clintonensis. 

Figs.  405,  406,  one  of  the  common   corals,  a  cup  coral   or  Cyatho- 
phylloid,  of  the  genus  Zaphrentis;  407,  a  small  Echinoid  ;  408,  a  fine- 


no 


.  410-422. 


MOLLUSKS. —Figs.  410,  n,  Fenestella  (?)  pri-ca ;  411,  Pentamerus  oblongus  :  412,  413,  part  of  casts 
of  the  interior:  414,  41">,  Atrypa  reticularis;  416,  417,  Athyris  (formerly  Atrypa)  congesta  ; 
418,  Chonetes  cornuta  ;  419,  Avicula  rhomboidea  ;  420,  Cyclouema  caucellatum  ;  421,  track  of  a 
Lamellibranch  (X>a) !  422,  track  of  an  Annelid  ?  ( XK)- 

columnar  coral,  of   the  genus    Ghcetetes ;  409,   a   Graptolite ;    410,  a 
delicate  reticulated  Bryozoan  coral ;   411  to  418,  some  of  the  Brachio- 


UPPER   SILURIAN. 

pods,  of  which  411,  Pentamerus  oUongus,  is  a  large  and  characteristic 
species,  occurring  also  in  the  Niagara  beds  of  Illinois,  Wisconsin,  and 

Fig.  422  A. 


'ipx&^*^  Mtii*  %rtil' 


Cruziana  ?  (llusophycus)  bilobatus. 

Iowa;  419,  a  Lamellibranch,  of  the  genus  Avicula  ;  420,  a  Gastero- 
pod,  of  the  genus  Cyclonema.  Fig.  421  represents  a  trail,  supposed  to 
be  that  of  a  Mollusk;  and  422,  that  of  a  worm  (Annelid). 

Fig.  422  A  represents  a  cast  common  in  the  Clinton  sandrock.  It 
was  formerly  supposed  to  be  a  sea-weed,  but  is  now  regarded  as  the 
cast  of  the  trail  of  an  Articulate. 

In  the  Niagara  group,  among  the  many  corals,  there  are  the  follow 
ing,  here  represented.  Fig.  423  is  one  of  the  Cyathophylloids  or  cup 
corals ;  424,  one  of  the  Favosites,  a  columnar  coral  so  named  from 


Figs.  423-428. 
425  __ 


CORALS.  —Fig.  423,  Chonophyllum  Niagarense  ;  424,  a,  Favosites  Niagarensis  ;  425,  Halysites 
catenulata  ;  426,  427,  Heliolites  spinipora;  428,  Stromatopora  concentrica. 


j  a  honeycomb,  in  allusion  to  its  columnar  structure  (shown  in 
Fig.  424  a)  ;  425,  a  chain  coral,  or  species  of  Halysites,  428  a  Strom 
atopora,  probably  a  Protozoan  coral,  either  a  calcareous  Sponge  or  a 
Foraminifer. 

Three   of  the  Niagara  Crinoids   are   illustrated  in  Figs.  429-431  ; 
429  shows  the  cluster  of  arms  at  top,  which  in  the  living  state  opened 
15 


226 


PALEOZOIC    TIME. 


out,  flower-like  ;  430   shows   the  box-like  body  above,  but  wants  the 
arms. 


Figs.  429-431. 


480 


CRINOIDS.  —  Fig.  429,  Ickthyocrinus  laevis  ;  430,  Caryocrinus  oraatus;  431,  a,  b,  c,  Stephano- 

criuus  angulatus. 

Some  of  the  characteristic  Brachiopods  are  represented,  natural 
size,  in  Figs.  432  to  444  —  all  very  abundant  species  in  the  Niagara 
limestone.  The  shell  of  a  large  Lainellibranch,  from  the  upper  part 

Figs.  432-444.     . 
432 


BRACUIOPODS.  —  Fig.  432,  Strophomena  rhomboidalis  ;  433,  Leptaena  transversalis  ;  434,  435, 
Atrypa  nodostriata  ;  436,  Merista  nitida;  437,  Anastrophia  interplicata ;  438,  a,  Rhynchonella 
cuneata;  439,  a,  b,  Leptocoelia  disparilis  ;  440,  a,  Orthis  bilobus  ;  441,  442,  Spirifer  Niagarensis; 
443,  444,  Sp.  sulcatus. 

of  the  Niagara  group,  is  represented  in  Fig.  444  A.  Another  more 
common  kind,  of  the  genus  Avicula,  is  shown  in  Fig.  445,  reduced 
one  half  in  breadth;  and  Figs.  446,  447  represent  two  Niagara  Gas- 
teropods. 


UPPER    SILURIAN. 


227 


Figs.  448  to  451  represent  some  of  the  Niagara  Trilobites ;  449  is 
one  third  the  actual  length,  and  450  a  fourth,  the  latter  attaining  some- 


Figs.  444  A-447. 


444. \  ^. 


LAMELLIBRAXCHS  and  GASTEROPODS.  —  Fig.  444  A,  Megalomus  Canadensis ;  445,  Avicula  emacerata  ; 
446,  Platyostoma  Niagarensis  ;  447,  a,  Platyceras  angulatum. 

Figs.  448-452. 


CRUSTACEANS.  —Fig.  448,  Dalmanites  limulurus  (Xl/2);  449,  Lichas  Boltoni  (XW,  450,  Homa- 
lonotus  delphinocephalus  (x%)]  451 ,  Illnenus  Barriensis (XX);  452,  Beyrichia  symmetrica  ;  452, 
a,  same,  natural  size. 

times  a  length  of  a  foot.  In  Fig.  448,  the  eyes  are  very  large,  and  in 
450,  small.  Fig.  452  is  a  side  view,  enlarged,  of  an  Ostracoid  or  bi 
valve  Crustacean.  Another  group  of  Crustaceans,  the  Phyllopocls, 
were  represented  by  species  of  the  genus  Oeratiocaris,  having,  as 
shown  in  Fig.  484,  on  page  247,  the  general  form  of  a  Shrimp. 


228  PALEOZOIC   TIME. 

Characteristic  Species. 

1.  MEDINA  EPOCH. 

Fig.  398,  Arthrophyctis  Harlnni  H.  Occurs  rarely  in  the  Oneida  conglomerate,  vert 
abundantly  in  the  Medina  beds.  Fig.  399,  Linyuldla  cuneata  II.  ;  400,  Modiolopsis  or- 
tlwnota  H.;  401,  J/.  (?)  jjrimiyenia  H. ;  402,  Pleurotomaria  litorea  H. ;  403,  Bucanelh 
trilobata  Sow.,  different  views.  Orthocerata  are  ocasionally  met  with.  The  only  Crus 
tacean  described  is  the  Ostracoid,  Leperditia  cylindrica  Hising. 

2.  CLINTON  EPOCH. 

1.  Radiates.  —  (,/.)  Polyps.  —  Figs.  405,  406,  Zaphrentis  (Caninia)  bilateralis  H..; 
408  a  branching    Chwtetes.     (b.)  Acalephs.  —  409,  a,  Graptolithus  Clintonensis  H.     (c.) 
Echinoderms:  Crinoids.  — A  few  species  are  known:  fragments  are  common,  and  they 
are  often  found  in  the  iron-ore,  as  well  as  in  the  limestones.     Echinoids.  —  Fig.  407, 
Paheocydus  rotuloides  H.,  a  small  species. 

2.  Mollusks.  —  (a.)  Bryozoam.  —Fig.  410,  Fenesiella,  (?)  prisca  Lonsdale. 

(I.)  Brachiopods. —  There  are  species  of  Linyuldla,  Ortlris,  Leptcena,  EJiynchonella, 
Spirifer,  and  also  of  the  new  genera  for  America,  Chonetes  and  Pentamerus.  Fig.  411. 
Pentamerus  oUonyus  Murch.;  some  specimens  are  more  than  twice  the  size  of  this  fig 
ure,  and  very  thick ;  it  is  abundant  in  New  York  and  the  West,  and  occurs  also  in  Great 
Britain;  Figs.  412,  413  show  casts  of  the  interior,  —  412  a  dorsal  view,  and  413  a  ven 
tral.  Figs.  414,  415,  Atrypa  reticularis  Linn.,  or  a  related  species;  the  A.  reticularis  is 
reputed  to  extend  through  the  Niagara  period  into  the  Hamilton  of  the  Devonian;  but 
more  than  one  species  are  probably  here  included;  this  also  is  a  foreign  species:  it  is 
one  of  the  few  species  of  true  Atrypa ;  the  interior  of  the  shell  is  shown  in  Fig.  225. 
Fig.  416,  Atliyris  (?)  conyesta  Con.;  Fig.  417,  smne,  different  view, —  it  has  a  spire 
within,  extending  downward  and  outward;  Fig.  418,  Chonetes  cornuta  Koninck. 

(c.)  Laniellibranchs. —  Fig.  419,  Avicula  rhomboidea  H. 

1/7.)  Gasteropods. — Fig.  420,  Cyclone  ma  cancellatum  H.  Bucanella  trilobata  of  the 
Medina  also  occurs  here,  besides  other  Gasteropods. 

(e.)  Cephalopods. — Species  of  Orthoceras. 

In  the  Anticosti  beds,  there  are  Cephalopods  of  the  genera  Orthoceras,  Cyrtocerrts, 
Oncoceras,  Ascoceras,  Glossoceras,  as  well  as  Beatricea ;  and  Trilobites  of  the  genera 
AsapJius,  Calymene,  Illcenus,  Phacops,  Dalmanites.  Encrinurus,  Harpes,  Lichas,  etc., 
and  among  these,  Asaplius  megistos  and  Calymene  Biumenbaclrii,  If  the  so-called  Bea- 
tricece  were  the  internal  bones  of  Cephalopods,  as  seems  probable  (after  Hyatt's  obser 
vations),  some  of  these  animals  must  have  been  20  or  30  feet  long.  The  fossils  are 
somewhat  like  a  long  straight  branch  of  a  tree,  with  an  irregularly  fluted  or  otherwise 
uneven  exterior,  and  have  been  described  as  remains  of  plants ;  but  they  have  a  cone- 
in-cone  structure,  with  cellular  interspaces  about  the  center,  and  the  plates  in  contact 
toward  the  sides.  They  are  from  1  to  14  inches  in  diameter. 

3.  Articulates. — Remains  of  Trilobites  of  the  genus  Homalonotits,  and  of  the 
same  species  figured  under  the  Niagara  epoch.     Tracks  or  scratches  occur,  which  have 
been  referred  with  good  reason  to  Crustaceans,  besides  others  like  Fig.  422,  that  are 
attributed  to  Worms. 

Among  the  Clinton  species  are  the  following  from  the  Lower  Silurian :  OrtJiis  lynx, 
Leptcena  sericea,  Belleroplwn  bilobatus.  The  following  are  known  in  Europe:  Orthis 
lynx,  Chonetes  cornuta  H.,  Atrypa  reticularis,  A.  hemispherica  Murch.,  Spirifer  radiatus 
Sow.,  Pentamerus  oblonyiis. 

3.  NIAGARA  EPOCH. 

1.  Protozoans.  —  Sponges  of  the  genera  Astrceosponr/ia.  Astylosponaia  and  Pal<x- 
omanon  in  Tennessee;  they  occur  In  the  upper  part  of  the  Niagara  (or  Meniscus)  lime- 


UPPER   SILURIAN.  229 

stone.  Roemer  made  out  six  species,  of  which  Astrceosponyia  meniscus  is  the  most  abun 
dant.  Fig.  428,  Stromatopora  concentrica  H.,  a  very  minutely  porous  coral,  often  in 
concentric  layers. 

2.  Radiates.  —  (a.)   Polyps  (Corals).  —  Fig.  423,    Chonophyllum  Niagarense  H., 
(Conophyllum  of  Hall,  a- genus  first  published  in  1852,  two  years  after  Chonophyllum 
by  Edwards);  424,  Favosites  Niayarensis  H. ;  424  a,  surface  of  same,  enlarged,  show 
ing  outline  of  cells ;   425,  Halt/sites  catenulata  ;   420,  Hdiolites  spinipora  H. ;  427,  an 
enlarged  view,  showing  the  12-rayed  cells  and  the  interval  of  a  cellular  character  sepa 
rating  them,  both  of  which  are  distinguishing  characteristics  of  the  genus  Hdiolites. 

(b.)  Echinoderms. —  Fig.  429,  Icthyocrinus  Iceiis  Conrad,  a  species  which  is  sometimes 
twice  as  large  as  the  figure;  430,  Caryocrinus  ornatus  Say,  of  Lockport,  the  nut-like 
shape  having  suggested  the  generic  name  (from  Carya,  the  hickory -nut);  431,  Stephan- 
ot'i'I nits  anr/ulatus  Conrad,  of  Lockport;  ft,  part  of  the  stem,  enlarged;  b,  joint  of  the 
stem,  top-view;  c,  base  of  the  body,  showing  the  three  pieces  of  which  it  consists. 
Also,  Fig.  146  (page  117),  the  Cystid  Callocystites  Jewettii  H.,  and  Fig.  144,  the  Star 
fish  Palteaster  Niayarensis  H. 

3.  Mollusks.  —  (a.)  Bryozoans. — Many  species  of  delicate  corals  of  the  genus 
Fenestella,  resembling  Fig.  410,  and  of  other  genera,     (b.)  Brachiopods. — Fig.  432, 
Stropltomena  rhomboidalis  Wahl. ;    433,   Leptcena   transversalis   Dalman;    434,  Atrypa 
nodostriata  H.,  the  Niagara  form  of  this  species;  435,  same,  side-view;  436,  Meritsta 
nitida  H.,  437,  Anastrophia  (or  Brachymerus)  interplicata  H. ;    438,  a,   Ehynchonella 
cuneata  H. ;  439,  ft,  Z»,  Leptoccelia  disparilis  H. ;  440,  Orthis  bilobusH.;  440  ft,  same,  en 
larged;  441,  Spirifer  Niayarensis  Con.;   442,  same,  side-view;    443,  444,  Sp.  sulcatus 
Rising.     Pentamerus  oblonyus  (Fig.  411),  a  Clinton -group  species,  is  very  abundant  in 
the  Niagara  limestone  of  the  Mississippi  basin.     Among  these,  all  but  the  Leptoccelia 
disparilis  H  ,  Atrypa  nodostriata  H.  and  the  Orthis  and   Spirifers,  are  found  also  in 
European  rocks. 

(c.)  Lamellibranchs. —  Fig.  444  A,  Meyalomus  Canadensis  H.,  from  the  Gait,  Canada; 
445,  Avicula  emacerata  Con. 

(d.)  Gasteropods.  —  Fig.  446,  Platyostoma  Niayarensis  H. ;  447,  Platyceras  angula- 
tum  H. ;  f,  same  in  different  position. 

(e.)  Pteropods.  —  Conularice  of  different  species. 

(f.)  Cephalopoda.  —  Species  of  Orthoceras,  Cyrtoceras,  Gomphoceras,  and  Lituites, 
which  are  common  in  the  Interior  basin. 

4.  Articulates.  —  («,)  Trilobites.  —  Fig.  448,  Dalmanites  limulurus  H.  (a  genus 
differing  from  Calymene  in  having  the  glabella,  or  middle  region  of  the  buckler,  largest 
anteriorly,  besides  having  large  reniform  eyes  and  other  peculiarities);  449,  Lichas  Bol- 
toni  H.,  a  large  and  characteristic  species,  much  reduced;  450,  Homalonotus  delphino- 
cephalns  Murch.  (the  genus  having  very  small  eyes,  the  glabella  faintly  outlined  and 
undivided, — the  middle  lobe  of  the  body  much  broader  than  the  lateral);  451,  fllce- 
nus  Barriensis  Burmeister;   Calymene  Blumenbachii  var.  Nmynrensis  H.,  near  Fig.  361 
(page  202).     (b.)  Ostracoids,  or  bivalve  Crustaceans. — Fig.  452,  Beyrichia  symmetrica 
H.,  showing  one  of  the  valves;  a,  same,  natural  size,     (c.)  Phyllopods.  —  Ceratiocaris 
Deweyi  Hall.      The  only  specimens  found  in  the  Niagara  beds  are  the  spine-like  ter 
minal  joint  of  the  body  (formerly  supposed  to  belong  to  a  fish,  and  named  Onchus 
Deweyi). 

The  following  are  some  of  the  species  common  to  the  Niagara  and  Clinton  groups :  — 

Halysites  catenulata  (Fig.  425).  Spirifer  radiatus. 

Caryocrinus  ornatus  (Fig.  430).  Avicula  emacerata  (Fig.  445). 

Hypanthocrinus  decorus.  Orthonota  curta '? 

Lingula  lamellata.  Modiolopsis  subalata  ? 

Orthis  elegantula  (Fig.  389).  Ceraurus  insignis. 

Strophomena  rhomboidalis  (Fig.  432).  Homalonotus  delphinpcephalus  (Fig.  450). 

Pentamerus  oblongus  (Fig.  411).  Calymene  Blumenbachii. 

Rhynchonella  neglecta.  Dalmanites  limulurus  (Fig.  448). 

Atrypa  reticularis  (Fig.  414).  IUwnus  Barriensis  (Fig.  451). 


230  PALEOZOIC    TIME. 

According  to  Salter,  a  number  of  species  of  the  Upper  Silurian,  and  probably  of  this 
part  of  it,  have  been  observed  in  Arctic  rocks  ;  as,  Halysites  catenulata,  OrtJiis  elegantula, 
Facoidtes  Gathlandica,  Ltperditia  Z?<7///caHising.,  species  of  Calophyllum,  Heliolites,  Cysti- 
phyJ/um,  Cyatkopkyllurn,  $yrint/opora,vr'ith  Peitfamenu  conchidiuni  Dalm.,  Atrypa  retic- 
ular/s,  etc.;  and,  at  the  southern  extremity  of  Hudson's  Bay,  Pentamerus  oblonyus, 
Atrypa  retioularis,  etc.  About  Lake  Winnipeg,  also.  Upper  Silurian  fossils  have  been 
found.  See  Am.  Jour.  Sci.,  II.  xxi.  313,  xxvi.  119. 

The  fossils  of  the  Coralline  limestone  (p.  222),  as  Hall  states,  are  mostly  peculiar  to 
it.  Out  of  thirty-two  species  (including  Corals,  Brachiopods,  Conchifers,  Gasteropods, 
Cephalopods,  and  Crustaceans)  only  the  following  are  set  down  as  identical  with  Niagara 
fossils :  Stramatopora  concentrica,  Favosites  Niayar  crisis,  Halysites  catenulata,  Spirifer 
crisjtus,  JRIiynchonella  lamtllatali.;  and  these  are  not  all  beyond  doubt.  Moreover,  three 
of  them  are  cosmopolite  species.  The  beds  are,  therefore,  strikingly  different  in  life  from 
the  Niagara,  and  may  represent  a  later  epoch.  Among  the  species,  there  are  very- 
large  spiral  chambered  shells,  of  the  genus  Trocliocerus  Hall,  which  are  unknown  in 
other  formations. 

General  Observations  on  the  Niagara  Period. 

Geography.  —  The  facts  upon  which  rest  the  conclusions  with  regard 
to  the  geography  of  the  Niagara  period  are, — 

1st.  The  occurrence  of  the  Oneida  conglomerate  over  the  region 
from  central  New  York  southward,  through  the  length  of  the  Appa 
lachians,  instead  of  extending  eastward  to  the  Hudson  River. 

2d.  The  Medina  sandstone  covering  the  same  region,  but  spreading 
farther  westward  on  the  north. 

3d.  The  Clinton  group  having  the  same  range  on  the  east,  and  ex 
tending  over  a  considerable  part  of  the  interior  basin  to  the  Missis 
sippi  ;  shales  characterizing  the  formation  in  the  Appalachian  region, 
shales  and  sandstones  prevailing  over  limestones  in  New  York,  and 
limestones,  more  or  less  argillaceous,  mostly  constituting  the  beds  in 
the  West. 

4th.  The  Niagara  rocks,  stretching  farther  east,  but  thinning  out  on 
the  Hudson  River,  and  thickening  westward ;  spreading  over  the  Ap 
palachian  region,  and  also  through  a  large  part  of  the  Interior  basin  ; 
consisting  of  shales  with  some  limestone  in  central  New  York,  more 
limestone  in  the  western  part  of  the  State,  shales  almost  solely  in  the 
Appalachian  region,  limestones  in  the  Interior  basin. 

5th.  The  formations  six  to  eight  times  thicker  in  the  Appalachian 
region  than  in  the  West. 

6th.  The  Niagara  limestone  existing  in  the  Eastern-Border  region, 
eastward  of  northern  Vermont,  to  Gaspe  ;  and  the  whole  period  rep 
resented  in  Anticosti  by  limestone. 

The  position  of  the  coarse  conglomerate  rocks  of  the  Oneida  epoch, 
spreading  over  neither  eastern  New  York  nor  the  Interior  basin  west 
of  the  State,  apparently  indicates  that  along  its  line  was  the  sea-coast 
of  the  time,  and  that  the  ocean  reached  it  in  full  force.  Such  coarse 
beds  of  marine  formation  are  formed  either  in  front  of  the  waves,  or 


UPPER    SILURIAN.  231 

under  the  action  of  strong  marine  currents.  It  is  stated  on  page  215 
that  the  Green  Mountains  must  have  been  out  of  water :  the  absence 
of  the  earlier  formations  of  the  Niagara  period  from  eastern  New 
York,  and  the  thinning  eastward  of  the  Niagara  beds,  harmonize  with 
this  view. 

The  fine  sandy  and  clayey  character  of  the  Medina  beds  shows  that 
at  this  time  central  New  York  must  have  become  an  extensive  area  of 
low,  sandy  sea-shores,  flats,  and  marshes,  not  feeling  the  heavy  waves ; 
and  this  kind  of  surface  extended  westward  over  Michigan,  instead  of 
having  a  limit  in  central  New  York.  There  is  abundant  evidence,  in 
the  ripple-marks,  wave-marks,  rill-marks,  and  sun-cracks,  of  the  exist 
ence  of  shallow  waters  and  emerging  sand-flats. 

The  clays,  clayey  sandstones,  and  limestones  of  the  Clinton  epoch, 
through  New  York  and  the  Appalachians,  show  that  the  mud-flats 
and  sand-banks,  and  hence  the  shallow  seas  of  the  coast  region,  still 
continued,  yet  with  some  greater  depth  of  water  at  times,  in  which 
impure  limestones  could  be  formed  ;  and  the  many  alternations  of 
these  limestones  with  shales  and  sandstones  imply  frequent  changes 
of  depth  over  these  areas,  as  remarked  by  Hall.  At  the  same  time, 
the  westward  extension  of  the  formation,  and  the  prevalence  of  lime 
stones,  indicate  that  the  waters  covered  a  considerable  part  of  the 
Interior  Continental  basin  ;  while  the  impurity  of  the  rock  suggests 
that  these  inner  seas  were  in  general  quite  shallow.  The  beds  of 
argillaceous  iron -ore,  which  spread  so  widely  through  New  York  and 
some  of  the  other  States  west  and  south,  could  not  have  been  formed 
in  an  open  sea ;  for  clayey  iron-deposits  do  not  accumulate  under 
such  circumstances.  They  are  proof  of  extensive  marshes,  and,  there 
fore,  of  land  near  the  sea-level.  The  fragments  of  Crinoids  and  shells 
found  in  these  beds  are  evidence  that  they  were,,  in  part  at  least,  salt 
water  marshes,  and  that  the  tides  sometimes  reached  them. 

The  beds  of  the  Niagara  epoch  on  the  east  indicate  that  the  waters 
shallowed  toward  the  Hudson  River ;  at  the  same  time,  the  thick 
limestones  of  western  New  York  and  the  Mississippi  basin  teach 
that  there  was  then  a  great  open  interior  sea,  nearly  as  in  the 
Trenton  period,  though  more  beautiful,  since  Corals  and  Crinoids 
were  a  more  prominent  feature  of  the  era. 

If  the  above  is  a  correct  view  of  the  geographical  changes,  it  is  seen 
that,  after  the  Medio-Silurian  revolution,  which  raised  the  Green 
Mountain  region,  even  eastern  New  York  was,  in  the  first  two  epochs 
of  the  Niagara  period,  above  water ;  but  there  was  then  a  gradual  sink 
ing  of  the  land,  which  moved  the  coast-line  in  New  York  eastward  to 
the  Hudson,  so  that,  over  New  York  and  the  Interior  basin,  there 
was  a  vast  limestone-making  sea.  We  infer  that  this  oscillation  of 


232  PALEOZOIC   TIME. 

level  was  slow,  from  the  fact  that  the  change  in  the  coast-line  in  New 
York,  from  central  New  York  to  the  Hudson,  demanded  the  whole 
of  the  Medina  and  Clinton  epochs.  This  change,  moreover,  was  the 
beginning  of  a  submergence  of  the  east  as  well  as  the  west  side  of 
the  Hudson  River  valley,  which  continued  through  the  Lower  Helder- 
berg  period. 

At  the  same  time  that  the  sea  of  the  Niagara  epoch  spread  over 
New  York  and  the  Interior  basin,  there  was  another  sea  of  no  small 
area,  over  the  Eastern  Border  region,  covering  the  Gulf  of  St.  Law 
rence  and  part  of  the  country  south  of  the  St.  Lawrence  region, — 
the  exact  extent  not  yet  ascertained.  In  the  course  of  these  oscilla 
tions,  from  the  beginning  of  the  Trenton  to  the  close  of  the  Niagara 
period,  over  12,000  feet  of  rock  were  deposited  along  the  Appalachians, 
indicating  a  vast  subsidence,  in  slow  progress  as  the  accumulations 
went  on.  Without  the  subsidence,  great  breadth  of  deposits  might 
have  been  formed,  but  not  great  thickness.  The  whole  change  of 
level  over  the  Interior  Continental  basin  may  not  have  exceeded 
1,000  feet. 

With  regard  to  the  continent  beyond  the  Mississippi,  we  have  small  basis  for  con 
clusions.  About  the  Black  Hills  and  the  east  side  of  the  Laramie  Range,  the  Carbon 
iferous  strata  are  stated  by  Hayden  to  rest  on  those  of  the  Lower  Silurian,  and,  there 
fore,  there  is  an  absence  of  all  the  formations  of  the  Upper  Silurian  and  Devonian; 
but  on  the  east  side  of  the  Wind  River  range  Comstock  has  found  some  Niagara  and 
Oriskany  species.  About  the  El  Paso  Mountains  in  New  Mexico,  between  the  rivers 
Pecos  and  Grande  (near  lat.  32°),  Dr.  G.  G.  Shumard  found  a  limestone  of  the  Trenton 
or  Cincinnati  era,  containing  the  fossils  Orthis  testudinaria,  0.  occidentalis  H.,  Rhyh- 
chonelln  capax  Conrad,  and  others;  but  to  this  succeeded  the  Carboniferous.  More 
investigation  is  needed  to  establish  the  general  fact;  but  if  true,  as  supposed,  a  part  of 
the  region  beyond  the  Mississippi  was  in  no  condition  for  the  formation  of  limestones 
or  sandstones,  between  the  Lower  Silurian  and  the  Carboniferous,  either  because  at  too 
great  a  depth,  or  because  emerged. 

The  Niagara  period  was,  in  part  at  least,  one  of  continental  sub 
mergence  also  in  Arctic  America  and  Europe.  Even  Great  Britain 
had  its  Coral  and  Crinoidal  seas,  and  thereby  its  limestone  formations 
in  progress,  —  although  the  Silurian  there  contains  comparatively 
little  limestone,  owing  to  the  fact  that  the  country  lies,  like  the  Appa 
lachian  region,  within  the  mountain-border  of  a  continent. 

2.  SALINA  PERIOD  (6). 

The  Salina  is  the  period  of  the  Onondaga  Salt-group,  the  series  of 
rocks  that  affords  the  salt  from  brines  in  Central  New  York. 

I.  Rocks :  kinds  and  distribution. 

The  Niagara  period  had  covered  the  sea-bottom  in  western  New 
York  with  an  extensive  formation  of  limestone.  With  the  opening 
of  the  Salina  period,  there  was  a  change  by  which  shales  or  marlytes 


UPPER    SILURIAN. 


233 


and  marly  sandstones,  with  some  impure  limestones,  were  formed  over  a 
portion  of  the  State  ;  and  in  some  way  the  strata  were  left  impreg 
nated  with  salt,  and  also  almost  destitute  of  fossils. 

The  beds  spread  through  New  York,  and  mostly  south  of  the  line 
of  the  Erie  Canal.  They  are  700  to  1,000  feet  thick  in  Onondaga 
and  Cayuga  counties,  and  only  a  few  feet  on  the  Hudson. 

The  following  sections  (Figs.  453,  454,  from  Hall),  taken  on  a 
north-and-south  line  south  of  Lake  Ontario,  show  the  relations  of  the 
Salina  beds  (6)  to  those  above  and  below,  —  they  being  underlaid  in 
one  section  (Fig.  454)  by  the  Niagara  (5  c),  Clinton  (5  b),  and  Medina 
(5  a)  beds,  and  overlaid  in  the  other  (Fig.  453)  by  rocks  of  the 

Fig.  453. 


10  , 


Fig.  454. 


Lower  and  Upper  Helderberg  (7,  9),  Hamilton  (10  a,  10  &,  10  c)  and 
Chemung  groups  (11). 

To  the  westward,  they  outcrop  between  Niagara  and  Lake  Huron, 
and  also  about  Mackinac. 

Through  the  Mississippi  basin,  the  limestone  of  the  Niagara  period 
is  followed  directly  by  that  of  the  next  or  Lower  Helderberg  period  ; 
and  the  Salina  period  is  not  represented,  unless  by  some  of  the  tran 
sition  beds  between  these  limestone  formations. 

In  Onondaga  County,  N.  Y.,  the  beds  in  the  lower  half  are  (1)  tender,  clayey- 
deposits  ( marly tes)  and  fragile  clayey  sandstones  of  red,  gray,  greenish,  yellowish,  or 
mottled  colors;  and  in  the  upper  half  (2),  calcareous  marlytesand  impure  drab-colored 
limestone,  containing  beds  of  gypsum,  overlaid  by  (3)  hydraulic  limestone.  This 
limestone  afforded  Dr.  Beck,  on  analysis — Carbonate  of  lime  44-0,  carbonate  of  mag 
nesia  41 '0,  clay  13 -5,  oxyd  of  iron  1'25.  The  rock  is  sometimes  divided  by  columnar 
striations,  like  the  Lockport  limestone,  the  origin  of  which  is  probably  the  same  as  for 
those  in  that  rock  (p.  222).  The  seams  sometimes  contain  a  trace  of  coal  or  carbon. 

Near  Syracuse,  there  is  a  bed  of  serpentine  in  this  formation,  along  with  whitish  and 
black  mica,  and  a  granyte-like  rock,  in  which  hornblende  replaces  the  mica,  making 
it  a  syenyte;  there  is  little  evidence  of  heat  in  the  beds  adjoining  these  metamorphic 
rocks.  (Vanuxem.)  (The  position  of  this  locality  is  not  now  known). 

In  the  peninsula  of  Michigan,  the  formation  includes  —  beginning  below  —  10  feet 
of  variegated  gypseous  marls,  14  feet  of  ash-colored  argillaceous  limestone,  3  feet  of 
calcareous  clay,  and  10 -feet  of  chocolate-colored  limestone.  (Winchell. )  In  western 
Ohio,  the  beds  are  20  to  30  feet  thick. 

In  southwest  Virginia,  a  few  feet  of  marly  shales  with  a  heavy  bed  of  gypsum  yield 
the  strong  brine  of  the  wells  at  Saltville. 


234  PALEOZOIC   TIME. 

The  beds,  especially  those  of  the  upper  half,  are  much  intersected 
by  shrinkage-cracks,  —  effects  of  the  drying  of  the  mud  of  the  ancient 
mud-flat  by  the  sun. 

Minerals.  —  The  gypsum  does  not  constitute  layers  in  the  strata, 
but  lies  in  imbedded  masses,  as  shown  in  the  annexed  figures.  The 

Fig.  455.  Fig.  456. 


lines  of  stratification  sometimes  run  through  it,  as  in  Fig.  456  ;  and 
in  other  cases  the  layers  of  the  shale  are  bulged  up  around  the 
nodular  masses  (Fig.  455).  In  all  such  cases,  the  gypsum  was  formed 
after  the  beds  were  deposited.  Sulphur  springs  are  now  common  in 
New  York,  and  especially  about  Salina  and  Syracuse.  Dr.  Beck 
describes  several  occurring  in  this  region,  and  mentions  one  near 
Manlius,  which  is  "  a  natural  sulphur-bath,  a  mile  and  a  half  long, 
half  a  mile  wide,  and  168  feet  deep,  —  a  fact  exhibiting  in  a  most 
striking  manner  the  extent  and  power  of  the  agency  concerned  in  the 
evolution  of  the  gas,"  and  showing,  it  may  be  added,  that  the  effects 
on  the  rocks  below  must  be  on  as  grand  a  scale.  These  sulphur- 
springs  often  produce  sulphuric  acid,  by  an  oxydation  of  the  sulphur 
etted  hydrogen.  There  is  a  noted  "  acid  spring  "  in  Byron,  Genesee 
County,  N.  Y.,  connected  with  the  Onondaga  formation,  besides  others 
in  the  town  of  Alabama.  This  sulphuric  acid,  acting  on  limestone 
(carbonate  of  lime),  drives  off  its  carbonic  acid  arid  makes  sulphate  of 
lime,  or  gypsum  ;  and  this  is  the  true  theory  of  its  formation  in  New 
York.  The  laminae  which  pass  through  the  gypsum  unaltered,  as  in 
Fig.  456,  are  those  which  consist  of  clay  instead  of  limestone.  The 
gypsum  is  usually  an  earthy  variety, of  dull  gray,  reddish  and  brownish, 
sometimes  black,  colors.  It  may  have  been  produced  at  any  time 
since  the  deposition  of  the  rocks  ;  and  it  is  beyond  doubt  now  form 
ing  at  some  places  in  the  State. 

The  salt  of  the  rocks  in  New  York  has  been  found  only  in  solution, 
in  waters  issuing  from  the  strata.  The  wells  at  Salina  are  150  to 
310  feet  deep,  and,  at  Syracuse,  between  255  and  340.  35  to  45  gal 
lons  of  the  water  afford  a  bushel  of  salt ;  while  it  takes  350  gallons 
of  sea-water  for  the  same  result.  At  Goderich,  in  Canada.  Rock  salt 
has  been  obtained  at  a  depth  of  from  964  to  1.180  feet,  and  is  reported 
to  exist  in  beds  from  14  to  40  feet  in  thickness. 


UPPER   SILURIAN.  235 

II.  Life. 

The  Salina  beds  are  for  the  most  part  destitute  of  fossils.  The 
lower  beds  in  New  York  contain  a  few  species,  imperfectly  preserved ; 
and  the  same  is  true  of  the  upper.  The  latter,  however,  are  regarded 
as  rather  of  the  next  (Lower  Helderberg)  period. 

III.  General  Observations. 

Geography.  —  The  position  of  the  Saliferous  beds  over  the  State  of 
New  York  indicates  that  the  region,  which  in  the  preceding  period  was 
covered  with  the  sea,  and  alive  with  Corals,  Crinoids,  Mollusks,  and 
Trilobites,  making  the  Niagara  limestone,  had  now  become  an  interior 
shallow  basin,  or  a  series  of  basins,  mostly  shut  off  from  the  ocean, 
where  the  salt  waters  of  the  sea,  which  were  spread  over  the  area  at 
intervals,  —  intervals  of  days,  or  months,  or  years,  it  may  be,  —  evap 
orated,  and  deposited  their  salt  over  the  clayey  bottoms.  In  such 
inland  basins,  the  earthy  accumulations  in  progress  would  not  consist 
of  sand  or  pebbles,  as  on  an  open  sea-coast,  but  of  clay  or  mud,  such 
as  is  produced  through  the  gentle  movements  of  confined  waters. 
Moreover,  the  salt  waters  would  become,  under  the  sun's  heat,  too 
densely  briny  for  marine  life,  and  at  times  too  fresh,  from  rains ;  and 
the  muddy  flat  might  be  often  exposed  to  the  drying  sun,  and  so  be 
come  cracked  by  shrinkage.  The  shrinkage-cracks,  the  clayey  nature 
of  the  beds,  the  absence  of  fossils,  and  the  presence  of  salt,  all  accord 
with  this  view.  Salt  cannot  be  deposited  by  the  waters  in  an  open 
bay ;  for  evaporation  is  necessary.  The  warm  climate  of  the  Silurian 
age  and  the  absence  of  great  rivers  were  two  conditions  favorable  for 
such  results.  At  some  of  the  smaller  coral  islands  in  the  Pacific,  the 
lagoon  (or  lake)  of  the  interior  is  so  shut  off  from  free  communication 
with  the  ocean,  as  to  exemplify  well  the  above-mentioned  conditions. 
In  the  confined  lagoon,  there  are  often  no  fragments  of  corals  or  shells 
along  the  shores,  but,  instead,  a  deep  mud  of  calcareous  material,  made 
out  of  the  broken  shells  and  corals  by  the  triturating  wavelets,  —  so 
deep  and  adhesive  that  the  waters  of  the  lagoon  are  somewhat  difficult 
of  access.  This  calcareous  mud,  if  solidified,  would  become  a  non-fos- 
siliferous  limestone,  like  a  large  part  of  the  coral  rock ;  and  yet,  a  few 
hundred  yards  off  on  the  sea-coast,  there  are  other  limestones  forming, 
that  are  full  of  corals  and  shells.  In  another  small  Pacific  coral  island, 
called  Baker's,  there  is  a  bed  of  gypsum  two  feet  thick,  attributable 
to  the  evaporation  of  sea-water,  as  remarked  by  the  describer,  J.  D. 
Hague.1 

The  Saliferous   flats  of  New  York  spread   nearly  across  the  State, 
1  Am.  Jour.  Sd.,  II.  xxxiv.  p.  224.     Dana's  Corals  and  Coral  Islands,  pp.  182,  294. 


236  PALEOZOIC   TIME. 

and  probably  opened  on  the  ocean  to  the  southeast.  The  existence  of 
such  interior  evaporating  flats  implies  intermittent  incursions  of  the 
sea,  perhaps  only  through  tidal  overflows,  but  also,  probably,  such  oc 
casional  floodings  as  may  take  place  where  coast-barriers  or  reefs  are 
broken  through  at  times  by  the  waves  or  currents. 

As  the  Saliferous  beds  of  New  York  are  nearly  1,000  feet  thick,  just 
west  of  the  centre  of  the  State,  and  since  there  is  proof  in  the  shrink 
age-cracks  and  other  peculiarities  that  the  layers  were  successively 
formed  in  shallow  waters,  it  follows  that  there  must  have  been  a  slow 
subsidence  of  the  region  during  the  progress  of  the  period,  —  it  may 
have  been  of  but  a  few  inches  or  feet  in  a  century. 

3.  LOWER  HELDERBERG  PERIOD  (7). 
I.  Rocks  :  kinds  and  distribution. 

The  Lower  Helderberg  period  was  marked  by  the  formation  of  thick 
limestone  strata.  There  was  a  gradual  passage  to  its  clear  open  seas 
over  New  York,  from  the  great  sea-marshes  of  the  Salina  period.  The 
period  is  so  named  because  its  beds  are  well  displayed  in  the  Helder 
berg  Mountains,  south  of  Albany,  beneath  Devonian  beds  called  the 
"  Upper  Helderberg." 

The  lower  beds  are  designated  the  Water-lime  group ;  they  overlie 
directly  the  Salina  beds,  in  New  York,  and  appear  as  if  a  continu 
ation  of  them.  Moreover,  they  spread  through  the  State,  from  the 
Hudson  River  to  its  western  border,  while  the  rest  of  the  series  does 
not  reach  west  beyond  Ontario  County.  The  whole  thickness  in 
eastern  New  York  is  400  feet.  A  single  isolated  summit  of  Lower 
Helderberg  rocks,  called  Becraft's  Mountain,  stands  just  east  of  the 
Hudson  River,  near  the  city  of  Hudson ;  and  another  is  Mount  Bob, 
three  miles  to  the  northeast :  these  are  evidently  remnants  of  a  great 
formation  that  once  spread  widely  in  that  direction.  Another  isolated 
patch  occurs  near  Montreal. 

The  Helderberg  rocks  outcrop  also  over  a  large  area  in  western 
Ohio,  and  are  continued  thence  into  Indiana.  They  come  out  to  view 
also  in  southern  Illinois. 

South  of  New  York,  along  the  Appalachian  region,  they  extend 
through  New  Jersey,  Pennsylvania,  Maryland,  and  Virginia,  increas 
ing  in  thickness,  being  in  all  500  feet  or  more  on  the  Potomac  ;  and, 
as  in  the  North,  they  diminish  westward. 

The  subdivisions  of  the  formation  observed  in  the  Helderberg 
Mountains  are  for  the  most  part  undistinguishable  out  of  New  York 
State.  The  lowest  rock,  the  Water-lime,  retains  its  characters  most 
widely,  and  has  a  thickness  of  350  feet  on  the  Potomac  (Rogers).  The 


UPPER   SILURIAN.  237 

Water-lime  is  so  called  because  used  for  making  water-  (or  hydraulic) 
cement ;  it  is  a  drab-colored  or  bluish  impure  limestone,  in  thin  layers. 
At  Bernardston,  Mass.,  a  few  miles  West  of  the  Connecticut  (on  the 
land  of  Mr.  Williams),  there  is  a  Crinoidal  limestone,  which,  as  C. 
H.  Hitchcock  has  stated,  is  either  Lower  or  Upper  Helderberg.  It 
underlies  quartzyte  and  mica  slate.  The  same  formation,  though 
without  limestone,  extends,  as  the  author  has  ascertained,  northeastward 
to  South  Vernon,  where  it  includes  staurolitic  slate,  hornblende  rocks, 
gneiss,  and  mica  slate  ;  and  these  rocks  are  the  kinds  characteristic  of 
the  Cods  group  of  Hitchcock,  which  stretches  northward  through 
New  Hampshire,  east  of  the  Connecticut,  and  probably  also  south 
ward  through  Massachusetts  and  Connecticut,  to  the  region  west  of 
New  Haven.1  Rocks  of  this  era  extend  from  northern  New  Hamp 
shire  over  Maine,  to  New  Brunswick  and  Nova  Scotia. 

The  following  are  the  several  New  York  subdivisions,  beginning  below,  — 1.  Ten- 
taculite  and  Water-lime  group,  150  feet  in  the  Helderberg  Mountains.  2.  Pentamerus 
limestone,  50  feet  in  the  Helderberg  Mountains.  3.  Catskill  or  Delthyris  Shaly  lime 
stone.  4.  Encrinal  limestone.  5.  Upper  Pentamerus  limestone. 

An  analysis  of  the  Water-lime  rock  afforded  Dr.  Beck  —  Carbonate  of  lime  48*4, 
carbonate  of  magnesia  34  3,  silica  and  alumina  13 '85,  sesquioxyd  of  iron  1*75,  moisture 
and  loss  1*70.  One  of  the  beds  of  the  Water-lime  strata,  consisting  of  thin  clinking 
layers,  abounds  in  fossils  called  Tentaculites,  and  has  been  named  Tentaculite  limestone. 

The  Pentamerus  limestone  (No.  2),  overlying  the  Water-lime,  is  so  called  from  its 
characteristic  fossil,  Pentamerus  galeatus  (Fig.  462).  It  is  compact,  and  mostly  in 
thick  layers.  The  Catskill  or  Delthyris  Shaft/  limestone  (No.  3)  consists  of  shale  and 
impure  thin-bedded  limestone,  and,  in  many  places  in  New  York,  abounds  in  the  large 
fossil  shell  Spirifer  macropleura  Con.  It  extends  as  far  west  as  Madison  County, 
and  is  full  of  fossils.  The  Encrinal  limestone  (No.  4)  is  confined  to  the  eastern  part  of 
the  State.  The  Upper  Pentamerus  (No.  5),  the  upper  layer,  is  of  limited  extent,  but 
has  many  peculiar  fossils:  it  is  named  from  the  Pentamerus  pseudo-c/aleatus  H.  (Figs. 
464,  465). 

The  Saliferous  beds  pass  rather  gradually  into  the  Water-lime,  —  their  upper  layers 
becoming  more  and  more  calcareous,  and  containing  some  of  the  Water-lime  fossils. 

In  Ohio,  the  rocks  outcrop  (owing  to  the  extension  northward  of  the  Cincinnati  up 
lift,  p.  217)  over  a  north-and-south  region  extending  from  the  western  portion  of  Lake 
Erie  southward  (Newberry),  nearly  to  the  Ohio  river,  and  westward  into  Indiana.  The 
rocks  make  part,  of  the  "Cliff  limestone  "  of  the  Interior  basin  (so  called  because  it 
stands  in  cliffs  along  the  river  valleys). 

In  West  Tennessee,  light-blue  limestones  of  this  period,  abounding  in  fossils,  occur  in 
Hardin,  Henry,  Benton,  Decatur,  and  Stewart  counties.  The  maximum  thickness  is 
about  100  feet.  In  southern  Illinois,  there  are  beds  of  siliceous  limestone  underlying 
the  Clear  Creek  limestone,  the  lower  part  of  which  Worthen  refers  to  this  period ;  they 
rest  directly  upon  limestones  of  the  Cincinnati  or  Hudson  River  age  (the  Cape  Girard- 
eau  limestone  of  the  Missouri  Report),  no  Niagara  limestone  intervening  (Worthen). 

In  the  Appalachian  region  in  Pennsylvania,  the  Water-lime  group  has,  in  the  middle 
belt  of  the  mountains,  a  thickness  in  some  places  of  350  feet,  while  in  the  southeast 
belt  it  is  50  to  200  feet:  it  thickens  to  the  southwestward.  The  rest  of  the  Lower 
Helderberg,  consisting  also  of  impure  limestones,  has  a  thickness  of  100  feet  or  more 
in  the  middle  belt,  and  200  to  250  in  the  southeastern,  which  thickness  is  maintained 
along  the  Appalachian  chain.  (Rogers.)  The  beds  have  not  been  observed  in  East 
Tennessee. 

1  Amer.  Jour.  Sti..  III.    vi.  1873. 


238 


PALEOZOIC    TIME. 


In  the  Eastern-border  region,  at  Pembroke,  Me.,  in  a  granytic  region,  slates  and  hard 
sandstones  occur,  with  many  fossils;  at  other  places  in  northern  Maine,  the  rock  is 
limestone.  In  Cutler  and  Lubec,  Me.,  there  is  a  fossiliferous  limestone,  either  of  this 
or  of  the  Niagara  period.  (C.  II.  Hitchcock.) 

The  formation  of  Maine  extends  northeastward  to  Cape  Gaspe",  where  there  are 
2,000  feet  of  limestones,  the  larger  part  referred  to  the  Lower  Helderberg  by  Logan, 
with  the  upper  beds  probably  Oriskany. 

In  southern  New  Brunswick,  rocks  of  this  period  occur  as  a  continuation  of  those  of 
Maine;  also  in  northern  New  Brunswick ;  also  in  the  Arisaig  district,  northern  Nova 
Scotia,  shales  and  limestone,  which  stretch  around  to  East  River  of  Pictou;  also  in  the 
Cobequid  Mountains,  Nova  Scotia. 


Figs.  457,  458. 


II.    Life. 

The  rocks  abound  in  fossils,  beyond  even  the  Niagara  or  Trenton : 
over  300  species  have  been  named  and  described.  Among  them,  there 
are  the  same  families  and  genera  as  in  the  preceding  periods,  but  with 
some  marks  of  progress  in  new  forms,  and  with 
a  range  of  species  almost  completely  distinct. 
Yet  it  has  been  noted,  as  a  striking  fact,  that 
very  many  of  the  species  of  the  Niagara  period 
have  their  closely-related  or  representative  spe 
cies  in  the  Lower  Helderberg. 

1.  Plants. 

Limestone  strata  seldom  contain  remains  of 
plants  ;  and,  accordingly,  little  is  known  of  the 
Botany  of  the  Lower  Helderberg  period. 

2.  Animals. 

Many  Corals  and  Crinoids  occur  in  the  beds  ; 
and  some  of  the   latter   are  of  remarkable  size 
and   beauty,  —  as  Mariacrinus  nobilissimns  H., 
and  other  species  of  the  same  genus.     The  last 
— Fig.  457,  Apio- known  remains  of  the  Haly sites,  or  Chain-coral, 
cystis  Gebuardi ;  458,  ADO-  occur  in  this  formation.     There  were  also  a  few 

malocystites  cornutus. 

species  of    tystids  (rigs.  4o7,  4o8). 

Among  Mollusks,  Brachiopods  are  far  the  most  numerous,  leading 
in  numbers  all  other  kinds  of  life.  Figs.  459-470  represent  some  of 
the  common  kinds. 

In  the  Water-lime,  there  occur  vast  numbers  of  a  little,  slender, 
straight  shell,  called  Tentaculites,  which  have  been  supposed  to  be  the 
shells  of  a  kind  of  worm,  of  the  Serpula  family.  Fig.  471  represents 
them, natural  size  ;  and  472,enlarged. 

Trilobites  were  common  still,  and  one  of  the  species  is  the  Dalmanites 


UPPER   SILURIAN. 


239 


pleuroptyx  H.,  near  Fig.  254  on  page  174.     Ostracoid  crustaceans  of 
large  size,  like  Fig.  473,  are  abundant  in  some  layers  of  the  Water- 


Figs.  459-470. 
461 


40U 


BRACHIOPODS.  —  Fig.  459,  Ilemipronites  radiata  ;  460,  461,  Rhynchonella  ventricosa ;  462,  463, 
Pentamerus  galeatus  ;  464,  465,  P.  pseudo-galeatus ;  466,  Eatonia  singularis ;  467,  Meristella 
sulcata  ;  468,  Orthis  varica  ;  469,  Spirifer  macropleura  ;  470,  Meristella  levis. 

lime.      Besides   these    Crustaceans,  there  was  also  a  new  kind,  here 


making  its  first  appearance  in  Amer 
ican  rocks.  One  species  of  the  group 
is  the  Eurypterus  remipes  of  Dekay 
(Fig.  474).  Unlike  Trilobites,  it 
has  large  jointed  arms,  and  a  body 
which  resembles  that  of  the  Sap- 
phirina  and  Caligus  groups  of  mod 
ern  Crustaceans.  (Figs.  165,  166, 
on  page  120,  represent  the  female 
and  male  of  a  Sapphirina  from  ex 
isting  seas.)  Many  specimens  of 
this  kind  of  Crustacean  from  the 

Water-lime    have  a  length    of  a    foot 


Figs.  471-474. 


472 


Figs.  471,472,  Ten  taculites  irregularis  ;  473, 
Leperditia  alta  ;  474,  Eurypterus  remipes. 


240  PALEOZOIC   TIME. 

Characteristic  Species. 

1.  Protozoans —  Stromatopora. 

2.  Radiates. —(o.)  Polyps.  —  Among  Corals,  there   are  species   of   Zaphrentis, 
Favosites,  Halysites,  Syrinyopora,  Chcetetes.     (b.)  Echinoderms.  — Group  of  Cystideans: 
Fig.  457,  Apiocystis  Gebhardi  Meek,  found  in  the  Lower  Pentamerus ;  Fig.  458,  Anoma- 
locystites  cornutus  H.,  a  remarkable  species  from  the  same  rock.     Of  Crinideans,  there 
are  species  of  the  genera  Mariacrinus,  Platycrinus,  Edriocrinits,  Aspidocrinus,  etc. 

3.  Mollusks.  —  Brachiopods,  —  Fig.  459,  Hemipronites  (Strojihomena)  radiata  of 
the  Catskill  shaly  limestone ;  460,  461,  Rhynchonella  rentricosa  H.  of  the  Upper  Penta 
merus;  462,  463,   Pentamerus  yaleatus  H.,   of  the  Lower  Pentamerus;  464,  465,  P. 
pseudo-yaleatus  H.,  of  the  Upper  Pentamerus;  466,  Eatonia  sinyularis  H.,  of  the  Cats- 
kill  Shaly;  467,  Meristella  sulvita  H.,  of  the  Water-lime;  468,  Orthis  varica  H.,  of  the 
Catskill  Shaly;  469,  Spirifer  macropleura  H.,  ibid.;  470,  Meristella  levis  H.,  ibid. 

There  are  also  Lamellibranchs  of  the  genus  Avicula,  and  others  related;  Gasteropods 
of  the  genera  Platyceras,  Platyostoma,  Ifolopea,  etc.  Also  the  Pteropod,Tent(tculites 
irreyularis  H.  (Figs.  471,  472,  the  latter  natural  size). 

4.  Articulates,  —  (a.)  TriloUtes.  — Dalmnnitcs  pleuroptyx,  near  Fig.  254;  others  of 
the   genera  Calymene,    Ceranrus,  Asnphus,    Homalonotus,    Phncops,   Lichfts,  Acidaspis, 
Proetus,  etc.     (b.)  Other  Entomostracans. —  Fig.  474,  Eurypterus  remipes  Dekay,  of 
the  Water-lime,  natural  size,  from  a  small  specimen  from  the  cabinet  of  E.  Jewett. 
Several  other  species  occur  in  the  Water-lime ;  also  species  of  the  allied  genus  Ptery- 
yotus  (Fig.  482  is  a  foreign  species),  and  of  the  genus  Ceratiocaris.     Fig.  473,  Leper- 
ditia  alta  H.,  an  Ostracoid,  abundant  in  the  Water-lime;  besides  other  Leperditice,  and 
several  species  of  Bey  rich  in,  related  Ostracoids. 

The  following  is  a  list  of  characteristic  species  of  the  subdivisions :  — 

1.  Water-lime.  —  Meristella  sulcata,  Leperditia  alta,  Tentaculites  irreyularis,  various 
species  of  Eurypterus  and  Pteryyotus. 

2.  Lower  Pentamerus.  —  Apiocystis  Gebhardi,  Rhynchonella  semiplicata  H.,  Pentamerus 
galeatus,  species  of  Lichenaliaf 

3.  Catskill  Shaly  Limestone.  —  Hemipronites  radiata,  ff.  punctidifera,  Meristella  leris, 
Eatonia  sinyularis,  Spirifer  macropleura,  Sp.  perlarnellosus  H.  (formerly  ruyosus),  Platy- 
ceras  rentricosum  Con.,  Dalmanites pleuroptyx  H.  (formerly  D.  Hausmanni). 

4.  Upper  Pentamerus. — Pentamerus  pseudoaaleattis,  Rhynchonella  ventricosa,  R.  no- 
biUs  H.,  Sjnrifer  concinnus  H. 

Atrypa  reticularis  and  StropJiomena  rnomboidalis  are  among  the  few  species  of  the 
Niagara  period  which  occur  in  the  rocks  of  the  Lower  Helderberg. 

III.  General  Observations. 

Geography.  —  In  the  Salina  period,  as  already  explained,  the  lime 
stone-making  seas  of  the  Niagara  period  in  New  York  had  been  suc 
ceeded  by  a  great  range  of  muddy  flats  and  shallow  basins ;  and,  in  the 
West,  the  basin  had  apparently  become  much  contracted  in  area,  judg 
ing  from  the  limited  extent  of  the  Salina  beds.  Neither  of  these  forma 
tions  reaches  to  eastern  New  York. 

In  the  Lower  Helderberg  period,  which  succeeds,  there  was  a  return 
of  the  conditions  for  making  limestones  ;  but,  in  striking  contrast  with 
the  formations  that  preceded,  the  beds  have  their  greatest  thickness  in 
eastern  New  York,  and  none  occur  in  western.  The  Lower  Helder 
berg  limestones  are  mainly  Appalachian  formations ;  for  even  the 
New  York  part  is  directly  in  the  range  of  the  Appalachians  of  Pemi- 


UPPER   SILURIAN.  241 

sylvania.  It  is  worthy  of  note  that  this  limestone  formation,  of  the 
later  Upper  Silurian,  was  the  first  limestone  that  was  produced  over 
the  Appalachian  region  after  the  Lower  Silurian.  But  the  Trenton 
beds  spread  through  the  west  as  well  as  the  east,  while  the  Helderberg 
occur  less  extensively  at  the  west ;  and  in  this  the  two  periods  are  in 
contrast,  the  older  limestone  having  the  widest  distribution. 

It  has  been  stated  that  the  Lower  Helderberg  limestone  occurs  even 
east  of  the  Hudson,  overlying  uriconformably  the  Lower  Silurian 
slates,  its  nearly  horizontal  beds  constituting  the  summit  of  Be- 
craft's  Mountain  and  Mount  Bob,  near  Hudson  ;  and  also  that  other 
patches  of  it  exist  near  Montreal.  Logan  suggests  that  a  conglomer 
ate  limestone  filling  a  break  in  the  rocks  near  Burlington,  Vermont, 
may  be  Lower  Helderberg,  as  the  conglomerate  closely  resembles  that 
near  Montreal.  Whatever  the  doubt  with  regard  to  the  last  men 
tioned  locality,  the  other  isolated  beds  are  proofs  of  a  former  wide  dis 
tribution  of  the  Lower  Helderberg  limestone  over  Canada,  and  along 
the  lower  part  of  the  western  slopes  of  the  Green  Mountain  chain. 

4.  ORISKANY  PERIOD  (8). 

I.  Rocks:  kinds  and  distribution. 

The  Oriskany  sandstone  extends  from  central  New  York  (the  region 
of  Oriskany,  Oneida  County)  southwestward  along  the  Appalachians, 
and  spreads  westward  through  Upper  Canada  and  Ohio,  into  Indiana, 
Illinois,  and  Missouri.  Unlike  the  Lower  Helderberg  beds,  it  thins 
out  toward  the  Hudson  River,  becoming  barely  recognizable.  The 
rock  over  these  regions  is  mostly  sandstone,  often  rough  in  aspect,  but 
is  partly  limestone  in  the  Mississippi  basin. 

In  the  Eastern-border  region  the  rock  is  mainly  limestone.  It 
constitutes,  in  many  places,  the  upper  portion  of  the  Silurian  forma 
tion,  lying  between  northern  Vermont  and  Moosehead  Lake  in  Maine, 
and  between  the  latter  and  Gaspe  on  the  Gulf  of  St.  Lawrence,  its 
characteristic  fossils  occurring  at  several  localities  over  the  region. 

The  Oriskany  sandstone  strata  are  passage-beds  between  the  Silurian 
and  Devonian. 

The  Oriskany  sandstone  was  made  the  commencement  of  the  Devonian  by  De  Ver- 
neuil;  but  Hall  has  since  referred  it  to  the  Upper  Silurian,  on  the  ground  of  the  rela 
tions  of  its  fossils.  In  New  York,  it  consists  either  of  pure  siliceous  sands,  or  of  argil 
laceous  sands.  In  the  former  case,  it  is  usually  yellowish  or  bluish,  and  sometimes 
crumbles  into  sand  suitable  for  making  glass.  The  argillaceous  sandstone  is  of  a  dark 
brown  or  reddish  color,  and  was  once  evidently  a  sandy  or  pebbly  mud.  In  some 
places,  it  contains  nodules  of  hornstone.  The  beds  are  often  distinguished  by  their  rough 
and  hard  dirty  look  (especially  after  weathering),  and  by  the  large  coarse  calcareous 
fossil  shells,  —  species  of  Brachiopods.  In  some  regions  they  are  cherty.  The  sand 
stone  appears  on  Lake  Erie  near  Buffalo,  and  enters  Canada  at  Waterloo,  on  the  Niagara 
16 


242 


PALEOZOIC   TIME. 


River.  It  outcrops  in  Ohio,  either  side  of  the  Lower  Helderberg  area,  and  extends 
thence  into  Indiana.  In  southern  Illinois,  there  are  250  to  300  feet  of  siliceous  lime 
stones.  In  St.  Genevieve  County,  Missouri,  the  rock  is  a  limestone  (Shumard). 

The  Nova  Scotia  strata  of  this  epoch  occur  at  Xictaux  and  on  Moose  and  Bear  rivers. 
They  include  a  thick  band  of  fossiliferous  iron-ore,  which  is  an  argillaceous  deposit  at 
Nictaux,  but,  owing  to  partial  metamorphism,  is  magnetic  iron-ore,  and  partly  specu 
lar,  on  Moose  River.  At  Gaspe,  it  includes  the  upper  part  of  the  limestone  formation, 
and  probably  the  lower  part  of  the  sandstone  beds,  a  Rensselaeria  having  been  found 
1,100  feet  above  the  base  of  the  sandstones. 


II.  Life. 
1.  Plants. 

Sea-weeds  are  not  uncommon.  No  remains  of  land-plants  have  yet 
been  observed  in  the  beds  of  New  York,  or  at  the  West.  But,  in  the 
upper  limestones  of  Gaspe,  remains  of  a  small  species  of  the  Lyco po 
dium  or  Ground-Pine  tribe  occur,  which  have  been  named  by  Dawson 
Psilophyton  princeps,  a  figure  of  which  is  given  on  p.  258.  The  Ly- 
copods  are  Cryptogams,  or  flowerless  plants,  but  belong  to  the  highest 
division  of  Cryptogams,  that  of  Acrogens.  The  plant  grew  to  about 
the  same  height  with  the  common  American  species  Lycopodium  den- 
droideum.  (For  further  description,  see  p.  257.) 

2.  Animals. 

The  most  common  Mollusks  are  the  coarse  Spirifer  arenosus  H. 
(Fig.  475),  and  the  Rensselaeria  oroides  H.  (Fig.  476.)  The  rock  is 

Figs.  475-470. 


BRACHIOPODS.  —Figs.  475,  475 a,  Spirifer  arenosus  ;  476,  Rensselaeria  ovoides. 


often  made  up  of  these  large  fossil  shells  crowded  together,  or  con 
tains  their  moulds,  with  the  cavities  the  shells  once  occupied.     Fig. 


UPPER   SILURIAN.  243 

475  a  represents  a  cast  of  the  interior  of  Spirifer  arenosus.  There  are 
also  many  other  species  of  J3rachiopods,  and  a  number  of  Lamelli- 
branchs,  Gasteropods,  and  Cephalopods.  Among  the  Gasteropoda,  the 
shells  of  Platyceras  are  in  some  places  very  numerous  ;  they  are  a  thin 
shell  of  a  floating  Mollusk,  related  to  the  delicate  lanthina  of  modern 
seas  ;  as  stated  by  Hall,  they  often  occur  in  the  Maryland  beds,  in 
groups,  as  if  drifted  together  by  the  winds  or  gentle  currents.  Cri- 
noids  are  rare  fossils  in  New  York,  but  common  in  Maryland.  No 
Fishes  have  yet  been  found  in  the  beds. 

The  Crinoids  in  Maryland  include  a  number  of  fine  species  of  the  genera  Mariacri- 
nus,  EdriocrinWj  and  others,  besides  three  species  of  Cystideans,  and  among  them  one 
of  the  peculiar  genus  Anomalocystites  (allied  to  Fig.  458).  The  rock  in  some  places  con 
tains  a  wonderful  profusion  of  shells,  although  the  number  of  species  is  small. 

Rensselaeria  ovoides,  Spirifer  arenosus,  together  with  the  Cauda-yallifucoid  (Fig.  484, 
p.  255)  and  three  species  of  Chonetes,  occur  in  the  upper  500  feet  of  the  Gaspe  lime 
stone,  as  determined  by  Billings,  associated  with  Favosites  Gothlandica  Lam.,  F. 
basfiltica  Goldf.,  F.  cervicwnis  De  Blainville,  two  species  of  Znphrentis,  Strophonuna 
rhomboidaUs,  S.  Becki,  S.  perplanu.  Con.,  Leptocoelia  concava  II.,  L.  flabellites  H.,  Eato- 
nitt peculiaris  H.,  Atrypa  reticularis,  Meristella  kecis  H.,  species  of  Modiolopsis,  Avicula, 
Mtirchisonifi,  Loxoneina,  Orthoceras,  Phncops,  Proetus,  also  Dalmanites  pleuroptyx, 
etc.  The  fucoid  extends  down  800  feet,  and  is  abundant.  At  Parlin  Pond,  in  northern 
Maine,  there  occur  Rensselaeria  ovoides,  Leptocoslia  Jinbellites,  Spirifer  arrectus  H.,  S. 
pyxidatus  H.,  Strophomena  (Hemipronites)  mitynifica  H.,  Rhynchondla  oblata  H.,  Orfhis 
musculosa  H.,  Dalmanitei pleuroptyx,  species  of  Chonetes,  Modiolopsis,  Cyrtodonta,  Avic- 
ula,  Murchisonin ,  Platyostoma,  Ortliocems. 

The  ribs  of  some  Oriskany  Spirifers  have  a  peculiarity  observed  in  only  one  other 
American  Silurian  species  (of  the  Niagara  epoch),  but  in  Europe  not  known  before  the 
Devonian  age,  —  which  is,  that  they  subdivide  dichotomously,  instead  of  being  simple. 
The  shell, in  the  genus  Rensselaeria  Hall,  contains  a  loop-like  arm-support,  a  little  like 
that  in  Terebratula,  but  it  is  only  curved,  instead  of  bent,  and  has  a  spade-shaped  ter 
mination. 

III.  General  Observations. 

The  Oriskany  sandstone  is  another  of  the  arenaceous  rocks  ranging 
from  central  New  York  to  the  southwest,  along  the  Appalachian 
region,  and  thus  serving  to  define  the  old  Appalachian  sand-reef.  As 
in  other  cases,  the  rock  thickens  on  going  from  New  York  to  the 
southwestward.  The  fossils  and  the  distribution  of  the  formation  over 
the  State  of  New  York,  seem  to  point  to  the  existence  at  this  epoch 
of  inland  waters  opening  into  the  ocean  to  the  southeast,  —  as  might 
have  existed  if  the  Green  Mountain  region  (as  before  in  the  Upper 
Silurian  era)  were  out  of  water,  and  if  also  the  Archaean  of  northern 
New  Jersey  (see  p.  150),  the  proper  continuation  of  the  Green  Moun 
tains,  were  an  island  or  reef  in  the  sea.  The  muddy  and  sandy  bot 
tom  of  the  bay  would  have  given  the  shells  a  fit  place  for  growth.  To 
the  south,  as  the  fossils  in  Maryland  and  beyond  show,  the  accumula 
tions  were  those  of  an  open  bay  or  coast,  where  there  were  at  least 


244  PALEOZOIC   TIME. 

purer  waters.  We  may  hence  conclude  that  the  Green  Mountain 
region  was  a  north-and-south  island  or  peninsula,  lying  between  seas 
of  the  Connecticut  valley  and  those  of  New  York,  and  having  the  St. 
Lawrence  channel  on  the  north.  The  region  of  Appalachian  sub 
sidence,  instead  of  including  the  Green  Mountains,  as  in  the  early 
Lower  Silurian  era,  extended  northward,  in  the  direct  line  of  the 
Alleghanies,  over  the  southern  half  of  central  New  York,  as  in  parts 
of  the  Upper  Silurian ;  for  this  is  indicated  by  the  position  of  the 
sandstone. 

2.  FOREIGN  UPPER  SILURIAN. 

Rocks.  —  The  rocks  of  the  Upper  Silurian  are  widely  distributed 
over  the  globe,  though  less  universal  than  those  of  the  Lower  Silurian. 
They  occur  in  Great  Britain,  Scandinavia,  Russia,  Germany,  Bohemia, 
and  Sardinia,  but  have  not  been  identified  in  France  or  Spain  ;  also  in 
Asia,  Africa,  and  Australia.  They  sustain  the  principle  that  the 
earlier  formations  are  in  general  of  continental  range.  They  seem  on 
a  geological  map  to  cover  but  small  areas,  but  only  because  they  are 
concealed  by  later  formations. 

The  Upper  Silurian  Rocks  of  Great  Britain  comprise,  commencing  with  the  ear 
liest  :  — 

1.  The    Upper  Llandorery  sandstone  of   South  Wales,  about  900  feet  in  thickness, 
which  generally  lies  unconformably  on  the  Lower  Silurian,  and  its  equivalents.     The 
May  Hill  sandstone  of  Shropshire,  which  was  first  so  named,  and  shown  to  be  Upper 
Silurian,  by  Sedgwick.     These  sandstones  terminate  in  the  Tarannon  shales,  GOO  feet 
where  thickest.     This  group  is  regarded  as  the  equivalent  of  the  Medina  and  Clinton 
groups. 

2.  The  Wenlock  Group,  consisting  of  the  gray  and  black  Wenlock  shales,  1,400  feet 
thick,  and  the  Wenlock  limestone,  100  to  300  feet  thick.    The}'  are  well  exposed  between 
Aymestry  and  Ludlow,  and  along  Wenlock  Edge  to  Bethel  Edge ;  also  near  Dudley, 
where  the  Woolhope  limestone,  a  lower  part  of  the   series,  50  feet   thick,  overlies  the 
Llandovery  sandstone.     The  limestone  is  full  of  fossils,  or  rather  is  made  up  of  them 
closely  compacted;  and   much  of  it  looks  as  if  it  were  a  deep-water  formation.    Its 
American  equivalent  is  the  Niagara  group. 

3.  The  Ludlow  Group,  made  up  of  (1)  the  Lower  Ludlow  rock  of  Shropshire,  con 
sisting  of  layers  of  shale  and  impure  sandstones  or  mudstones,  900  feet  thick;  (2)  the 
Aymestry  limestone,  an  impure  limestone,  150  feet  thick;  (3)  the  Upper  Ludlow  rock, 
a  shaly  or  impure  sandstone,  much  like  the  Lower  Ludlow,  900  feet  thick.     The  Tile- 
st,ones  are  series  of  red  and  gray  sandstones,  marlytes  and  red  conglomerates,  ],000  feet 
thick,  regarded  as  passage-beds  to  the  Devonian.    These  Ludlow  beds  and  the  Tilestones 
are  apparently  equivalents  of  the  later  half  of  the  American  Silurian.     There  are  one 
or  two  thin  bone-beds  between  the  Tilestones  and  the  Ludlow,  consisting  of  remains  of 
fishes  and  crustaceans.     The  limestone  of  the  Upper  Silurian  fails  in  North  and  South 
Wales,  and  in  some  parts  even  the  distinction  of  Wenlock  and  Ludlow  cannot  be  made 
out. 

In  Cumberland  or  Northern  England,  the  Coniston  grits,  Ireleth  slates,  and  Kendal 
group  correspond  to  the  above  groups  1,  2,  3.  In  Scotland,  the  lower  Sandstone  is 
represented  in  Southern  Ayrshire,  and  the  Wenlock  in  the  Pentland  Hills.  Upper  Si 
lurian  rocks  occur  also  hi  Ireland. 


UPPER   SILURIAN.  245 

In  Scandinavia,  the  limestones  and  sandstones  of  Gothland  represent  the  Niagara, 
and  the  Calciferous  flags  and  Upper  Malmo  group  the  Lower  Helderberg.  In  Bohemia, 
the  rocks  include  the  limestones  and  schists  of  Barrande's  formations  E,  F,  G,  H. 

Life.  —1.  Plants.  —  Besides  sea-weeds,  there  are  the  remains  of  ter 
restrial  plants.  In  the  Upper  Ludlow  beds,  occur  seed-vessels  called 
Pachytheca  by  Hooker,  and  also  fragments  of  stems,  supposed  to  be 
those  of  Lycopods  (Ground  Pines)  related  to  the  Psilophyton.  In 
Germany  at  Lobensteiu,  and  at  Hostin  in  Bohemia,  Lycopods  of  the 
Lepidodendron  family  occur  —  a  kind  having  the  bark  marked  regu 
larly  with  scars  where  the  leaves  have  dropped  off,  similar  to  those  on 
a  young  dry  branch  of  a  spruce.  The  word  Lepidodendron  is  from 
Xe— iV,  scale,  and  ScpSpup,  tree,  the  bark,  owing  to  the  scars  over  it,  often 
looking  as  if  scale-covered.  The  species  are  referred  to  the  genus 
Sagenaria.  These  plants,  like  modern  Lycopods,  had  much  of  the 
habit  of  the  spruce  or  pine  tribe.  For  figures  see  pages  323,  324. 

Besides  these  flowerless  species  (Cryptogams),  others  of  genera  of 
the  Pine  tribe  —  the  lowest  division  of  flowering  plants  (Phenogams) 
—  are  supposed  by  Dawson  to  have  existed,  he  referring  pieces  of 
carbonized  wood  in  the  Upper  Ludlow  beds  to  the  genus  Prototaxites 
(so  named  from  Trpwro?,  jfirst,  and  taxus,  yew-tree).  Carruthers  con 
siders  the  plant  a  sea-weed. 

2.  Animals.  —  The  range  of  Invertebrate  animal  life  and  the 
general  types  are  similar  to  those  of  America,  while  the  species  are 
for  the  most  part  different. 

A  few  species  are  represented  in  Figs.  477  to  482.  Figs.  477,  477  a  represent  a 
Cyathophylloid  coral  Omphyma  turbinatum'M.  Edw.,  of  the  Wenlock,  reduced  one-half  ; 
478,  a  section  of  another  coral,  a  species  of  Cyetfykyttum,  from  the  same  beds;  479,  a 
peculiar  Crinoid,  Crotalocrinus  ruyosus  Miller,  from  the  Wenlock  ;  480,  the  Pent.amerus 
Kniyht'd  Sow.,  a  characteristic  fossil  of  the  Aymestry  limestone;  481,  a  Lamellibranch, 
Grammy  sin  cinyulata  Morris,  of  the  Dudley  limestone:  482,  the  Crustacean,  Ptery- 
yotus  bilobus  Salter,  from  the  upper  Ludlow;  and  482  a,  one  of  the  jaws.  The  ear 
liest  species  of  these  Pteryyoti  occur  in  the  upper  beds  of  the  Upper  Llandovery,  the 
lower  part  of  the  Upper  Silurian ;  while  in  North  America  none  have  been  found 
below  the  Lower  Helderberg. 

Besides  Invertebrates,  there  were  the  earliest  Vertebrates  —  Fishes. 
The  first  (Pteraspis)  is  from  the  lower  Ludlow.  Fig.  483  a  repre 
sents  Pteraspis  Banksii  Huxl.  &  S.,  a  head-shield,  related  to  the  fol 
lowing.  Fig.  483  b  is  the  head-shield  of  a  Cephalaspis  —  so  named 
from  the  Greek  for  a  shield-like  head  ;  a  complete  animal,  but  different 
in  species,  is  shown  on  page  286.  Fig.  483  d,  represents  probably 
part  of  the  jaw-bone  of  a  Cephalaspis. 

Other  fishes  were  of  the  shark  tribe.  Fig.  483  c,  represents  a  spine 
from  the  margin  of  the  fin  of  one  of  them  ;  and  483  e,  two  of  the 
minute  pieces  much  magnified  (the  natural  size  is  shown  in  the  upper 


246 


PALEOZOIC   TIME. 


of  the  three  figures)  which  constituted  the  hard  rough  skin  (shagreen) 
of  a  shark.     A  number  of  Upper  Silurian  fishes  have  been  described. 


Figs.  477-482. 
482 


477 


Fig.  477,  Omphyma  turbinatum  ;  478,  Cystiphyllum  Siluriense  ;  479,  Crotalocrinus  rugosus  ;  480, 
Pentamerus  Knightii  ;  481,  Grammysia  cingulata  ;  482,  482  a,  Pterygotus  bilobus. 

from  the  rocks  of  Russia  and  Bohemia,  including  species  of  Coccosteus 
and  Pterichthys,  and  the  fin-spines  of  sharks  ;  figures  of  other  species 

Fig.  483. 


FISHES.  —  Fig.  483  a,  Pteraspis  Banksii,  tail-shield  ;  483  b,  Cephalaspis  Murchisoni,  inside  of  head- 
shield  ;  c,  spine  of  Onchus  tenuistriatus  ;  d,  Plectrodus  mirabilis  :  e,  Shagreen  pieces  of  Thelodus 
parvidens. 

of  these  genera  are  given  on  p.  285.     For  further  remarks  on  the 
subdivision  to  which  these  fishes  belong,  see  page  262. 


UPPER   SILURIAN.  247 


Characteristic  Species. 

1.  Upper  Llanduvery. — Petraia  bina  Phillips,  Atrypahemisphairica,  Rhynchonelln,  ney~ 
lecta,  R.  anyustifronsS.,  R.   Wilscmi  Strophomena  arenacea  (or  concent rica  Portl.),  S. 
compressd  S.,  Pentamerus  ylobosus  Sow.,  P.  oblonyus  Sow.,  Orthislata  Sow.,  Lyrodesma 
cuneata  Phil.,  Pterinea  sublcevis  M'Coy.,  Murchisonia  anyulata  Sow.,  Cyclontma  quad- 
ristriatum,  Phil.,  Raphistoma  lenticularis  Sow. 

2.  Wenlock  (/roup. — Petraia  bina,    Cyathopliyllum  truncatum  Linn.,   Ompliyma  tur- 
binatum  (Fig.   477),   Favosites  Gothlandica,   F.   alveolaris,   Halysites  oitenul'tta,  lit  Ha 
lites  Gr«yi  E.  &  H.,  //.  interstincta,    Syrinyopora  bifurcata  Lonsd  ,  Cystipltyllum  Silnr- 
iense  Lonsd.  (Fig.  478),   Stenopora  Jfbrosa,  Ptilodictya  scalpvllum  Lonsd.,   and  many 
other  Bryozoans,  Actinocrinus  pulcher  S.,  Crotalocrinus  rugosus  (Fig.  479),  Hyprmth- 
oerintudecorus'Phill,,  Marsupiocrinus  ccd'itus  Phill.,  Atrypareticularit,  OrtMs  eleymitula, 
Rhynchonella  Wilsoni,   Pentamerus  yaleatus,  Strophomena  rhomboidalis,  Spirifer  pllvi- 
tellus,   Modioloptis    antiqua  Sow.,    Conocardium    (equicostntum,    Pterinea     retroflexa, 
Grammytin  cinyulnta  (Fig.  481),  Orthoceras  annulatum  Sow.,  Tentaculites  ornatus  Sow., 
Addnspis  Bnrrand'ti  Ketley,    Calymene   Blumenlmclrii,    Homalonotus  delphinocephalus, 
Lichas   Anglicus,   Phacops  caudatus,  Encrinurus  vnriol'iris  Brngt.      The  earliest   re 
mains  of  Cirripeds  yet  known  occur  in  the  Wenlock  limestone. 

3.  Ludloii'   Croup. —  GraptolitJius  priodon   Bronn.,  Cyathaxonia    Siluriensis  M'Coy, 
Pentamerus  Kniyhtii  (Fig.  480),  Rhynchonella  nucula  Sow.,  R.  pentayona  Sow.,  Linyula 
Lewisii  Sow.,  Modioloj)sis  complanata,  Pterinea  retrojlexa,  Acicula,  Danbyi  M'Coy,  Rtl- 
lerophon  expansus  Sow.,   Loxonema  sinuosum   Sow.,   Conularia  subtilis  S.,   Orthoctras 
bullatum,  Calymene  Blumenbachii,  Encrinurus  punctatus  Wahl.,  Homalonotus  Kniyhtii 
Konig,  Lichas  Anylicus  Beyrich,  Phacops  caudatus  Briinn,  several  species  of  Euryp- 
terus  (the  earliest  in  the  Upper  Ludlow),  Pteryyotasbilobus  (Fig.  482),  and  other  species 
(one  from  the  Upper  Llandovery),  Ceratiocaris  inornatus  M'Coy,  C.  tllipticus  M'Coy. 

Fig.  484. 


Ceratiocaris. 

Salterhas  illustrated  the  form  of  the  Ceratiocaris  by  Fig.  484:  the  length  is  some 
times  four  inches  or  more. 

In  the  Ludlow  group,  mostly  its  upper  part,  occur  remains  of  the  earliest  known  fishes 
of  British  seas,  among  which  are  the  species,  Onchus  tenuistriatus  (Fig.  483  c), 
Plectrodus  miraUlis  Ag.  (Fig.  483  d),  (perhaps  Cephalaspis\P.pustuliferus  Ag.,  Pter- 
aspisBanksii  Huxley  &  Salter  (Fig.  483  a),  Pt.  truncatus  H.  &  S.,  species  of  Sphayodus. 
A  species  of  Pteraspis  occurs  in  the  Lower  Ludlow,  and  this  therefore  is  the  earliest 
form  of  fish  known.  This  genus  is  related  to  Cephalaspis.  There  are  also  in  the 
same  rocks  Coprolites  from  some  of  these  Fishes,  containing  fragments  of  the  shells  of 
the  Mollusks  and  Crinoids  on  which  they  fed.  Remains  of  Fishes  have  also  been  found 
in  the  upper  part  of  the  Upper  Silurian  of  Russia  and  Bohemia.  The  Pteraspis  has 
been  referred  to  Crustaceans. 

The  following  tables  show  the  distribution  in  other  countries  of  some  species  of  the 
Niagara  and  Lower  Helderberg  periods. 


248  PALEOZOIC   TIME. 


1.  American  Clinton  and  Niagara  Species  occurring  elsewhere, 

Stromatopora  concentrica,  Great  Britain  (Dudley),  Sweden,  Russia,  Eifel. 

Halysites  catenulata,  Great  Britain  (Llandeilo,  Dudley,  Aymestry),  Norway,   Sweden 

Russia,  Eifel. 
Heliolites  pyriformis,  Great  Britain  (Wenlock,  Aymestry),  France,  Sweden,  Russia, 

Eifel. 

Limaria  fruticosa,  Great  Britain  (Dudley,  Aymestry),  Russia. 
Limaria  clathrata  (?),  Great  Britain  (Dudley),  Russia. 
Ichthyocrinus  lens  Con.  (  ?),  Great  Britain  (Dudley). 
Eucalyptocrinus  decorus,  Great  Britain  (Dudley). 
Orthls  eleyantula,  Great  Britain  (Wenlock),  Gothland  (in  Sweden). 
Ortlris  hybrida  Sow.,  Great  Britain. 
Orthis  biloba,  Great  Britain  (Dudley),  Gothland. 
Orthisjlabellulum,  Great  Britain  (Bala.) 
Leptcena  transversalis,  Great  Britain,  Gothland. 
Strophomena  rhomboidnlis  (formerly  Leptcena  depressa  and  Stroph.  ruyosa],  Great  Britain 

(Dudley,  Aymestry),  Sweden,  Russia,  Belgium,  Eifel,  France,  Spain. 
Spirifer  crispus  Hising.,  Great  Britain  (Llandeilo,  Dudley),  Gothland. 
Spirifer  radiatus,  Great  Britain  (Dudley). 
Spirifer  sulcatus  Hising.  (  ?),  Great  Britain  (Dudley). 
Nucleospira  pisum,  Great  Britain  (Wenlock  and  in  Scotland). 
Atrypa,   reticularis,    Great  Britain    (Wenlock),    Gothland,    Germany,   Russia   (L'rals, 

Altai). 

Merista  (Rhynchonella)  nitidn,  Great  Britain  and  Gothland. 
Rhynchonella  bidentata,  Great  Britain  (Wenlock). 
Rhynchonella  cunenta,  Great  Britain  (Wenlock),  Gothland. 
RkynchoaeUa pKc<itella  Dalm.,  Great  Britain  (Wenlock,  Aymestry). 
Rhynchonella  Wilsoni,  Great  Britain  (Wenlock). 
Rhynchospira?  (Atrypa)  aprinis,  Russia. 
Pentamerus  brevirostris  Ff.,  Great  Britain. 
Pentamerus  oblonf/m,  Great  Britain  (Wenlock). 

Pentamerus  levis,  Great  Britain  (Wenlock).  —P.  Knightii,  Great  Britain  (Ludlow). 
Anastrophia  interplicata,  Great  Britain. 
Orthoceras  implicatum,  Great  Britain  (Ludlow),  Gothland. 
Orthoceras  annulatum,  Great  Britain  (Wenlock). 
Orthoceras  viryatum,  Great  Britain. 
Orthoceras  undulatum,  Great  Britain,  Eifel. 
lllcemis  (Bumastis)  Barriensis,  Great  Britain  (Dudley). 
Phacops  limulurus  (?),  Great  Britain  (Dudley),  Bohemia,  Sweden. 
Ceraurus  insiynis,  Bohemia. 
Calymene  Blumenbachii,  Great  Britain  (Bala,  Wenlock),   Sweden,  Norway,  Bohemia, 

France. 

Homalonotus  detphinocephalus,  Great  Britain  (Dudley). 
Proetus  Stokesii  Murch.,  Great  Britain  (Dudley). 

2.  American  Lower  Helderbery  Species  occurring  elsewhere. 

Strophomena   niyosa,    Great   Britain    (Dudley,   Aymestry),   Gothland,   Russia,    Eifel, 

France,  Spain. 

Atrypa  reticularis,  Great  Britain  (Wenlock),  Sweden,  Russia  (Urals,  Altai),  Bohemia. 
Dalmanites  nasuta,  Great  Britain,  Sweden,  Russia. 
Eurypteriis  remipes,  Russia  (island  of  Oesel,  according  to  Keyserling). 
Pentamerus  yaleatus,  Great  Britain  (Aymestry,  Dudley,  Ludlow),  Eifel. 

There   are  a  number  of  other  species  closely  like  European,  but  they  are  regarded 
bv  Hall  as  distinct. 


UPPER   SILURIAN.  249 


3.  Arctic  American  Upper  Silurian  Species  occitrrin, 

Btromntopora  concentrica,  Great  Britain,  Eifel. 

Haly sites  catenulatn.  Great  Britain,  Norway,  Sweden,  Russia,  United  States. 

Favosites  Gotkhndicd,  Great  Britain,  Sweden,  United  States. 

Favositetpolymorpka,  Great  Britain,  France,  Belgium,  Eifel. 

Receptaculites  Neptuni,  Great  Britain,  Belgium,  Eifel,  United  States. 

Orthis  elegantula,  Great  Britain,  Gothland,  Russia,  United  States. 

Atrypa  reticulirig,  Great  Britain,  Gothland,  Urals,  Altai  in  Siberia,  United  States. 

Pentamerus  conchidium  Dalman,  Gothland. 

Rhynchonella  (f)  &ublep>da(?)  De  Verneuil,  Urals. 

Encrinurus  leris  (?)  Angelin,  Gothland. 

Leperditia  Baltics  Hisinger,  Gothland. 

A  considerable  number  of  species  in  the  British  Lower  Silurian  pass  into  the  Upper 
Silurian.  They  are  found  mingled  in  the  intermediate  Llandovery  formations  ;  which, 
although  classed  with  the  Upper  Silurian,  contain  between  40  and  50  species  that  occur 
also  below. 

Barrande  has  found  nearly  2,800  species  of  fossils  in  the  Bohemian  Silurian  basin, 
including  the  Primordial  strata.  The  limestone  E  abounds  in  organic  remains;  and 
among  them  are  400  species  of  Cephalopods,  and  18-3  species  of  Trilobites  (of  the  genera 
Catymene,  Acidaspis,  Ceraurus,  Cyphasjjis,  Lichas,  Phacops,  Harpes,  Bronteus,  and 
Proetus).  Barrande  regards  this  as  the  culminating  period  for  the  Trilobite  race.  Lime 
stone  F  also  contains  88  species  of  Trilobites,  and  of  the  same  genera,  associated  with  a 
profusion  of  Brachiopods.  In  G,  there  are  many  Goniatites  anil  other  species,  which 
show  that,  while  the  strata  are  intimately  connected  with  E  and  F  physically,  and  in 
their  fossils,  the  period  probably  corresponds  in  part  with  the  early  Devonian.  Besides 
56  species  of  Trilobites  of  the  above  genera,  there  are  others  of  the  Devonian  genus 
Dalmunites.  In  Bohemia,  57  Lower  Silurian  species  pass  into  the  Upper  Silurian. 

A  list  of  the  genera  common  to  the  American  and  European  continents  would  show 
almost  a  complete  identity,  and  the  same  system  of  progress  from  the  Lower  Silurian 
onward.  In  each,  the  genera  Spirifer  and  Chonetes,  among  the  Brachiopods,  were 
added  to  Orthis,  Leptcena,  and  Atrypa;  Halt/sites  (Chain-corals),  Facosites,  and  Cyatho 
phyllidce  became  abundant;  Crinoids  were  greatly  multiplied ;  and  the  Eurypterus  group, 
or  Cyclopoid  Crustaceans,  commenced  a  new  line  among  the  Articulates;  while  Grap- 
tolites,  so  common  in  the  Lower  Silurian,  were  few  in  species  and  numbers. 

The  number  of  Silurian  species  described,  up  to  1872,  according  to  Barrande,  is  as 
follows :  — 

Sponges  and  other  Protozoans     .     153  Bryozoans 478 

Polyp  Corals 718  Brachiopods 1,567 

Echinoderms  (Crinoids,  etc.)  .     .     588  Lamellibranchs 1,086 

Worms 185  Heteropods  and  Pteropods     .     .      390 

Trilobites 1,579  Gasteropods 1,316 

Other    Crustaceans    ( including  Cephalopods 1,622 

some  Cirripcds) 348  Fishes 40 

Which,  with  4  of  uncertain  relations,  make  in  all  10,074  species. 

3.  OBSERVATIONS  ON  THE  UPPER  SILURIAN. 
1.  General  features.  —  Fresh-water  lakes  and  rivers,  fresh-water  de 
posits,  and  land  or  fresh-water  animal  life,  continue  unknown  through 
the  American  records  of  the  Upper  Silurian,  as  thus  far  investigated. 
Such  rivers  and  lakes  probably  existed,  as  it  is  certain  there  was  dry 
laud ;  but  they  have  left  nothing  that  survived  subsequent  changes. 


250  PALEOZOIC   TIME. 

It  is  barely  possible  that  some  of  the  Mollusks  may  have  lived  in 
fresh  waters ;  but  the  remains  are  so  mingled  with  species  that  are 
obviously  salt-water  types  that  it  cannot  be  proved  to  be  true  of  any. 

2.  Individuality  of  the  Eastern-border  region  in  American  geo 
logical  history.  —  Some  general  facts  bearing  on  this  subject  are  men 
tioned  on  page  160.  The  individuality  of  the  region  is  illustrated 
most  conclusively  by  the  life  of  the  waters,  as  shown  by  Salter  and 
Billings. 

Thus,  there  are,  in  the  beds  of  this  region  of  the  Primordial  and  Canadian  periods, 
Salterella  ruyosa  Billings,  closely  like  the  Scottish;  S.  Maccullochi,  Salter;  Kutoryina 
cinyulata  B.,  said  by  Davidson  and  Hall  to  occur  in  the  Lingula  flags;  Acrotretu 
yfmma  B.,  very  near  A.  subconica  Kutorga;  four  species  of  Piloceras,  a  genus  de 
scribed  from  Scotland,  but  not  known  in  the  United  States;  Ilolometojms  Anydini  B., 
very  near  //.  limbatus  Angelin,  of  Sweden;  Niltus  macrops  B.,  JV.  scrutatus  B.,  N. 
affinis  B.,  all  closely  allied  to  N.  armadillo  of  Dalman;  Harpides  Atlanticus.  very  near 
Angelin's  H.  ruyosus  of  Sweden.  In  the  beds  of  Cincinnati  group  age,  there  are 
Ascoceras  Canadense  B.,  A.  Newberryi  B.,  and  Glossoceras  desideratum  B.,  not  found  in 
the  United  States.  In  the  Upper  Silurian,  there  are,  as  shown  by  Salter,  the  British  spe 
cies  Rhynch one lla  Wilsoni  Sow.,  Grammysia  trianyulata  Salter,  G.  cinyulata  His.,  Platij- 
scJtisma  Ilelicites  Sow.,  Acroculiq  II  tliotis  Sow.,  Bellerophon  expansus  Sow.,  B.  carina- 
tus  Sow.,  0.  bullatum  Sow.  (?),  0.  ibex  Sow.,  Homnlonotus  Kwjjhtn  Kunig,  PJiocojM 
Doicniiiyii  Salt.,  to  which  Billings  adds  Rhynclwndl-i  StricUnndii  Sow.,  and  Lituites 
Ameiicanum  B.,  very  near,  if  not  quite  identical  with  L.  yiyanteuin  Sow.  Mr.  E.  Bil 
lings,  who  furnished  this  work  the  above  list  of  species,  adds  that,  through  the  Pri 
mordial  and  Canadian  periods,  there  is  a  decided  European  tinge  in  the  life ;  but  in 
the  Trenton  period  its  character  was  peculiarly  American.  Then  in  the  Cincinnati 
epoch  there  was  again  a  European  tinge,  which  increased  in  strength  through  the  Upper 
Silurian. 

3.  Conditions  of  the  North  American  Continent.  —  The  survey 
of  the  successive  formations  of  the  Upper  Silurian  teaches  that  the 
geological  changes  in  progress,  like  those  of  the  earlier  Silurian, 
operated  widely  over  the  continent.  The  causes  in  action  were  not 
making  a  mere  edging  to  the  continent,  as  in  Tertiary  times,  but  were 
building  up  the  very  continent  itself  by  wide-spread  accumulations  of 
limestone,  sands,  and  clays. 

Moreover,  the  continental  seas  were  not  the  ocean's  bed,  although 
they  may,  over  wide  areas  at  times,  have  exceeded  500  or  1,000 
fathoms  in  depth.  In  many  of  the  rocks,  the  ripple-marks  of  some 
layers,  rill-marks  of  others,  and  cracks  from  sun-drying  of  others, 
often  in  the  same  stratum,  prove  the  shallowness  of  the  water  over 
great  regions,  and  a  wide  expanse  of  exposed  beaches  and  marshes 
elsewhere.  The  beds  of  iron  ore  in  the  Clinton  group,  which  have 
great  extent,  are  other  proof  of  wide-spread  marshes  over  the  coun 
try,  since  such  deposits  cannot  form  in  the  open  sea.  The  brines  of 
the  Salina  period  again  mark  a  time  of  salt  marshes  or  inland  salt 
lakes  in  New  York. 

The   continent    still   included  comparatively   little    permanent    dry 


UPPER    SILURIAN.  251 

land,  and  that  was  mainly  to  the  north.  It  had  enlarged  somewhat 
since  the  Lower  Silurian  era  ;  but  the  greater  part  of  the  United 
States  was  yet  to  be  completed,  by  the  deposition  of  the  Devonian, 
Carboniferous,  and  later  beds. 

Shales  and  sandstones  prevailed  in  the  East,  from  the  vicinity  of 
the  Archaean  of  New  York  southwest  along  the  Appalachian  region. 
But,  in  the  west,  the  rocks  of  the  Upper  Silurian  are  mainly  limestones  ; 
for  the  Niagara  limestone  is  widely  distributed  in  the  Interior  basin  ; 
and  even  in  the  Oriskany  period,  the  beds  are  partly  calcareous.  The 
West  was  therefore  in  certain  parts  still  making  limestones,  while 
the  East  interposed  between  its  limestones  extensive  clay  and  sand 
deposits.  The  limestones  of  the  West  prove  that  there  were  but 
slight  changes  of  level  there  during  the  long  era  when  each  stratum 
was  forming ;  for,  if  great,  they  would  have  resulted  in  an  extermi 
nation  of  the  life,  and  a  change,  therefore,  in  the  character  of  the 
limestone.  At  the  same  time,  the  great  thickness  of  the  argillaceous 
beds  and  sandstones  of  the  East  indicate  great  oscillations  over  the 
Appalachian  region ;  during  the  Niagara  period,  they  amounted,  in 
Pennsylvania,  to  at  least  500  feet  in  the  Oneida  epoch,  1,500  feet  in 
the  Medina,  over  2,000  feet  in  the  Clinton,  1,500  feet  in  the  Niagara 
and  Salina,  and  500  in  the  Lower  Helderberg,  —  in  all  6,000  feet. 
In  the  Salina  period,  the  subsiding  area  stretched  up  into  New  York, 
west  of  its  centre  ;  for  it  was  there  that  the  Salina  beds  were  formed 
to  a  thickness  of  1,000  feet,  with  evidence  in  many  parts  of  shallow- 
water  origin. 

After  the  Salina  period  closed,  limestones  (the  Lower  Helderberg) 
were  formed,  some  hundreds  of  feet  thick,  over  the  Hudson  lliver 
valley,  and  probably  all  the  way  to  Montreal,  showing  that  the  sea 
had  again  free  access  over  eastern  New  York.  East  of  the  Green 
Mountain  region  also,  there  wras  probably  salt  water  and  some  lime 
stone  making,  along  a  large  part  of  the  Connecticut  valley,  and  over 
much  of  the  country  thence  to  the  St.  Lawrence  Gulf. 

The  conclusion  cited  from  Mr.  Billings,  on  page  250,  that  the 
Trenton  period,  in  the  region  of  the  Gulf  of  St.  Lawrence,  fails  of 
that  commingling  of  European  species  which  occurs  in  the  period  pre 
ceding  and  those  following,  accords  with  the  fact  that  the  Trenton 
limestone  was  eminently  continental ;  it  extending  across  the  continent, 
even  over  the  Appalachian  region  ;  and  it  sustains  the  conclusion 
that  the  Trenton  limestone  was  made  in  an  interior  sea,  and  hence 
that,  to  the  north,  the  outside  barrier  of  that  sea  lay  to  the  east  of 
the  present  coast  line,  and  thus  prevented  the  introduction  of  British 
species.  But  in  the  following  Cincinnati  period  there  was  a  change 
which  resulted  in  making  the  Appalachian  region  again  a  region  of 


252  PALEOZOIC   TIME. 

shales  and  sandstones,  and  this  fact,  together  with  the  new  incursion 
of  British  species,  is  evidence  that  this  eastern  coast-barrier  had 
dipped  down  beneath  the  ocean  again  ;  while  the  additional  fact  that 
the  rocks  of  the  same  Atlantic  border,  which  follow  the  Trenton,  in 
the  Upper  Silurian  era,  are  mainly  limestones,  would  seem  to  prove 
that  the  barrier  was  only  partly  submerged. 

Life.  —  The  closing  period  of  the  Upper  Silurian  gives  the  first 
positive  evidence  of  the  existence  of  terrestrial  plants  in  the  world.  As 
stated  in  connection  with  the  Archasan,  on  pp.  157,  158,  the  fact  that 
Lichens  are  not  found  fossil,  nor  the  destructible  Fungi,  is  no  evidence 
that  these  classes  of  terrestrial  vegetation  were  not  well  represented. 
But,  considering  the  millions  of  years  that  passed  in  the  course  of 
the  Lower  Silurian  and  the  first  half  of  the  Upper  Silurian  (nearly 
half  of  all  geological  time  from  the  commencement  of  the  Primordial 
onward),  and  the  numberless  chances  for  the  burial  of  a  drifted  leaf, 
or  broken  stem,  or  a  whole  uprooted  plant,  if  any  such  existe'd  along 
the  sea-shores,  or  in  valleys  which  poured  streams  into  the  continental 
seas,  the  absence  of  remains  of  all  higher  land  plants  affords  a  strong 
presumption  that  they  did  not  exist.  What  were  the  precursors  of 
the  Oriskany  and  Ludlow  Lycopods  and  Gymnosperms,  is  yet  wholly 
unexplained.  We  have  no  right  to  suppose  them  to  have  been 
Mosses,  since  no  moss  has  yet  been  found  fossil,  even  in  the  rocks  of 
the  long  Devonian  and  Carboniferous  eras  which  follow.  The  species 
of  Eophyton  (p.  176)  are  too  doubtful  to  be  here  considered. 

The  animals  of  the  Upper  Silurian,  found  fossil  in  American  rocks, 
are  all  Invertebrates,  like  those  of  the  Lower  Silurian,  and  similar 
in  general  types.  The  Cephalopods  are  the  highest  species  among 
Mollusks,  and  the  Trilobites  or  Eurypterids  among  Crustaceans.  But, 
in  Great  Britain  and  Europe,  the  existence  of  Fishes  is  made  certain 
by  various  fossils  ;  and  these  Fishes  were  either  of  the  tribe  of  Sharks 
or  of  that  of  Ganoids. 

Among  the  Invertebrates,  there  was  constant  change,  some  groups  beginning,  others 
expanding  to  their  climax,  and  others  disappearing.  Graptolites,  which  passed  their 
climax  hi  the  Lower  Silurian,  had  comparatively  few  species  in  the  Upper.  Crinoidi 
and  Corals  were  brought  out  in  various  new  forms,  and  of  increasing  variety.  The 
Chain  corals  (Haly  sites)  are  an  example  of  a  genus  that  ended  in  the  Upper  Silurian, 
while  the  Favosites  and  Cyathophylloids  are  more  multiplied  in  after  time. 

Mollusks  were  still  most  abundantly  represented  by  Brachiopods.  The  genera  Spi 
rifer,  Athyris,  Chonetes,  Rensselaeria,  and  others,  were  added  to  Linyula,  Ortln*.  Lcp- 
tcena,  Rhynchondla,  Atryp",  etc.,  of  the  Lower  Silurian;  at  the  same  time,  Ortliis  had 
lost  its  preeminence,  and  was  of  few  species.  The  Lower  Silurian  Brachiopods  have 
no  bony  arm-supports  internally,  excepting  those  of  Atnjpa  and  PJiynclwndla.  In 
both  Spirifer  and  Atrypa,  these  supports  were  long  and  rolled  spirally.  The  genus 
Spirifer  commenced  with  narrow  species,  little  broader  than  high;  but  in  the  later  part 
of  the  Upper  Silurian  they  were  already  much  wider,  though  not  as  extravagantly  so 
as  in  many  species  of  the  Devonian  and  Carboniferous.  In  the  Niagara  occurred  the 


UPPER   SILURIAN.  253 

first  species  of  that  division  of  the  genus  Spirifer  in  which  the  ribs  of  the  shell  are 
bifurcated;  a  kind  that  afterward  became  common. 

The  Lamellibranchs  and  Gasteropods  were  few,  compared  with  Brachiopods;  and,  in 
both  groups,  the  species  were  mostly  siphonless ;  that  is,  the  Gasteropods  had  the  aper 
ture  without  a  beak,  and  the  Lamellibranchs,  with  the  exception  of  the  Cardium 
family,  had  the  pallial  impression  entire  (Fig.  153).  The  species  of  Lamellibranchs 
were  mostly  of  the  Mytilus,  Avicula,  Area,  and  Cardium  families;  those  of  the  Heter- 
opods  and  Gasteropods,  mainly  of  the  Bellerophon  and  Trochus  families. 

The  Tentnculitts  had  their  climax  in  the  Upper  Silurian,  occurring  in  great  numbers 
in  some  of  the  rocks;  after  this,  the}*  were  comparatively  rare. 

Among  Cephalopoda,  the  Orthocerata,  while  common,  were  neither  so  large  nor  so  nu 
merous  as  in  the  Lower  Silurian.  The  genus  Onnoceras  —  with  large  beaded  siphuncle 
—  ceased  with  the  Niagara  period.  Both  the  straight  and  the  curved  or  coiled  shells 
had  the  partitions  simply  arched,  and  not  plicate  as  in  after-time. 

The  Conularice  were  more  numerous  and  larger  than  before. 

The  subkingdom  of  Articulates,  as  far  as  knowledge  from  fossils  goes,  still  em 
braced  only  the  water-types  of  Worms  and  Crustaceans.  Trilobites  were  multiplied  in 
genera,  —  Homalonotus,  Phacops,  and  others  being  added  to  Calymene,  Aynostus,  Asa- 
phus,  Illcenus,  Lichas,  Acidaspis,  and  Dalmanites,  etc.,  of  the  Lower  Silurian.  The  bi 
valve  Crustaceans,  or  Ostracoids,  are  very  common.  In  the  Eurypterus  and  PteryyotoM 
(Fig.  461),  there  is  a  new  step  in  the  development  of  the  Crustacean  type,  and,  in  the 
Ceratiocaris,  an  advance  in  still  another  direction.  Yet  the  class  of  Crustaceans  had 
not  made  progress  beyond  its  lowest  order,  that  of  Entomostracans,  —  except  it  be 
that  the  earliest  group,'  that  of  Trilobites,  overstepped  these  bounds  at  the  very  begin 
ning  (p.  123).  The  Ostracoids  were  precursors  of  the  modern  Ostracoids;  the  Cera- 
tiocarids,  of  the  modern  typical  Cyclopoids;  and  the  Eurypterids,  of  other  Cyclopoids 
of  flattened  forms.  But  while  precursors  in  time,  many  of  the  species  of  these  groups 
were  gigantic  compared  with  the  largest  of  those  of  the  present  day,  exceeding  the 
latter  ten  to  fifty  times  in  lineal  dimensions;  and  it  is  not  easy  to  prove  that  the 
smaller  moderns  are  in  any  way  their  superiors  in  grade.  While  the  middle  of  the 
Silurian  age  was  the  time  of  greatest  expansion  for  the  group  of  Trilobites,  the  closing 
period  of  it,  with  the  early  Devonian,  appears  to  have  been  the  time  of  culmination  of 
the  Entomostracan  order. 

Extinction  of  species. — The  number  of  Upper  Silurian  species  thus  far  described 
from  the  American  rocks  is  about  3,500,  which  is  at  least  500  short  of  the  number 
existing  in  collections.  There  is  no  evidence  that  a  species  existed  in  the  later  half 
of  the  Upper  Silurian  that  was  alive  in  the  later  half  of  the  Lower  Silurian.  A  num 
ber  of  species  are  continued  into  the  Devonian ;  but  these  disappear  long  before  the 
close  of  that  age. 

Genera  of  existing  seas.  — To  the  list  of  existing  genera,  no  additions  are  made  in  the 
course  of  the  Upper  Silurian.  All  but  Lingula  (?),  Discina,  Nautilus,  JRhynchonella, 
Pleurotomaria,  and  Crania,  become  extinct. 

Climate.  —  There  is  no  evidence  that  the  climate  of  America  in 
cluded  frigid  winds  or  seas.  The  living  species  in  the  waters  between 
the  parallels  of  30°  and  45°  were  in  part  the  same  with,  or  closely 
related  to,  those  that  flourished  between  the  parallels  of  65°  and  80°. 
(See  pages  221  and  230.)  From  this  life-thermometer  we  learn  only 
of  warm  or  temperate  seas. 


254  PALEOZOIC   TIME. 


II.  AGE  OF  FISHES,  OR  DEVONIAN  AGE. 

The  Devonian  formation  was  so  named  by  Murchison  and  Sedg- 
wick,  from  Devonshire,  England,  where  it  occurs,  and  abounds  in 
organic  remains.  In  America,  and  also  in  other  countries,  the  beds 
pass  into  those  of  the  Silurian  by  an  easy  transition. 

1.  AMERICAN. 

The  periods  and  epochs  in  the  American  Devonian,  as  deduced  from 
the  series  of  rocks  laid  down  by  the  New  York  geologists,  are  the 
following,  commencing  above  :  — 

4.  CATSKILL  PERIOD  (12)    •.    .     .  Catskill  Red  Sandstone  (12). 

(  2.   Chemuny  Epoch  —  Chemung  group  (11  b). 
3.  CHKMUXG  PERIOD  (11)     .    j  ±   Pot^geJ£f0ch  _Portage  ^ip  (11  «). 

;  3.   Genesee  Epoch  —  Genesee  beds  (10  c). 

2.  HAMILTON  PERIOD  (10)    .  <  2.  Hamilton  Epoch  —  Hamilton  group  (10  b). 
(  1.    Marcellus  Epoch  —  Marcellus  group  (10  «). 

(3.   Corniferous  Epoch  —  Upper  Helderberg  group 
a  l9^'- 
2.  Schohane  Epoch  —  Schohane  grit  (9  b). 
1.   Cauda-yalli  Epoch  —  Cauda-galli  grit  (9  «). 

The  beds  of  the  first  period  are  sometimes  designated  the  Lower 
Devonian,  and  those  of  the  second,  third,  and  fourth  periods,  the 
Upper  Devonian.  The  Corniferous  period  was  the  great  limestone- 
making  period  of  the  Devonian  age  in  America.  The  rocks  of  the 
succeeding  periods  (Upper  Devonian)  are  mostly  shales  or  sandstones, 
with  only  subordinate  layers  of  limestone. 

1.   CORNIFEROUS   PERIOD  (9). 

Epochs.  —  1.  CAUDA-GALLI,  or  that  of  the  Cauda-galli  grit  (9  a) ; 
2.  SCHOHARIE,  or  that  of  the  Schoharie  grit  (9  I)  ;  3.  CORNIFEROUS, 
or  that  of  the  Onoiidaga  and  Corniferous  limestones  (9  c). 

I.  Rocks :  kinds  and  distribution. 

The  rocks  in  New  York,  of  the  first  two  divisions  of  the  Corniferous 
period,  are  sandstones  or  gritty  shales.  Like  the  beds  of  the  pre 
ceding  period,  they  have  their  largest  development  along  the  Appa 
lachian  region.  But  the  Cauda-galli  grit,  unlike  the  Oriskany  sand 
stone,  lies  in.  the  eastern  half  of  the  State  of  New  York,  and  thickens 
toward  the  Hudson,  being  fifty  or  sixty  feet  thick  in  the  Helderberg 
Mountains.  The  Schoharie  grit,  named  from  its  occurrence  in  Scho 
harie,  N.  Y.,  has  nearly  the  same  distribution ;  and  the  rock  is  much 
like  the  preceding,  though  very  different  in  its  fossils.  The  term 
Cauda-galli  alludes  to  the  feathery  forms  of  a  common  fossil,  supposed 
to  be  a  sea- weed  (Fig.  484). 


DEVONIAN   AGE.  255 

In  contrast  with  the  above,  the  rock  of  the  Oorniferous  epoch  is  one 
of  the  great  limestones   of  the  continent.     The   layers  of  limestone 


484. 


Spirophytou  Cauda-galli. 

sometimes  contain  seams  of  hornstone  (flint-like  quartz);  and  to  this 
the  name  Oorniferous  alludes,  from  the  Latin  cornu,  horn,  and  fero, 
I  bear.  Much  of  it  abounds  in  corals,  as  much  so  as  the  reef-rock  of 
modern  coral  seas.  The  formation  extends  from  east  to  west  through 
New  York,  and  is  continued  westward  through  Canada  and  much  of 
the  great  Interior  basin,  having  fully  as  wide  a  range  as  the  Niagara 
limestone.  It  exhibits  its  coral-reef  character  grandly  at  the  Falls  of 
the  Ohio,  near  Louisville,  where  corals  are  crowded  together  in  great 
numbers,  some  standing  as  they  grew,  others  lying  in  fragments,  as 
they  were  broken  and  heaped  up  by  the  waves,  branching  forms  of 
large  and  small  size  mingled  with  massive  kinds,  of  hemispherical  and 
other  shapes.  Some  of  the  cup  corals  (Cyathophylloids)  are  six  or 
seven  inches  across  at  top,  indicating  a  coral  animal  seven  or  eight 
inches  in  diameter.  Hemispherical  compound  corals  occur  five  or  six 
feet  in  diameter.  The  various  Coral-polyps  of  the  era  had,  beyond 
doubt,  bright  and  varied  coloring,  like  those  of  our  own  tropics ;  and 
the  reefs  were  therefore  an  almost  interminable  flower-garden. 

A  limestone  made  up  of  similar  corals  occurs  on  Lake  Memphrema- 
gog,  between  Vermont  and  Canada,  showing  that  coral  reefs  flourished 
there  also ;  and  other  localities  exist  to  the  eastward.  At  Cape 
Gaspe  on  the  St.  Lawrence  Gulf,  over  the  Gaspe  limestones,  there  are 
7.036  feet  of  sandstones,  a  portion  of  which,  in  the  lower  part,  are  sup 
posed  to  be  of  the  Corniferous  period. 

The  formation  in  Xew  York  consists  of  two  members,  the  Onondaya  limestone  or 
lotcer  part,  and  the  Corniferous  limestone  or  upper.  The  hornstone  occurs  in  the  latter. 
This  hornstone  contains  various  microscopic  fossils  (Fig.  484  A),  and  also  minute 
rhombic  crystals,  l-500th  inch  across,  which  are  probably  calcite.  The  thickness  of 
the  two  limestones  in  New  York  is  in  some  places  350  feet. 


256  PALEOZOIC   TIME. 

1.  The  Cauda-galli  grit  is,  in  New  York,  a  drab  or  brownish  argillaceous  sandstone, 
or  grit,  often  shaly  and  crumbling.  In  New  Jersey,  it  occurs  along  the  northwestern 
boundary,  and  also  on  the  eastern  borders  of  Pennsylvania,  as  a  dark  compact  gritty 
slate,  and  has  a  thickness  in  some  places  of  400  feet. 

2  The  Schoharie  epoch,  if  represented  in  the  rocks  of  the  Interior  basin,  is  so  by 
limestone  referred  to  the  Coniiferous  epoch. 

3.  The  Corniferous  limestone,  in  New  York,  is  dark  grayish,  and  occasionally  black; 
in  the  Interior  basin,  it  is  usually  light-gray,  drab,  or  buff. 

(a)  Interior  Continental  basin.  In  New  York,  the  thickness  of  the  limestone  seldom 
exceeds  20  feet  for  the  Onondaga,  and  50  for  the  Corniferous.  The  limestone  forma 
tion  has  been  recognized  in  Ohio,  along  the  shores  of  Lake  Erie,  in  Michigan,  Indiana, 
Illinois,  Kentucky,  Wisconsin,  Iowa,  Missouri,  and  other  parts  of  the  Mississippi  basin: 
but  the  subdivisions  above  mentioned  are  not  distinguishable.  In  the  Michigan  penin 
sula,  the  thickness  is  354  feet  (Wine-hell);  in  Ohio,  GO  feet;  in  Iowa.  50  to  GO  feet 
(Hall);  in  Missouri,  from  a  few  feet  to  75.  The  upper  part  of  the  limestone  in  Illinois 
is  regarded  by  Worthen  as  of  the  Hamilton  period. 

The  upper'  layers  of  the  rock,  which  are  usually  dark  grayish  in  New  York,  are 
nearly  black  on  the  Niagara.  In  some  localities  west  of  New  York,  the  rock  is  oi'litic. 
The  hornstone  of  the  Corniferous  beds  is  often  left  in  rough  projecting  masses,  where 
the  limestone  portion  has  been  worn  away  by  the  action  of  water.  In  Missouri,  siliceous 
and  sandstone  layers  alternate  with  the  limestone.  These  rocks  outcrop  also  in  western 
Canada,  north  of  Lake  Erie. 

(b.)  Appalachian  reyion.  — This  formation  extends  from  New  York  into  New  Jersey, 
where,  in  the  northwestern  part  of  the  State,  it  has  a  thickness  of  500  feet.  It  has  not 
vet  been  distinguished  among  the  rocks  of  Pennsylvania,  except  northwest  of  the  Kit- 
tatinny  Mountain,  between  the  Delaware  and  Lehigh  Rivers. 

(c.)  Eastern  Border  reyion.  — At  Owl's  Head,  on  Lake  Memphremagog,  near  the 
northern  borders  of  Vermont,  the  coral-reef  rock  is  overlaid  by  mica  schist;  and, 
although  it  is  partially  metamorphic,  many  of  the  specimens  of  fossils  are  tolerably  per 
fect.  Among  the  species,  Billings  has  recognized  Synnyopora  Hisdnytri  B.,  Favosites 
basaltica  Goldf.,  Diphyphyllum  stmmineum  B.,  and  Zaphrentis  yiyantea  Lesueur.  Be 
sides  these,  according  to  Hitchcock,  Atrypa  reticularis  has  been  identified  by  Hall. 

The  limestone  at  Bernardston,  Mass.,  containing  large  crinoidal  stems,  described  on 
page  237,  under  the  Lower  Helderberg  period,  may  possibly  be  of  the  Corniferous 
or°Upper  Helderbtrg  period.  At  Littleton,  New  Hampshire,  there  is  a  similar  lime 
stone,  containing  corals  like  those  of  Lake  Memphremagog;  and  conformable  with 
it  are  beds  of  quartzyte  and  other  rocks :  the  fossils  are  referred  to  the  Corniferous 
period*  by  Billings.  Between  Littleton  and  Bernardston  extends  a  strip  of  schistose 
or  slaty  rocks,  in  some  places  calcareous,  and  often  staurolitic,  called  by  Hitchcock  the 
Cods  Group,  which  are  either  Lower  or  Upper  Helderberg. 

Between  northern  Vermont  and  Cape  Gaspe",  there  are  many  localities  of  Devonian 
fossils.  One  locality,  given  by  Logan,  is  on  the  Chaudiere  River,  where  there  occur, 
besides  Favosites  Gothlandica  and  F.  bnsnlticn,  the  species  Syrintjopora  ffisinyeri, 
Diphyphyllum  arundinnceum  B.,  a  small  Product-US  resembling  a  Corniferous  species,  a 
Znphrentis,  Spirifer  duoden'iriun  H.,  S.  ^re^armsClapp,  S.  acuminatusH.,  a  Cyrtina  like 
C.  rostrata  H.,  etc.  Other  localities  occur  at  Uudswell  and  on  Famine  River.  At  Cape 
Gaspe",  the  upper  part  of  the  2,000  feet  of  limestone  contains  Oriskany  fossils  (p.  243), 
but  none  indicative  of  the  Corniferous  period. 


Economical  Products. 

The  limestone  of  this  period  in  some  places  abounds  in  mineral  oil.  The  oil  wells  of 
Enniskillen,  Western  Canada,  are  traced  to  this  rock  by  Hunt  ;  large  areas  are  there 
covered  with  the  inspissated  bitumen.  At  Rainham,  Canada,  on  Lake  Erie,  shells  of 
Pentamerus  nrntus  are  sometimes  filled  with  the  oil:  and,  in  other  localities,  corals  of 
the  genera  Heliophyttum  and  Fai'osites  have  their  cells  full,  in  some  layers  of  the  lime- 


DEVONIAN   AGE.  257 

stone,  while  empty  in  other  layers.  At  Terre  Haute,  Indiana,  a  well  1,900  feet  deep, 
into  the  Corniferous  limestone,  yields  two  barrels  of  oil  a  day,  and  a  second  well,  1,775 
feet,  but  to  the  same  level  (the  first  150  feet  through  gravel),  25  barrels. 

II.  Life. 

1.  Plants. 

Among  Seaweeds,  the  most  remarkable  is  the  spirally  convoluted 
Spirophyton  cauda-gatti,  figured  on  page  255. 

Fig.  484  A. 


MICROSCOPIC  ORGANISMS  IN  HORNSTONE. —  Figs,  a-i,  Protophytes  ;  j-n,  Spicula  of  Sponges  ;  0,77, 
fragments  of  dental  apparatus  of  Gasteropods. 

The  hornstone  in  the  Corniferous  limestone,  as  shown  by  Dr.  M.  C. 
White,  is  full  of  miscroscopic  plants,  or  protophytes,  from  1 -500th  to 
l-5000th  of  an  inch  in  diameter ;  and  with  them  are  sponge-spicules 
and  teeth  of  mollusks.  Some  of  them  are  represented  in  Fig.  484  A : 
a  to  e  are  Xanthidia,  spore-capsules  of  Desmids  (p.  135),  /*,  y,  con 
ferva-like  filaments,  made  of  a  series  of  cells ;  ?',  a  Diatom,  one  of  the 
silica-secreting  protophytes  ;  while  j,  &,  /,  m,  n  represent  siliceous 
spicula  of  sponges,  and  o,  p,  teeth  of  mollusks.  The  mass  of  the  horn- 
stone  was  probably  made  out  of  siliceous  diatoms,  sponge-spicules,  and 
perhaps  also  polycystines. 

The  terrestial  plants  are, — first,  under  the  division  of  Acrogens,  or 
the  higher  Cryptogams,  species  of  Lycopods  (or  Ground  Pines)  and 
Ferns ;  second,  under  Gymriosperms,  or  the  lower  division  of  Pheno- 
gnms,  Conifers.  In  the  lower  sandstones  of  Gaspe  occur  remains  of 
the  Lycopods  arid  Conifers,  and  in  the  Corniferous  limestone  of  Ohio, 
the  Ferns. 

1.  Lycopods.  —  The  Lycopods  include  species  of  Psilophyton,  like 
those  of  the  Oriskany  period  :  portions  of  the  plant,  with  its  dried 
leaves,  are  shown  in  Figs.  484  B,  a,  /;,  and  its  fructification  in  c,  d. 

The  species  differ  from  the  common  Ground  Pine  in  having  the 
leaves  nearly  wanting,  on  the  flowering  stems,  and  also  in  having  the 
axis,  or  a  cylinder  around  the  centre,  made  up  of  scalariform  vessels, 
and  the  spore-cases  (fruit)  usually  in  pairs  on  short  pedicels  ;  and  in 
these  respects  they  resemble  the  plants  of  the  genus  of  Lycopods 
17 


258 


PALEOZOIC    TIME. 


called   Psilotum,  whence  the  name  PsUophyton.     The  species  of  the 
Corniferous  era  thus  far  described  were  from  one  to  three  feet  high. 

Fig.  484  B.  a-e. 


Fig.  484  C. 


Figs,  a,  b,  c,  d,  Psilophyton  priuceps  ;  e  Prototaxites  Logani(  XM)- 

2.  Conifers.  —  The  Conifers  are  species  of  the  earliest  known  genus 
of  the  family  Prototaxites  ;  and  portions  of  two  branches  are  shown, 
reduced,  in  Fig.  484  B,  e  (from  Dawson);  the  larger  was  18  inches 
across.    Another  was  three  feet  in  diameter,  indicating  that  there  were 
forests  of  these  Devonian  yews. 

3.  Ferns.  —  Newberry  has  found  the  remains  of  Tree-ferns  in   the 

Corniferous  of  Ohio,  showing  that  these  also 
were  among  the  trees  of  the  forests.  A  portion 
of  one  is  represented  in  Fig.  484  C. 

The  projecting  parts  over  the  trunk  are  the 
bases  of  the  fallen  fronds,  just  such  as  occur 
over  the  exterior  of  some  modern  tree-ferns.  In 
the  plate  on  page  322,  a  modern  tree-fern  stands 
to  the  left  of  the  middle,  and  the  plants  below 
are  small  ferns. 

Fig- 484  B.  a,  PsilopJiyton  princeps;    6,  the  growing  ex 
tremity  of  a  branch,  incurved  or  circinnate ;  c,  d,  fructifica 
tion.   ^Fig.   484  B,  e,   Protot.nxi.tes  Loyani,  one   eighth  the 
natural  size.   The  species  of  Tree-ferns  found  in  the  Ohio  limc- 
Caulopteris  antiqua.          stone  are  Cmdopteris  antlqua  Newb.  (Fig.  484  C),  Cmiloptens 

peregrina  Newb.  (Prdtcpterii peregrina  Dn). 
Meek  has  found,  in  the  Corniferous  beds  of  Ohio,  globular  particles,  about  a  twentieth 


DE  VOX  I  AN    AGE. 


259 


of  an  inch  in  diameter,  marked  with  eight  spiral  ridges,  which  he  regards  as  seeds  of  a 
Chara.     These  frequently  occur  also  in  the  cellular  chert  at  the  Falls  of  the  Ohio. 

2.  Animals. 

The  Corniferous  period  was,  as  has  been  stated,  eminently  the  coral- 
reef  period  of  Paleozoic  time. 

1.  Invertebrates.  —  The  existence  of  Sponges  is  indicated  by  the 

Figs.  485-491. 

487 


Fig.  4U2. 


POLYPS.  —  Fig.  485,  Zup'.irentis  gigantea  ;   486,  Z.  llafinesquii ;    487,  Phillipsastrea  Verneuili ; 
488  a,  Cyathophyllum  rugosum ;   489,  Favosites  Goldfussi  ;    490,  Syriugopora  Maclurii ;    491, 
Aulopora  coriiuta. 

presence  of  their  siliceous  spicula  in  the  hornstone,  two  slender  forms 
of  which  are  shown  in  Figs.  484  A,j,  k,  page  257,  and  others  in  /,  m,  n, 

Figures  485  to  491  represent  some  of  the  corals; 
486  shows  well  the  radiated  cup-shaped  termination 
to  which  the  name  Cyathophylloid  corals  (from  Kva- 
$09,  cup,  and  c^vAAor,  leaf}  refers  ;  485  has  both 
extremities  broken  off,  but  exhibits  the  interior  radia 
tion  ;  489  is  a  portion  of  a  common  species  of  Favo- 
sites  (honey -comb  coral,  named  from  favus,  honey 
comb),  a  kind  that  sometimes  occurs  in  hemispheres 
five  feet  in  diameter  ;  487  is  part  of  the  surface  of 
a  common  massive  coral. 

Among  Echinoderms,  the  most  interesting  are  species  of  the  group 
of  Blastids,  or   Bud-Crinoids,  having  no  proper  arms,  one  of  which  is 


Nucleocrinus  Ver- 


260  PALEOZOIC    TIME. 

represented  in  Fig.  492.     Though  ovoidal  in  form,  it  is  related  to  the 


Figs.  493-495. 
495 


URACHIOPODS.  —  Figs.  493,  494,  Spirifer  acuminatus  ;  495,  Sp.  gregarius. 


pentagonal  Pentremites,  a  kind  that  was  particularly  abundant  in  the 
Lower  Carboniferous  (Fig.  580,  p.  298). 


Figs.  496-497. 


196 


CONCHIFERS.  —  Fig.  496,  Lucina  (?)  proavia  ;  497,  Conocardium  trigonale. 

Brachiopods  were  very  numerous ;  and  figures   493  to  495    repre 
sent  common  species.     The  genus  Productus  here  had  its  first  species 

—  a  genus  that  was  very  numerously 
represented  in  the  Carboniferous 
formation.  Its  earliest  species  are 
half  an  inch  broad,  and  some  of  the 
later  three  or  four  inches.  The  char 
acter  of  the  shell  is  illustrated  in 
Figs.  238,  239,  a,  page  173. 

There  were  also  various  other  kinds 
of  Mollusks.  Among  them  occur  spi- 
nous  species  of  the  genus  Platyceras, 
one  of  which  is  represented  in  Fig. 
498.  In  the  hornstone  was  found  (by 
Dr.  White)  the  dental  apparatus  of  a 
Gasteropod,  represented  in  Fig.  484  A  o.  \_p  is  another  form,  in  horn- 


Platyceras  durnosum. 


DEVONIAN    AGE.  261 

stone  of  the  Black  River  limestone  (p.  194),  from  AVatertown,  N.  Y., 
which  affords  also  Desmids  and  spicules  of  Sponges.] 

Characteristic  Species. 

1.  Radiates.  —  (a.)  Polyps.  —  Fig.  485,  Zaphrentis  yiyantea ;  Fig.  486,  Zaph.  Ra- 
finesquii  E.  &  H.,  from  the  Falls  of  the  Ohio.     Another  Cyathophylloid  coral,  of  the 
genus  Chonophyllum  (C.  itnujnlftcam  B.),  has  a  diameter  at  top  of  six  or  seven  inches; 
it  is  from  Wai  pole,  Canada  West.     Fig.  487,  Phillipsastrea  Vtrneuili  E.  &  H. ;  Fig. 
488,  Ggathophyllum  niyoaum,  a  fragment  from  a  large  mass  from  the  Falls  of  the  Ohio; 
488  «,  section  of  a  cell;  Fig.  489,  Favosites  Golclfussi  D'Orb.,  from  the  Falls  of  the  Ohio, 
a  fragment  of  a  large  specimen;  Fig.  490,  Syringopora  Macluiii  B.,  from  Canada  West, 
a  coral  consisting  of  a  cluster  of  small  tubular  cells;  Fig.  491,  Aidopora  cornuta  B.,  from 
Canada. 

(b.)  Acalephs.  —  No  species  are  known,  unless  some  of  the  Corals  belong  here. 

(c. )  Echinodcrms.  —  There  are  many  species  of  Crinoids,  and  the  large,  smooth  stems 
of  some  of  them  are  half  an  inch  to  an  inch  in  diameter.  Of  the  Nucleocrtni  (also  called 
Olivanites),  Fig  492  represents  the  X.  Vemtuili  L.  &  C.  The  name  N ucleocrinus  of 
Conrad  antedates  Oilcan  tes  T  roost,  and  Efaacrinus  Koemer. 

2.  Mollusks.  —  (a.)  Bftchiopods. —  Figs.  493  and  494,  Spirifer  acuminatus  Ton. 
(S.  cultrijuyatus  Roemer),  from  New  York  and  the  West.     Fig.  495,  Spirifer  greyarius 
Clapp,  very  common  in  Indiana  and  Kentucky,  at  the  Falls  of  the  Ohio,  and  at  Middle- 
ton,  Canada  (Billings).     Also,  Pentamerella  arata  H.,  Chonetes  kei/iuphcericaH.,  Afrypa 
reticid((i-!s,  A.  imprtssa  H.,  A.  spinosa  H.  (A.  aspera),  Amphiytnia,  dony<tta  (formerly 
Pentdmerus  elony<itus  Vanuxem,  and   Stricklandinia  elonyata  Billings),  Rhynchontlla 
venustuld  Hall  (Atrypa  cuboide*  of  Sowerby,  also  Vanuxem),  found  in  Tennessee.     Two 
small  species  of  Product  us  have  been  collected  by  Billings    in  Canada,  and  one  bv 
Jewett  in  the  New  York  Corniferous. 

(b.)  LmnelUbmndis.  —  Fig.  496,  Lucina  (?) pronvin  Goldf.,  also  occurring  in  Europe; 
Fig.  497,  Conocardium  triyonale,  of  both  New  York  and  the  West.  The  first  known 
species  of  Solenomya  (Meek),  and  also  of  Orthonema,  another  Carboniferous  genus. 

(c.)  Pttropods,  Gusttrupods,  and  Cephalopods.  —  Pteropods  are  represented  bv  the 
Ttntaculites  scalaris  Schlot.  There  are  also  several  species  of  Gasteropods.  Fig.  498  is 
the  Platyceras  dumosum  Con.,  of  (he  Corniferous  in  New  York. 

A  few  Orthocerata  occur  in  the  beds.  The  Cyrtoceras  unduhttu/n,  a  large  shell  coiled 
in  a  plane,  is  supposed,  as  the  name  implies,  to  be  related  to  the  Cephalopods. 

3.  Articulates.  —  Trilobites  are  the  only  Articulates  known.    The  most  common 
species  are  the  Dalman'itvs  (Odontocephalus)  selenurus  H.,  having  a  two-pointed  tail; 
and  the  Proetus  (Calyniene)  crassimaryinatus  H.,  having  the  posterior  margin  of  the 
body  (the  pygidium)  thickened  and  rounded.     There  are  also  Phacops  bufo  H.,  and 
some  other  species. 

The  following  species  continue  on  into  the  Hamilton :  Orthis  Vanuxemi  H.  V  Sfrepto- 
rhynchus  Chemunyens:s  H.,  Strophodonta  (Strophomena)  demissa  H.,  S.  perplana  H. 
(=  S.  creni-tria  H.),  Spirifer  ftmbriatus  Con.  (found  also  in  the  Oriskany,  Atrypa  im- 
pressa  H.  (=var.  of  A.  retictdaris),  Phacops  bufo. 

4.  Vertebrates.  —  The  remains  of  Vertebrates,  under  the  form  of 
Fishes,  appear  first,  in  America,  according  to  present  knowledge,  in 
the  rocks   of  the  Corniferous  period.     The  subdivisions  of  fishes  rep 
resented   are   the   same   that  have  been  distinguished  in  the  foreign 
Upper  Silurian.     They  are  the  following,  — 

1.  The  Shark-tribe  or  Selachians  (so  named  from  o-eXa^os,  a  carti 
laginous  fish),  the  bones  being  cartilaginous  or  mostly  so.  In  this 
division,  the  gill-openings,  as  shown  in  Fig.  502,  have  no  operculum. 


262 


PALEOZOIC    TIME. 


Fig.  499  represents  a  spine  from  the  fin  of  a  Shark  (from  Ontario 
County,  N.  Y.),  which  was  originally  at  least  ten  inches  long.  Figures 
502,  504,  illustrate  the  positions  of  such  spines.1 

Fig.  49'J. 


Fin-spine  of  a  Shark,  Machseracanthus  sulcatus  (  X  ?s  )• 

Other    remains  of   sharks    are  the   teeth   or  bones   of  the  mouth. 
The  masticating  apparatus  in  some  of  the   ancient  sharks,  as  in  the 

Figs.  502-512. 

jf\ 


SELACHIANS.— Fig.  502,  Spinax  Blainvillii  (X>s):  503,  Spine  of  anterior  dorsal  fin,  natural  size: 
504,  Cestracion  Philippi  (XK);  505,  Tooth  of  Lamna  elegans  ;  506,  id.  Carcharodon  augusti- 
dens;  507,  id.  Notidanus  primigenius  ;  508,  id.  Hybodus  minor;  509,  id.  Hyb.  plicatili*  ;  510, 
Mouth  of  Cestracion,  showing  pavement -teeth  of  lower  jaw  ;  511.  Tooth  of  Acrodus  minimus: 
512,  id.  Acrodus  nobilis. 

modern  Cestracion  of  Australia  (Fig.  504,  reduced),  was- a  pavement 
of  bony  pieces;   Fig.  510  shows  the  pavement  of  the   lower  jaw  of 

1  In  several  genera  of  Selachians,  the  dorsal  fin  is  armed  at  its  anterior  margin  with 
a  large  spine.  In  the  genus  Spinix  (Fig.  502,  reduced),  there  are  such  spines,  one  to 
each  dorsal  fin;  Fig.  503  represents  one  of  natural  size  for  a  fish  (Spinax)  about  2£  feet 
long.  — Such  spines  exist  also  in  the  Cestracionts  (Fig.  504),  the  HyborJonts,  and  the 


DEVONIAN   AGE. 


263 


the  Cestracion.  The  Corniferous  of  Ohio  and  Indiana  has  afforded 
such  bony  pieces,  showing  that  Cestraciont  sharks  were  among  the 
first.  For  further  illustration  of  these  species,  Figs.  511,  512  are 
introduced,  giving  the  forms  of  these  pieces  in  Cestraciont  sharks  of  a 
later  age.  The  Cestracionts  had  teeth  of  nearly  the  usual  form,  at 
the  front  margin  of  the  jaw. 

Besides  these  Cestracionts,  there  were  Hybodont  sharks,  having 
teeth  much  like  those  of  the  more  modern  kinds  of  sharks.  These 
teeth  occur  in  the  American  Corniferous  ;  but  no  figures  have  yet  been 
published.  Figs.  508,  509  represent  those  of  early  Mesozoic  Hybo- 
donts,  while  Figs.  505,  506,  507  give  the  forms  of  the  teeth  in  other 
sharks  of  a  still  later  era. 

2.  Ganoids,  having  the  body  covered  with  shining  bony  scales  or 
plates,  as  in  the  Gar-pike  of  existing  waters,  and  hence  named  Ganoid 
by  Agassiz,  from  yai/oc,  shining.  The  bones  of  the  early  species  were 
cartilaginous.  The  scales  of  the  ordinary  Ganoids  are  often  rhombic 
in  form  (Fig.  513),  and  are  fitted  to  one  another  like  tiles ;  Figs.  513, 
514,  515,  515  a  illustrate  some  of  their  forms  and  modes  of  junction, 
though  not  drawn  from  Corniferous  species.  Fig.  570,  p.  286,  is  a 
foreign  Devonian  Ganoid,  having  scales  of  this  form  (Fig.  570  a). 
Others  have  the  bony  scales  nearly  circular,  and  set  on  more  like 
shingles,  as  in  the  genus  Holoptychius.  A  foreign  Devonian  species 
is  represented  in  Fig.  569,  p.  286. 
The  head  of  a  large  Ganoid,  found 
in  Indiana  and  Ohio,  which  New- 
berry  supposes  to  have  had  no  teeth, 
is  represented,  reduced,  in  Fig.  522. 
Remains  of  a  still  larger  species, 
called  Onychodus  by  Newberry, 
occur  in  the  Ohio  Corniferous,  which 
had  scales  and  teeth  much  like  the 
Holoptychius.  It  had  jaws  a  foot 
to  a  foot  and  a  half  long,  with  teeth 
two  inches  or  more  long  in  the 
lower  jaw  (Fig.  523),  and  three- 
fourths  of  an  inch  in  the  upper. 
Some  of  them  probably  had  a  length  of  twelve  or  fifteen  feet. 

In  another  type  of  Ganoid,  a  bony  plate  covers   the  head,  and  this 

Chimceroids.  In  these  Squaloid  groups,  the  spine  is  usually  laterally  compressed,  and 
if  denticulate  it  is  so  along  the  posterior  margin.  In  Try  yon  and  some  other  genera 
among  the  Rays,  there  is  a  similar  spine;  but  it  is  flattened  in  a  direction  transversa 
to  the  body,  and  has  both  outer  edges  denticulate,  when  either  is  at  all  so.  These 
spines  in  some  ancient  fishes  were  two  feet  or  more  in  length  (see  Fig.  612,  p.  308.)  In 
a  living  Cestracion,  23  inches  long,  it  is  1J  in  length. 


Figs.  522,  523. 


Fig.  522,  Head  of  MacropetalicUthys  Sulli- 
vanti  (X^);  523,  tooth  of  lower  jaw  of 
Onvchodus. 


264 


PALEOZOIC    TIMK. 


is  the  most  ancient  kind  of  fish  known.  From  the  name  of  the  genus 
Cephalaspis  (signifying  shield-like  head],  the  group  is  called  Cephal- 
aspids.  Two  of  these  head-shields  are  figured  among  Upper  Silurian 
fish-remains,  on  page  246,  and  the  form  of  an  entire  British  Devonian 
specimen,  in  Fig.  568,  on  page  286.  The  only  species  of  the  kind  in 
the  American  Corniferous  is  a  Cephalaspis,  from  Gaspe,  on  the  Gulf 
cf  St.  Lawrence. 

Figs.  513-521. 

518, 


GANOIDS  (excepting  516,  517). —Fig.  513,  Tail  of  Thrissops  (X>z);  514,  Scales  of  Cheirolepis 
Traillii  (Xl2) ;  515,  id.  Palaeoniscus  lepidurus  (X  6) ;  515  a,  under-view  of  same  ;  516,  Scale  of 
a  Cycloid  ;  517,  id.  of  a  Ctenoid  ;  518,  part  of  pavement-teeth  of  Gyrodus  umbilicus  ;  519,  Tooth 
of  Lepidosteus  ;  520,  id.  of  a  Cricodus  ;  521,  Section  of  tooth  of  Lepidosteus  osseus. 

The  teeth  in  these  Ganoids  are  often  large  and  conical.  Two  of 
them  are  represented  in  Figs.  519,  520  ;  they  are  furrowed  vertically, 
and  have  an  internal  labyrinthine  structure,  as  represented  (in  one  of  its 
simpler  varieties),  in  Fig.  521,  a  view  of  a  transverse  section  enlarged. 

The  tails  of  the  ancient  Ganoids  were  vertebrated,  that  is,  the 
vertebral  column  extended  nearly  or  quite  to  the  extremity  ;  generally 
following  the  course  of  the  upper  lobe  of  the.  caudal  fin,  as  in  Fig. 
570,  p.  286,  and  Fig.  696,  p.  371,  but  sometimes  terminating  at  the 
extremity  of  the  middle  of  the  tail  (p.  336).  In  modern  Ganoids,  on 
the  contrary,  as  in  ordinary  fishes,  the  vertebral  column  stops  at  the 
commencement  of  the  caudal  fin,  as  in  Fig.  513.  Five  genera  of 
living  Ganoids  (Lepidosteus  or  Gar-pike,  ^mm,  Accipenser  or  Sturgeon, 
Spatularia,  and  Scaphirhynchus),  belong  to  North  America,  and  the 
other  two  known  are  African. 

3.  Placoderms,  fishes  having  the  body  partly  or  wholly  covered  by 
bony  plates,  turtle-like,  and  named  from  7rAa£,  plate,  and  Sep/^u,  skin, 
with  which  the  Cephalaspids  are  often  united.  It  is  questioned 
whether  they  were  more  nearly  related  to  the  sharks  or  to  the 
Ganoids.  Two  foreign  species  of  Placoderms  are  represented,  reduced, 
in  Figs.  566,  567,  p.  285.  Newberry  has  described  a  dorsal  plate  of 
a  related  fish,  found  in  the  Ohio  Corniferous,  which  has  a  length  and 
breadth  of  eight  inches. 


DEVONIAN    AGE.  265 

The  Osseous  Jishes  or  Teliosts,  which  include  nearly  all  modern  kinds, 
except  the  Sharks  and  Rays,  and  have  usually  membranous  scales 
(like  Figs.  516,  517,  the  former  a  "  Cycloid "  scale  and  the  latter  a 
"Ctenoid"},  are  not  known  among  fossils  before  the  Middle  Mesozoic. 

The  lowest  division  of  modern  fishes  includes  a  few  very  small  kinds, 
like  the  Amphiojcus,  which  are  scale-less,  fin-less,  brain-less,  without 
special  organs  of  sense  beyond  feelers  around  the  mouth,  and  with 
the  skeleton  membranous,  and  the  heart  rudimentary.  These  lowest 
of  Vertebrates,  inferior  even  to  the  higher  Radiates,  would  naturally 
be  looked  for  as  precursors  of  the  Selachians  and  Ganoids  ;  but  no 
remains  of  them  have  been  found.  Had  such  species  existed,  however,, 
they  could  scarcely  have  left  remains,  as  they  have  no  hard  parts. 

III.  General  Observations. 

Geography.  —  In  the  first  epoch  of  this  period,  that  of  the  Cauda- 
galli  grit,  the  beds  were,  as  a  body,  more  easterly  in  position  over 
New  York  than  those  of  the  preceding  period.  In  the  Schoharie 
epoch,  they  were  still  farther  to  the  east  than  the  Cauda-galli  grit ; 
at  the  same  time,  they  continue  to  be  sandstones.  But  with  the  next 
epoch  there  was  a  change.  The  continent,  from  eastern  New  York 
westward,  became  to  a  large  extent  covered  with  coral-growing  seas. 
The  wide  distribution  of  the  rocks  proves  the  vast  area  of  those  coral 
seas.  It  also  teaches  that  they  were  shallow  seas ;  for  so  large  corals 
would  form  limestones  only  where  they  were  within  the  reach  of  the 
waves. 

The  presence  of  the  hornstone,  through  many  layers  of  the  lime 
stone,  indicates  that,  over  the  bottom,  where  mollusks  and  other  species 
were  living  and  making  the  material  for  the  limestones,  there  were 
often  also  Sponges  and  Diatoms  or  Polycystines,  making  microscopic 
siliceous  shells  and  spicules  ;  so  that,  while  the  calcareous  sands  of  the 
former  were  solidifying  into  limestone,  the  microscopic  grains  of  silica 
became  aggregated  here  and  there  into  siliceous  concretions  or  masses 
of  hornstone. 

Climate.  —  The  question  of  the  occurrence  of  rocks  of  this  period 
in  the  Arctic  region  is  not  yet  decided.  It  is  probable  that  they  exist 
there,  on  North  Somerset  and  elsewhere,  judging  from  the  fossil  corals 
and  Brachiopods.1  Among  the  former,  besides  the  Favosites  Goth- 
landica  (Upper  Silurian  in  Europe),  there  are  Heliolites  porosa  and 
Cyathophyllum  helianthoides,  Devonian  species  common  to  both  Europe 
and  America. 

This  identity   of   species    between   Arctic   lands    and  Europe  and 

1  Am.  Jour.  Sci.,  II.  xxvi.  120. 


266  PALEOZOIC   TIME. 

America,  just  illustrated,  favors  an  approximate  identity  of  climate : 
there  is  no  sufficient  evidence  of  any  cold  Arctic,  or  even  of  any  wide 
diversity  of  zones. 

2.  HAMILTON  PERIOD.     (10.) 

Epochs — l.  MARCELLUS,  or  that  of  the  Marcellus  shale  (10  a)  ; 
2.  HAMILTON,  or  that  of  the  Hamilton  beds  (10  b)  ;  3.  GENESEE,  or 
that  of  the  Genesee  shale  (10  c). 

I.  Rocks:  kinds  and  distribution.     • 

The  rocks  in  New  York  and  along  the  Appalachians  are  either 
shales  or  sandstones,  with  some  thin  limestone  beds.  Shales  especially 
abound  in  New  York. 

The  Marcellus  shale  (10  a)  is  for  the  most  part  a  soft,  argillaceous 
rock  ;  the  lower  part  is  black  with  carbonaceous  matter,  and  contains 
traces  of  coal  or  bitumen,  so  as  sometimes  to  afford  flame  in  the  fire. 
The  Hamilton  beds  (10  b)  in  New  York  (so  named  from  Hamilton, 
Madison  County,  N.  Y.)  consist  of  shales  and  flags,  with  some  thin 
limestone  beds.  The  excellent  flagging-stone  in  common  use  in  New 
York  and  some  adjoining  States,  often  called  North-River  flags,  comes 
from  a  thin  layer  in  the  Hamilton.  The  Genesee  shale  (10  c)  is  a 
blackish  bituminous  shaly  rock,  overlying  the  Hamilton. 

The  Hamilton  formation  spreads  across  the  State  of  New  York, 
having  its  northern  limit  along  a  line  running  eastward  from  Lake 
Erie.  The  greatest  thickness  —  about  1,200  feet  —  is  found  east  of 
the  centre  of  the  State.  It  extends  southwest,  into  Pennsylvania  and 
Virginia ;  also  westward,  as  a  thin  rock,  mainly  of  limestone,  through 
parts  of  Ohio,  Michigan,  and  Illinois  (at  Rock  Island,  etc.),  to  Iowa 
(New  Buffalo,  etc.)  and  Missouri.  Following  this  limestone,  in  Ohio, 
Indiana,  and  Illinois,  there  is  what  is  called  the  Black  shale  (or  Black 
slate)*  corresponding  apparently  to  the  Genesee  shale  ;  it  occurs  also  in 
Kentucky  and  Tennessee,  but,  although  so  wide  spread,  does  not  ex 
ceed  3oO  feet  in  thickness,  and  is  usually  about  100  feet. 

Hamilton  beds  occur  also  in  the  valley  of  the  Mackenzie  River, 
between  Clear  Water  River  and  the  Arctic  Ocean,  some  of  the  species 
of  fossils  being  identical  with  those  of  the  United  States  arid  Canada ; 
and,  as  stated  by  Meek,  Devonian  rocks  are  probably  continuous,  or 
nearly  so,  from  western  Illinois  northwesterly  to  the  Arctic  Ocean,  a 
distance  of  2,500  miles. 

In  the  Eastern-border  region,  the  Hamilton  beds  are  chiefly  sand 
stones,  and  are  confined  to  regions  near  the  sea-border.  They  occur 
in  Maine  and  New  Brunswick,  near  the  boundary  between  these 
States,  and  beyond  up  the  New  Brunswick  coast ;  also  at  Gaspe,  on 
the  Gulf  of  St.  Lawrence. 


DEVONIAN    AGE.  267 

(a.)  Interior-Continental  basin.  —  The  Hamilton  beds  consist  of  shales,  separated  into 
two  parts  by  a  thin  layer  of  Encrinal  limestone,  and  in  many  places  overlaid  by  a  thin 
limestone  stratum  called  the   Tally  lime 
stone.     In  the  annexed  section,  from  the  fi*  524. 
coast  of  Lake  Erie  (as  given  by  Hall),  the 
Hamilton    beds,    10   b,   include    (1)   blue 
shale,  (2)  Encrinal   limestone,    (3)  Upper 
or  Moscow  shale:    the  Tully  limestone  is 
wanting.      Above   lie  (10  c)  the  Genesee 
slate,  and  (11)  a  part  of  the  Portage  group 
of  the   next  (Chemung)  period.      In    the             Section  of  Hamilton  Beds,  Lake  Erie, 
lower  part  of  the  Marcel! us  shale  (the  rock 

of  the  first  epoch)  in  New  York,  there  are  also  layers  of  concretions  of  impure  limestone, 
and  these  abound  most  in  fossils;  but  the  fossils  of  the  shale  are  generally  small. 

The  flagging-stone  of  the  Hamilton  is  quarried  near  Kingston,  Saugerties,  Cox- 
sackie,  and  elsewhere  on  the  Hudson,  in  Ulster,  Greene,  and  Albany  counties,  N.  Y. 
The  bed  is  but  a  few  feet  thick.  It  breaks  into  very  even  slabs  of  great  size.  It  is 
almost  without  fossils,  but  is  penetrated  in  many  parts  by  the  filling  of  a  slender  worm- 
hole;  and  its  surfaces  are  often  marked  with  tracks  of  Mollusks.  The  Genesee  slate 
overlies  the  Tully  limestone,  when  this  is  present.  It  is  not  recognized  in  the  eastern 
part  of  the  State  of  New  York.  The  limestone  stratum  of  Illinois,  referred  to  the  Mar- 
cellus  and  Hamilton  epochs,  is  not  over  120  feet  in  thickness. 

The  Marcellus  shale  rarely  exceeds  in  thickness  50  feet.  The  Hamilton  strata  are 
1,000  feet  thick  in  central  New  York,  but  not  half  this  along  Lake  Erie.  They  are 
also  comparatively  thin  and  more  sandy  on  the  east,  in  the  Helderberg  Mountains. 
They  are  well  exposed  along  the  valleys  of  Seneca  and  Cavuga  Lakes.  The  Genesee 
shale  is  150  feet  thick  near  Seneca  Lake:  it  thins  westward,  and  is  not  over  25  feet  on 
Lake  Erie. 

The  Black  shale  is  350  feet  in  Ohio,  and  10  to  60  feet  in  Illinois.  In  Tennessee,  west 
of  the  Cumberland  table-land,  it  has  at  top  a  thin  layer  of  small  concretions,  and 
below  it,  a  bed  of  fetid  limestone;  it  outcrops  on  the  slopes  around  the  central  basin 
of  the  State.  As  no  other  rock  intervenes  between  the  Corniferous  and  Carboniferous, 
this  Black  shale  has  been  suspected  to  be  Chemung,  but  without  any  satisfactory  evi 
dence  from  fossils.  A  thin  band  of  concretions  at  the  top  of  this  bed,  in  central  Ken 
tucky,  contains  many  remains  of  fishes,  and  also  crustaceans,  of  the  genera  Colpocaris, 
Solenocaris,  Archceocaris,  the  two  former  closely  allied  to  Ceratiocaris. 

In  Missouri,  the  Hamilton  formation  consists  of  about  50  feet  of  shale,  with  some 
beds  of  limestone.  In  Iowa,  there  are  200  feet  of  shales  and  limestone,  and  no  other 
Devonian  rocks. 

(b. )  Appalachian  region.  —  In  Pennsylvania,  H.  D.  Rogers  makes  three  divisions  of 
the  Hamilton  formation,  a  lower  of  black  shales,  which  is  250  feet  thick  in  Huntingdon, 
a  middle  of  variegated  shales  and  flags,  GOO  feet  thick  at  the  same  place,  and  an  upper 
black  shale  of  300  feet.  In  East  Tennessee,  the  thickness  is  100  feet.  (Safford.) 

The  thickness  of  the  Hamilton  formation  east  of  central  New  York  shows  that  this 
region  was  at  this  time,  as  in  the  Oriskany  period,  on  the  northern  border  or  limits  of 
the  Southern  Appalachian  region. 

(c.)  In  the  Eastern-border  region,  at  Gaspe*,  the  6,000  feet  of  sandstones,  above  the 
1,100  referred  to  the  Corniferous  period,  are  believed  to  be  for  the  most  part  of  Hamil 
ton  age.  St.  John's,  in  New  Brunswick,  is  a  noted  locality  of  fossil  plants  of  this  era. 

Ripple-marks.  —  The  rocks  of  this  formation,  especially  the  Hamil 
ton  beds,  are  remarkable  for  the  abundance  of  ripple-marks  on  the 
layers.  The  flagging-stone  is  often  covered  with  ripple-marks  and 
wave-lines.  The  joints  intersecting  the  strata  are  often  of  great  ex 
tent  arid  regularity.  They  have  been  referred  to  on  page  88 ;  and 


268  PALEOZOIC   TIME. 

a  sketch  is  there  given,  representing  a  scene  on  Cayuga  Lake.     The 
rock  at  the  place  is  the  Moscow  shale. 

Economical  Products. 

The  Hamilton  beds  afford  the  best  flagging-stone  of  the  country. 

The  Black  shale,  or  Genesee  shale,  is  remarkable  as  an  oil -yielding 
rock.  This  is  true  in  New  York  and  all  through  the  West,  wherever 
it  has  much  thickness.  In  Tennessee,  the  shale  sometimes  yields  fif 
teen  to  twenty  per  cent,  of  mineral  oil  and  tars.  In  Ohio,  where  it 
is  350  feet  thick,  it  contains,  according  to  Newberry,  ten  per  cent,  of 
combustible  matter,  and  is  therefore  equivalent  to  a  coal  seam  40  feet 
thick. 

This  oil,  obtained  from  the  rock,  is  not  present  in  it  as  oil,  for  no 
solvents  will  separate  it :  it  is  produced  by  the  heat  of  distillation 
out  of  the  carbonaceous  substances  present.  This  shale  has  been 
regarded  as  the  main  original  source  of  the  oils  in  the  oil  region  of 
Ohio  and  Western  Pennsylvania  ;  but  there  is  reason  to  believe  that 
part  at  least  of  the  supply  in  these  regions  has  come  from  the  Cor- 
niferous  limestone  below  it. 

In  the  oil  regions,  gas  is  often  given  out  from  the  borings,  and  is 
used  for  lighting  and  warming  houses,  and  various  other  economical 
purposes. 

The  same  rock  often  contains  much  pyrite,  and  might  be  used  for 
making  copperas  and  alum.  Efflorescences  of  both  of  these  substances 
are  common  in  sheltered  places.  It  is  a  source  also  of  numerous 
sulphur  springs. 

II.  Life. 
1.  Plants. 

The  carbonaceous  material  of  the  black  Marcellus  shale  is  of  or 
ganic  origin ;  but  whether  due  to  sea-weeds  or  to  land-plants,  or  partly 
to  fishes  or  other  animals,  has  not  been  ascertained. 

In  the  Hamilton  beds,  the  evidences  of  verdure  over  the  land  are 
abundant.  The  remains  show  that  there  were  trees,  as  well  as  smaller 
plants ;  that  there  were  forests  of  moderate  growth,  and  great  jungles 
over  wide-spread  marshes. 

These  terrestrial  plants  include  Lycopods,  Ferns,  and  Equiseta,  the 
three  orders  of  Acrogens,  or  higher  Cryptogams,  and  also  Charce,  but 
no  true  Mosses  ;  and  with  these  there  were  Gymnosperms,  or  the 
lower  Phenogams. 

1.  Lycopods.  —  The  Lycopods  of  the  Hamilton  were  of  three  types  ; 
(1)  the  Psilophyta,  or  the  slender  forms,  which  were  the  earliest  repre- 


DEVONIAN  AGE. 


269 


sentatives  of  the  order  (pp.  242,  245),  and  which  in  the  Hamilton 
are  the  least  common  kind ;  (2)  the  Lepidodendrids,  having  the  scars 
which  mark  the  places  of  the  leaves  in  alternate  or  quincunx  order 
(Fig.  525)  ;  and  (3)  the  Sigittarids,  which  have  the  scars  in  vertical 
series  (Fig.  526). 

The  Lepidodendrids  were  in  part  trees,  and  they  much  resembled 
in  habit  modern  Spruces  and  Pines,  the  leaves  having  been  long  and 
narrow  and  crowded  over  the  branches.  A  portion  of  the  scarred 
exterior  of  a  branch,  from  New  York,  is  represented  in  Fig.  525. 
Good  examples  of  such  scars  are  to  be  found  on  a  small  branch  of 
a  common  spruce.  Fig.  527  represents  a  bijoad  leaf  of  the  genus 
Cordaites,  which  belonged  to  a  Lycopod,  according  to  some  authori 
ties,  but  more  probably  to  a  Conifer  (p.  329). 


Figs.  525-530. 


527 


ACROGENS.—  Fig.  525,  Lepidodendron  primsevum  ;  526  Sigillaria  Hallii ;  527,  Cordaites  Robbii; 
528,  Neuropteris  polymorpha  ;  529,  530,  Cyclopteris  Jacksoni. 

The  Sigillarids  grew  up  as  stout  trunks,  some  of  them  thirty  or  more 
feet  high,  with  rarely  a  branch,  and  with  long  linear  leaves  (or  fronds) 
about  the  summit.  Fig.  520  represents  a  portion  of  a  very  small 
species,  from  New  York,  showing  the  vertical  series  of  scars.  Trunks 
of  SigiUaria  have  been  found  having  a  base  of  spreading  branches 
looking  like  roots  ;  but  the  supposed  roots,  according  to  Lesquereux, 
are  underwater  stems.  These  stems  have  round,  scattered,  pit-like 
depressions  over  the  surface,  where  the  underwater  leaves  were  at 
tached,  and  are  called  Stigmarice,  from  the  Latin  stigma,  a  dot.  Part 
of  a  stem  of  a  Carboniferous  Stigmaria  is  represented  in  Fig.  624, 


270 


PALEOZOIC    TIME. 


p.  324).  The  modern  Isoetes  (referred  to  the  Lycopods  by  many 
Botanists)  are  regarded  by  the  best  authorities  as  the  nearest  allies  of 
the  ancient  Sigillarids  ;  they  are  from  an  inch  to  two  feet  in  height, 
and  have  nearly  linear  leaves,  bnt  no  trunk ;  if  they  were  capable  of 
growing  upward,  like  many  other  Acrogens,  and  producing  a  trunk, 
the  plant  with  its  long  leaves  would  much  resemble  the  Sigillarids. 

2.  Ferns.  —  Forty   or  more   species  of  Ferns   have  been  described 
from  beds  of  the  Hamilton  period,  the  most  of  them  from  those  of  St. 
John,  New  Brunswick.     One  species,  a  Neuropteris,  is  represented  in 
Fig.  528  ;  part  of  a  frond  of  another,  a  Cydopteris,  in  Fig.  529,  and  a 
single  leaflet  in   Fig.   p30.     Large   trunks   of  tree-ferns  (peculiar  in 
their  very  large  scars),  have  been  found  in  the  New  York  and  Ohio 
Hamilton  beds. 

3.  Equiseta  or  Horse-tails.  —  This  tribe   of  plants  was  represented 
by  plants  called   Galamites  (from  calamus,  a  reed],  in  allusion  to  their 

Figs.  531,  532. 


681 


Fig.  531,  Caiamites  Transitionis ;  532,  Asterophyllites  latifolia. 

reed-like  or  rush-like  aspect.  Fig.  531  represents  a  portion  of  a  stem 
(in  horizontal  position)  flattened  out,  Like  the  modern  Equisetum, 
the  stem  was  jointed  (at  ab  in  Fig.  531),  and  separated  easily  at  the 
joints,  and  the  surface  was  finely  furrowed.  The  modern  Equiseta 
have  hollow  stems.  Fig.  532  represents  a  species  of  Asterophyllites,  — 
the  name  signifying  star-leaf —  a  plant  of  undetermined  relations. 

4.  Gynmosperms.  —  These  plants  belong  to  the  order  of  Conifers, 
which  includes  plants  related  to  the  Yew,  Pine,  Spruce,  etc.  Les- 
quereux  mentions  the  occurrence  of  trunks  of  Conifers  a  foot  in  diam 
eter,  in  the  Black  shale  of  the  Hamilton  ;  and  others,  as  large  or 
larger,  are  described  by  Dawson  from  the  New  Brunswick  beds. 

For  the  descriptions  of  American  Devonian  plants,  science  is  largely  indebted  to  Dr. 
J.  W.  Dawson  (Quart.  J.  G.  Soc.,  xv.  -483,  xviii.  296,  xix.  458,  xxvii.  270;  also  his 


DEVONIAN   AGE.  271 

Acadian  Geology,  3d  ed.,  1868;  also  On  the  Fossil  Plants  of  the  Devonian,  etc.,  pub 
lished  by  the  Geol.  Survey  of  Canada  in  1871).  Some  species  have  been  described  also 
by  C.  F.  Hartt  (Bailey's  New  Brunswick  Geol.  Rep.,  1865),  and  by  Newberry  and 
Lesquereux. 

Lepidodendron  primcevum  Rogers  (Fig.  525)  is  from  Huntingdon,  Pa.;  the  small 
Siyillaria  Hallii  D.,  Fig.  526,  from  Otsego  County,  New  York.  Species  of  Psilophyton 
have  been  reported,  by  Dawson,from  the  Hamilton  and  Chemung  of  New  York  and 
Ohio,  as  well  as  from  Gaspe  and  from  Perry,  Maine.  Lepidodendron  Gaspiamim  Dn.,  a 
Gaspe  species,  occurs  also  in  the  Upper  Hamilton  and  Catskill  beds  of  New  York  and 
New  Brunswick.  Psaronius  Erianas  Dri.  and  Caulopteris  Lockwoodl  Dn.  are  tree-ferns 
from  the  Hamilton  of  Madison  County,  New  York.  Arthrostigma  yracile  Dn.  is  the 
name  of  a  Gaspe  plant,  much  resembling  Psilophyton.  Psilophyton,  Prototaxites,  and 
Arthrostiyma  are  regarded  by  Dawson  as  forms  becoming  nearly  extinct  in  the  Middle 
Devonian. 

The  following  are  some  of  the  St.  John  species ;  those  that  occur  also  at  Gaspe"  are 
marked  with  an  asterisk,  and  those  also  in  New  York  or  the  West,  with  a  dagger. 

Psilophyton  princeps  Dn.*t  (Fig.  484  B,  p.  258),  Lepidodendron  Gas/nanum  Dn., 
Siyillaria  palpebra  Dn.,  Stiymaria  perlata  Dn.,  Cordaites  Robbii~\  (Fig.  527),  Cyclopteris 
Jacksoni  (Figs.  529,  530)  Neuropteris  polymorpha  Dn.  (Fig.  528),  .V.  Daivsoni  Ilartt. 
(leaflet  over  six  inches  long),  Sphenopteris  HitchcocJciana  Dn.,  S.  Hcsninyhausi  Brngt., 
S.  Harttii  Dn.,  Callipteris  pilosa  Dn.,  Hymenophyllites  Gersdorffii  Gopp.,  //.  obtusilobus 
Gopp.,  Alethoptens  discrejians  Dn.,  Pecopteris  preciosa  Hartt.,  species  of  Tricho- 
manites,  Catamites  transitionis  Gopp.  (Fig.  531),  C.  cannfeformis  Brngt.;  Aster  ophyUites 
acicvlaris  Dn.,  A.  latifolia  Dn.  (Fig.  532),  SphenopJtyUuut,  antiquum  Dn.;  Dadoxylon 
(Araucarites)  Ouanyondiunum  Dn.,  besides  fruits  of  the  genera  Cardiocarpum  and 
Triyonocarjnim. 

A  kind  of  fossil  wood  from  Eighteen-mile  Creek,  New  York,  named  Syrinyo.rjlon 
mirabile  by  Dawson,  and  announced  by  him  as  having  the  structure  of  an  Angiospcrm, 
is  made  a  Conifer,of  the  genus  Arauc(ti'oxylon,\)y  Lesquereux. 

The  figure  of  Cyclopteris  Jacksoni,  529,  is  from  a  Gaspe  specimen  (Dawson).  A  New 
Brunswick  specimen,  figured  by  Dawson,  is  ten  inches  long,  and  only  part  of  a  frond; 
it  has  a  dozen  pinnules  (branchlets)  like  Fig.  529,  either  side  of  the  stem;  and  Fig. 
530,  showing  the  neuration,  is  taken  from  it.  The  genus  (sometimes  called  also 
Ncegyerathia,  and  by  Schimper  Palceopteris)  is  prominently  Devonian,  it  disappearing 
in  the  early  Carboniferous.  Other  species  are  figured  on  pages  277,  279.  These  early 
ferns,  with  the  species  of  Cfdlipteris,  and  probably  those  of  Neuropteris  and  Splieno^>teris, 
kinds  that  commence  during  or  before  the  middle  Devonian,  are  probably,  as  sug 
gested  to  the  author  by  D.  C.  Eaton,  related  to  the  modern  Botrychium  and  Ophioylos- 
sum,  genera  having,  as  Hooker  states,  the  fruit  nearly  like  that  of  Lycopods,  and  differ 
ing  from  ordinary  ferns  also,  in  the  leaf  not  being  rolled  into  a  coil  when  first  de 
veloped,  and  therefore  riot  uncoiling  as  it  opens.  This  would  make  them  intermediate 
between  the  Lycopods,  the  earliest  known  form  of  terrestrial  plants,  and  the  true  Ferns. 

2.  Animals. 

The  animal  remains  of  the  Marcellus  are  comparatively  few,  and, 
excepting  the  Goniatites,  generally  small :  their  small  number  corre 
sponds  with  the  fact  that  the  rock  is  a  fine  shale.  In  the  Hamilton 
beds,  which  are  coarser,  and  often  resemble  a  consolidated  mud-bed, 
fossils  are  much  more  numerous.  With  the  Genesee  slate,  there  is  a 
return  to  the  fineness  of  the  Marcellus,  and  also  in  part  to  some  of 
the  same  species  of  shells.  The  Black  shale  contains  but  few  fossils ; 
among  them,  Lingula  subspatulata  M.  &  "W.,  a  Discina  and  a  Chonetes, 
with  remains  of  Fishes  and  Crustaceans. 


272 


PALEOZOIC   TIME. 


The  preceding  period  had  abounded  in  corals,  arid  hence  in  lime 
stones  ;  in  the  Hamilton,  when  the  condition 
was  unfavorable  for  Coral  reefs,  over  New 
York  and  to  the  south,  there  were  still  some 
large  species  of  corals  and  Crinoids  ;  but  the 
predominant  fossils  were  Brachiopods  and 
Lamellibranchs  —  species  that  live  on  muddy 
bottoms.  There  were  many  broad-winged 
Spirifers,  among  which  the  Sp.  mucronatus 
(Fig.  539)  was  very  common.  The  limestone 
layers  mark  an  occasional  change  to  clearer 
waters,  when  crinoids  and  corals  had  a  chance 
to  flourish. 

Brachiopods  continued  to  be  the  most  common  of  fossils.  Figures 
536  to  543  represent  the  most  common  kinds. 

Figs.  536-543. 


Ilelioph}  Hum  Halli. 


BRACHIOPODS.  —  Fig.  536,  Atrypa  aspera ;  537;  A.  reticularis  ;  538,  Tropidoleptus  carinatus  ;  539, 
Spirifer  mucronatus  ;  540,  Athyris  spiriferoides  ;  541,  Spirifer  (Martinia)  umbonatus  ;  542,  Cho- 
netes  setigera  ;  543,  Productus  subalatus. 

Lamellibranchs  are  more  numerous  than  in  former  eras.  The  fol 
lowing  figures,  544  to  547,  show  some  of  the  characteristic  species. 

With  this  period  commenced  the  genus  Goniatites  (Fig.  548)  — 
a  group  of  Cephalopods  with  Nautilus-like  shells,  but  differing  from 
Nautilus  in  having  the  siphuncle  dorsal,  and  the  septa  with  one  or 
more  flexures  at  the  margin  ;  in  case  of  one  flexure  or  more,  there  is 
always  one  on  the  dorsal  margin,  as  in  Fig.  548  a.  The  Goniatites 
became  more  and  more  complex  in  the  flexures  of  the  septa  during 
the  following  periods  of  the  Paleozoic,  and  afterward  were  replaced 
by  the  Ceratites  and  Ammonites,  to  which  they  are  closely  related. 


DEVONIAN   AGE. 


273 


Among  Articulates,  there  were  new  species  of  Trilobites,  one  of 

Figs.  544-547. 


CONCHIFERS.  —  Fig.  544,  Ortkonota  undulata  (X  f);  545,  Pterinea  flabella  ( X  i);  546,  Granimysia 
bisulcata  ;  547,  Microdon  bellistriatus. 

which  is  represented  in  Fig.  549,  and  the  tail  portion  of  another  in 

s.  548-550. 


Fig.  550  A. 


CEPHALOPOD.  —  Fig.  548,  548  a.  Goniatites  Marcellensis.    TRILOBITES.  —  Fig.  549,  Phacops  bufo; 
550,  Caudal  extremity  of  Dalmanites  calliteles. 

550.  There  were  also  the  earliest  yet  discovered  of  the  remains  of 
Insects,  obtained  at  St.  John,  N.  B. 
They  are  the  wings  of  Neuropterous 
Insects,  and  one  of  these  is  repre 
sented  in  Fig.  550  a  —  the  Plate- 
phemera  antiqua  of  Scudder.  It  is 
related  to  the  Ephemera  or  May-flies, 
species  whose  larves  live  in  the  water, 
and  which  frequent  moist  places,  and 

therefore  stood  a  good  chance  of  be-  natephemwa  antiqua. 

coming  preserved  as  fossils. 

It  was  a  gigantic  species,  measuring  five  inches  in  spread  of  wings. 
One  species  has  what  appears  to  be  a  stridulating  organ,  according  to 
18 


274  PALEOZOIC    TIME. 

Scudder  ;  and  Dawson  thereupon  observes  that  "  the  trill  and  hum  of 
insect  life  must  have  enlivened  the  solitudes  of  the  strange  old  Devo 
nian  forests."  Insects  appear  to  have  been  the  only  winged  life  of 
the  Devonian  and  Carboniferous  ages. 

Vertebrates  are  represented  only  by  fishes  ;  and  the  species  are  of 
the  Selachian  (or  Shark),  Ganoid,  and  Placoderm  groups,  as  in  the  Cor- 
niferous  era.  One  of  the  Placoderms  from  the  Black  shale  of  Ohio, 
called  Dinichthys  Hertzeri  by  Newberry,  had  a  head  three  feet  long 
by  two  broad,  and  under  jaws  two  feet  long :  the  fish  could  hardly 
have  been  less  than  twenty  feet  in  length.  The  remains  are  very 
numerous.  A  fin-spine  (  Ctenacanthus  vetustus)  a  foot  long,  from  the 
same  shale,  belonged  to  a  shark  probably  fifteen  feet  long. 

Characteristic  Species. 

1.  Radiates.  —  Fig.  535,  the  Coral  IlcUopJiyUum  Ilalll  E.  &  H.,  common  in  the 
Hamilton,  at  Moscow,  York,  and  elsewhere,  and  found  also  in  England.     The  Encrinal 
limestone  is  made  up  of  fragments  of  crinoidal  columns. 

2.  Mollusks. — (n.)  Brachiopods. —  Fig.  536,  Atrypa  aspera  Dalm.,  also  Euro 
pean  ;  537,  A.  reticidaris,  regarded  as  the  same  species  as  that  of  the  Corniferous  period, 
but  usually  much  larger  and  fuller,  being  sometimes  nearly  two  inches  broad;  538, 
Tropidoleptus  carinatus  H.,  in  New  York,  Illinois,  Iowa,  Europe ;  539,  Spirifer  mucro- 
natus  Con.,  very  common;  540,  Athyris  spinferoides  H.  (Atrypa  concentrica  of  Conrad), 
—  it  has  the  spire  internally  of  a  Spirifer;  541,  Spirifer  (Amboccelia)  umbonatus ;  542 
Chonetes  setiytra  H.,  found  in  both  the  Marcellus  and  Genesee  shales;  543,  Product-its 
(Productella)  subalatus  H.,  Rock  Island,  111.     A  shell  closely  like  the  S.  umbonatus,  but 
higher,  occurs  in  Iowa  and  Illinois,  and  is  named  Cyrtlna  umbonata  by  Hall.     Spirifer 
yramdiferus  H.  is  a  large  Hamilton  species,  having  a  granulated  surface. 

(b. )  Lamellibranchs. — The  species  are  often  of  large  size;  but  none  yet  described 
have  a  sinus  in  the  pallial  impression.  Fig.  544,  Orthonota  undulata  Con. ;  545,  Pterinea 
fltibclla  Con.;  546.  Grammysia  bisulcaia  Con.  (Hamiltomnsis  of  Verneuil),  —  also  Euro 
pean,  in  the  Eifel;  547,  Microdon  bellistria tits  Con. 

(c. )  Gasteropoda.  — A  few  species  have  been  described.  They  are  all  without  a  beaked 
aperture,  like  those  of  older  time.  The  Bellerophon  patulus  H.  is  a  broad  species  of 
the  genus,  with  a  flaring  aperture.  Platyceras  ventricosum  Con.,  Isonema  (ffolopea) 
depressa  M.  &  "W. 

(d. )  Cephalopoda.  — Fig.  548,  Goniatites  Marcellensls  Van.,  a  species  sometimes  a  foot 
in  diameter,  occurring  in  the  Marcellus  shale;  548  «,  dorsal  view.  Two  small  species, 
the  G.  unianyularis  and  G.  punctatus,  are  reported  by  Conrad  from  the  Hamilton  beds. 
The  genus  Orthoceras  is  represented  by  a  few  species  of  moderate  size ;  there  are  also 
Gomphoceras  turbiniforme  M.  &  W.,  Cyrtoceras  sacculum  M.  &  W.,  and  Gyroceras(?) 
constrictum  M.  &  W.,  in  Illinois  and  Indiana. 

3.  Articulates. —  (a.)  Crustaceans.  — The  Trilobites  Phacops  biifo  (Fig.  549)  and 
Dalmanitts  EoothiiH.  (D.  calliteles)  (Fig.  550,  representing  the  posterior  extremity)  are 
common  in  the  Hamilton  beds;  also  Phacops  rand  Green.     Eurypterus  pulicaris  Salter, 
a  minute  species,  occurs  at  St.  John,  New  Brunswick,  and  with  it  a  peculiar  crustacean, 
Macrural  in  habit,  the  Amphipeltis  pctradoxtu  Salter. 

(b.)  Insects.  —  At  St.  John,  N.  B.,  besides  the  Platephemera  antiqua  Sc.  (Fig.  550  A.), 
there  are  two  other  Neuropters  with  a  spread  of  wing  of  3i  inches,  and  a  fourth,  the 
Xenoneura  urttiquomm  Sc.,  with  the  same  2^  inches;  this  last  is  the  one  having  the 
stridtilatirig  organ  alluded  to  above. 

4.  Vertebrates.  —  The  fossil  fishes  of  the  Hamilton  rocks  are  of  several  genera 
and  species.     In  the  Gaspe  sandstones  occur  remains  of  Cephalaspis,  and  "  apparently 


DEVONIAN   AGE.  275 

Coccosteus,  Ctenacanthus,  and  Lepta-canthus"  (Dawson).  The  gigantic  Dinichthys  of 
Newberry,  from  the  Black  Shale  of  Ohio,  occurs  in  great  concretions,  some  of  them 
twelve  feet  in  diameter.  Remains  of  a  species  of  Paleeoniscus  have  been  found  in  the 
top  of  the  same  shale,  near  Danvjlle,  Ky.  (F.  H.  Bradle}'.) 

General  Observations. 

Geography.  —  The  positions  and  nature  of  the  Hamilton  beds  in 
dicate  similar  geographical  conditions  to  those  of  many  earlier  periods, 
—  that  a  shallow  sea  covered  New  York  and  spread  widely  to  the 
west,  and  that  many  changes  were  experienced  in  the  water-level. 
The  beds  are  to  a  great  extent  mud-beds,  whence  we  learn  that  they 
were  deposited  in  quiet  waters :  the  fossils  are  marine,  proving  marine 
waters.  The  beds  in  New  York  are  thickest  about  its  central  parts, 
and  yet  spread  to  its  eastern  and  western  limits,  excepting  the  upper 
most,  the  G-enesee  shale,  which  is  not  known  in  the  eastern  part ; 
they  are  partly  calcareous  in  the  lower  part  of  the  Marcellus  beds, 
proving  that  the  change  from  the  condition  of  the  limestone-making 
Corniferous  period  was  gradual ;  limestone  layers  occur  higher  up,  at 
intervals,  indicating  changes  of  level,  which  favored  at  times  the 
growth  of  Oinoids  and  Corals ;  ripple-marked  flags  make  up  some 
layers,  proving,  by  their  evenness  and  extent,  and  the  regularity  of 
the  lamination,  that  the  sea,  at  the  time  of  their  formation,  swept  over 
extensive  sand-flats,  coming  in  over  the  present  region  of  the  Hudson 
River  or  of  New  York  Bay.  The  existence  of  a  barrier  of  sand  along 
the  ocean,  such  as  is  thrown  up  and  at  intervals  removed  again  by 
the  waves,  would  account  for  the  varying  conditions  and  also  for 
changes  in  the  living  species  by  extermination. 

Moreover,  while  these  mud- accumulations  were  here  in  progress, 
there  were  Hamilton  limestones  forming  in  some  of  the  Western 
States,  indicating  again  the  existence  of  the  Interior  or  Mississippi 
sea,  —  a  feature  in  a  large  part  of  both  Silurian  and  Devonian  geog 
raphy  ;  and  then  the  wide-spread,  but  thin,  Hamilton  black  shale, 
almost  destitute  of  fossils,  and  very  bituminous,  indicating  probably 
quite  shallow  waters  over  the  Interior  basin,  —  yet  not  so  shallow  but 
that  fishes  could  live  abundantly  through  them. 

The  Appalachian  region  was  still  an  area  of  vastly  the  thickest 
deposits,  and  hence  of  the  greatest  change  of  level  by  subsidence ;  and 
the  great  thickness  of  the  formation  (1,000  feet)  in  central  New  York 
makes  it  another  example  of  the  prolongation  of  the  subsiding  Appa 
lachian  region  northward  over  southern  New  York.  This  fact  and  the 
thinning  of  the  beds  toward  the  Hudson  River  indicate  that  the  Green 
Mountain  region  was  above  the  sea,  so  that  the  great  New  York  bay, 
alluded  to  in  the  observations  on  the  Oriskany  beds,  was  still  outlined 
on  the  east,  although  communicating  westward  more  or  less  perfectly 
with  the  Interior  basin. 


276  PALEOZOIC    TIME. 

Life.  —  The  land  plants  of  the  Hamilton  beds  prove  that,  over  the 
rocks  and  soil  of  the  emerged  continent,  with  its  islands,  there  were 
forests  and  jungles  of  Conifers,  Sigillarids,  Lepidodendrids,  Calamites, 
and  Tree-ferns.  As  to  animal  life,  the  Hamilton  beds  give  us  the 
first  evidence  that  the  sub-kingdom  of  Articulates  contained  terrestrial 
species.  It  is  altogether  probable  that,  besides  Insects,  there  were 
also  Myriapods  (Centipeds),  and  Spiders,  the  other  kinds  of  terrestrial 
Articulates.  All  these  types  may  have  appeared  much  earlier,  with 
the  terrestrial  vegetation  of  the  Upper  Silurian ;  but  there  is  as  yet  no 
positive  assurance  of  this. 

3.  CHEMUNG  PERIOD  (11). 

Epochs. —  1.  PORTAGE,  or  that  of  the  Portage  group  (11  a)  ; 
2.  CHEMUNG,  or  that  of  the  Chemung  group  (11  b). 

I.   Rocks:  kinds  and  distribution. 

The  Portage  group  in  New  York  consists  of  shales  and  laminated 
or  shaly  sandstones.  Westward,  the  shales  increase  in  proportion, 
and  eastward  the  sandstones  ;  and  there  are  changes  in  the  fossils,  cor 
responding  with  these  variations.  The  rocks  have  a  thickness  of 
1,000  feet  on  the  Genesee  River,  and  1,400  near  Lake  Erie.  (Hall.) 
They  are  well  developed  about  Cayuga  Lake,  but  have  not  been  rec 
ognized  in  the  eastern  half  of  the  State  of  New  York. 

The  Chemung  group  extends  widely  over  the  southern  tier  of 
counties  of  New  York,  and  consists  of  sandstones  and  coarse  shales,  in 
various  alternations.  The  thickness  has  been  estimated  at  1,500  feet 
near  the  longitude  of  Cayuga  Lake,  and  less  toward  Lake  Erie  and 
beyond. 

Rocks  of  this  period  fail  over  a  large  part  of  the  Interior  Basin, 
nothing  intervening  between  the  Black  shah  and  the  Subcarboniferous. 

To  the  south  and  southwest  of  New  York,  in  Pennsylvania,  and 
beyond  along  the  Appalachian  region,  the  corresponding  beds  have 
great  thickness,  amounting  in  some  places  to  more  than  3,000  feet. 
They  are  sandstones,  as  in  New  York.  The  upper  part  of  the  sand 
stone  beds  about  Gaspe  are  referred  to  this  period;  and  also  the 
plant-bearing  beds  at  Perry,  Maine. 

The  beds  in  New  York  abound  in  ripple-marks,  obliquely-laminated 
layers,  mud-marks  and  cracks  from  sun-drying,  —  evidences  of  the 
existence  of  extensive  exposed  mud-flats,  of  sandy  or  muddy  areas 
swept  by  the  waves,  and  of  tidal  currents  in  contrary  movement 
through  the  shallow  waters. 

In  western  New  York,  the  lower  beds  are  the  Cashaqua  shales;  next,  the  Gardeau 
shales  and  flags;  then,  above  these,  the  Portage  sandstones. 


DEVONIAN   AGE. 


277 


In  this  section,  from  one  by  Hall,  taken  in  Yates  County,  X.  Y.,  10  a,  10  b,  10  c  are 

Fig.  550  B. 


116 


11  a 


10  c 


10  a  Mb 

Section  of  rocks  of  the  Hamilton  and  Chemung  Periods. 

rocks  of  the  Hamilton  period;  o,  the  Marcellus  shale;  b,  the  Hamilton  group;  c,  the 
Genesee  shale;  and,  in  the  Hamilton  group,  2  is  the  Encrinal  limestone,  and  4  the  Tully 
limestone;  11  a  is  the  Portage  group,  lib  the  Chemung  group. 

Westward  of  New  York,  the  Portage  and  Chemung  groups  are  continued  into  Ohio, 
just  along  the  south  side  of  Lake  Erie;  and  the  Black  shale  of  Ohio  and  the  States  west 
and  south,  is  regarded  by  Newberry  as  partly  of  Portage  age. 

II.  Life. 

The  fossils  of  the  Chemung  period  are  almost  wholly  different  in 
species  from  those  of  the  Hamilton. 

1.  Plants. 

Besides  the  Cauda-galli  and  other  Sea-weeds,  there  are  remains  of 
many  land-plants.  They  are,  in  genera,  like  those  of  the  preceding 
period.  Some  of  the  kinds  are  here  represented. 

Figs.  551-554. 
552 


PLANTS.  — Fig.  551,  Cyclopteris  Halliana;  552,  Sigillaria  Vanuxemi ;   553,  Lepidodendron  Chemun 
gense.     BRACHIOPOD.  —Fig.  554,  Atrypa  hystrix. 

A  large-leaved  fern, from  the  Chemung  of  Gilboa,  N.  Y.,  is  named  by  Dawson  Cyclop- 
.teris  Gilboensis.     The  form  somewhat  resembles  Fig.  557  A,  p.  279,  of  aCatskill  species. 


278  PALEOZOIC   TIME. 


2.  Animals. 

The  Portage  beds,  though  abounding  less  in  fossils  than  the  Che- 
mung,  contain  various  species  of  Crinoids,  Brachiopods,  Lamellibranchsy 
(Aviculopectens,  Auiculce,  and  others),  Bellerophons,  and  Goniatites. 
A  large  Crinoid  —  the  Poteriocrinus  (?)  ornatissimus  M.  —  occurs  in 
great  numbers,  broken  to  fragments,  through  a  small  area  in  the  town 
of  Portland,  N.  Y.,  on  Lake  Erie  shore. 

The  Chemung  group  in  New  York  affords  great  numbers  of  Avic- 
ulce ;  many  Brachiopods,  including  broad-winged  Spirifers,  and  some 
Producti ;  among  Cephalopoda,  a  huge  Goniatite  (four  or  five  inches 
in  diameter)  ;  and  rarely  a  Trilobite. 

Characteristic  Species. 

1.  Plants. — Fig.  551,  Cyclopteris  (or  Palceopteris)  Hattiana  Gopp.,  Upper  Chemung 
beds;  552,  Lepidodendron  Chemunyense  Hall,  from  near  Elmira,  X.  Y. ;  553,  Sigillarin 
Vanuxemi  Gopp.,  from  near  Owego,  N.  Y. ;  S.  sifnplicittts  Vanuxem,  from  near  North 
Bainbridge,  N.  Y.  A  Coniferous  fossil  wood,  from  Schoharie  County,  N.  Y.,  has  been 
named  Ormoxylon  Emanum  by  Dawson.  At  Perry,  Me.,  occur  Lepidodendron  Gaspi- 
anum  Dn.,  Leptophleum  rhombicum  Dn.,  Cyclopteris  Jacksoni  Dn.,  C.  Hattiana  Gopp., 
C.  RoyersiDn.,  C.  BrotcniiDn.,  Caulopteris  LocJcwoodi  Dn.,  Anartnrocanna  Perryuna 
Dn.,  Stigma Ha  jmsilh  Dn.,  and  others,  there  being  very  few  of  the  St.  John  species. 
Some  species  are  the  same  that  occur  in  the  Subcarboniferous  beds,  particularly  the 
marsh  species. 


Figs.  555-557. 


Fig  555,  Aviculopecten  duplicates  ;  556,  Pteronites  (?)  Chemungensis ;  557,  Orthoceras  acicula. 


2.  Animals.  —  Fig.  554,  Atnjpa  hystrix  H. ;  Fig.  555,  Aviculopecten  duplicatus  H. ;  Fig. 
556,  Pteronites  (?)  Chemungensis  II. ;  Fig.  557,  Orthoceras  acicula  H. 

Teeth  of  fishes  of  the  genus  Onychodus,  and  others,  have  been  found  in  the  beds  at 
Franklin,  Delaware  County,  X.  Y. 

III.  General  Observations. 

Geography.  — The  character  of  the  beds  —  the  shales  and  shaly  sand 
stones —  which  spread  over  western  and  southern  New  York  and  south 
west  along  the  Appalachian  region,  becoming  more  shaly  toward  the 
western  limit  of  the  State,  and  more  sandy  in  the  opposite  direction, 
tells  nearly  the  same  story  with  regard  to  the  geography  of  this  portion 
of  the  continent  as  the  beds  of  the  Hamilton  period.  The  rocks  were 


DEVONIAN    AGE. 


279 


largely  shallow-water  or  sand-flat  formations,  as  shown  by  the  ripple- 
marks,  shrinkage-cracks,  and  oblique  lamination  ;  and  they  therefore  in 
dicate,  by  their  great  thickness,  a  subsidence  during  their  progress,  to  a 
corresponding  extent,  and,  further,  that  this  subsidence  or  change  of 
level  affected  most  the  Appalachian  region.  The  shallow  sea  extended 
westward  along  the  southern  border  of  Lake  Erie.  But  it  is  probable 
that,  over  the  larger  part  of  the  Interior  basin,  the "  land  lay  mostly 
above  the  water  level.  It  is  difficult,  otherwise,  to  account  for  the  ab 
sence  of  beds  between  the  Black  Shale  and  the  Subcarboniferous. 

4.  CATS  KILL  PERIOD  (12). 
I.  Rocks  :  kinds  and  distribution. 

The  rocks  of  the  Catskill  period  are  shales  and  sandstones  of  vari 
ous  colors,  in  which  red  predominates.  The  sandstones  are  far  more 
extensive  than  the  shales,  and  pass  into  conglomerates  or  coarse  grit- 
rock,  and  also  into  a  rough  mass  looking  as  if  made  of  cemented  frag- 

Fig.  557  A. 


FERN.  —  Cyclopteris  obtusa. 

inents  of  hard  slate.  The  upper  part  is  generally  a  conglomerate. 
There  are  ripple-marks,  oblique  lamination,  and  other  evidences  of  sea 
shore  action  in  many  of  the  strata.  Some  of  the  layers  are  partially 
calcareous. 

The  formation,  instead  of  thickening  to  the  westward,  in  New  York, 


280 


PALEOZOIC    TIME. 


like  those  preceding  it  in  time,  thins  out  in  that  direction,  and  thickens 
toward  the  Hudson,  being  two  or  three  thousand  feet  thick  in  the  Cats- 
kills.  It  stretches  south  along  the  Appalachian  region,  beneath  the 
Coal  formation  of  Pennsylvania  and  Virginia,  where  it  is  5,000  or 
6,000  feet  thick.  It  is  eminently  an  Appalachian  formation. 

II.  Life. 

The  rocks  afford  but  few  relics  of  life.  The  plants  are  related  tc 
those  of  the  preceding  period.  A  portion  of  one  large  fern,  Devonian 
in  character,  is  represented  in  Fig.  557  A ;  and  another  of  the  same 


Figs.  557  B-5GO. 


FERN.  —  Fig.  557  B,  Cyclopteris  minor.    FISH  REMAINS.  —  Fig.  558,  scale  of  Tloloptychius  Ameri- 
canus  ;  559,  tooth,  id.;  559  a,  section  of  tooth  ;  560,  scale  of  Bothriolepis  Taylori. 

genus,  in  Fig.  557  B  —  a  genus  characteristic  especially  of  the  Devo 
nian  (p.  271).  There  were  also  other  ferns,  besides  Lepidodendra, 
Sigittnria,  Calamites,  etc. 

Remains  of  large  fishes  occur  in  the  beds.  Figs.  558.  560  repre 
sent  scales  of  two  species,  and  559,  a  tooth  of  the  first  of  them.  The 
fish  that  had  this  tooth  was  a  very  large  Ganoid,  and  resembled  that 
represented  in  Fig.  569,  page  286. 

Characteristic  Species. 

1.  Plants.  —The  fern,  of  which  a  portion  is  represented  in  Fig.  557  A,  was  over  a  foot 
broad;  it  was  obtained  at  Montrose,  Pa.,  by  H.  A.  Riley.  Cyclopteris  minor  (Nceyyera- 
thia  wiworLsqx.),  Fig.  557  B,  is  from  Pottsville,  Pa. 


DEVONIAN   AGE.  281 

2.  Antmnla.  —  Among  animals,  no  Corals,  Crinoids,  Brachiopods,  or  Trilobites  are  yet 
known;  the  coarse  character  of  the  beds  accounts  for  their  absence.  There  are  some 
Lamellibranchs,  such  as  (Fig.  561)  the  Modiola  anyusta  (Cypricardia  angusta  Con.),  and 
a  few  other  species,  and  a  Euomphalus;  these,  with  fragments  of  fishes,  make  up  about 

Fig.  561. 


LAMELLIB RANCH.  —Modiola  angusta. 

all  that  is  yet  known  respecting  the  animal  fossils  of  the  beds.  Among  the  fishes,  there 
are  (Fig.  558)  Holoptychius  Americanus  Leidy  (559  being  a  tooth  of  the  same,  and  559  a, 
a  section  of  it);  560,  Sothriolepis  Taylorl  Newb.  (Sauripteris  Taylorl  H.)  The  latter 
species  was  of  large  size,  a  portion  of  one  of  the  fins  found  in  New  York  indicating  a 
length  of  more  than  a  foot  for  the  entire  fin. 

III.  General  Observations. 

Geography.  —  The  location  of  the  Catskill  beds  in  eastern  New 
York,  instead  of  central  or  western  (like  the  Hamilton  and  Chemung), 
and  their  thickness  there,  seem  to  show  that  a  great  geographical 
change  preceded  the  opening  of  the  period.  The  Appalachian  sub 
sidence,  instead  of  extending  north  over  central  New  York,  involved 
the  Hudson  River  valley,  far  to  the  eastward;  and  the  amount  of 
subsidence  both  here  and  in  Pennsylvania  and  Virginia  was  much 
greater  than  in  the  preceding  periods.  After  this,  New  York  State, 
excepting  a  border  on  the  south,  lay  to  the  north  of  the  region  under 
going  progress  through  new  formations  :  the  greater  part  of  it  was 
probably  part  of  the  dry  land  of  the  growing  continent ;  for  the  rocks 
of  the  Coal  age,  with  the  small  exception  alluded  to,  do  not  spread 
over  it. 

If  the  view  presented  be  correct,  there  is  a  bold  transition  from  the 
closing  period  of  the  Devonian  age  to  the  opening  of  the  Carbon 
iferous.  The  former  was  a  period  in  which  the  grand  Appalachian 
subsidence  (as  in  other  parts  of  the  Devonian)  reached  north  into  the 
State  of  New  York,  while  in  the  latter  it  hardly  passed  the  limits  of 
Pennsylvania.  The  former  was  characterized  by  dry  land,  over  a 
large  portion  of  the  great  Interior  Continental  basin ;  the  latter,  by  a 
wide-spread  arid  clear,  though  not  deep,  sea,  growing  Crinoids  and 
forming  limestones ;  for  the  Subcarboniferous  limestone  formations 
are  among  the  most  extensive  in  the  geological  series,  and  crinoidal 
remains  are  in  great  profusion. 


282  PALEOZOIC    TIME. 


2.  FOREIGN    DEVONIAN. 
I.  Rocks:  kinds  and  subdivisions. 

The  Devonian  rocks  occur  as  surface-strata  in  most  of  the  countries 
of  Europe,  and  in  parts  of  all  the  other  continents. 

In  the  British  Isles,  they  are  exposed  to  view  in  southern  Wales 
and  the  adjoining  county  of  Herefordshire ;  in  the  peninsula  of 
Devonshire  and  Cornwall ;  along  the  southern  flank  of  the  Grampians, 
and  on  the  northwestern  side  of  Lammermuir  from  Dunbar  to  the 
coast  of  Ayrshire,  in  the  valley  of  the  Tweed  and  elsewhere,  in  Scot 
land  ;  also  in  Ireland,  and  in  the  Isle  of  Man. 

On  the  map,  Fig.  681  A,  p.  344,  the  Devonian  areas  are  distinguished 
by  vertical  lines. 

The  strata  in  England  and  Scotland  have  long  gone  by  the  name  of 
the  Old  Red  Sandstone,  —  red  sandstone  beir.g  the  prevailing  rock  in 
Wales  and  Herefordshire,  as  well  as  in  Scotland.  In  Devonshire  and 
Cornwall,  these  rocks  are  slates  and  limestone,  instead  of  red  sand 
stone. 

The  beds  of  "Wales  are  argillaceous  shales  or  marlytes,  of  red  and  other  colors,  with 
some  Avhitish  sandstone  and  impure  limestone,  overlaid  by  red  sandstone  which  passes 
above  into  a  cong'omerate;  and  the  whole  thickness  is  estimated  by  Murchison  at 
8,000  or  10,000  feet.  The  limestone  is  concretionary,  and  is  called  Cornstone. 

In  Scotland,  the  following  subdivisions  have  been  made  out :  — 

(  3.  Yellow  sandstone ;  containing  ffofaptychiits,  etc. 

3.  Upper.    <  2.  Concretionary  limestone. 

'  1.  Red  sandstone  and  conglomerate. 
Gray  sandstones  and  shales;  containing  Onchus,  Ctenodus,  Polyptems, 

Osteolepis,  Pterichthys,  etc. 
( 3.  Red  and  variegated  sandstone. 

j  2.  Bituminous    schists;  containing  Dipterus,   Pterichthys,  Coccosteus, 
Lower,    -j  Cephalaspis  ;  also  Eurypterus,  Pteryyotus,  etc. 

1 1.  Conglomerate  and  red  sandstone. 
In  Devonshire  and  Cornwall,  the  strata  are,  according  to  Sedgwick:  — 

4.  Petherwin  group.         (  2"  Pether™  slatc  and  Clymenia  limestone. 

I  1.  Marwood  sandstones. 

(  Roofing-slates  and  quartz,   with  variegated   sandstones 
3.  Dartmouth  group. 

(      above,  in  north  Devon. 

f  3.  Red  sandstone  and  flagstone. 
2.  Plymouth  group.         <  2.  Calcareous  slates. 

( 1.  Plymouth  limestone. 
1.  Liskeard  or  Ashburton  group. 

The  Clymenia  limestone  has  been  referred  by  some  to  the  Lower  Carboniferous. 
In  the  "south  of  Ireland,  Devonian  beds  occur  as  a  thin   deposit  in  the  counties  of 
Kilkenny  and  "Wexford,  rapidly  thicken  in  Waterford,  and  have  great  bulk  in  Cork 
and  Kerry  (Jukes).     The  rocks  are  red  sandstones  and  slates,  like  those  in  the  upper 
part  of  the  series  in  "Wales. 

In  the  Eifel  (Rhenish  provinces),  there  are,  below,  slates  and  sandstones;  next,  the 
great  Eifel  limestone,  the  equivalent,  apparently,  of  the  Corniferous;  above  this,  slates, 
with  an  intermediate  limestone,  — the  whole  termed  the  Cypridina  slates,  and  perhaps 
Lower  Carboniferous  in  age. 


DEVONIAN   AGE.  283 

In  Russia,  the  Devonian  formation  is  exposed  over  a  great  extent  of  country.  The 
rocks  are  mostly  marlytes  and  sandstones,  with  some  laminated  limestones.  According 
to  Kutorga,  the  pi-evailing  order  is  —  marlytes  below,  then  sandstones,  then  argillaceous 
limestone. 

There  is  thus  a  great  diversity  in  mineral  character,  and  no  con 
formity  in  the  subdivisions  of  the  Devonian  with  those  in  America. 
As  already  explained,  these  subdivisions  are  in  general  due  to  causes 
that  have  acted  too  locally  to  be  often  alike  and  synchronous  in  very 
distant  regions. 

II.  Life. 
1.   Plants. 

Europe  and  Britain  have  afforded,  in  addition  to  sea-weeds,  remains 
of  plants  mostly  related  in  genera  to  those  of  the  United  States ;  so 
that  the  other  continents  besides  America  had  their  Ferns,  Lycopods, 
Catamites,  and  Conifers.  Devonian  plants  have  been  reported  also 
from  Queensland,  Australia. 

Among  the  Devonian  plants  of  Ireland,  in  beds  that  contain  also  remains  of  Coccos- 
teus  and  Glyptolepis,  there  are  Cyclopteris  Ilibernica  Forbes,  Spkenopteris  Hookeri  Baily, 
S.  Humph  riesiana,  Catamites  radiitus  Br.,  Lepidodendron  VeltJieimianum  Sternb.,  Knor- 
ria  acicularis  Gopp.,  Cydostigma  minutum  Haughton,  C.  Kiltorkense  Haughton,  and 
others.  Heer  has  identified  Catamites  (JSornia)  radiatus  Brngt.,  Lipidodendron  Velthei- 
mianum,  Cyclopteris  JRwmeriana  Gi'pp.  (a  European  species  near  C.  Ilibtrmca),  Sjriie- 
noptcris  Schimperi  Gopp.,  Knorria  imbricata  Sternb.,  Cyclostiyma,  minutum  and  (7.  Kil- 
torkense,  etc.,  in  beds  of  sandstone  on  Bear  Island  (74°  30X  N.),  which  he  refers  to  the 
lower  part  (his  Ursa  stage)' of  the  Subcarboniferous,  fifteen  out  of  the  eighteen  species 
there  found  being  known  and  partly  wide-spread  species,  and  several  occurring  in  the 
Ursa  beds  of  the  Vosges  and  Black  Forest.  In  a  shale,  regarded  as  Devonian,  under 
the  Subcarboniferous  of  Moresnet,  occurs  Cyclopteris  Rcemeriana,  with  Spiriftr  dis- 
junctus  Sow. 

2.  Animals. 

The  range  of  animal  life  was  similar  to  that  of  America.  A  few 
species  of  Europe  and  America  were  identical ;  but  the  great  majority 
were  distinct :  as  regards  genera,  the  identity  was  very  nearly  com 
plete. 

Corals  were  abundant  in  Europe,  especially  Favosites  and  the 
Cyathophylloid  species ;  and  coral-reefs  were  forming  in  the  Eifel  and 
some  other  parts.  Mollusks  were  most  abundantly  represented  by 
BracMopods,  and  Crustaceans  by  TriloUtes  and  the  little  Ostracoids. 
There  were  also  large  species  of  Eurypterus,  Pterygotus,  and  allied 
forms,  some  of  which  had  the  length,  enormous  for  Crustaceans,  of 
five  feet.  For  details  respecting  these  Entomostracans,  see  Wood 
ward's  "  Memoir,"  published  by  the  Paleontographical  Society. 

Among  Brachiopods,  Spirifers  were  very  common  ;  and  the  genus 
Productus  made  its  first  appearance,  along  with  others  of  less  prom- 


284 


PALEOZOIC    TIME. 


inence.  Goniatites  also  (a  genus  of  Cephalopods)  was  a  new  type, 
and  became  well  represented  before  the  close  of  the  age.  Another 
genus,  Clymenia  (Fig.  562),  was  represented  by  many  species  in  the 
Upper  Devonian. 

The  sub-kingdom  of  Vertebrates  included  numerous  fishes  of  the 
orders  of  Selachians  and  Ganoids,  as  in  America.  A  few  are  repre 
sented,  of  reduced  size,  in  Figs.  566-570.  Figs.  566,  567  represent 
two  of  the  Placoderms  —  one  that  moved,  unlike  most  fishes,  by  means 
of  side  paddles  ;  and  the  other,  one  that  sculled  with  its  tail,  in  ordi 
nary  piscatory  style. 

Characteristic  Species. 

1.  Radiates. — Among  Radiates,  there  were  species  of  Pentremites,  the  earliest 
in  Europe  of  the   group   of  Blastoid  Crinoids.     The   Corals  included    Cyathophyllum 
ccespitosum  Goldf.,  HtUolites  %)orosa  E.  &  H.,  Pleurodictyum  problematicum  Goldf.,  Aulo- 
pora  serpens  Goldf. 

2.  Mollusks.  —  Brachiopods   included   species   of    Ortltis,    Strophomena,   Atrypa, 
RJiynchonella,   Spirifcr,   Chonetes,  etc.;  besides  Productus  and  Strinyocephalus,  which 
are  not  known  in  Great  Britain  before  the  Devonian. 

Lamellibranclts  were  numerous,  of  the  genera  Aricula,  Aviculopecten,  Pterinea,  Nu- 
cula,  Conocardium;  also  of  Area,  Grammysia,  Meyalodon,  etc.;  also  Anodonta  Jukesii, 
a  freshwater  species.  Fig.  241,  p.  173,  is  the  Calceola  sandalina  (so  called  from  the 
sandal-like  shape  of  the  shell).  This  genus  characterizes  the  Calceola  schist,  which 
underlies  the  great  Devonian  limestone  of  the  Eifel.  Gasteropods  (all  without  beaks)  of 
the  old  genera  Murchisonia,  Ettomphahu,  Pleurotomaria,  Loxonema,  Bdlerophon,  etc. 

Figs.  562,  563. 
563a 


CEPHALOPODS.  —  Fig.  562,  Goniatites  retrorsus  ;  563,  Clymenia  Sedgwickii ;  5r3  a,  dorsal  view  of 

septa. 

There  were  others  also  of  the  neAv  genus  Porctllia,  which  is  near  BeUerophon,  and 
somewhat  resembles  an  Ammonite  in  form,  but  has  a  deep  dorsal  slit  in  the  aperture 
of  the  shell. 

Ccphnlopods  include  a  few  species  of  the  Orthoceras  family, — also  Nautili,   and 
several  species  of  the  new  genus  Goniatites,  of  the  Ammonite  family,  and  of  another, 


DEVONIAN   AGE. 


285 


called  Clymenia.  Fig.  502,  Goniatites  retrorsus ;  Fig.  563,  Cfymenia  Sedffwickii.  The 
shell  in  Cfymenia  has  the  form  of  the  Ammonites,  but,  unlike  the  Goniatites  and  Am 
monites,  the  siphuricle  is  ventral  instead  of  dorsal ;  and  the  septa  have  no  distinct 
dorsal  lobe  on  the  medial  line,  as  shown  in  Fig.  503  a. 

3.  Articulates — There  were  a  number  of  species  of  Trilobites,  though  fewer  than 
in  the  Silurian :  the  genera  Phacops  and  Dalmanites  were  common.  Homalonotus  had 
European  species;  and  one,  //.  armatm,  had  spines  on  the  head,  and  two  rows  along 
the  back.  This  spinous  feature  appears  to  have  reached  its  maximum  in  the  Devonian 
Aryes  armatus  (Fig.  504),  and  some  species  of  Acidaspis. 


Figs.  564,  565. 


CRUSTACEANS.  —  Fig.  564,  Arges  armatus  ;  565,  Slate  containing  Cypridina  serrato-striata,  natural 
size  ;  565  a.  same,  enlarged. 

Minute  Ostracoids.  referred  to  the  genus  Cypridina,  abound  in  the  Cypridina  slate, 
giving  this  name  to  the  beds ;  Fig.  565  represents  a  portion  of  the  slate  or  shale,  with 
the  shells  of  the  C.  serrato-striata  on  its  surface,  natural  size,  and  565  a,  one  of  them 

Figs.  566,  567. 


506 

•"-"~~ ——-•<•"  •"     .Y.V  v  v;.v  <;: 

?&&&* 


PLACODERMS.  — Fig.  566,  Pterichthys  Milled  (x  ?3');  567,  Coccosteus  decipiens  (X 


enlarged.  There  were  also  other  Ostracoids.  The  Prcearcturus  giyas  Woochvard,  from 
the  Old  Red  Sandstone  of  Herefordshire,  is  a  gigantic  Isopod  crustacean;  and  Stylonu- 
rus  Scuticus  Wd.,  another  from  the  Old  Red  of  Forfarshire.  They  must  have  been  over 
a  foot  long. 


286 


PALEOZOIC    TIME. 


4.  Vertebrates.  —  In  the  Devonian  rocks  of  Great  Britain  and  Europe,  large 
numbers  of  species  of  fishes  have  been  found. 

Among  the  Placoderms,  which  occur  in  the  two  lower  divisions,  there  were  two  prom 
inent  groups.  Fig.  566,  Pterichthys  Milleri  Ag.,  represents  one;  and  Fig.  567,  Coccos- 
teus  dedpiens  Ag.,  represents  the  other.  Also  Fig.  568,  Cfphalaspis  Lyellii  Ag. ;  Figs. 
Figs.  568  a,  568  b,  scales  of  the  same:  a  type  sometimes  referred  to  the  Placoderms. 
Of  other  Ganoids,  there  were,  Fig.  569,  a  Holojrtychius ;  Fig.  569  a,  scale,  id. ;  Fig.  570, 
Dipterus  macrolepidotus,  Sedgw.  &  Murch. 

Figs.  568-570. 


GANOIDS.  —  Fig.  568,  Cephalaspis  Lyellii  (x  %);  568 a, b,  scales,  id.;    569,  Holoptychius 
569 a,  scale,  id.  ;  570, .Dipterus  macrolepidotus  (X  >£) ;  570 a,  scale,  id. 

Species  of  Pterichthys,  Diplopterus,  Glyptokpis,  Dendrodus,  Platyynathus,  etc.  Holo 
ptychius  (Fig.  569)  belongs  to  the  Upper  Devonian  only,  and  also  to  the  early  Carbonif 
erous.  Pterichthys  (Asterolepis)  Asmusi  Ag.,  whose  remains  occur  both  in  Russia  and 
Scotland,  is  supposed  to  have  been  twenty  to  thirty  feet  long. 

3.  GENERAL  OBSERVATIONS  ON  THE  DEVONIAN  AGE. 
American  Geography.  —  1.  General  features.  —  The  Archaean  area, 
which  had  been  enlarged  on  the  north  by  successive  additions  from 
emergence  during  the  Silurian,  continued  expanding  in  the  same  direc 
tion,  during  the  Devonian;  and, at  its  close,  the  State  of  New  York 
formed  a  part  of  the  land.  For,  as  seen  on  the  map,  p.  165,  the  rocks 
which  succeed  one  another  reach  less  and  less  far  northward,  indicating 


DEVONIAN   AGE.  287 

that  there  was  some  progress  southward  with  each  period.  Nearly  all 
of  Eastern  Canada  and  New  England  was  probably  part  of  the  dry 
continent,  from  the  close  of  the  Lower  Devonian,  there  being  no  Upper 
Devonian  or  Carboniferous  rocks  over  these  regions,  excepting  in  part 
of  Nova  Scotia,  and  near  the  sea  border  of  Canada,  New  Brunswick, 
eastern  Maine,  and  southeastern  New  England. 

The  general  map  on  page  144  shows  the  area  over  which  the  Si 
lurian  and  Devonian  formations  are  now  uncovered  in  other  parts  of 
North  America.  We  cannot  positively  conclude  that  no  later  rocks 
ever  existed  over  these  areas ;  for  extensive  strata  may  have  been 
washed  away  in  the  course  of  subsequent  changes.  Yet  the  progress 
of  the  emerged  land  southward,  noted  in  New  York,  is  apparent  also 
along  the  region  of  Ohio  and  Wisconsin ;  and  there  was  extension  also 
from  the  Archaean  axis  of  the  far  north,  westward  and  eastward :  so 
that  a  general  expansion  of  the  old  Archaean  land  had  taken  place  by 
additions  to  all  of  its  borders.  South  of  New  York,  and  over  a  large 
part  of  the  continent,  the  surface  was  still  liable  to  alternate  sinking 
and  rising,  and  was  therefore  open  to  new  formations. 

North  America  was  to  a  great  extent  a  continental  sea,  with  the 
amount  of  land  that  was  permanently  dry  very  limited,  as  compared 
with  the  present  finished  continent.  In  place  of  the  Rocky  Moun 
tains  and  Appalachians,  there  were  only  islands,  reefs,  and  shallow 
waters,  marking  their  future  site  ;  for  Carboniferous  strata  and  others 
of  later  age  cover  the  slopes  of  many  of  the  Western  mountains,  and 
a  limestone  of  the  Carboniferous  age  exists  on  them  at  a  height  of 
13,000  feet  above  the  sea.  The  Appalachians  also  contain,  in  their 
structure,  rocks  of  the  Devonian  and  Carboniferous  eras.  The  Green 
Mountains  were  above  the  water,  through  the  Devonian,  but  had  only 
part  of  their  present  height. 

It  follows,  from  the  limited  area  of  the  land  and  the  absence  of  high 
mountains,  that  there  were  no  large  rivers  at  the  time.  With  the 
close  of  the  Devonian,  the  Hudson  River  may  have  existed  with 
nearly  its  present  limits ;  the  Connecticut  and  some  other  New  Eng 
land  rivers  may  have  begun  their  work  ;  and,  in  Canada,  the  Ottawa 
and  other  streams  drained  the  northern  Archaean.  Even  the  St.  Law 
rence,  above  Montreal,  may  have  been  a  fresh-water  stream. 

3.  Geographical  changes.  —  The  history  of  the  periods  of  the  De 
vonian  has  been  shown  to  be,  like  that  of  the  Silurian  periods,  a 
history  of  successive  oscillations  in  the  continental  level,  —  the  posi 
tion  of  the  accumulating  deposits  varying  more  to  the  east  or  to  the 
west  with  the  varying  location  of  the  subsiding  or  emerging  areas. 
Throughout  the  whole,  the  Appalachian  region  continued  to  be  well 
denned.  Its  Devonian  deposits  consist  mainly  of  shales  and  sand- 


288  PALEOZOIC    TIME. 

stones,  and  have  a  total  thickness  of  not  less  than  15,000  feet ;  while, 
in  the  West,  the  rocks  are  for  the  most  part  limestones,  with  a  thick 
ness  of  less  than  500  feet. 

Hence,  the  oscillations  of  level  over  the  Interior  basin  were  small, 
as  compared  with  those  of  the  Appalachian  region.  Moreover,  the 
prevalence  of  limestone  strata  in  the  basin  is  evidence  that  the  great 
mediterranean  sea  of  the  Silurian  age  was  continued  far  into  the 
Devonian,  opening  south  into  the  Atlantic  and  Gulf  of  Mexico,  and 
reaching  north  probably  to  the  Arctic  Ocean.  Through  pome  parts  of 
the  west,  the  Niagara  and  Corniferous '  limestones  —  the  formations 
of  that  interior  sea  —  follow  each  other  with  but  little  interruption. 

European  Geography.  —  The  European  continent  in  the  Devonian 
age  could  not  have  had  the  simplicity  of  features  and  movement  that 
characterized  the  American.  It  is  obvious  from  the  great  diversity 
of  the  Devonian  rocks  —  sandstones  at  one  end  of  Britain  and  lime 
stones  at  the  other,  limestones  in  the  Eifel  on  the  Rhine  and  almost 
none  in  Bohemia  —  that  the  continent  had  not  its  one  uniform  inte 
rior  sea,  like  North  America,  but  was  an  archipelago,  diversified  in  its 
movements  and  progress. 

There  may  have  been  proportionally  more  elevated  heights  over 
the  area  ;  but  it  is  still  true  that  there  was  little  of  it  dry  ;  that  the 
loftier  mountains  had  not  been  made,  —  the  Alps  and  Pyrenees  being 
hardly  yet  in  embryo ;  and  that,  with  small  lands  and  small  moun 
tains,  rivers  must  have  been  small. 

Life.  —  The  expansion  of  the  types  of  land-plants,  insects,  and  jishes 
especially  marks  the  Devonian  age. 

The  progress  of  life  during  the  Devonian  is  further  seen  in  — 

(a.)  The  introduction  of  many  new  genera  under  old  tribes  ;  for 
example,  Productus  among  Brachiopods,  which  began  in  America  in 
the  Corniferous  period,  and  had  its  maximum  display,  and  also  its 
extinction,  in  the  Carboniferous  age  ;  Goniatites  among  Cephalopoda, 
which  had  its  earliest  American  species  in  the  Hamilton  period,  and 
became  extinct  at  the  same  time  with  Productus  —  a  genus  of  inter 
est,  as  it  is  the  first  of  a  family  (that  of  Ammonites)  which  had  a 
wonderful  extension  under  other  genera  in  the  Reptilian  age,  and  be 
came  extinct  at  the  close  of  that  age  ;  Nucleocrinus  (Fig.  492),  an 
early  form  of  the  Pentremites,  another  of  the  eminently  Carboniferous 
types. 

(b.)  The  complete  or  approximate  extinction  of  tribes:  as  that  of 
the  Cystids,  which  disappeared  with  the  Oriskany  period  in  America  and 
the  Eifel  limestone  in  Europe ;  that  of  Favistella,  Heliolites,  and  other 
genera  of  Corals  and  Crinoids  ;  that  of  Atrypa,  Stringocephalus,  and 
other  genera  of  Brachiopods  ;  that  of  the  Chain-coral,  or  Halysites, 


DEVONIAN   AGE.  289 

which  does  not  appear  above  the  Upper  Silurian  in  America,  hut  is 
found  in  the  Eifel  limestone  in  Europe  ;  that  of  TriloUtes,  which, 
after  there  had  been,  under  a  succession  of  genera,  over  1,700  species, 
came  nearly  to  its  end  with  the  Devonian,  the  old  genera  being  all  ex 
tinct,  and  only  three  new  ones  appearing  in  the  Carboniferous,  to  close 
off  this  prominent  Paleozoic  type  ;  the  Orthoceras  family,  species  of 
which  were  few  after  the  Devonian  age.  Extinction  here  means 
merely  no  reappearance  among  known  fossil  remains.  The  types  may 
have  long  afterward  had  representatives  in  the  deep  ocean  if  not  in 
some  shallow  seas.  Loven  reports  the  existence  of  a  Cystid  among 
the  living  species  of  the  deep  Atlantic. 

(c.)  In  the  historical  changes  in  tribes  or  genera :  for  example,  the 
Spirifers,  which  began  in  narrow  species  in  the  Upper  Silurian,  be 
came  broad-winged  and  very  numerous  in  the  Devonian,  and  continued 
thus  into  the  Carboniferous ;  the  species  of  Producing,  the  earliest  of 
which  were  very  small  and  few,  were  afterward  of  large  size  and  nu 
merous. 

Each  of  these  points  admits  of  extensive  illustration  ;  but  the  above 
is  sufficient  to  give  an  idea  of  the  kind  of  progress  life  was  under 
going.  Each  period  had  its  new  species  or  tribes,  and  its  extinctions, 
and  often,  also,  there  were  many  successive  faunas  in  a  single  period. 
Families  and  tribes  were  in  constant  change;  and,  through  all  these 
changes,  the  system  of  life  was  in  course  of  development. 

Climate.  —  The  occurrence  in  the  Arctic  region  of  Devonian  species, 
of  the  Hamilton  era  of  the  United  States  (p.  266),  shows  that  there 
was  little  diversity  of  temperature  at  that  time  between  the  temperate 
and  Arctic  zones. 

4.  DISTURBANCES  CLOSING  THE  DEVONIAN  AGE. 

In  eastern  Canada,  Nova  Scotia,  and  Maine,  the  Devonian  and  Si 
lurian  strata  are  uplifted  at  various  angles  beneath  unconformable  beds 
of  the  Carboniferous ;  and  many  of  them  have  undergone  more  or  less 
complete  metamorphism  (Dawson,  Logan,  C.  Hitchcock).  Dawson 
says  that  "  in  the  Acadian  Provinces,  in  passing  downward  from  the 
Carboniferous  to  the  Devonian,  we  constantly  find  unconformability," 
and  part  of  the  granyte  of  Nova  Scotia  "  belongs  to  the  close  of  the 
Devonian."  Again,  in  New  Brunswick  and  Maine,  the  Devonian  beds 
near  Perry  underlie  unconformably  the  Carboniferous ;  the  latter  rest 
ing,  with  small  dip,  on  the  upturned  edges  of  the  plant-bearing  De 
vonian  strata.  It  appears  then  that  an  epoch  of  great  disturbance 
over  the  Eastern-border  region  intervened  between  the  Devonian  and 


Carboniferous  ages. 


19 


290 


PALEOZOIC   TIME. 


The  results  exceeded  in  extent  those  that  occurred  over  this  same 
region  after  the  Carboniferous  age.  At  this  epoch,  the  raising  of  the 
region  of  Maine  above  the  sea,  which  had  been  carried  forward 

O 

through  its  northern  portion  after  the  Corniferous,  appears  to  have 
been  completed ;  for  no  rocks  later  than  Devonian  are  known  to  occur 
over  it.  The  existence  of  Helderberg  rocks — probably  Upper  Hel- 
derberg  —  in  the  Connecticut  Valley  has  been  stated  on  a  former 
page ;  and  it  may  be  here  added  that  the  upper  beds  of  the  series, 
now  mica  slate,  gneiss,  and  quartzyte,  may  be  of  the  Hamilton  period. 
The  crystallization  and  upturning  of  these  rocks  of  the  Connecticut 
valley,  as  well  as  those  of  Lake  Memphremagog  and  the  St.  Law 
rence  Valley,  may  have  been  a  part  of  the  events  of  this  epoch. 
At  this  time  too,  the  region  of  eastern  New  York,  west  of  the  Hud 
son,  which,  during  the  Catskill  period  —  that  of  the  closing  Devonian 
—  was  subsiding  and  receiving  thick  marine  formations,  probably 
emerged  from  the  sea,  leaving  only  a  narrow  southern  margin  of  the 
State  under  salt  water. 

The  other  events  of  this  epoch  of  disturbance,  over  North  America,  are  not  made 
out.  In  the  county  of  La  Salle,  Illinois,  and  that  adjoining  it  on  the  southeast,  there  is 
a  N.  33°  W.  anticlinal  axis  in  the  beds  underlying  the  Coal-formation,  as  illustrated  in 

Fig.  571. 


Fig.  571.  But  these  underlying  beds  are  Lower  Silurian,  including  <7,  the  Calciferous 
formation;  b,  St.  Peter's  sandstone;  c,  the  Trenton  limestone;  and  it  is  not  certain, 
therefore,  that  the  disturbance  occurred  directly  before  the  Carboniferous  age.  In  other 
sections  in  northern  Illinois,  the  Niagara  limestone  is  included  among  the  upturned 
beds  conformable  to  the  Trenton,  and  hence  the  movement  was  not  at  the  close  of  the 
Lower  Silurian  like  that  producing  the  Cincinnati  uplift. 

In  Great  Britain,  Russia,  and  Bohemia,  also,  examples  of  disturbances  between  the 
Devonian  and  Carboniferous  have  been  observed,  but  not  in  Central  and  Southern 
France. 

But  all  these  cases  are  small  exceptions  to  the  general  fact  that  the  Lower  Carbon 
iferous  and  the  underlying  rocks  are  conformable,  almost  the  whole  world  over.  The 
epoch  of  transition  was  not  an  epoch  of  general  disturbance.  There  were  extensive 
oscillations  of  level;  but  for  the  most  part  they  involved  no  violent  upturnings.  The 
Carboniferous  age  opens  with  a  period  of  marine  formations;  and  the  beds  accumulated, 
in  most  regions  where  they  occur,  as  a  direct  continuation  of  the  deposits  of  the  Devo 
nian. 


CARBONIFEROUS   AGE.  291 


III.   CARBONIFEROUS   AGE. 

The  Carboniferous  age  is  divided  into  three  periods :  — 

I.    The    SUBCARBONIFEROUS    PERIOD    (13). 

II.  The  CARBONIFEROUS  PERIOD  (14). 

III.  The  PERMIAN  PERIOD  (15). 

The  Carboniferous  age,  both  in  America  and  Europe,  commenced 
with  a  preparatory  marine  period,  —  the  SUBCARBONIFEROUS  ;  had 
its  consummation  in  a  long  era  of  extensive  continents,  covered  with 
forests  and  marsh-vegetation,  and  subject  at  long  intervals  to  inunda 
tions  of  fresh  or  marine  waters,  — the  CARBONIFEROUS  ;  and  declined 
through  a  succeeding  period, —  the  PERMIAN,  in  which  the  marsh- 
vegetation  became  less  extensive,  and  the  sea  again  prevailed  over 
portions  of  the  Carboniferous  continents. 

American  Geographical  Distribution. 

The  rocks  of  the  Carboniferous  age  lie  at  the  surface,  over  large 
areas  of  North  America,  as  shown  on  the  accompanying  map  (Fig. 
572),  in  which  the  black  areas  and  those  cross-lined  or  dotted  on  a 
black  ground  are  of  this  age. 

1.  Eastern-border  Region.  —  1 .  A  small  area  in  Rhode  Island,  con 
tinued  northward  into  Massachusetts. 

2.  A  large  area  in  Nova  Scotia  and  New  Brunswick,  stretching 
eastward  and  westward  from  the  head  of  the  Bay  of  Fundy. 

These  two  areas  are  now  separated  ;  but  it  is  probable  that  they 
were  once  united  along  the  region,  now  submerged,  of  the  Bay  of 
Fundy  and  Massachusetts  Bay. 

II.  Alleghany  Region.  —  This  great  area  commences  at  the  north 
on  the  southern   borders  of  New  York,  and   stretches  southwestward 
across  Pennsylvania,  Western  Virginia,  and  Tennessee   to  Alabama, 
and  westward  over  part   of  eastern  Ohio,  Kentucky,  Tennessee,  and 
a  small  portion  of  Mississippi.     To  the  north,  the  Cincinnati  geanti- 
clinal,  or  the  low  elevation  extending  from  Lake  Erie  over  Cincinnati 
to  Tennessee,  forms  the  western  boundary. 

III.  Interior  Region.  —  1.  The  Michigan  coal  area,  an  isolated  area 
wholly  confined  within  the  lower  peninsula  of  Michigan. 

2.  The  Eastern  Interior  area,  covering  nearly  two  thirds  of  Illinois, 
and  parts  of  Indiana  and  Kentucky. 

3.  The  Western  Interior  area,  covering  a  large  part  of  Missouri, 
and  extending  north  into  Iowa,  and  south,  with  interruptions,  through 
Arkansas  into  Texas,  and  west  into  Kansas  and  Nebraska. 

The  Illinois  and  Missouri  areas  are  connected  now  only  through  the 


292 


PALEOZOIC   TIME. 
Tig.  572. 


CARBONIFEROUS    AGE.  293 

Subcarboniferous  rocks  of  the  age  ;  but  it  is  probable  that  formerly 
the  coal  fields  stretched  across  the  channel  of  the  Mississippi,  and  that 
the  present  separation  is  due  to  erosion  along  the  valley. 

Besides  these,  there  are  the  following  barren  of  coal,  or  nearly  so. 

IV.  The    Rocky  Mountain  and  Pacific  Border  Regions. —  1.  The 
great  Basin  and  Summit  area,  embracing  parts  of  Montana,  Wyoming, 
Colorado,  Utah,  and  Nevada. 

2.  The  California  area,  in  the  northern  half  of  California. 

V.  The  Arctic  Region.  —  In  Melville  Island,  and  other  islands  be 
tween  Grinnell  Land  and  Banks  Land,  on  Spitzbergen,  and  on  Bear 
Island  north  of  Siberia. 

The  extent  of  the  coal-bearing  area  of  these  Carboniferous  regions  is  approximately 
as  follows :  — 

Rhode  Island  area    . 500  square  miles. 

Alleghany  area     .        .        .                 .         •        .         .  59,000  square  miles. 

Michigan  area           .         .         .         .                  .         .         .  6,700  square  miles. 

Illinois,  Indiana,  West  Kentucky        .        .        .         .  47,000  square  miles. 

Missouri,  Iowa,  Kansas,  Arkansas,  Texas       .         .         .  78,000  square  miles. 

Nova  Scotia  and  New  Brunswick         ....  18,000  square  miles. 

The  whole  area  in  the  United  States  is  over  190,000  square  miles, 
and  in  North  America  about  208,000.  Of  the  190,000  square  miles, 
perhaps  120,000  have  workable  beds  of  coal. 

1.  SUBCARBONIFEROUS  PERIOD  (13). 
I.  Rocks:  kinds  and  subdivisions. 

In  the  Interior  Continental  region,  the  Subcarboniferous  rocks  are 
mainly  limestones.  They  are  largely  displayed  in  Illinois,  Kentucky, 
Iowa,  and  Missouri,  and  have  at  some  points  a  thickness  of  1,200  feet. 
They  also  occur  in  Arkansas  and  Texas.  To  the  eastward,  the  pro 
portion  of  limestone  diminishes.  In  Tennessee,  the  lower  beds  are 
siliceous,  and  the  upper,  limestone.  In  Michigan,  there  are  about 
seventy  feet  of  limestone,  resting  upon  480  feet  of  shales  and  sand 
stones  ;  in  Ohio  there  are  over  600  feet  of  sandstones  and  shales,  with 
twenty  feet  or  less  of  limestone  at  top,  in  some  parts. 

In  the  Appalachian  Region  in  Pennsylvania,  the  beds,  instead  of 
being  limestones,  are  sandstones  or  shales,  excepting  small  portions  in 
the  southwestern  part  of  the  State.  The  thickness  increases  from  tho 
westward  and  northward  toward  Pottsville  and  the  Lehigh  region, 
where  in  some  places  it  is  4,000  to  5,000  feet.  In  Virginia,  the  beds 
are  more  calcareous,  and  the  limestone  increases  in  amount  to  the 
southwest,  and  continues  to  Alabama  and  Mississippi. 

There  are  thin  workable  seams  of  coal  in  some  of  these  Subcar 
boniferous  beds  of  Pennsylvania,  Virginia,  western  Kentucky,  and 
southern  Indiana,  and  also  valuable  beds  of  clay-ironstone. 


294  PALEOZOIC   TIME. 

The  subdivisions  of  the  Subcarboniferous  rocks  are  best  exhibited  in  the  limestones 
of  the  era  in  the  Mississippi  valley  or  Interior  Continental  basin:  and  hence,  in  giving 
further  details  respecting  the  formation,  they  are  first  considered. 

(a.)  Interior  Continental  Busin.  —  In  Jllinois,  the  subdivisions,  according  to  Worthen, 
—  partly  following  those  of  Hall,  —  are  the  following,  beginning  with  the  oldest. 

1.  KINDEHIIOOK  GROUP.  — Consists  of  sandstones,  grits,  and  shales,  with  thin  beds  of 
oolitic  limestone;  100-200  feet  thick.     The  "Choteau  limestone,"  "  Lithographic  lime 
stone,"  and   "  Vermicular  sandstone  and  shales,"   of  Missouri,  are  here  included,  and 
also  the  "Goniatite   limestone "  of  Rockford,  Indiana.     It  rests  on  the  Devonian  Black 
shale. 

2.  BURLINGTON  GROUP. —Limestone,  with   cherty  layers   at  top,    and   nodules  of 
hornstone  through  portions  of  the  limestones;  25  to  200  feet  thick.    Much  of  it  is  ex 
cellent  building  stone. 

3.  KEOKUK  GKOUP.  — Mainly  limestone,  with  thin- bedded  cherty  layers  below  along 
the  junction  with  the  Burlington  limestone,  gray  limestone  at  middle,  and  a  shaly, 
argillaceous,  magnesian  limestone  above,  often  abounding  in  geodes  of  quartz,  etc., 
called  the  Geode  bed.     The  geodes  vary  from  half  an  inch  in  diameter  to  twenty  inches 
or  more;  and  many  are  beautiful  for  their  agates,  or  druses  of  quartz  crvstals,  and  some 
for  crystallized  calcite,  dolomite,  blende,  pyrite,  etc. 

4.  ST.  Louis  GROUP. — Evenly-bedded   limestone   of  Alton  and  St.  Louis;  oolitic 
limestone,  three  miles  above  Alton ;  and  equivalent  beds  at  Bloomington  and  Spergen 
Hill,  Indiana;  blue  calcareous  shales  and  arenaceous  limestoHe  at  Warsaw.    In  some 
places  250  feet  thick. 

o.  CHESTER  GROUP.  —  Limestone,  in  three  or  four  beds,  with  some  intercalated  shale 
and  sandstone;  occasionally  600  feet  thick.  Includes  the  "  Pentremital "  limestone, 
and  the  "  Upper  Archimedes  "  limestones.  The  Upper  Archimedes  has  also  been  called 
the  "Kaskaskia"  limestone. 

The  whole  series  in  southwestern  Illinois  has  a  thickness  of  1,200  to  1.500  feet:  it 
thins  out  rapidly  to  the  north,  and  disappears  before  reaching  Rock  Island  County, 
leaving  the  Coal-measures  resting  on  the  Devonian  limestones. 

In  7o/m,  according  to  C.  A.  White,  the  Carboniferous  is  the  surface  formation  over 
all  the  State,  excepting  the  northeastern  third  where  the  rocks  are  older,  and  an  area  in 
the  northwestern  part  which  is  Cretaceous;  and  the  Subcarboniferous  occurs  along  the 
eastern  portion  of  the  Carboniferous  area.  It  includes  about  175  feet  (maximum  thick 
ness)  of  Kinderhook  beds,  consisting  of  alternating  strata  of  sandstone  and  limestone, 
the  latter  partly  magnesian;  190  feet  of  Burlington  limestone,  in  which  are  some 
siliceous  beds;  50  feet  of  Keokuk  limestone,  well  developed  about  Keokuk;  75  feet  of 
St.  Louis  limestone,  having  magnesian  limestone  below,  next  a  gray  friable  sandstone, 
and  above  gray  limestone.  The  Kinderhook  beds  reach  farthest  north;  the  Burling 
ton  and  Keokuk,  much  less  so;  the  St.  Louis,  nearly  to  the  limit  of  the  Kinderhook. 
The  Chester  group  is  not  present,  the  Coal-measures  resting  directly  on  the  St.  Louis 
limestone. 

In  Missouri,  the  whole  thickness  of  the  Subcarboniferous  limestone  is  1,150  feet. 

In  Kentucky  and  Tennessee,  the  subdivisions  of  the  Subearboniiierous  formation 
observed  in  Illinois  are  not  distinct.  In  Middle  Tennessee,  according  to  Safford, 
there  are  two  groups.  The  lower  is  the  Siliceous  group,  consisting,  commencing  below, 
of  (1)  the  Protean  beds,  cherty  and  argillaceous  beds,  with  some  limestone,  250  to  300 
feet,  and  (2)  the  Lithostrotion  or  Coral  beds,  an  impure  cherty  limestone,  the  equiva-. 
lent  of  the  St.  Louis  limestone,  about  250  feet  thick.  The  upper  member  is  limestone, 
400  feet  thick  on  the  northern  borders  of  the  State,  and  720  on  the  southern.  These 
two  divisions  occur  also  in  East  Tennessee. 

The  Upper  member  also  extends  into  the  northeast  corner  of  Mississippi,  where 
it  is  overlaid  by  Cretaceous  beds  (Hilgard).  At  Huntsville,  Ala.,  Worthen  found  it  to 
consist  principallv  of  gray  limestones,  partly  oiilitic,  partly  cherty,  with  some  shaly 
beds,  in  all  about  900  feet.  The  larger  portion  of  the  series  yields  Chester  fossils;  but 
characteristic  forms  of  the  St.  Louis  group  mark  the  age  of  the  lowest  250  to  300 
feet. 


CARBONIFEROUS   AGE.  295 

The  Michigan  Carboniferous  area  appears  to  have  been  an  independent  basin,  at  the 
time  of  the  formation  of  the  rocks.  There  are  four  groups  of  strata,  according  to 
Winchell :  the  first,  or  lowest,  173  feet  of  grits  and  sandstones,  which  he  has  called  the 
Marshall  Group;  the  second,  123  feet  of  shales  and  sandstones,  called  the  Napoleon 
Group;  the  third,  184  feet  of  shales  and  marlyte,  with  some  limestone  and  gypsum, 
called  the  Michigan  Salt-group;  the  fourth,  the  Carboniferous  limestone,  sixty-six  feet 
thick.  This  limestone  is  well  exposed  at  Grand  Rapids. 

In  Ohio,  the  chief  part  of  the  Subcarboniferous  is  the  Waverley  sandstone,  640  feet 
thick  on  the  Ohio  River,  bearing  evidences  of  shallow- water  origin,  and  containing, 
130  feet  above  its  base,  a  black  shale  sixteen  feet  thick ;  going  northward,  the  middle 
portion  is  a  conglomerate.  Above  the  sandstone,  there  is  in  some  places  a  limestone 
ten  to  twenty  feet  thick,  of  the  age,  according  to  Meek,  of  the  Chester  and  St.  Louis 
groups.  It  was  first  found  by  E.  13.  Andrews.  It  is  a  magnesian  limestone,  and  occurs 
in  Muskingum,  Perry,  Hocking,  Vinton,  Jackson,  and  Scioto  counties. 

(b.)  Appalachian  ref/ion.  —  In  Pennsylvania,  two  groups  are  recognized  by  H.  D. 
Rogers,  the  lower  called  by  him  the  Vespertine  series,  and  the  upper  the  Umbral 
series.  It  is  probable  that>  these  divisions  are  equivalents  of  those  in  Tennessee.  The 
rocks  of  the  lower  group  are,  in  the  main,  coarse  grayish  conglomerates  and  sand 
stones;  those  of  the  upper  group,  soft  shales,  mostly  of  a  red  color.  The  lower  group 
is  2,000  feet  thick  near  Pottsville.  Through  much  of  the  anthracite  coal  basin,  it  con 
stitutes  the  encircling  hills,  as  around  the  Wyoming  basin,  and  in  many  places  forms 
a  grayish-white  band,  over  another  of  red,  the  latter  due  to  the  Catskill  beds, — the 
two  thus  making  a  red  and  white  frame,  as  Lesley  says,  around  the  valleys  or  basins. 
It  thins  rapidly  to  the  westward,  the  rock  retaining  its  whitish  color  and  siliceous 
character  in  Virginia.  Sandstone  beds  alternate  with  the  conglomerate ;  and,  in  New 
York,  these  finer  layers  abound  in  ripple-marks,  and  that  oblique  lamination  (Fig.  61  e) 
which  is  due  to  contrary  currents. 

The  shales  of  the  upper  group  are  soft,  reddish,  clayey  beds,  easily  returning,  on 
exposure,  to  mud,  the  original  condition  of  the  material.  They  alternate  with  sand 
stone  layers,  especially  in  the  lower  part.  At  Towanda,  Blossburg,  Ralston,  Lock- 
haven,  Portage  Summit,  etc.,  in  upper  Pennsylvania,  the  formation  consists  of  two  or 
three  thick  strata  of  shale,  separated  by  as  many  strata,  50  to  200  feet  thick,  of 
greenish  sandstone.  (Lesley.)  Some  thin  layers  consist  of  an  impure  rough-looking 
limestone.  This  red-shale  formation  is  3,000  feet  thick  at  the  Lehigh,  Schuylkill,  and 
Susquehanna  rivers;  but  on  crossing  the  Coal-measures  to  the  westward,  it  rapidly 
diminishes.  At  Broad  Top,  it  is  less  than  1,000  feet;  at  the  Alleghany  Mountain, 
hardly  200;  at  Blairsville,  30  feet;  and  beyond,  it  is  lost  to  view.  (Lesley.)  The  soft 
shales  retain  still  the  ripple-marks  from  the  ancient  waves,  and  rain-drop  impressions 
from  the  showers  of  the  day.  The  Amphibian  footprints  described  beyond  are  from 
this  formation.  To  the  southwest,  in  Laurel  Hill  and  Chestnut  Ridge,  there  is  some 
impure  limestone,  along  with  red  marlytes. 

In  West  Virginia,  Monongalia  County,  the  Chester  limestone  has  been  recognized 
by  Meek,  six  of  its  fossils  being  identical  with  Illinois  species  (Am.  Jour.  Sci.,  III. 
ii.  217).  On  the  Potomac,  at  Westernport  (W.  B.  Rogers),  there  are  about  eighty  feet 
of  impure  limestone  in  the  lower  part  of  the  formation,  and  840  feet  of  overlying  sand 
stone  and  shales.  But,  farther  south  and  west,  in  Greenbrier  Mountain,  Pocahontas 
County,  the  formation  thickens  to  over  2,000  feet,  and  includes  822  feet  of  limestone. 

Seams  of  coal  occur  in  the  Subcarboniferous,  at  many  places  in  Pennsylvania  and 
Virginia.  In  Montgomery  County,  Virginia,  there  is  a  layer  of  coal,  two  to  two  and 
a  half  feet  thick,  resting  on  a  bed  of  conglomerate;  and,  thirty  to  forty  feet  higher, 
there  is  another  layer,  six  to  nine  feet  thick,  consisting  of  alternations  of  coal  and 
slate.  These  coal-beds  occur  in  the  Lower  group,  and  are  covered  by  the  shales  of 
the  Upper.  In  Pennsylvania,  there  is  a  coal-bed  (and  possibly  two)  in  the  same  Lower 
group,  at  Tipton,  at  the  head  of  the  Juniata,  600  feet  below  the  Upper  shales;  but,  so 
far  as  known,  it  is  a  local  deposit.  (Lesley.)  The  Subcarboniferous  coal  deposits  are 
sometimes  called  false  Coal-measures, 


296  PALEOZOIC   TIME. 

(c.)  Eastern-border  region. —  In  Nova  Scotia  and  New  Brunswick,  the  Subcar- 
boniferous  rocks  are.  below,  red  sandstones,  conglomerates,  and  red  and  green  marlvtes, 
of  two  groups:  the  Horton  series,  consisting  of  red  sandstones,  conglomerates,  red  and 
green  marlytes;  and,  above  these,  the  Windsor  series,  consisting  of  thick  beds  of 
limestones,  full  of  fossil  -,  with  some  red  marlytes,  and  beds  of  gypsum,  affording  the 
gypsum  exported  from  Nova  Scotia  and  New  Brunswick.  Thus  the  upper  part  of  the 
Subcarboniferous  is  the  calcareous  part,  as  in  Ohio,  Tennessee,  and  Western  Virginia. 
The  estimated  thickness  is  6,000  feet.  To  the  ^north,  toward  the  Archaean,  the  lime 
stones  fail ;  and,  instead,  the  rocks  are  to  a  greater  extent  a  coarse  conglomerate.  To 
the  south,  limestones  prevail.  The  localities  of  these  beds,  mentioned  by  Dawson,  are 
the  Carboniferous  districts  of  northern  Cumberland,  Pictoti,  Colchester,  and  Hants, 
Richmond  County  and  southern  Inverness,  Victoria,  and  Cape  Breton.  The  best  ex 
posures  of  the  lower  or  Horton  series  are  at  Horton  Bluff,  Hillsborough,  and  other 
places  in  southern  New  Brunswick. 

In  the  lower  part  of  these  Subcarboniferous  beds,  as  in  those  of  Virginia,  there  are, 
on  a  small  scale,  "false"  Coal  measures,  and,  in  one  instance,  a  bed  of  ertct  trees, 
under-clays,  and  thin  coal  seams;  and  the  same  beds  confain  numerous  remains  of 
fishes.  The  fish-bearing  shales  of  Albert  Mine,  New  Brunswick,  are  of  this  period. 
(Dawson.)  This  mine  affords  a  peculiar  coaly  material,  pitch-like  in  aspect,  which  has 
been  named  Albertite ;  it  fills  a  fissure,  instead  of  constituting  a  true  coal-bed. 

(f.)  Rocky- Mountain  and  Pacific-border  regions. — Over  large  portions  of  these 
regions,  the  limestones  of  the  Subcarboniferous  have  not  been  distinguished  from  those 
of  the  following  epoch.  In  most  cases,  their  recognition  only  waits  for  the  more  care 
ful  study  of  the  fossils ;  but,  at  some  points,  they  appear  to  be  really  wanting.  They 
have  been  identified  in  the  Elk  Mountains,  and  other  ranges  of  the  crest  chain  of  the 
mountains  in  western  Colorado;  on  the  eastern  slopes  of  the  "Wind  River  Mountains,  in. 
Wyoming.  In  Montana,  at  "  Old  Baldy,"  near  Virginia  City,  there  are  fossils  of  the 
Chester  group,  and  probably  the  Lower  Subcarboniferous  beds  are  also  present. 
(Meek.)  In  Idaho,  near  Fort  Hall,  Bradley  found  masses  of  limestone  filled  with 
minute  shells,  many  species  of  which  Meek  has  identified  with  forms  characteristic  of 
the  oolitic  beds  of  the  St.  Louis  group,  at  Spergen  Hill,  Indiana.  In  Utah,  the  same 
beds  occur  in  the  limestones  which  surround  the  silver  mines  of  the  Wahsatch  and 
Oquirrh  ranges.  From  the  latter  range,  near  Lake  Utah,  a  species  of  Archimedes 
has  been  reported.  The  Carboniferous  limestones  reported  from  the  Humboldt  and 
other  ranges  of  the  Great  Basin,  doubtless  include  beds  properly  referable  to  the  Sub- 
carboniferous,  though  G.  K.  Gilbert  reports  that,  over  the  southern  portion  of  this 
area,  he  has  been  unable  to  separate  them  from  the  beds  including  typical  Coal- 
measure  fossils.  In  northern  California,  the  Subcarboniferous  occurs  in  the  Gray 
Mountains  near  Bass's  Ranch,  and  at  Pence's,  eighty  miles  farther  south.  In  the  Gray 
Mountains,  the  limestone  is  1,000  feet  thick,  forming  part  of  the  auriferous  series,  and 
is  doubtingly  referred  by  Meek  to  the  St.  Louis  horizon. 


H.  Life. 
1.  Plants. 

The  sea-weeds  included  the  Spirophyton,  which  first  appeared  under 
the  species  S.  cauda-galli,  in  the  Lower  Devonian,  and  characterized 
the  Cauda-galli  grit  (p.  254)  :  it  is  found  in  the  sandstone  of  Ohio. 

The  terrestrial  vegetation  of  the  Subcarboniferous  period  was  very 
similar  to  that  of  the  lower  part  of  the  Carboniferous.  There  were 
Lycopods,  of  the  tribes  of  Lepidodrendon  and  Sigillaria,  and  various 
Ferns,  Conifers,  and  Calamites.  The  vegetation  may  have  been  as 


CARBONIFEROUS   AGE.  297 

profuse  for  the  amount  of  land,  although  the  circumstances  were  lees 
favorable  for  its  growth  and  accumulation  in  marshes,  —  the  essential 
prerequisite  for  the  formation  of  large  beds  of  coal. 

In  the  Subcarboniferous  of  Pennsylvania  occur,  according  to  Lesquereux,  Cydopteris 
obtusa  Lsqx  (also  found  in  the  Catskill  group  of  the  Upper  Devonian),  C.  Bockschiana 
Gopp-,  remains  of  Lepidodtndra  and  Stiymar'm  minuta  Lsqx. ;  also,  in  Illinois,  the 
Tree-fern  Meyapfiytum  protuberans  Lsqx.,  Caulupteris  Worth  enii  Lsqx.,  Lepidoden 
dron  costatum  Lsqx.,  L.  tnrbinatum  Lsqx.,  L.  obscurum  Lsqx.,  L.  Vdtheimianum 
Sternb.,  L.  Worthianum  Lsqx.,  Stiymaria  anrib-tthra  Corda,  S.  minor  Gt'pp.,  S.  umbo- 
nata  Lsqx.,  and  others;  Catamites  Suckowii  Brngt.,  Knorria  imbricata  Sternb.,  all 
from  the  Chester  group. 

In  the  Chester  group  sandstones  of  Indiana,  according  to  Collett,  occur  Stiymaria, 
Lepidodendron  aculeatum,  L.  diploteyioides  Lsqx.,  L.  forulatum  Lsqx.,  Lepidostrobus, 
Knorrii,  Ilymenoplnjlliles  Clarkii  Lsqx.,  Cordaites  borassifolia,  Neuropteris  dilatata 
Lsqx.,  N.  rarmenis  Lsqx.,  Alethopteris  Owenii  Lsqx.,  Callipteris  Sidlivantii  Lsqx.,  etc. 
One  specimen  of  Lepidodendron  had  portions  of  the  leaves  attached  to  the  stem,  and 
twelve  to  fourteen  inches  long,  though  only  from  one-eighth  to  one-fourth  of  an  inch  in 
width. 

In  the  Subcarboniferous  of  Xova  Scotia  and  New  Brunswick,  Dawson  has  made 
out  the  following  species:  FERNS,  Cydopttris  Acadica  Dn.,  and  another  species  sup 
posed  to  be  a  Hymenojihyllites ;  LYCOPODS:  Lepidodendron  corruyatum  Dn.,  L.  Stern- 
bergii  Brngt.,  L.  tetrayonum  Sternb.,  L.  aculeatum  Sternb.,  Lycopodites  plumula  Dn.; 
also  Stiymariajicoides  Brngt.,  Cordaites  borassifolia  Ung. 

Of  the  above,  the  Stiyni'irice,  Calamites,  Cordaites,  and  Lepidodendron  Worthianum 
occur  higher  in  the  series,  the  Calamites  and  Cordaites  continuing  even  into  the  Upper 
Coal-measures. 

2.  Animals. 

The  animal  life  was  remarkable  for  the  great  profusion  and  diver 
sity  of  Crinoids, —  or  Sea-lilies,  as  they  are  sometimes  called.  Some 
of  the  Crinoids  —  mutilated  of  their  rays  or  arms,  as  is  usual  with 
these  fragile  species,  except  when  buried  in  shales  —  are  represented 
in  Figs.  573-582.  The  period  might  well  be  called  the  Crinoidal 
period  in  geological  history.  Among  the  kinds,  the  Pentremites  (Figs. 
580-582)  are  perhaps  the  most  characteristic.  Instead  of  having  a 
circle  of  arms,  like  most  Crinoids,  the  summit  is  closed  up,  so  as  to 
look  like  a  bud  (whence  the  name  Blastids,  applied  to  the  family,  from 
the  Greek  /^Aacrrfk,  a  bud]  ;  and  the  delicate  jointed  tentacles  are 
arranged  in  vertical  lines  along  the  pseudo-ambulacral  areas. 

There  were  also  other  Echinoderms,  related  to  the  modern  Echinus, 
but  peculiar  in  the  large  number  of  vertical  series  of  plates  of  which 
the  shell  consists.  One  species  is  represented  in  Fig.  586,  but  one 
half  the  natural  size.  The  vertical  series  of  plates  in  the  ambulacra! 
series,  which  are  indistinct  in  this  figure,  are  shown,  enlarged,  from 
another  species,  in  Fig.  587  b.  Fig.  587  represents  a  top  view,  and 
587  a  a  portion  of  the  lateral,  of  still  another  of  these  ancient  Echi- 
noids.  A  true  Polyp-Coral,  eminently  characteristic  of  the  period,  is 
the  Lithostrotion  Canadense  (Figs.  588,  a).  It  is  a  columnar  coral, 
having  a  conical  elevation  at  the  bottom  of  each  of  the  cells,  and  grows 
often  to  a  very  large  size. 


298 


PALEOZOIC    TIME. 
Figs.  573-585. 


ECHIXODERMS. — Fig  573,  Poteriocrinus  Missouriensis  ;  574,  Actiuocrinus  proboscidialis ;  575,  Do- 
rycrinus  unicornis  ;  576,  Zeacrinus  elegans  ;  577,  Batocrinus  Christyi ;  678,  Platycrinus  Saffordi ; 
579,  the  proboscis  of  Batocrinus  longirostris  ;  580,  Pentremites  pyriformis  ;  581,  582,  P.  Godonii 
(florealis);  583,  Archaeocidaris  Wortheui ;  584,  584 a,  A.  Shumardana  ;  585,  A.  Norwood!. 


Figs.  586-587. 


587 


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Ifm&^liir^^ 

Iv^t1  >8r^' 


ECUINOIDS.  —  Fig.  5S6,  Uligoporus  iiobilis  (x  %)]  587,  Melonites  multipora,  view  of  top  (X  2). 


CARBONIFEROUS   AGE. 
Figs.  587  a,  b. 


299 


587a 


ECHINOIDS.  —  Fig.  587  a,  Melonites  multipora  ( X  2),  side  view,  showing  a  portion  of  one  of  the 
ambulacral  series  of  plates  ;  587  6,  Oligoporus  Dance  (X  2),  id. 

Among  Mollusks,  there  were  the  coral-making,  auger-shaped  Rete- 
pores,  called  Archimedes,  belonging  to  the  order  of  Bryozoans.  The 
cells,  in  which  the  animals  were,  are  represented  of  natural  size,  in 


Figs.  588-590. 

588a 


589« 


POLYP-CORAL. —  Fig.  588,  Portion  of  the  Coral,  Lithostrotion  Oanadense ;  588  a,  vertical  view  of 
the  same.    BRYOZOAN.  —  Figs.  589  a,  b,  590,  Archimedes  Wortheni. 

Fig.  589  b,  showing  a  portion  of  the  under  surface  of  the  expanded 
frond  of  the  screw-shaped  coral. 

Besides  these,  Brachiopods  were  numerous,  especially  of  the  genera 
Spirifer  and  Productus.  One  of  the  Spirifers  is  represented  in  Fig. 
593,  and  a  common  Productus  in  Fig.  596  ;  another  Spirifer  in  Fig. 


300 


PALEOZOIC    TIME. 
Figs.  501-596. 


BRACHIOPODS.  —  Fig.  591,  Orthis  Michelini,  var.  Buriingtonensis  ;  592,  Spiriferina  octoplicata ; 
593,  Spirifer  bisulcatus  ;  594,  Retzia  Verneuiliana  ;  595  a,  Choaetes  variolata ;  596,  Productus 
punctatus. 


Figs.  597,  598. 


597,  and  straight-hinged  species    allied   to  Productus  (of  the  genus 

Chonetes),  in  Figs.  595,  598. 

There  were  also  many  Cephalopods,  of 
the  genera  Goniatites  and  Nautilus,  and 
a  few  of  the  Orthoceras  family. 

Among  Articulates,  Trilobites,  so  abun 
dant  in  earlier  time,  were  rare  fossils. 

r™  ^    i  i  T  e  • 

There    must    have  be611  ^SCCtS  of  various 

kinds.     Fig.  599  represents  a  wing  found 
near  Paoli,  Indiana;  the  insect  was  one  of  the  four-winged   kinds 

Fig.  599. 


Fig.   697,    Spirifer   biplicatus 
593a,Chonetesornata. 


WING  OF  A  NEUROPTER.  —  Paolia  vetusta  (X  |) 

having  net-veined  wings  —  that  is,  a  Neuropter;  but  differed  in  the 
character  of  the  veining  from  ordinary  May-flies,  and  other  modern 
kinds  of  the  tribe. 


CARBONIFEROUS   AGE. 


301 


Under  Vertebrates,  there  were  only  Fishes  and  Reptiles.  The 
Fishes  were  either  Ganoids  or  Selachians  ;  and  the  latter  embraced 
large  numbers  of  the  Cestraciont  kind,  having  great  bony  plates  in 
the  mouth,  for  mastication.  Fig.  600  represents,  natural  size,  one 
from  a  large  species,  of  the  genus  Cochliodits,  from  Illinois.  The  posi- 

Figs.  600,  600  A. 


TEETH  OF  CESTRACIOXT  SHARKS.  —Fig.  600,  Cochliodus  uobilis  ;  6^0  A,  C.  coutortus  (x 


tion  in  the  mouth  is  shown  in  Fig.  600  A,  representing,  one  third 
the  natural  size,  the  jaw  of  a  foreign  species.  The  teeth  of  other 
sharks,  called  Hybodonts,  are  shown  in  Figs.  601  to  603.  These  also 


Figs.  601-603. 


TEETH  OF  SHARKS.  — Fig.  601,  Carcharopsis  Wortheni ;  602,  Cladodus  spinosus ;  603,  Orodus  mam- 

millaris. 

were  numerous.     Large  fin-spines  of  some  of  the  Sharks  have  been 
found  in  the  rocks,  one  of  them  eight  inches  long. 

The  class  of  Reptiles  is  represented  by  Amphibians,  the  earliest 
kind  known.  The  relics  are  tracks.  A  reduced  view  of  a  slab  from 
near  Pottsville,  Pennsylvania,  is  shown  in  Fig.  604.  There  is  a  suc 
cession  of  six  steps,  along  a  surface  little  over  five  feet  long :  each 
step  is  a  double  one,  as  the  hind-feet  trod  nearly  in  the  impressions 


302 


PALEOZOIC    TIME. 


of  the  fore-feet.     The  print  of  the  fore-feet  is  something  like  that  of  a 
hand  with  five  stout  fingers,  the  whole  four  inches  broad ;  that  of  the 

Fig.  604. 


hind-foot  is  similar,  but  somewhat  smaller,  and  four-fingered.  The 
Amphibian  was  therefore  large  ;  this  is  also  evident  from  the  length 
of  the  stride,  which  was  thirteen  inches,  and  the  breadth  between  the 
outer  edges  of  the  footprints,  eight  inches.  There  is  also  a  distinct 
impression  of  a  tail,  an  inch  or  more  wide.  The  slab  is  crossed  by  a 
few  distant  ripple-marks  (eight  or  nine  inches  apart),  which  are  par 
tially  obliterated  by  the  tread.  The  whole  surface,  including  the  foot 
prints,  is  covered  throughout  with  rain-drop  impressions. 

We  thus  learn  that  there  existed,  in  the  region  about  Pottsville,  at 
that  time,  a  mud-flat  on  the  border  of  a  body  of  water  ;  that  the  fiat 
was  swept  by  wavelets,  leaving  ripple-marks  ;  that  the  ripples  were 
still  fresh  when  a  large  Amphibian  walked  across  the  place  ;  that  a 
brief  shower  of  rain  followed,  dotting  with  its  drops  the  half-dried 
mud  ;  that  the  waters  again  flowed  over  the  flat,  making  new  deposits 
of  detritus,  and  so  buried  the  records. 

Characteristic  Species. 

1.  Protozoans.  —  Although  the  class  of  Rhizopods  probably  commenced  in  the 
lowest  Silurian,  the  earliest  described  species  from  an  American  rock  is  the  Rotalia 
Baileyi  H..  from  the  St.  Louis  limestone  of  Indiana. 

Sponges.  —  The  hornstone  of  the  Subcarboniferous  limestones  of  Illinois  and  Indiana 
abounds  in  microscopic  spicula  of  sponges,  along  with  a  few  Desmids  similar  in  general 
to  those  of  the  Corniferous  limestone  (p.  257).  (M.  C.  White.)  P«la>(tcis  (Sphenopote- 
rium)  obtusa  M.  &  W.,  from  the  Keokuk  beds;  P.  cuneata  M.  &  W.,  from  the  St.  Louis 
limestone. 

2.  Radiates.  —  («.)  Polyps.  —  Figs.  588,  a,  Lithostrotion  Canadense  Castelneau 
(L.  mamillare  of  some  authors, — among  whom  Milne  Edwards,  after  thus  naming  it, 
makes  a  correction  in  a  note),  from  the  St.  Louis  limestone. 

(b.)  Echinoderms;  Crinaids. — Fig.  580,  Pentremites  pyriformu  Say;   Figs.  581,  582, 


CARBONIFEROUS   AGE.  303 

P.  Godon'd  Defr.  (P.  Jlorealis,  in  part), — both  from  the  Kaskaskia  limestone;  P. 
Woodmani  M.  &  W.  Fig.  573,  Poteriocrinus  Jlissouriensin  Shumard,  from  the  St.  Louis 
limestone ;  Fig.  574,  Actinocrinus  proboscidialis  H. ;  Fig.  575,  Dorycrinus  unicornis  M. 
&  W. ;  Fig.  576,  Zeacrinm  tleyans  H., —  this  and  the  two  preceding  from  the  Burling 
ton  limestone;  Fig.  577,  Batocrimu  ChrittyitS*  &  W.,  the  arms  fallen  off, — from  the 
Encrinal  limestone  of  Missouri;  Fig.  579,  proboscis  of  Batocrinus  lonyirostris  H. ;  Fig. 
578,  Platycrinus  Saff'ordi  Troost,  side-view,  from  Burlington.  Most  of  the  above  Cri- 
noids  have  lost  their  arms  and  pedicels.  The  most  prolific  locality  of  Crinoids,  as  yet 
known,  is  Burlington,  Iowa,  where  Mr.  Charles  Wachsmtith  lips  collected  three  hundred 
and  fifty-five  species,  representing  forty-four  genera,  besides  six  Echinoids,  four  Asteri- 
oids,  and  one  Ophiuroid.  The  Keokuk  beds  of  Crawfordsville,  Indiana,  yield  much 
more  numerous  specimens,  and  in  more  nearly  perfect  condition;  but  less  than  fifty 
species  have  yet  been  found  there.  The  genera  most  numerously  represented  are  Actin 
ocrinus  (including  several  subgenera),  Cyathocrinus,  Dichocrinus,  Furbesiocrinus,  Pla 
tycrinus,  Poteriocrinus,  Scaphiocrinus,  and  Ztacrinus. 

Echinoids. — Fig.  583,  Archceocidaris  Wortheni  H.,  of  the  St.  Louis  limestone;  Fig. 
584,  A.  Shutnardana  H.,  of  the  St.  Louis  limestone,  —  a  spine  enlarged;  Fig.  584  (<r, 
plate  of  the  same  species,  enlarged  about  two  diameters;  Fig.  585,  plate  of  ArcJtceo- 
cid'iris  Norwoodi  H.,  natural  size,  from  the  Chester  limestone.  Fig.  587,  Melonites  mul- 
tipora  O.  &  X.,  from  the  St.  Louis  limestone,  the  apical  disc;  587  a,  a  portion  of  one  of 
the  ambulacra!  series,  enlarged  two  diameters;  Fig.  586,  Olif/oporus  nobilisbl.  &.  W.,  half 
natural  size,  from  the  Burlington  limestone;  Fig.  587  b,  ambulacra!  plates  of  0.  Dame 
M.  &  W.,  enlarged  two  diameters.  Figures  586,  587,  a,  b,  are  from  Worthen's  Report 
on  the  Geology  and  Paleontology  of  Illinois.  The  genus  Archceocidaris,  like  the  mod 
ern  Cidaris,  has  large  prominences  on  the  plates,  to  support  the  spines,  which  are  also 
large.  In  Melonites  and  Palceechimu,  the  plates  are  without  prominences,  and  the  spines 
small. 

3.  Mollusks. —  (a.)  Bryozoans.  —  Fig.  590,  Archimedes  Wortheni  H..  being  a 
portion  of  the  spiral  axis,  with  the  reticulated  expansion  removed.  Fig.  580  rr,  a  por 
tion  of  the  reticulated  expansion,  magnified  and  showing  the  non-poriferous  surface. 
Fig.  589  b,  the  poriferous  side  of  the  same.  « 

(b.)  Brachiopods. —  Fig.  598,  Chonetes  ornata  Shum.  (natural  size),  from  the  Litho 
graphic  and  Chouteau  limestones,  Missouri;  598  a,  enlarged  surface-markings  of  same; 
Fig.  597,  Spirifer  biplicatus  H.,  from  Burlington  and  Quincy,  Illinois;  Sp.  Keokuk  H., 
from  the  Keokuk  beds;  Fig.  591,  Orthis  Mickelini  Morr.  (var.  Burlinytonensis  H.),  from 
the  Burlington  limestone;  Hemipronites  crenistria  Dav.  (  Orthis  or  Streptorhynchus  um- 
braculum)  (Fig.  G05);  Fig.  592,  Spiriferina  octoplicata  M. ;  Fig.  593,  Spirifer  bisulcatus 
Sow.  (increbescens  H.);  Fig.  594,  Retzia  Verneuiliana  H.;  Fig.  595,  Chonetes  variolata 
D'Orb.;  Fig.  595  a,  hinge-line  of  same,  and  aperture,  closed  by  a  pseudo-deltidium; 
Fig.  596,  Productus  punctatus  Mart.;  also  P.  Fleminyu  Sow.,  P.  eleyans  N.  &  P.,  Spi 
rifer  incrassatus  Eichw.,  Sp.  spinosus  N.  &  P.,  from  the.  Chester  limestone,  etc.  The 
Spirifer  incrassatus  is  confined  in  Missouri  to  the  lower  Archimedes  limestone.  Many 
of  the  other  Brachiopods  occur  not  only  in  the  Subcarbonifcrous,  but  also  in  the  Coal- 
measures.  They  are  common  also  in  Europe. 

(c.)  Lamellibranchs.  —  Nucula  Shumardana  H.,  N.  n-asuta  H.,  Cypricardina  India n- 
ensis^L,  Conocardium  MeeTcanum  H.,  all  from  the  St.  Louis  limestone  of  Indiana,  Illi 
nois,  and  Idaho;  Pinna  Missouriensis  Swallow,  of  the  Chester  limestone  of  Illinois; 
species  of  Yoldia,  Nuculani.,  Myalina,  Schizodus,  Aviculopccten. 

(d.)  Pteropods.  — Species  of  Bellerophon,  Conularia,  etc. 

(e.)  Gasteropods.  —  E-uomplialus  Speraenensis  H.,  Pleurotomaria  Meehma  H.,  and 
many  other  species  of  these  genera,  as  well  as  Platyceras.  Strapnrollus,  Naticopsis,  Na- 
tica,  Bulimella,  Loxonema,  etc. 

(/•)  Cephalopods.  —  The  Cephalopods  are  of  the  genera  Nautilus  (N.  spect((bilis  M.  & 
W.,  from  the  Chester,  two  feet  in  diameter),  Orthoceras  (0.  nubile  M.  &  W.,  from  the 
Chester,  five  to  six  feet  long  and  one  foot  in  diameter),  Gyroctras  ( G.  Burlinytonense 
H.,  from  Iowa,  five' inches  in  diameter),  Goniatites,  etc, 


304  PALEOZOIC    TIME. 

4.  Articulates.  —  Trilobites,  of  the  genus  Phillipsia,  and  Ostracoids,  of  the  gen 
era  Cythere,  Beyrichia.     A  bed  of  limestone,  four  feet  thick,  north  of  Fella,  Iowa,  is 
mostly  made  up  of  shells  of  a  Beyrichia.     The  Crustaceans  allied  to  Ceratiocaris,  from 
the  top  of  the  "  Black  Slate,"  in  Kentucky  (p.  267),  though  referred  to  the  Devonian, 
may  possibly  belong  rather  to  the  Subcarboniferous. 

The  Insect,  Puolia  vetusta  Smith  (Fig.  599),  is  from  the  whetstone  beds  of  Orange 
County,  Indiana,  which  have  also  yielded  large  numbers  of  tracks  of  Insects  and  Crus 
taceans,  with  some  trails  of  Mollusks.  These  beds  are  of  the  age  of  the  Chester  group. 

5.  Vertebrates.  —  Fishes.  —  The  species  of  American   Subcarboniferous  Fishes 
have  been  described  mainly  by  Newberry,  and  Newberry  &  Worthen.     They  include 
Hybodont  Selachians,  of  the  genera  Diplodus,  Car  chart  >psis ;  of  Cestracionts,  of  the  gen 
era  Orodus,  Ftelodus,  Cocltliodus,  Sandnlodus,  Pwmmodus,  Dtltodus,  Cladodus,  etc.;  and 
Petalodonts,  of  the  genera  Petalodus,  Petalorhynchus,  Antliodus,   Chomatodus,  etc.,  be 
sides  spines  of  the  genera  Leptacanthus,  Ctenacanthus,  Homacanthus,  DrepCHtacttothvs, 
Gyracanthus.     The  species  described  by  Newberry  &  Worthen,  from  Illinois  specimens, 
are  sixteen  of  Hybodonts,  twent^v-six  of  Petalodonts,  and  fifty -two  of  Cestracionts, 
with  nine  of  fin-spines.     Fig.  600,  tooth  of  Cochliodus  nobilis  N.  &  W.,  from  Illinois. 
Fig.  602,  Cladodus  spinosus  N.  &  W.,  from  the  St.  Louis  limestone,  Missouri ;  a,  section 
of  the  same;  Fig.  601,  Carcharoftsis  Wurtheni  Newb.,  from  Huntsville,  Ala.,  Fig.  603, 
OrodusmammillarisN.&W.,  from  the  Warsaw  limestone,  Warsaw,  Illinois. 

Rej)tiles.  —  Fig.  604,  Tracks  of  Saurapus  primcevus  Lea,  one-eighth  natural  size,  dis 
covered  near  Pottsville,  Pa.,  by  Isaac  Lea,  who  has  published  a  memoir  upon  them  in 
large  folio,  with  a  full-sized  engraving  of  the  slab. 

The  Subcarboniferous  limestones  of  Nova  Scotia  and  New  Brunswick  contain  some 
fossils  that  ally  the  fauna  more  with  the  European  than  with  that  of  the  Interior  Conti 
nental  basin  of  North  America.  Among  them  are  the  Sjririfer  ylaber  Sow.  (Fig.  554) 
and  Productus  Martini  Sow.,  both  of  which  are  European  species. 


III.  General  Observations. 

Geography.  —  As,  in  the  first  half  of  the  Upper  Silurian,  there  was 
a  period  —  the  Niagara  —  when  a  sea,  profuse  in  life,  and  thereby 
making  limestones,  covered  a  large  part  of  the  Interior  Continental 
basin;  and  again,  in  the  early  part  of  the  Devonian  age, —  the  Corn- 
iferous  period, —  the  same  conditions  were  repeated ;  so,  in  the  early 
Carboniferous,  there  was  a  similar  clear  and  open  mediterranean  sea, 
and  limestones  were  forming  from  the  relics  of  its  abundant  popula 
tion.  In  the  period  of  the  Upper  Silurian  referred  to,  the  living  spe 
cies  were  of  a  miscellaneous  character,  Brachiopods,  Crinoids,  and 
Corals  occurring  in  nearly  equal  proportions ;  but  in  that  of  the  De 
vonian,  Corals  were  greatly  predominant,  and  in  that  of  the  Carbon 
iferous,  Crinoids  had  as  remarkable  a  preeminence.  By  an  open  sea 
is  meant  one  having  free  connection  in  some  part  with  the  ocean ;  and 
this  connection  must  have  been  on  the  south,  toward  the  Mexican 
Gulf;  for  the  arenaceous  deposits  of  the  wide  Appalachian  region 
show  that  the  opening  eastward  into  the  Atlantic  was  for  the  most 
part  imperfect.  The  mediterranean  sea  alluded  to  was,  in  fact,  only 
an  extension  northward  of  the  Mexican  Gulf. 

As  the  Subcarboniferous  period  opened,  the  conditions  of  the  Later 


CARBONIFEROUS   AGE.  805 

Devonian  still  lingered  ;  and  fragmental  deposits,  either  clayey  or  sandy, 
were  made  over  the  Mississippi  region,  as  well  as  to  the  eastward. 
With  its  progress,  the  crinoidal  sea  increased  in  depth  and  in  freedom 
from  sediments  ;  yet  these  continued,  at  intervals,  through  the  forma 
tion  of  the  Kinderhook  beds,  though  to  a  less  extent  in  Missouri  than 
farther  north.  The  earthy  depositions  then  became  less  frequent,  the 
rock  of  the  Burlington  and  Keokuk  group  being  mainly  limestone ; 
but,  at  the  same  time,  as  remarked  by  Hall,  the  northern  border  of 
the  Interior  sea  had  moved  southward,  the  northern  limit  of  the  Bur 
lington  limestone  being  two  hundred  miles  farther  south  than  that  of 
the  earlier  beds,  and  that  of  the  Keokuk  and  St.  Louis  group  still  far 
ther  south.  This  limestone-making  sea,  though  gradually  deepening 
in  the  valley,  did  not  entirely  preserve  its  freedom  from  sediments,  far 
east  of  Illinois  ;  for  even  central  Tennessee  and  Ohio,  as  well  as  the 
Appalachian  region,  was  contemporaneously  a  region  of  accumulating 
sand  and  gravel  beds,  and  probably  for  the  most  part  one  of  shallow 
waters.  During  the  progress  of  the  St.  Louis  epoch,  the  sea  deepened 
in  Tennessee,  and  some  limestones  were  made,  from  Crinoids  and 
shells ;  and  moreover,  according  to  C.  A.  White,  it  extended  north 
ward,  in  Iowa,  nearly  to  the  limit  of  the  Kinderhook  group.  After 
ward,  there  was  again  a  contraction  on  the  north,  the  Chester  lime 
stones  reaching  only  to  Alton,  Illinois ;  but  in  other  directions  the 
sea  had  then  greatly  widened  limits  and  increased  depth,  the  lime 
stone  spreading  to  the  southward,  through  Tennessee  and  Kentucky 
to  West  Virginia,  Alabama,  and  Mississippi,  and  being  represented  by 
thin  beds  in  Ohio  and  western  Pennsylvania.  In  the  Appalachian 
region,  there  were  not  only  fragmental  beds,  but  a  very  great  thick 
ness  of  them,  the  thickness  increasing  from  the  New  York  boundary 
on  the  north  and  from  western  Pennsylvania  on  the  west,  toward  the 
region  of  Pottsville,  where  the  whole  was  4,000  to  5,000  feet,  proof  that, 
along  the  central  portions  of  the  region,  there  was  this  amount  of  sub 
sidence  during  the  period,  and  that  the  State  of  New  York  on  the 
north  did  not  participate  in  it,  as  it  had  done  in  the  preceding  Catskill 
period.  This  thickness  of  Subcarboriiferous  rocks  is  four  times  that  in 
the  Mississippi  valley. 

The  region  of  the  Cincinnati  geanticlinal,  from  Lake  Erie  into  Ken 
tucky,  was,  as  stated  by  Newberry,  a  peninsula  during  the  era. 

Michigan  was  to  some  extent  independent  in  its  movements,  and  yet 
there,  as  elsewhere,  the  latter  part  of  the  period  was  the  time  of  lime- 
storie-making,  and  therefore  of  clearer  waters.  This  was  true  also  of 
the  Carboniferous  region  of  Nova  Scotia  and  New  Brunswick,  where 
the  beds  are  mainly  fragmental. 

The  chert,  which  abounds  in  some  of  the  beds,  probably  has  the 
20 


306  PALEOZOIC   TIME. 

same  infusorial  origin  as  that  of  other  formations  (p.  257)  ;  and  so 
also  the  quartz  constituting  the  geodes.  Beyond  this,  the  origin  of  the 
geodes  has  not  been  explained. 

2.  FOREIGN  SUBCARBONIFEROUS. 

The  Subcarboniferous  period  was  a  time  of  limestone-making  also 
in  Britain  and  Europe.  There  is  proof,  therefore,  of  a  wide  extension 
of  those  geographical  conditions  that  characterized  America,  —  that 
is,  of  an  extensive  submergence  of  the  continental  lands,  as  a  prelude 
to  the  period  of  emergence  and  terrestrial  vegetation  that  followed. 
Moreover,  the  later  part  of  the  series  is  most  purely  limestone,  the 
earlier  in  many  places  consisting  of  shale  or  sandstone.  The  lime 
stone  is  often  called  the  "  Mountain  limestone." 

In  Great  Britain,  the  limestone  occurs  in  portions  of  South  and  North  Wales,  and  near 
Bristol,  500  to%l,500  feet  thick;  in  Derbyshire  and  North  Staffordshire,  in  central  Eng 
land,  1,000  to  4,000  feet;  in  Cumberland,  in  Northern  England,  1,000  to  1,500  feet; 
along  the  midland  counties  of  Scotland,  but  of  little  thickness  compared  with  that  in 
England;  in  Ireland,  with  a  thickness  of  3,000  feet  or  more. 

There  is  more  or  less  of  shale  or  sandstone  in  the  limestone  formation  of  these 
regions.  In  Wales,  the  limestone  is  underlaid  by  200  to  300  feet  of  Subcarboniferous 
shale,  and  in  Ireland,  by  500  to  5,000  feet  of  shale  and  sandstone.  The  series  in 
southern  Ireland  includes  2,000  feet  of  Subcarboniferous  shale,  resting  on  3,000  feet  of 
grit  called  the  Coomhola  grit,  and  that  on  reddish  Devonian  sandstones;  and  that  of 
northern  Ireland  consists  of  (1)  500  feet  of  yellow  sandstone,  and  (2)  2,700  feet  of 
limestone,  with  some  intercalcated  shale  and  sandstone.  The  Coomhola  grit  is  referred 
by  some  geologists  to  the  Devonian;  but  it  includes  nearly  the  same  fossil  shells  as 
the  slate  above,  along  with  abundance  of  Spirifer  disjunctus,  Spirifer  cuspidatus,  and 
other  Subcarboniferous  forms. 

In  Belgium,  near  Liege,  there  are,  at  base,  shales  and  sandstone  overlaid  by  Crinoidal 
limestone,  partly  cherty ;  together  they  constitute  the  Comlrusian  system  of  Dumont. 

Over  Russia  —  a  great  Interior  Continental  region  like  that  of  North  America —  the 
Subcarboniferous  rocks  are  mainly  limestone,  and  have  a  wide  distribution.  The  for 
mation  is  well  displayed,  according1  to  Murchison,  on  the  western  flank  of  the  Ural 
Mountains,  upturned,  and  overlying  the  Devonian,  and  along  parts  of  the  Volga. 
Near  Moscow,  it  has  been  reached  by  boring  through  the  Jurassic  and  Coal-measures. 

In  the  Subcarboniferous  limestone  of  Great  Britain,  there  are  beds  of  trap  and  other 
igneous  rocks.  In  Durham  and  Northumberland,  the  interstratified  sheets  of  basaltic 
rock  extend  for  miles.  In  Scotland,  the  interpolations  of  trap,  porphyryte,  and  tufas 
are  numerous,  and  occur  throughout  the  series,  especially  its  lower  part.  They  form 
a  conspicuous  chain  of  terraced  heights,  from  near  Stirling,  through  the  range  of  the 
Campsie,  Kilpatrick,  and  Renfrewshire  hills,  to  the  banks  of  the  Irvine  in  Ayrshire, 
and  thence  westward  by  the  Cumbrae  Islands  and  Bute  to  the  south  of  Arran. 
(Geikie.)  In  Ireland,  county  of  Limerick,  there  are  masses  of  trap  1.200  to  1,300  feet 
thick,  with  tufaceous  beds,  intercalated  with  the  limestone  strata. 


Life. 

Plants.  —  Small  coal-beds  and  a  number  of  species  of  coal-plants 
occur  in  the  strata.  The  plants  are  related  to  those  of  the  lower  part 
of  the  Coal-measures,  and  are,  for  the  most  part,  the  same  in  species. 


CARBONIFEROUS   AGE. 


307 


At  Moresnet,  near  Aix,  in  shales  under  the  Sitbcarboniferous  limestone,  has  been 
found  Cycloptevis  Rcemeriana  Gi  pp.,  with  Sj)ir[fcr  disjunct  us  Sow.  A  number  of  species 
have  been  obtained  in  the  Vosges,  among  them  Cdlainitts  radiatus  Brngt.;  Lepidodtn- 
dra,  Knorrlai,  Stiymarice.  Heer  has  designated  the  horizon  of  these  plants,  the  Ursa 
stage.  He  refers  to  it  the  species  from  Bear  Island,  mentioned  on  page  283,  and  also 
includes  the  species  from  the  Yellow  sandstone  of  Ireland,  which  underlies  the  Sub- 
carboniferous  slate  and  limestone,  as  stated  on  the  same  page. 

Animals.  —  The  "  Mountain  limestone,"  like  the  American  beds,  is 
noted  for  its  Crinoids  ;  its  Brachiopods,  of  the  genera  Productus  and 
Spirifer  ;  its  Corals,  of  the  genus  Lithostrotion  ;  its  Ganoid  Fishes  and 
Sharks  ;  its  few  Amphibian  relics  ;  and  also  for  the  absence  of  Trilo- 
bites  of  all  the  old  genera.  There  are  also  various  Rhizopods  ;  and, 
among  them,  the  kind  called  Fusulina  (Fig.  646,  p.  332)  is  especially 
interesting  on  account  of  its  wide  distribution,  and  its  being  exclu 
sively  a  Carboniferous  type ;  it  is  common  in  the  Upper  beds  in  Rus 
sia,  the  Southern  Alps,  Armenia,  and  Spain  ;  also  the  Carboniferous 
beds  of  North  America,  but  not  the  Subcarboniferous. 

Characteristic  Species. 

Among  Rhizopods,  the  limestone  in  northern  England  contains  aggregations  of  the 
spheroidal  species,  Saccammina  Carte  ri  Brady,  occurring  as  groups  of  single  isolated 
spheroids,  or  occasionally  of  strings  of  them,  the  diameter  of  each  averaging  an  eighth 

Figs.  605-607. 


Fig.  605,  Heinipronites  crenistria  ;  606,  Spirigera  lamellosa  ;  607,  Terebratula  hastata. 
Figs.  608-610. 


Fig.  608,  Productus  longispinus;  609,  Spirifer  glaber;  610,  Nautilus  (Trematodiscus)  Koninckii. 

of  an  inch,  though  rarely  a  fifth  of  an  inch,  a  remarkable  size  for  this  class.  They  lie 
so  closely  together,  that  a  mass  seems  to  be  made  up  of  them.  It  is  very  abundant  in 
the  ''four-fathom  "  limestone  of  the  English  Subcarboniferous.  The  only  other  species 


308 


PALEOZOIC   TIME. 


of  the  genus  thus  far  described  is  the  Snccnmmina  sphcerica  Bars,  a  species  now  living 
over  the  bed  of  the  northern  Atlantic,  off  Norway.  Fusullnn  cylindrica  Vern.  occurs 
in  Russia,  Spain,  etc.;  /'".  robusta  M.,  in  Russia,  Southern  Alps,  Armenia:  neither  species 
has  been  found  in  Great  Britain. 

Among  Mollusks:  Fig.  605,  ffemipronites  (formerly  Streptorhynchus  or  Orthis  umbrac- 
ulum)  crenistrid,  common  in  the  American  Carboniferous;  Fig.  606,  Sjririyera  (Athyris) 
lamdlosa  Dav. ;  Fig.  607,  Ttrrbratulu   hastata  Sow. :  Fig.  608,  Product  us  lonyisplnus 
Sow.,  P.  scabriculus  Sow.;  Fig.  (509,  Spirtfer  ylnber  Sow.,  S.  speciosus  Br  ,  S.  cuspida- 
tus  Sow.,  S.  disjunctus  Sow.;  Chonetes  Dalmanianti  Kon. ;    Orthis  Michvllni  Morr.,  0. 
resupinata  Phill.     Pleurotomaria  carinata  Sow.  retains  its  original  colored  markings, 
as  h'rst  observed  by  the  late  Professor  Forbes;  this  author  hence  inferred  that  it  was  a 
shallow-water  species,  but  it  is  now  known  that  colored  species  occur 
Fig.  611.          at  a  great  depth  in  the  ocean.     Fig.  610,  Nautilus  (Trematodiscus)  Ko- 
ninckii  D'Orb. 

Trilobites  occur,  of  the  only  three  Carboniferous  genera,  Phillip$fa) 
Grij/ithides,  and  Brachymetopus.  Fig.  611,  Phillipsia  seminifera  Morr. : 
P.  pustulata  Kon.  occurs  in  the  Irish  rocks. 

Remains  of  lishes  are  very  common  in  Europe  and  Britain.     Among 
Cestracionts  (or  sharks  with  pavement-teeth),  Cochliodxs  contort u-s  Ag., 
Fig.  600  A;  among Hybodonts  (or  sharks  with  regular  teeth,  the  teeth 
with  obtuse  or  rounded  edges),  Cladodus  marginatus  Ag.     Fig.  612, 
part  of  the  fin-spine,   Ctenaatnthus  major  Ag. ;    one  specimen  has  a 
length  of  fourteen  and  a  half  inches,  and  was  probably  eighteen  inches 
Phillipsia  semi-      in  the  living  Cestracicnt.     The  old  fishes,  as  Agassiz  observes,  must 
nifera.  have  had  gigantic  dimensions.     Another  spine,    Omcanthus  Milleri 

Ag-,  is  nine  and  a  half  inches  long  and  three  inches  Avide  at  base; 
and  yet  it  has  lost  some  inches  at  its  extremities.     These  species  and  many  other  re- 
Fig.  612. 


Part  of  a  spine  of  Ctenacanthus  major. 

mains  of  fishes  are  found  in  fish-bone  beds  in  the  limestone  at  Bristol,  England,  and  at 
Armagh,  Ireland. 

3    DISTURBANCES  PRECEDING  THE  CARBONIFEROUS  PERIOD. 
It  has  been  stated,  on  page  290,  that  the  Coal-measures,  in  parts  of 
northern  and  western  Illinois,  rest  on  tilted  Silurian  strata  ;  and  the 

fact  is  illustrated  by  a  section  from  La 
Salle   County.     Another   section,    pub 
lished  by  Hall,  is  shown  in  the  annexed 
figure  ;  it  represents  the  Coal-measures 
(A),  in  Rock  Island  County,  at   Port 
Byron,  overlying  upturned  Niagara  beds  (B).     Like  that  of  La  Salle 


Fig.  612  A. 


CARBONIFEROUS   AGE.  309 

County,  it  gives  no  good  reason  for  concluding  that  the  upturn  of  the 
Silurian  formation  took  place  directly  before  the  era  of  the  Coal-meas 
ures  ;  but  simply  teaches  that  the  disturbance  occurred  at  some  time 
between  the  Niagara  period,  in  the  Upper  Silurian,  and  the  Carbon 
iferous  period.  A  geographical  change,  however,  occurred  in  the 
region  of  the  Upper  Mississippi,  as  remarked  upon  by  Hall,  which 
gave  the  Coal-measures  a  northern  extension  beyond  the  Chester 
limestone,  the  last  of  the  Subcarboniferous,  and  even  beyond  tho 
Kinderhook  beds  ;  and  thus  was  produced  an  overlapping  of  the  latter 
by  the  former,  instead  of  perfect  conformability.  Hall  says,  in  his 
Report  on  Iowa  (1858),  u  I  have  ascertained,  in  the  most  satisfactory 
manner,  that  the  coal-fields  of  Iowa,  Missouri,  and  Illinois  rest  un- 
conformably  upon  the  strata  beneath,  whether  these  strata  be  Car 
boniferous  limestones,  Devonian,  Upper  Silurian,  or  Lower  Silurian 
rocks/'  As  unconformability  by  overlap  is  all  that  is  certainly  known 
to  occur  between  the  Coal-measures  and  the  Subcarboniferous  forma 
tion,  this  was  apparently  the  foundation  for  including  this  formation 
in  the  above  general  statement. 

In  Great  Britain,  Russia,  and  the  most  of  Europe,  the  Carbon 
iferous  and  Subcarboniferous  beds,  when  occurring  together,  are  con 
formable.  But,  in  central  and  southern  France,  as  Murchison  says, 
the  two  are  always  unconformable.  In  Bavaria  also,  at  Hof,  the  Sub- 
carboniferous  limestones  and  Devonian  follow  one  another  regularly, 
though  inclined  together  at  a  large  angle ;  while  the  Coal-measures 
of  Bohemia  lie  in  horizontal  strata,  over  their  tilted  edges. 

2.  CARBONIFEROUS  PERIOD  (14). 
1.  Distribution  of  the  Carboniferous  Rocks. 

The  areas  of  Carboniferous  rocks,  and  of  the  Coal  fields  of  North 
America,  have  been  pointed  out  on  page  291,  and  also  on  the  map  on 
page  292. 

The  principal  coal-producing  fields  are  (1)  the  Appalachian  ;  (2). 
the  Eastern  Interior,  or  that  of  Illinois  and  the  adjoining  States;  (3) 
the  Western  Interior,  or  that  of  Missouri  and  the  States  adjoining  on 
the  north,  west,  and  south,  and  reaching,  though  with  some  interrup 
tions,  into  Texas;  (4)  the  Michigan;  (5)  the  Rhode  Island-,  (6)  the 
Acadian,  or  that  of  Nova  Scotia  and  New  Brunswick. 

The  thickness  of  the  Coal-measure  rocks  in  these  regions  varies 
from  100  to  1,000  feet  in  the  Interior  coal  areas,  to  4,000  feet  where 
greatest  in  Pennsylvania,  and  over  8,000  feet  in  Nova  Scotia.  The 
maximum  thickness  of  the  rocks  of  the  Carboniferous  age  in  Penn 
sylvania  is  about  9,000  feet,  though  not  over  6,000  feet  in  any  one  sec- 


310 


PALEOZOIC   TIME. 


tion  ;  while  in  Nova  Scotia,  at  the  Joggins,  there  are,  according  to  Logan 
and  Dawson,  14,570  feet.  The  coal-fields  in  some  regions  are  broken 
more  or  less  into  patches,  either  by  uplifts  that  have  brought  lower 
rocks  to  the  surface,  or  by  the  occurrence  of  overlying  deposits.  Those 
of  the  Interior  basin  are  but  little  subdivided,  while  that  of  the  great 
Appalachian  Mountain  region  is  in  many  pieces,  as  illustrated  on  the 
annexed  map  of  a  part  of  Pennsylvania.  Between  the  various  patches, 


from  Pottsville  to  the  Lackawanna  coal-field,  the  outcropping  rocks  are 
mostly  Devonian  and  Subcarboniferous. 


II.  Kinds  of  Rocks. 

1.  Stratification.  —  The  Carboniferous  period  opened  with  a  marked 
change  over  the  continent.  The  Subcarboniferous  limestones  and 
shales,  which  had  been  formed  upon  the  submerged  land,  became 


CARBONIFEROUS   AGE.  311 

covered  with  extensive  gravel  or  pebble  beds,  or  deposits  of  sand ; 
and  these,  hardened  into  gritty  rocks,  make  up  the  millstone  grit  and 
sandstone  which  underlie  the  Coal-measures.  Similar  conglomerates 
and  sandstones  were  formed  afterward  in  the  course  of  the  Coal- 
measures  ;  but  this  rock  is  prominent  for  its  extent,  and  for  marking 
the  commencement  of  the  Coal  era. 

The  rocks  of  the  Carboniferous  period  are  accordingly  divided  into 
(1)  The  Millstone  grit  section  ;  and  (2)  the  Coal-measure  section. 

The  Millstone  grit  extends  over  parts  of  some  of  the  southern 
counties  of  New  York,  with  a  thickness  of  twenty -five  to  sixty  feet ; 
and,owing  to  the  regularity  of  the  joints,  in  Cattaraugus  and  Alleghany 
counties,  it  stands  out  in  huge  blocks,  walls,  and  square  structures, 
that  have  suggested  such  names  as  "  Rock  City  "  and  k'  Ruined  City." 
It  occurs  through  all  the  Coal-areas  of  Pennsylvania,  both  the  eastern 
and  western  ;  it  is  from  1,000  to  1,500  feet  thick,  about  the  centre  of 
the  anthracite  region,  and  diminishes  rapidly  to  the  westward.  It 
stretches  southwestward  through  Virginia  and  Tennessee,  to  Alabama. 
Throughout  the  Appalachians,  it  is  commonly  a  conglomerate ;  but,  in 
the  Interior  basin,  the  beds  are  mainly  arenaceous  sandstones,  and  in 
some  parts  are  absent. 

The  Coal-measures  include  all  the  kinds  of  sedimentary  rocks : 
sandstones,  laminated  or  shaly  sandstones  and  shales ;  conglomerates, 
fine  and  coarse  ;  buhrstone  (a  cellular  siliceous  rock),  and  limestones. 
Interstratified  with  these  rocks  occurs  the  coal  in  layers,  and  often, 
also,  beds  of  iron-ore.  There  is  no  fixed  order  of  superposition.  The 
•  following  is  an  example,  from  Western  Pennsylvania,  as  published  by 
Lesley :  the  beds  are  numbered  in  accordance  with  their  succession, 
beginning  below,  — 

Feet. 
A.  Millstone  Grit V 

1.  Coal  No.  A,  with  4  feet  of  shale 6 

2.  Shale  and  mud-rock 40 

3.  Coal  No.  B.     (Of  Mammoth  bed  of  Central  Pennsylvania.)       .  3-5 

4.  Shale,  with  some  sandstone  and  IRON-ORE 20-40 

5.  FOSSILIFEROUS  LIMESTONE 10-20 

6.  Buhrstone  and  IRON-ORE •  1-10 

7.  Shale 25 

8.  Coal  No.  C.     The  Kittanning  Cannel 3| 

9.  Shale,  —soft,  containing  two  beds  of  Coal,  1  to  1^  feet  thick     .  75-100 

10.  Sandstone 70 

11.  Lower  Freeport  Coal  No.  D 2-4 

12.  Slaty  sandstone  and  shale 50 

13.  LIMESTONE 6-8 

14.  Upper  Freeport  Coal,  No.  E 6 

15.  Shales 50 

16.  MAHONING  SANDSTONE 75 

17.  Coal  No.  F    .  1 


312 


PALEOZOIC   TIME. 


Feet. 

18.  Shale  ;  thickness  considerable    .....        •        .        .  I 

19.  Shaly  sandstone     .                 ........  30 

20.  Red  and  blue  calcareous  marly  tes               .    -     .        .        .        .        »  20? 

21.  Coal  No.  G    .....        ,       :.        .        .  '      .      '  .  1 

22.  LIMESTONE  fossiliferous     .........  2 

23.  Slates  and  shales     ......        .....  100 


24.  Gray  clayey  sandstone 

25.  Redmarlyte 

26.  Shale  and  slaty  sandstone 

27.  LIMESTONE,  non-fossiliferous 

28.  Shales 

29.  LIMESTONE 

30.  Red  and  yellow  shale 

31.  LIMESTONE 

32.  Shale  and  sand 

33.  LIMESTONE,  with  bands  of  spathic  IRON-ORE 

34.  Pittsburg  Coal,  No.  H 


70 
10 
10 

3 
32 

2 
12 

4 
30 
25 


In  other  regions  the  succession  is  widely  different.  The  rocks  are 
distinguished  from  those  of  other  ages,  not  by  their  colors  or  kinds, 
nor  by  their  succession,  but  by  the  species  of  fossil  plants  and  animals 
they  contain. 

The  Coal  beds  are  thin,  compared  with  the  associated  rock  strata, 
usually  not  exceeding  one-fiftieth  of  the  whole  thickness. 

The  rock  underlying  a  coal  bed  may  be  of  either  of  the  kinds  men 
tioned  ;  but  usually  it  is  a  clayey  layer  (or  bed  of  fine  clay),  which 
is  called  the  under-day.  Being  frequently  suitable  for  making  fire 
brick,  such  beds  often  go  by  the  name  of  fire-clay.  This  under-clay 
generally  contains  fossil  plants,  and  especially  the  roots  or  under-water 
stems  of  Carboniferous  plants,  called  Stigmarice,  and  it  is  often  called 
the  old  dirt-bed,  or  the  bed  of  earth  over  which  the  plants  grew  that 

Fig.  614. 


Section  of  Coal-measures  at  the  Joggins,  Noya  Scotia  (with  erect  stumps  iu  the  sandstone,  and 
rootlets  in  the  under-clays) 

commenced  to  form  the  coal-bed.  It  is  either  this,  or  the  clayey  bot 
tom  of  the  plant-bearing  marshes  or  lakes.  In  some  cases,  trunks  of 
trees  rise  from  it,  penetrating  the  coal  layer  and  rock  above  it. 


CARBONIFEROUS    AGE.  313 

The  Nova  Scotia  Coal  region  abounds  in  erect  trunks,  standing  on 
the  old  k- dirt-beds,"  as  illustrated  in  Fig.  614,  from  a  memoir  by  Daw- 
son.  Each  of  the  seventy-six  coal  seams  at  the  Joggins  has  its  dark 
clayey  layer,  or  u  dirt-bed,"  beneath.  In  fifteen  of  them,  there  is  only 
a  trace  of  coal ;  but  these,  as  well  as  the  rest,  contain  the  Stiymarice, 
and  often  support  still  the  old  stumps. 

The  limestones  are  more  extensive  in  the  Coal-measures  of  the 
Mississippi  basin  than  in  those  of  Pennsylvania  and  Virginia,  while, 
on  the  contrary,  conglomerates  are  much  less  common  in  the  West. 
This  accords  with  the  fact,  learned  from  the  earlier  ages,  that  the 
Appalachian  region  is  noted  for  its  conglomerates  and  sandstones,  and 
the  Interior  basin  for  limestones. 

The  rock  capping  a  coal-bed  may  be  of  any  kind,  for  the  rocks  are 
the  result  of  whatever  circumstances  succeeded ;  but  it  is  common  to 
find  great  numbers  of  fossil  plants,  and  fragments  or  trunks  of  trees. 
in  the  first  stratum. 

The  shaly  beds  often  contain  the  ancient  ferns,  spread  out  between 
the  layers  with  all  the  perfection  they  would  have  in  an  herbarium, 
and  so  abundantly  that,  however  thin  the  shale  be  split,  it  opens  to 
view  new  impressions  of  plants.  In  the  sandstone  layers,  broken 
trunks  of  trees  sometimes  lie  scattered  through  the  beds.  Some  of  the 
logs  in  the  Ohio  Coal-measures,  described  by  Dr.  Hildreth,  are  fifty  to 
sixty  feet  long  and  three  in  diameter. 

2.  Coal  Beds.  —  The  thickness  of  the  coal  beds  at  times  hardly 
exceeds  that  of  paper ;  and  again  it  is  from  thirty  to  forty  feet.  Some 
of  the  larger  beds  may  extend  continuously  over  thousands  of  square 
miles  ;  but,  if  so,  they  vary  greatly  in  thickness ;  and  many  beds  thin 
out  laterally,  or  graduate  into  coaly-shales,  in  the  course  of  a  few  scores 
of  miles.  Shaly  layers  sometimes  make  up  a  large  part  of  the  so 
called  coal-bed.  The  Mammoth  bed  of  the  Lackawanna  region  is,  at 
Wilkesbarre,  twenty-nine  and  one  half  feet  thick  ;  while  in  western 
Pennsylvania,  according  to  the  section  by  Lesley  on  page  311,  the 
thickness  is  but  three  to  five  feet.  Where  thickest,  it  is  nearly  pure 
coal ;  yet  there  are  some  black  shaly  layers,  one  to  twelve  inches 
thick.  The  same  great  bed  is  worked  at  Carbondale,  Beaver  Meadows, 
Mauch  Chunk,  Tamaqua,  Minersville,  Shamokin,  etc. 

The  Pittsburg  bed,  at  Pittsburg,  Penn.,  is  ten  feet  thick  ;  but  it  is 
made  tip  of  one  foot,  at  bottom,  of  coal  with  pyritiferous  shale ;  five  to 
six  feet  of  good  coal  ;  and,  above  this,  shale  and  coal,  left  as  the  roof 
in  working,  though  sometimes  including  one  or  two  feet  of  pure  coal. 
It  borders  the  Monongahela  for  a  long  distance,  the  black  horizontal 
band  being  a  conspicuous  object  in  the  high  shores,  and  in  some  places 
containing  seven  or  eight  feet  of  good  coal.  It  may  be  traced,  accord- 


314  PALEOZOIC    TIME. 

ing  to  Rogers,  into  West  Virginia  and  Ohio,  over  an  area  at  least  two 
hundred  and  twenty-five  miles  by  one  hundred ;  and  into  Kentucky, 
according  to  Lesquereux.  It  varies  in  thickness,  being  twelve  to 
sixteen  feet  in  the  Cumberland  basin,  six  feet  at  Wheeling,  four  to 
eight  feet  in  Athens  County,  Ohio,  four  feet  two  inches  at  Pomeroy, 
where  it  is  the  "  Pomeroy  "  bed,  six  and  one-half  to  nine  and  one-half 
feet  in  West  Virginia,  at  Morgantown,  and  farther  south,  on  the 
Guyandotte,  two  to  three  feet. 

At  Pictou,  in  Nova  Scotia,  one  of  the  coal-beds  has  the  extra 
ordinary  thickness  of  thirty-eight  feet,  and  a  second  fifteen  and  one 
half  feet. 

A  bed  of  coal,  even  when  purest,  consists  of  distinct  layers.  The 
layers  are  not  usually  separable,  unless  the  coal  is  quite  impure  from 
the  presence  of  clay  ;  but  they  are  still  distinct  in  alternating  shades 
of  black,  and  may  be  seen  in  almost  any  hand  specimen  of  the  hard 
est  anthracite,  forming  a  delicate,  though  faint,  banding  of  the  coal. 

In  some  of  the  bituminous  coal  of  the  Interior  basin,  a  cross-fracture 
shows  it  to  be  made  up  of  alternate  laminae  of  black,  shining,  compact 
bituminous  coal,  and  a  soft,  pulverulent  carbonaceous  matter,  looking 
much  like  common  charcoal. 

The  Coal-measures,  from  the  bottom  (No.  1)  to  No.  15,  in  the  pre 
ceding  section,  are  sometimes  designated  the  Lower  Coal-measures. 
Of  the  rest,  or  Upper  division,  Nos.  1G  to  33  are  called  the  Barren 
Measures. 

3.  Kinds  of  Mineral  Coal.  —  The  Mineral  Coals,  setting  aside  im 
purities,  are  essentially  compounds  of  carbon  (the  fundamental  ele 
ment  of  charcoal),  hydrogen,  and  oxygen.  The  carbon  varies  from 
75  to  93  per  cent.,  or,  impurities  excluded,  —  which  constitute  usually 
2  to  10  per  cent,  —  from  77  to  98  per  cent.  The  most  of  them  yield, 
when  highly  heated,  mineral  oil  or  mineral  tar,  along  with  some  in 
flammable  gas  ;  and  it  is  owing  to  this  that  they  burn  with  a  bright 
yellow  flame.  The  oil,  like  the  most  of  the  gas,  consists  of  carbon 
and  hydrogen.  The  coals,  like  the  black  carbonaceous  shales  mentioned 
on  page  268,  do  not  contain  mineral  oil,  any  more  than  hydrocarbon 
gas,  as  is  shown  on  treatment  with  the  solvents  of  mineral  oils.  The 
oil  is  a  product,  and  not  an  educt.  Since  such  oils,  tars,  and  gas  burn 
like  bitumen,  and  with  similar  odor,  coals  of  this  kind  are  said  to  be 
bituminous,  although  actually  containing  no  bitumen,  and  also  yielding 
none,  —  bitumen  being  mainly  an  oxygenated  hydrocarbon,  and  thus 
differing  from  mineral  oil.  Coals  also  contain  traces  of  nitrogen ; 
they  afford  generally  3  to  5  per  cent.,  or  more,  of  moisture,  which  is 
driven  off  at  a  temperature  of  250°  F. 

The  following  are  the  characters  of  the  kinds  of  Carboniferous 
mineral  coals  :  — 


CARBONIFEROUS   AGE.  315 

1.  Anthracite,  which  has  high  lustre  and  firmness,  and  burns  with  a 
feeble  flame,  yielding  little  moisture,  only  traces  of  hydrocarbon  gas, 
and  84  to  95  per  cent,  of  carbon.     Specific  gravity  1-3  to  1-8.     Free- 
burning  anthracite,  or  Semi -anthracite,  affords  more  flame,  and  of  a 
yellow  color  ;  but  still  the  proportion  of  volatile   matters  given  off  is 
small,  not  exceeding  10  or  12  per  cent. 

2.  Bituminous  Coal,  having  less  firmness  and  lustre  than  anthracite, 
and  burning  with  an  abundant  yellow  flame,  the  volatile  combustible 
substances  afforded  amounting  usually  to  25  or  35   per  cent,  of  the 
whole,  and  sometimes  to  50  or  60  per  cent.     When  these  substances 
are  only  15  to  20  per  cent.,  the  coal  is  called  semi-bituminous.     There 
are  in  fact  all  grades,  between  the  true  bituminous  coal  and  the  hardest 
anthracite.     Ordinary  bituminous  coal  breaks  with  straight  or  irregular 
lustrous    surfaces  :  it  sometimes  divides  into  rectangular  blocks,  but 
this   is  a  result   of  a  jointed  structure,  and  never  of  crystallization. 
Specific  gravity  mostly  between  1'22  and  1.32. 

Some  bituminous  coals  soften  in  the  fire,  becoming  semi-pasty,  and 
then  cake  over ;  such  kinds  are  called  caking  coals.  Others,  undis- 
tinguishable  from  the  caking,  both  chemically  and  physically,  are  non- 
caking.  The  "  Block  Coal,"  of  Ohio,  Indiana,  and  the  neighboring 
States,  is  of  the  non-caking  kind. 

Cannel  Coal  (or  Parrot  Coal)  is  a  variety  of  bituminous  coal  having 
almost  no  lustre,  a  very  fine  texture,  and  a  conchoidal  fracture.  It  is 
remarkable  for  the  large  proportion  of  volatile  combustible  material, 
or  mineral  oil,  which  it  yields.  It  received  its  name  from  its  affording 
a  flame,  like  candles.  Torbanite,  a  variety  of  cannel  from  Torbane 
Hill,  near  Bathgate,  in  Scotland,  yields  over  60  per  cent,  of  volatile 
substances. 

Anthracite  is  the  coal  of  Rhode  Island,  and  of  the  areas  in  central  Pennsylvania, 
from  the  Pottsville  or  Schuylkill  coal-field  to  the  Lackawanna  field  (see  map,  page  310); 
while  the  coal  of  Pittsburg,  and  of  all  the  great  coal-fields  of  the  Interior  basin,  is 
bituminous,  excepting  a  small  area  in  Arkansas.  Anthracite  belongs  especially  to 
regions  of  upturned  rocks,  and  bituminous  coal  to  those  where  the  beds  are  little  dis 
turbed.  In  the  area  between  the  anthracite  region  of  central  Pennsylvania  and  the 
bituminous  of  western,  and  farther  south,  the  coal  is  semi-bituminous,  as  in  Broad  Top, 
Pennsylvania,  and  the  Cumberland  coal-field,  in  western  Maryland,  the  volatile  matters 
yielded  by  it  being  15  to  20  per  cent.  The  more  western  parts  of  the  Anthracite  coal 
fields  afford  the  free-burning  anthracite,  or  semi-anthracite;  as  atTrevorton,  Shamokin, 
and  Birch  Creek. 

Albertite,  from  the  Nova  Scotia  Subcarboniferous  (p.  296),  and  Gra-Jinmite,  from  the 
Carboniferous  in  West  Virginia  (about  twenty  miles  south  of  Parkersburg),  are  pitch- 
like  substances  in  aspect,  constituting  veins  instead  of  beds,  and  not  true  coals.  They 
are  supposed  to  have  originated  in  distillation  from  some  underlying  carbonaceous 
shales,  which  set  free  the  material,  as  Wtirtz  observes,  in  a  pasty  state.  Though  like 
asphaltum  in  color  and  lustre,  they  are  not  as  fusible  or  as  soluble  in  benzine  or  ether. 

The  following  are  analyses  of  a  few  of  the  coals  of  the  Carboniferous  period.  Others, 
of  albertite  and  of  the  more  recent  coal,  called  brown  coal,  and  also  of  peat  (the 
ash  excluded),  are  added  for  comparison. 


316 


PALEOZOIC    TIME. 


Carbon 

Hydr. 

Ox. 

Nitr. 

gulph. 

Ash. 

Analysts. 

1. 

Anthracite,  Pennsylvania      .     . 

90-45 

2-43 

2-45 

- 

- 

4-67, 

Regnault- 

2. 

Anthracite,  Pennsylvania      .     . 

92-59 

2-63 

1-61 

0-92 

- 

2-25, 

Percy. 

3. 

Anthracite,  South  Wales  .     . 

92-56 

3-33 

2-53 

- 

- 

1-58, 

Regnault. 

4. 

Caking  Coal,  Kentucky  . 

74-45 

4-93 

13-08 

1-03 

0-91 

5-00, 

Peters. 

5. 

Caking  Coal,  Xelsonville,  0.     . 

73-80 

5-79 

16-58 

1-52 

0-41 

1-90, 

Wormley. 

8. 

Caking  Coal,  South  Wales    .     . 

82-56 

5-36 

8-22 

1-65 

0-75 

1-46, 

Noad. 

7. 

Caking  Coal,  Northumberland  . 

78-69 

6-UO 

10-07 

2-37 

1-51 

1-36, 

Tookey. 

8. 

Non-caking,  Kentucky     .     .     . 

77-89 

5-42 

12-57 

1-82 

3-00 

2-00, 

Peters. 

9. 

Non-caking,  "Block  Coal,"  Ind. 

82-70 

4-77 

9-39 

1-62 

0-45 

1-07, 

Cox. 

10. 

Non-caking,  Briar  Hill,  Ohio    . 

78-94 

5-92 

11-50 

1-58 

0-56 

1-45, 

Wormlev. 

11. 

Non-caking,  S.  Staffordshire     . 

76-40 

4-62 

17-43 

- 

0-55 

1-55, 

Dick. 

1-2. 

Non  caking,  Scotland       .     . 

76-08 

5-31 

13-33 

2-09 

1-23 

1-96, 

Rowney. 

18, 

Cannel  Coal,  Breckenridge   .     . 

68-13 

6-49 

5-83 

2-27 

2-48 

12-30, 

Peters. 

14. 

Cannel  Coal,  Wigan      .... 

80-07 

5-53 

8-10 

2-12 

1-50 

2-70, 

Vaux. 

15. 

Cannel  Coal,  "Torbanite"   . 

64-02 

8-90 

5-66 

0-55 

0-50 

20-32, 

Anderson. 

16. 

Albertite,  Nova  Scotia      .     .     . 

86-04 

8-96 

1-97 

2-93 

trace 

o-io, 

Wetherill. 

17. 

Brown  Coal,  Bovey      .... 

66-31 

5-63 

2286 

0-57 

2.36 

2.27, 

Vaux. 

18. 

Brown  Coal,  Wittenberg  .     . 

64-07 

5-03 

27-55 

- 

3-35, 

Baer. 

19. 

Peat,  light  brown  (imperfect)    . 

50-86 

5-80 

42-57 

0-77 

- 

- 

Websky. 

2n. 

Peat  dark  brown     

59-47 

6-52 

31-51 

2-51 

Webskv. 

•21. 

Peat,  black      

59-70 

5-70 

33-04 

1-56 

Websky. 

22. 

Peat,  black     . 

59-71 

5-27 

32-07 

2-59 

Webskv. 

The  Coal  No.  4,  from  "  Roberts'  seam,"  Mnhlenburg  County,  Kentucky,  has  sp.  gr. 
=  1"26;  No.  9,  from  "Wolf  Hill,"  Daviess  County,  Indiana,  has  sp.  gr.  =1*275. 

No.  13,  the  Breckenridge  cannel,  of  Hancock  County,  Kentucky,  consists,  when  the 
ash  is  excluded,  of  carbon  82'36,  hydrogen  7'84,  oxygen  7'05,  nitrogen  2-75;  and  the 
Bog-head  cannel  of  Scotland,  called  also  torbanite,  contains  carbon  80*39,  hydrogen 
11*19,  oxygen  7*11,  nitrogen  and  sulphur  1'31. 

The  "Mineral  charcoal  "  differs  little  in  composition  from  ordinary  bituminous  coal: 
there  is  less  hydrogen  and  oxygen.  Rowney  obtained,  for  that  of  Glasgow  and  Fife- 
shire,  Carbon  82.97,  74*71,  hydrogen  3*34,  2*74,  oxygen  7*59.  7*67,  ash  6'08,  14-86. 
The  nitrogen  is  included  with  the  oxygen;  it  was  0'75  in  the  Glasgow  charcoal.  Ex 
clusive  of  the  ash,  the  composition  is,  Carbon  88-36,  87*78,  hydrogen  3*56,  3*21,  oxygen 
and  nitrogen  7 '28,  9'01. 

The  following  are  average  results,  from  many  analyses :  — 


1.  Pennsylvania  anthracites 

2.  Pennsylvania  semi-anthracites  11 

3.  Pennsylvania  semi-bituminous  6 

4.  Maryland  semi-bituminous 

5.  Pennsylvania  bituminous 

6.  Virginia  bituminous     .     . 

7.  Ohio  bituminous 

8.  Indiana  bituminous 

9.  Illinois  bituminous  .     .     . 
10.  Iowa  bituminous 


Nos. 

7 
16 

5  11 

s   6 
9 

10 
11 
142 
126 
50 
59 

«,_    _             Vol. 
combust. 

1-59-1-61      3*92 
1-39-1*60      5-70 
1-33-1-45       9-98 
1-30-1-41    16-85 

1-30-1-43    15*50 

-       28*35 
1*29-1*45    29-88 
1-24-1-47    35-24 
119-1-41    43-2) 
1-21-1-35    31-90 

Fixed 
Carbon. 

89-77 
88-23 
82-86 
72-95 

7403 

65-18 
59-06 
60-26 
53-47 
62-44 
43-02 

Ash. 

6.31 

6-07 
7-16 
10-20 

10*47 

6-47 
11*06 
4*50 
3-33 
d-fil 
6-82 

Analysts. 

Johnson. 

Geol.  Survey. 

Geol.  Survey. 

Johnson. 

|  Johnson  &  Geol. 
(      Survey. 

Johnson. 

Johnson. 

Wormley. 

Cox. 

Blaney. 

Emery. 


The  ordinary  impurities  of  coal,  making  up  its  ash,  are  silica,  a  little  potash  and  soda, 
and  sometimes  alumina,  with  often  oxyd  of  iron,  derived  usually  from  sulphid  of  iron, 
besides,  in  the  less  pure  kinds,  more  or  less  clay  or  shale.  The  amount  of  ash  does  not 
ordinarily  exceed  6  per  cent.,  but  it  is  sometimes  30  per  cent. ;  and  rarely  it  is  less  than 
2  per  cent.  There  is  present  in  most  coal  traces  of  sulphid  of  iron  (pyrite),  sufficient 


CARBONIFEROUS   AGE. 


317 


to  give  sulphur  fumes  to  the  gases  from  the  burning  coal,  and  sometimes  enough  to 
make  the  coal  valueless  in  metallurgical  operations.  Some  thin  layers  are  occasionally 
full  of  concretionary  pyrite. 

Sulphur  also  occurs,  in  some  coal-beds,  as  a  constituent  of  a  resinous  substance;  and 
Wormley  has  shown  that  part  of  the  sulphur  in  the  Ohio  coals  is  in  some  analogous 
state,  there  being  not  iron  enough  present  to  take  the  whole  into  combination. 

Wormley  gives  the  following  analyses  (besides  others)  of  the  ash  of  two  coals,  one 
from  the  Yougliiogheny,  in  Western  Pennsylvania,  and  the  second  from  Pigeon  Creek, 
Jackson  County,  Ohio:  Silica  49-10,  37'40,  alumina  38-60,  40*77,  sesquioxyd  of  iron 
3-68,  9-73,  magnesia  0-16,  1'Gu,  lime  4*53,  6'27,  potash  and  soda  1-10,  1-29,  phosphoric 
acid  2-23,  0'51,  sulphuric  acid  0-07,  1-99,  sulphur  (combined)  044,  0'08,  chlorine  trace  = 
99-61,  99-64.  The  fact  that  there  is  too  much  sulphur  in  the  Ohio  coals  for  combination 
with  the  iron  present,  is  shown  in  the  following  table,  containing  some  of  his  results:  — 

Sulphur  in  the  coals  ....  0-57  1-18          2'00          0'91          0'86 

Iron  in  the  coals 0-075         0'742        0-425         0-122        0-052 

Sulphur  required  by  the  iron     0-086        0-848        0-486        0-139        0-06 

The  average  amount  of  ash,  in  eight-eight  coals  from  the  southern  half  of  Ohio,-  ac 
cording  to  Wormley,  is  4-718  per  cent.;  in  sixty-six  coals  from  the  northern  half ,  5-120; 
in  all,  from  both  regions,  4-891;  or,  omitting  ten,  having  more  than  ten  per  cent,  of 
ash,  the  average  is  4-28.  In  eleven  Ohio  cannels,  the  average  amount  of  ash  was 
12-827. 

In  rare  cases,  an  occasional  bowlder  or  rounded  stone  has  been  found  in  a  coal-bed, 
as  well  as  in  other  layers  of  the  Coal-measures.  E.  B.  Andrews  describes  one  of 
quartzyte,  lying  half  buried  in  the  top  of  the  Nelsonville  coal-bed,  at  Zaleski,  Ohio, 
which  was  twelve  and  seventeen  inches  in  its  two  diameters.  F.  11.  Bradley  reports 
one,  also  of  quartzyte,  about  four  by  six  inches,  found  in  the  middle  of  the  coal-bed 
mined  at  Coal  Creek,  East  Tennessee.  These  may  have  been  dropped  from  the  roots  of 
floating  trees,  as  are  the  masses  of  basaltic  rocks  occasionally  found  upon  the  coral 
atolls  of  the  Pacific. 

4.    Vegetable   Remains   in   the  Coal  —  In    many  places,  there    are 
vegetable  remains  in  the  coal  itself,  such  as  impressions  of  the  trunks 


615c 


Figs.  615-616. 
6l5a 


616 


Fig.  615  a,  b,  c,  Vegetable  tissues  in  anthracite  ;  616,  Spores  and  part  of  a  Sporangium,  in  bitumi 
nous  coal  of  Ohio  (X  70). 

or  stems  of  trees,  or  of  leaves,  or  charcoal-like  fragments,  which  in 
texture  resemble  charcoal  from  modern  wood ;  but  which  have  been 
found  to  be  carbonized  stems,  leaves,  or  tissues  of  plants. 


318  PALEOZOIC   TIME. 

Even  the  solid  anthracite  has  been  found  to  contain  vegetable  tis 
sues.  On  examining  a  piece  partly  burnt,  Professor  Bailey  found 
that  it  was  made  up  of  carbonized  vegetable  fibres.  The  preceding 
figures,  615  a,  &,  e,  are  from  his  paper  on  this  subject.  He  selected 
specimens  which  were  imperfectly  burnt  (like  Fig.  615  «),  and  ex 
amined  the  surface  just  on  the  borders  of  the  black  portion.  Fig. 
615  b  represents  a  number  of  ducts,  thus  brought  to  light,  as  they  ap 
peared  when  moderately  magnified,  and  Fig.  615  c,  two  of  the  ducts, 
more  enlarged  ;  the  black  lines  being  the  coal  that  remained  after  the 
partial  burning,  and  the  light  spaces  silica.  The  ducts  were  one  tenth 
of  a  millimeter  (about  four  thousandths  of  an  inch)  broad.  Dawson  re 
ports  like  results  with  bituminous  coal. 

The  spores  (fruit-cellules)  and  the  spore-cases  (sporangia)  of  the 
Lycopods  (Lepidodendrids)  abound  in  the  coal,  to  such  an  extent,  in 
some  places,  that  it  has  been  suggested  that  mineral  coal  was  made 
mainly  out  of  them.  While,  as  Dawson  has  shown,  this  inference  is 
not  sustained  by  facts,  such  spore-cases  are  still  very  common  in  most 
coal.  (The  Lycopodium  powder  of  the  shops,  used  in  fire  works,  on 
accou?it  of  its  inflammability,  consists  of  the  spores  of  the  common 
species  of  the  woods  of  Europe.)  Fig.  616  represents,  very  much  mag 
nified,  the  surface  of  a  piece  of  Ohio  bituminous  coal,  showing  a  frag 
ment  of  a  spore-case  and  many  of  the  spores.  The  spore-cases  vary 
in  size,  from  a  tenth  to  a  hundredth  of  an  inch  ;  and  in  the  coal  they 
often  have  an  amber-yellow  color.  Dr.  Dawson  states  that  he  has  a 
specimen  of  Pennsylvania  anthracite  full  of  spore-cases,  but  that  the 
Pictou  coal  is  remarkably  free  from  them. 

5.  Iron-ore  Beds.  —  The  iron  ore  of  the  Coal-measures  is  usually 
in  the  form  of  concretionary  masses,  sometimes  closely  aggregated 
into  a  bed  from  a  few  inches  to  three  or  four  feet  thick,  and  some 
times  distributed  through  a  shaly  or  calcareous  layer,  and  often  too 
sparsely  to  be  of  economical  value.  The  ore  is  generally  the  car 
bonate  of  iron,  called  siderite  (or  often  spathic  iroii).  It  contains  as 
impurity  ten  to  thirty  per  cent,  or  more  of  silica  and  other  earthy 
matters,  and  hence  is  called  clay-ironstone. 

The  concreting  took  place  amid  the  sediments,  and  sometimes  through  silica;  and 
hence  a  portion  of  the  sediments  is  included.  Such  ores  are  of  a  bluish-gray  or  drab 
color,  and  are  easily  distinguished  from  other  stones  by  the  weight.  In  the  Coal- 
measures  of  Pennsylvania,  according  to  Lesley,  the  most  valuable  layer  for  its  iron 
ore  is  the  buhrstone  bed,  in  the  Lower  Coal-measures,  between  the  Coal-beds  B  and  C 
in  the  section  on  page  311;  but  at  Johnstown,  on  the  Conemaugh,  the  ore  used  at  the 
iron  works  is  from  a  layer  sixty  feet  above  the  Coal-bed  E.  No  valuable  deposits  are 
known  in  the  anthracite  region. 

Some  of  the  clay-ironstone  has  the  composition  of  limonite,  or  the  hydrous  oxyd  of 
iron:  but,  in  general,  the  limonite  beds  have  been  made  through  the  alteration  of  the 
siderite  (p.  58).  Occasionally,  the  ore  of  the  Coal-measures  is  hematite,  or  the  red 
oxvd  of  iron. 


CARBONIFEROUS  AGE.  319 

The  iron-ore  beds  often  contain  remains  of  plants,  in  the  form  of 
stems  and  leaves  ;  and  the  concretions,  which  are  of  siderite,  and  of 
very  fine  texture,  often  include  portions  of  ferns,  with  even  impres 
sions  of  the  hairs  of  the  surface  well  preserved  ;  and  also  remains 
of  Insects,  Spiders,  Centipedes,  Amphibians,  etc.,  all  wonderfully  per 
fect. 

(a.)  Eastern-border  reyion.  —  In  Nova  Scotia,  at  the  Joggins,  over  beds  in  some 
places  3,000  feet  in  thickness,  regarded  as  Subcarboniferous,  there  are,  according  to 
Logan  and  Dawson,  beds  of  sandstone,  conglomerates,  shale,  impure  calcareous  layers, 
"dirt-beds,"  and  thin  coal-beds,  of  an  aggregate  thickness  of  about  13,000  feet.  Daw- 
son  gives  the  same  as  the  thickness  in  Pictou;  and  Mr.  R.  Brown  makes  the  thickness 
at  Cape  Breton,  above  the  Subcarboniferous,  10,000  feet.  Of  the  13,000  feet  at  the 
Joggins,  Dawson  refers  5,000  to  6,0<K)  feet  to  the  Millstone-grit  horizon;  4,000  feet  to 
the  "  Middle  "  Coal  formation,  or  "  Coal-measures  proper,"  and  3,000  feet,  or  more, 
to  the  "  Upper  "  Coal  formation.  The  last,  or  part  of  it,  he  has  since  referred  to  the 
Permian.  The  Millstone-grit  portion  includes  thick  beds  of  coarse  gray  sandstones, 
containing  prostrate  trunks  of  Coniferous  trees  in  its  upper  and  middle  parts,  with  red 
and  comparatively  soft  beds  in  its  lower;  many  layers  of  coaly  shale  occur  through 
out,  but  no  coal  beds.  In  the  Coal-measures  proper,  there  are  dark-colored  shales  and 
gray  sandstones,  with  no  conglomerates  or  marine  limestones;  they  comprise  several 
coal  beds,  and  many  "dirt-beds."  The  uppermost  series  consists  of  sandstones, 
shales,  and  conglomerates,  with  a  few  thin  beds  of  limestone  and  coal.  Many  of  the 
beds  of  sandstone  and  shale  are  red. 

Over  New  Brunswick,  the  formation  is  little  disturbed;  and,  according  to  Dawson, 
the  thickness  near  Bathurst  is  400  feet.  The  coal  beds  are  very  thin,  and  of  little 
productive  value,  the  thickest  but  two  feet. 

At  the  Joggins,  —  of  the  Cumberland  coal-region,  —  the  main  coal-bed  is  five  feet 
thick,  with  an  intercalated  bed  of  clay,  a  foot  or  less  in  thickness.  At  Pictou,  where 
the  beds  dip  20°,  the  average  thickness  of  the  main  coal  bed  is  38  feet;  159  feet 
below  this,  there  is  the  "deep  seam,"  15 J  feet  thick;  and,  280  feet  still  lower,  the 
"M'Gregor  seam,"  12  feet  thick.  (Dawson.)  Dawson  states  that  there  are  twenty- 
four  feet  of  good  coal  in  the  "main  seam;"  twelve  feet  in  the  "deep  seam."  The 
workings  of  the  "  main  seam  "  are  mostly  confined  to  the  upper  twelve  feet.  The  bed 
dips  under  the  Gulf  of  St.  Lawrence :  its  workable  extent  has  been  estimated  at  thirty 
square  miles.  In  the  Cape  Breton  region,  according  to  Lesley,  there  is,  at  Glace  Bay, 
one  bed  of  coal,  ten  or  eleven  feet  thick,  but  of  very  limited  range ;  another  of  six 
feet;  and  still  another  of  eight  feet,  besides  smaller  seams.  The  whole  workable  area 
has  been  stated  at  250  square  miles. 

The  Rhode  Island  Carboniferous  covers  the  most  of  the  southern  part  of  the  State, 
and  extends  northward,  through  Providence,  to  the  northern  border;  there  it  passes 
into  Norfolk  Count}',  Massachusetts,  and  thence  eastward,  through  Bristol  County  to 
Plymouth  County.  The  exact  limits,  east,  west,  and  north,  have  not  been  made  out, 
the  stratification  of  the  rocks  being  much  obscured  by  displacements  or  flexures  and 
metamorphism.  There  are  conglomerates  and  slates  which  are  supposed  by  Hitchcock 
and  Jackson  to  be  a  part  of  the  formation.  The  quartzose  conglomerate  outcrops  at 
Newport  and  elsewhere,  and  forms  a  bold  feature  in  the  landscape  at  "Purgatory," 
2J  miles  east  of  Newport,  and  at  the  "  Hanging  Rocks."  The  stones  vary  in  size  from 
an  inch  to  a  foot,  or  more.  Associated  with  the  slate,  there  are  beds  of  limestone.  It 
has  been  supposed  that  the  rocks  extend  along  the  valley  of  Blackstone  River  to 
Worcester,  near  which  city  there  are  graphitic  slates. 

The  principal  points  where  coal  outcrops  are  near  Providence,  Cranston,  Bristol, 
Portsmouth,  Valley  Falls,  Cumberland,  and  Newport  (a  thin  bed  outcropping  on  the 
coast),  in  Rhode  Island;  and  in  Raynham,  \Vrentham,  Foxborough,  and  Mansfield  in 
Massachusetts.  The  beds  are  much  broken  and  very  irregular  in  thickness,  owing  to 


320  PALEOZOIC   TIME. 

the  upturning  and  flexures  the  formation  has  experienced ;  and  the  coal  is  an  exceed 
ingly  hard  anthracite,  because  of  the  metamorphism.  Still,  the  slates  often  contain 
fossil  plants,  part  of  which  are  identical  in  species  with  those  of  Pennsylvania.  Xear 
Portsmouth,  at  Aquidneck,  three  beds  are  reported  to  exist,  2  to  20  feet  thick.  ?nd  at 
Case's,  one  of  the  three  is  13  feet  thick;  at  Providence,  one,  of  10  feet:  at  Valley 
Falls,  five,  6  to  9  feet;  at  Cumberland,  two,  15  to  2-3  feet;  near  Mansfield,  several, 
with  the  maximum  thickness  10  feet.  The  earliest  opening  was  made  at  Case's,  near 
Portsmouth,  in  1808. 

(b.)  Appalachian  Reyion.  —  The  Millstone-grit,  at  the  base  of  the  Coal-measures,  in 
Pennsylvania,  is  mostly  a  whitish  siliceous  conglomerate,  with  some  sandstone  1  avers 
and  a  few  thin  beds  of  carbonaceous  shale.  It  overlies  the  Subcarboniferous  shale  or 
sandstone.  At  Tamaqua,  the  thickness  is  1,400  feet;  at  Pottsville,  1,000  feet;  in  the 
Wilkesbarre  region,  200  to  300  feet;  at  Towanda,  Blossburg,  etc.,  where  it  caps  the 
mountains,  it  is  50  to  100  feet  thick  (H.  D.  Rogers). 

In  Virginia,  the  thickness  is  in  places  nearly  1,000  feet;  the  rock  is  mainly  a  sand 
stone,  but  contains  heavy  beds  of  conglomerate.  The  conglomerate  of  the  Subcarbon 
iferous,  in  a  similar  manner,  becomes  an  arenaceous  rock  in  Virginia.  In  Alabama, 
the  rock  is  a  quartzose  grit  of  great  thickness:  it  is  used  for  millstones.  In  Tennessee, 
there  are  two  heavy  beds  of  conglomerate,  with  several  heavv  coal  beds  between  them 
and  below  both,  which  are  generally  referred  to  the  "  False  Coal-measures,"  of  the 
Millstone-grit  epoch,  though  the  relations  of  the  series  with  that  of  Pennsylvania  have 
not  yet  been  determined  by  actual  connected  explorations. 

The  great  Anthracite  region  of  Pennsylvania  is  largely  Lower  Carboniferous.  The 
Upper  Carboniferous  is  present  there  (at  Pottsville,  Shamokin,  and  Wilkesbarre)  up  to 
the  top  of  the  Pittsburg  group  (Lesley);  but  the  rest  does  not  extend  so  far  eastward. 
The  greatest  development  of  the  Lower  coal  is  in  Pennsylvania;  and  of  the  Upper,  in 
the  States  farther  west.  The  highest  beds  in  the  series  appear  to  occur  west  of  the 
Mississippi,  in  Kansas,  where  they  merge  into  the  Permian.  A  section  of  the  Coal- 
measures  in  western  Pennsylvania,  to  the  top  of  the  Pittsburg  bed,  is  given  on  pages 
311,  312.  The  following  is  a  section  of  the  part  above  this  coal-bed,  in  Waynesburg, 
Greene  County,  as  published  by  J.  P.  Lesley,  in  his  work  entitled  "  Manual  of  Coal  and 
its  Topography  "  :  — 

Feet. 

1.  Shale,  brown,  ferruginous,  and  sandy 30 

2.  Sandstone,  gray  and  slaty 25 

3.  Shale,  yellow  and  brown 20 

4.  LIMESTONE,  —  the  Great  Limestone  south  of  Pittsburg  (including  two  Coal 

beds,  2J  feet  and  1  foot) 70 

5.  Shale  and  sandstone 17 

6.  LIMESTONE 1 

7.  Shale  and  sandstone         ...........  40 

8.  Coal 6 

9.  Shale,  brown  and  yellow        ..........  10 

10.  Sandstone,  coarse,  brown    ...........  35 

11.  Shale 7 

12.  Coal .        .        .  1J 

13.  LIMESTONE  4  feet,  shale  4,  LIMESTONE  4,  shale  3 15 

14.  Shale  10  feet,  sandstone  20,  shale  10 40 

15.  Coal 1 

16.  Sandstone  (at  Waynesburg),  with  4  feet  of  shale 24 

The  thickness  in  Pennsylvania,  according  to  Rogers,  is  from  2,500  to  3,000  feet.  The 
anthracite  region,  as  shown  on  the  map,  page  310,  is  divided  into  three  ranges,  a  south 
ern,  a  middle,  and  a  northern.  Near  Pottsville,  the  southern  or  Schuylkill  range  in 
cludes  fifteen  coal-beds,  which  vary  from  three  to  twenty-five  feet  in  thickness:  and  the 
whole  thickness  of  the  coal  is  one  hundred  and  thirteen  feet,  eighty  feet  of  it  market- 


CARBONIFEROUS   AGE.  321 

able.  The  average  amount  for  the  southern  range  is  one  hundred  feet,  and  for  the 
middle  and  western,  sixty  feet  each. 

In  western  Pennsylvania,  where  the  coal  is  bituminous,  the  workable  coal  is  confined 
to  the  beds  A  to  H  of  the  section  on  page  311 ;  and  B,  E,  and  H,  or  the  Mammoth,  Free- 
port,  and  Pittsburg  beds,  are  the  largest  and  best. 

(c.)  Inferior-Continental  Basin.— In  Ohio,  the  Millstone-grit  is  in  some  places  a  coarse 
conglomerate;  but  it  often  rather  abruptly  thins  out,  or  passes  into  sandstone.  In  Ar 
kansas,  it  is  represented  by  a  conglomerate  740  feet  thick  (Lcsquereux). 

The  thin  limestones  of  the  measures  in  Pennsylvania,  Virginia,  and  Tennessee, 
thicken  somewhat  as  we  go  westward,  form  heavy  beds  in  Indiana,  Illinois,  and  west 
ern  Kentucky,  and  occupy  nearly  the  whole  of  the  upper  part  of  the  section  in  Missouri 
and  Nebraska,  where,  on  the  contrary,  the  coal-beds  are  few  and  thin.  Broadhead 
states  that  the  1,900  feet  of  measures  in  Missouri  contain  24|  feet  of  coal. 

The  following  are  regarded  as  the  equivalents  of  the  Mammoth  and  Pittsburg 
beds:  — 

(1.)  Mammoth  Bed  (Second  workable  Pennsylvania  bed).  — The  bed  at  Leonards, 
above  Kittanning,  Pa.  (3^  feet  thick),  etc.;  Mahoning  Valley,  Cuyahoga  Falls,  Chip- 
pewa,  etc  ,  Ohio;  the.  Kanawha  Salines;  the  Breckenridge  Cannel  Coal  and  other  mines 
in  Kentucky,  the  first  (or  second)  Kentucky  bed;  the  lower  coal  on  the  Wabash,  Ind.; 
Morris,  etc.,  111. 

(2.)  Pittsburg  Bed  (Eighth  Pennsylvania  bed).  —Bed  at  Wheeling;  at  Athens,  Ohio; 
the  Pomeroy  bed,  Ohio;  at  Mulford's,  in  Western  Kentucky,  the  eleventh  Kentucky  bed. 


III.    Life. 
1.  Plants. 

The  abundance  of  Fossil  Plants  is  the  most  striking  characteristic 
of  the  Coal  era ;  and  the  remains  are  so  widely  diffused,  and  are  dis 
tributed  through  so  great  a  thickness  of  rock  and  coal,  that  we  may 
be  sure  that  we  have  in  them  a  good  representation  of  the  forest  and 
marsh  as  well  as  marine  vegetation  of  the  Carboniferous  age.  In 
the  marine,  there  is  little  peculiar  to  note.  The  land-plants,  on  the 
contrary,  reveal  an  expansion  of  some  departments  of  the  Vegetable 
kingdom,  which  would  not  have  been  suspected  were  it  not  for  the  evi 
dence  in  the  rocks. 

This  terrestrial  vegetation  began,  as  already  shown,  in  the  Silurian, 
and  was  well  displayed  before  the  close  of  the  Devonian.  The  same 
orders  of  plants  were  represented,  but  by  more  numerous  species. 
These  orders,  as  stated  on  page  268,  included  the  Acrogens,  or  higher 
Cryptogams,  and  the  Gyrnnosperms,  or  lower  Phenogams. 

Of  Acrogens,  there  were  (1)  Lycopods  ;  (2)  Ferns  ;  (3)  Equiseta  ; 
and  of  Gymnosperms,  the  Conifers.  To  these,  the  Carboniferous 
period  adds  the  first  known  of  Cycads,  another  tribe  of  Gymnos 
perms. 

Among  the  lower  terrestrial  Cryptogams,  the  remains  of  Mosses 
have  not  been  found ;  but  of  Fungi  or  Mushrooms  some  evidence  has 
been  obtained.  There  were  no  Angiosperms  and  no  Palms. 

A  general  idea  of  the  character  of  the  vegetation,  and  also  of  the 
21 


322 


PALEOZOIC    TIME. 


scenery  of  the  era,  may  be   gathered  from  the  accompanying  ideal 
sketch,  Fig.  617. 


Although  the  vegetation  was  very  largely  cryptogamous,  yet  it  was 
in  a  great  degree  forest  vegetation.     Should  we  collect  all  the  existing 


CARBONIFEROUS   AGE. 


323 


terrestrial  Cryptogams  of  North  America,  in  order  to  make  a  forest  of 
them,  the  forest  would  hardly  overtop  a  man's  head  ;  and  the  Ferns 
would  have  an  undergrowth  of  Toad-stools,  Mosses,  and  Lichens. 

Tree-ferns,  one  of  which  stands  near  the  middle  of  the  sketch  on 
page  322,  now  grow  only  in  the  warmer  zones  of  the  globe.  The 
largest  modern  Lycopods  are  four  to  five  feet  in  height ;  the  ancient, 
the  features  of  which  are  shown  near  the  sides  of  the  sketch,  were 
sixty  to  eighty  feet.  The  Equiseta  of  our  North  American  marshes 
are  slender,  herbaceous  plants,  with  hollow  stems,  and,  when  of  large 
size,  hardly  three  feet  high ;  the  Calami tes  of  the  Carboniferous 
marshes  had  partly  woody  trunks,  and  some  were  a  score  of  feet,  or 
more,  in  height.  The  damp  forests  of  Caraccas  afford  the  largest  of 
the  modern  Equiseta  ;  and  these  are  thirty  feet  in  height,  but,  unlike 
the  Calamites,  they  are  quite  slender. 

The  Conifers  of  the  period  were  abundant,  and  were  the  modern 
feature  in  the  Paleozoic  forests.  But  these,  like  the  Devonian,  were 


Extremity  of  a  branch  of  Lepidodendron,  with  the  leaves  attached 

in.  the  main  related  to  the  Araucarian  Pines  (see  p.  134),  —  a  group 
which  now  lives  in  Araucania,  Chili,  and  Brazil,  on  the  continent  of 


324 


PALEOZOIC    TIME. 


South  America,  and  in  Australia  and  Norfolk  Island,  in  the  South 
Pacific,  and  which  are  therefore  confined  at  the  present  time  to  the 
Southern  hemisphere. 

1.  Lycopods.  —  The  Lepidodendrids  —  tall  trees,  with  the  exterior 
embossed  with  scars  in  alternate  or  quincunx  order  —  were  of  many 
kinds.  In  foliage,  they  resembled  the  Pines  and  Spruces  of  the  present 
day,  as  illustrated  in  Fig.  618,  representing  the  extremity  of  a  branch, 

Figs.  619-621. 

620 


019 


621 


Fig.  619,  Lepidodendron  aculeatum,  Sternb. ;  620,  Lepidodendron  clypeatum  ;  621,  Ilalonia  pul- 

chella. 

restored.  Leaves  have  been  found,  of  the  slender  kind  here  exhibited, 
over  a  foot  long ;  and,  as  the  scars  are  the  bases  of  the  leaves,  their 
forms  and  crowded  position  on  the  branch  are  no  exaggeration.  Others 

Figs.  622-624. 


Fig.  622,  Sigillaria  oculata  ;  623,  S.  obovata;  624,  Stigmaria  ficoides. 

had  shorter  leaves,  and  a  more  Spruce-like  habit.  The  character  and 
size  of  the  scars  in  some  of  the  species  are  shown  in  Figs.  619jx> 
621. 


CARBONIFEROUS   AGE. 


325 


The  SigiUarids  differed  from  the  Lepidodendrids  in  having  the 
scars  in  vertical  series,  as  shown  in  Figs.  622,  623. 

In  both  the  SigiUarids  and  Lepidodendrids,  the  appearance  of  the 
scars  of  the  same  species  varied  much  with  age ;  and  the  same  scar  is 
wholly  different  in  form  at  surface  from  what  it  is  below  it,  as  shown 
in  Figs.  622  and  623,  in  the  part  of  each  of  which,  to  the  right,  an 
impression  of  inner  surface  of  the  stem  is  shown.  The  trunk,  while 
woody,  was  not  firmly  so  within ;  and  it  had  a  large  pith.  Stumps 
made  hollow  by  decay,  and  now  filled  with  sand  and  clay,  and  fossil 
ized,  are  common  in  the  Coal-measures.  Of  many  such,  there  remain 
only  casts  in  sand,  showing  an  impression  of  the  scarred  exterior. 


Figs.  625-629  A. 


Fig.  625,  Antholithes  priscus  ;  626,  A.  ?    627,  A.  Pitcairneae?    SCARS  OF  TREE-FERNS.  —  Fig. 

628,  Caulopteris  punctata(X  %)',  629,  Megaphytum  McLeayi ;  629  A,  Cyathea  compta. 

The  Stigmarice,  described  on  page  269,  as  the  under-water-stems  of 
SigiUarids  or  Lepidodendrids,  were  often  large,  many  of  the  fossil 
stems  being  four  to  six  inches  in  diameter.  Fig.  624  represents  a  por 
tion  of  a  stem,  with  its  rounded  depressions  or  scars,  to  each  of  which 
there  is  sometimes  a  long  leaf-like  appendage  attached. 

The  accompanying  figures,  from  Newberry,  represent  peculiar  forms 
which  have  been  supposed  to  be  remains  of  flowers,  and  have  hence 


326 


PALEOZOIC   TIME. 


been  called  Antholites.  Newberry  now  regards  the  kind  represented 
in  Fig.  625  as  the  fruit  bearing  stem  of  a  Lycopod,  of  some  yet  un 
determined  kind.  It  is  well  known  that  many  Lepidodendrids  had 


Figs.  630-633. 
£ 


Fig.  630,  Odontopteris  Schlotheimii :  631,  Alethopteris  lonchitiea :  632,  Hymenophyllites  Hil- 
drethi ;  632  a,  portion  of  the  same,  enlarged  ;  633,  Sphenopteris  Gravenhorstii ;  633  a,  portion 
of  the  same,  enlarged. 

long  cones,  much  resembling  those  of  ordinary  Conifers.  Fig.  626 
looks  like  the  incipient  stage  of  the  form  in  Fig.  625.  Hooker  has 
regarded  such  specimens  as  containing  undeveloped  leaf-buds.  Fig. 
627  appears  to  represent  the  fruit  of  some  plant,  but  of  what  there  is 
still  doubt. 

2.  Ferns.  —  The  Ferns  were  mostly  of  the  low  herbaceous  kinds, 
although  Tree-ferns  occurred.  Some  of  the  fronds  were  six  to  eight 
feet  in  length.  Two  large  scars  left  by  the  fallen  fronds  of  a  Tree- 
fern  are  shown  in  Figs.  628,  629,  and  the  form  and  structure  of  a 


CARBONIFEROUS   AGE. 


327 


scar  from  a  modern  species  (resembling  that  figured  near  the  middle 
of  the  sketch,  page  322),  in  Fig.  629  A,  — all  half  the  natural  size. 
The  trunks  of  Tree-ferns  consist  within  of  vertically  plicated  woody 
plates,  with  more  or  less  cellular  tissue  between,  and  not  of  concentric 
rings.  The  twisted  plates  are  well  shown  in  a  transverse  section  of 
a  fossil  trunk  from  the  Coal-measures. 

Figs.  634-641. 


Figs.  634,  634  a,  Neuropteris  Loschii,  parts  of  same  leaflet ;  635,  Neuropteris  hirsuta;  636,  Pecop- 
teris  arborescens  ;  636  a,  a  portion  of  the  same,  enlarged  ;  637,  Cyclopteris  elegans  ;  638,  Aste- 
rophyllites  ovalis,  with  the  nutlets  in  the  axils  of  the  leaves;  639,  A.  sublevis  ;  640,  Sphe- 
nophyllum  Schlotheimii ;  641,  Calamites  cannaeformis ;  641  a,  surface-markings  of  same,  en 
larged. 

The  variety  of  Ferns  was  very  large.  Some  of  the  more  common 
forms  are  shown  in  Figs.  630  to  633,  and  still  others  in  Figs.  634  to 
637. 

3.  Equiseta  or  Horsetails.  —  The  prominent  genus  of  Equiseta  was 
Catamites,  as  in  the  Devonian.  One  of  the  jointed  stems  is  rep 
resented  in  Fig.  641. 


328 


PALEOZOIC    TIME. 


The  AsteropJiylUtes  (Fig.  638)  were  plants  having  the  leaves,  or 
rather  branchlets,  in  whorls  around  the  jointed  stems,  as  in  Calamites  ; 
and  Sphenopltylla  are  others,  like  Fig.  640,  with  the  leaf-like  ap- 
appendages  broader  and  wedge-shaped. 

The  Lepidodendrids  were  especially  characteristic  of  the  Lower 
Coal-measures,  as  well  as  of  the  Middle  and  Upper  Devonian.  The 
Sigillarids  and  Calamites  abound  in  the  Lower,  but  also  run  through 
the  Upper.  The  Asterophyllites  belong  especially  to  the  Upper, 
though  occurring  below. 

4.  Conifers.  —  Coniferous  trunks  and  stumps  are  common  through 
the  Coal-measures.  Cordaites  are  strap-shaped  leaves,  half  an  inch  to 


Figs  042-643. 


342  A  6i2B 


643 


•342  C. 


FRUITS.  — Fig.  642  A,  Cardiocarpus  elongatus  ;  642  B,  C.  bisectus  ;  642  C,  C.  samarseformis.  Fig 
643,  Welwitschia  mirabilis,  showing  transverse  section  of  fruit,  with  the  outline  of  the  fruit 
finished  in  dotted  lines. 

an  inch  and  a  half  wide,  sometimes  short,  as  in  the  Devonian  species 
represented  on  page  269,  and  sometimes  a  foot  or  more  long.  They 
are  often  crowded  together  in  great  numbers  in  the  slates  overlying 
the  coal-beds,  and  are  common  in  other  positions,  thus  showing  that 
they  were  shed  in  great  numbers  by  some  plants  of  the  era.  They 
have  been  referred  both  to  the  Lepidodendrids  and  to  the  Cycads, 
and  by  Schimper  are  embraced  in  Brongniart's  genus  Pycnophyllum, 
under  the  latter  order.  Geinitz  has  observed,  in  Saxony,  and,  later, 
Newberry,  in  Ohio,  the  winged  fruits  of  the  genus  Cardiocarpus 
(Figs.  642  A,  B,  C)  associated  with  the  leaves  of  Cordaites;  and 
both  have  regarded  it  as  highly  probable  that  the  fruit  and  leaves 


CARBONIFEROUS   AGE. 


329 


belong  to  the  same  plant.  The  nut-like  character  of  the  fruit  separates 
Cordaites  widely  from  the  Lepidodendrids ;  and  the  fact  that  the  leaves 
fell  from  the  trees  bearing  them,  instead  of  being  persistent,  and  were 
simple  instead  of  pinnate,  removes  them  from  ordinary  Cycads,  and 
affiliates  the  genus  with  Conifers,  the  other  family  of  Gymnosperms. 
The  South- African  Conifer,  Welwitschia,  has  both  the  broad  strap-like 
leaves  of  Cordaites,  and  also,  as  shown  in  Fig.  643,  the  winged  fruit 
of  Cardiocarpus  ;  sufficient  to  sustain  the  reference  of  the  leaves  and 
•fruit  to  the  Conifers,  notwithstanding  the  anomalous  character  of  the 
African  plant. 

Fig.  644  is  a  view  of  a  large  nut-like  fruit  of  the  genus  Trigono- 


Figs.  644-646  A. 


644a 


6444 


846 


FRUITS.  —  Fig.  644  a,  6,  c,  Trigonocarpus  tricuspidatus  ;   a,  the  exterior  husk  or  rind  ;    b,  the  nut 

separate  from  the  rind  ;  644  c,  kernel ;  645,  nut  of  Trigonocarpus ?  ;  646,  T.  ornatus  ;  646  a. 

vertical  view  of  summit,  showing  the  six  ribs  of  the  surface  ;  646A,  Cardiocarpus  bicuspidatus. 

carpus,  generally  three  or  six-sided,  whose  species  are  common  in  the 
Coal-measures.  Fig.  644  a  is  the  husk ;  b,  the  nut ;  and  c,  the  kernel. 
Fig.  645  is  the  nut  of  another  species.  According  to  Hooker,  the 
Triyonocarpi  most  resemble  the  nuts  of  the  genus  Scdisburia  (of 
China),  of  the  Yew  family. 

Characteristic  Species. 

1.  Lepidodendrids. — Fig.  618,  view  —  partly  ideal — of  the  extremity  of  a  branch 
of  a  Lepidodendron.  The  slender,  pine-like  leaves,  in  the  Lejridodendron  Sternberyii 
Brngt.,  as  shown  in  magnificent  specimens  from  the  coal-mines  of  Radnitz,  in  Austria, 
figured  by  Ettingshausen,  are  over  a  foot  long,  and  are  as  closely  crowded  about  the 
branches  as  in  any  modern  Pine.  Fig.  619,  part  of  the  surface  of  the  Lepidodendron 
nctileatum  Sternb.,  a  common  species  both  in  the  United  States  and  in  Europe.  Fig. 
620,  L  clypeatum  Lsqx.  The  cones  (Lepidostrobus)  found  in  the  same  rocks  with  the 
Lepidodendrci .  are  regarded  as  their  fruit.  They  have  some  resemblance  to  the  cones  of 
Pines.  Fig.  621  represents  a  portion  of  the  stem  of  Halonia  pulchella  Lsqx.,  a  plant 
similar  to  Lepidodendron,  from  the  Coal-measures  of  Arkansas. 

Fig.  625,  Antholithes  pi-iscus  Newb ;  626,  Antholithes,  species  undetermined;  627,  A, 
PitcairnecB  Newb. 


330  PALEOZOIC    TIME. 

2.  Sif/illnrids,  Stigmarice.  —  Fig.  622,  SiyiU'o-ia  oculata  Brngt.,  from  Trevorton,  Pa.; 
623,  S.  obovata  Lsqx.,  from  Pennsylvania  and  Kentucky;  624,  St  iymaria  fcoides  Brngt  , 
portion  of  a  stem,  showing  the  scars  and  the  bases  of  the  root-like  appendages. 

According  to  Carruthers,  who  sustains,  by  his  observations,  the  cryptogamic  character 
of  Siyillarids  and  Stiymariue,  the  fruit  of  the  Sigittaria  is  a  cone  with  a  single  patch  of 
small  sporangia  on  the  enlarged  base  of  the  scale.  Schimper  gives  it  the  name  Siyilla- 
riostrobtu,  and  figures  a  cone. 

3.  Ferns.  — Fig.  628,  the  scar  of  the  Tree-fern,  Cftulopteris  punctata  Lsqx.,  from  the 
Gate  vein,    Pennsylvania  ;  Fig.  629,  same  of  Meynphytum  McLeayi  Lsqx.,  from  Il 
linois.     Fig.  629  A,  scar  of  Cyathea  compta,  a   species   growing  in  the  islands  of   the 
Pacific.     With  the  growth  of  the  tree,  as  new  fronds  are  unfolded,  the  old  ones  drop 
off,  each  of  which  leaves  its  scar.    The  manner  in  which  the  fronds  of  ferns  unroll,  as 
they  expand,  is  shown  in  the  sketch  on  page  322. 

Fig.  630,  portion  of  a  frond  of  Odontopteris  Scltlotheimii  Brngt.,  from  Pennsylvania 
and  Europe;  the  whole  frond  is  tripinnately  divided,  and  of  very  large  size.  This 
genus  is  mostly  of  the  Lower  Coal-measures.  All  the  species  of  Ifyintnophyllites,  with 
several  of  Alethopteris,  Neuropteris,  and  Pecopteris,  are  found  in  the  Lower  Coal. 
Fig.  631,  Alethopteris  lonchitica  Brngt.,  exclusively  of  the  Lower  Coal;  Sphenoj)teris 
tridftctylites  Brngt.  is  also  from  the  Lower  Coal;  Fig.  632,  ffymenophyllites  IliUlrtthi 
Lsqx.,  from  the  Kanawha  Salines,  and  632  «,  the  same,  enlarged;  Fig.  633,  Sphenopteris 
Grarenhorstii  Brngt.,  common  in  Ohio  and  farther  west,  at  the  Gate  Vein,  Pennsylvania, 
and  occurring  also  in  England  and  Silesia;  633  <i,  a  portion  of  the  same,  enlarged. 

Figs.  634,  634  a,  Neuropteris  Loschii  Brngt.,  and  Fig.  635,  Neuropteris  hirsitta  Lsqx. 
from  figures  by  Lesquereux,  both  very  common  in  the  Upper  Coal-measures,  in  Ohio 
and  Kentucky,  and  the  former  particularly  abundant  in  the  Pomeroy  bed;  the  speci 
mens  of  the  latter  are  sparsely  covered  with  hairs,  which  are  well  shown  in  specimens 
from  Morris,  Illinois.  Fig.  636,  Pecopteris  arborescens  Brngt.,  common  in  Pennsylvania 
and  Ohio.  P.  cyathen  Brngt.  and  P.  unita  Brngt.  are  also  common  in  the  United  States, 
occurring  in  the  Rhode  Island  coal-fields  as  well  as  elsewhere.  Alethopteris  Serlii  G<  pp. 
is  another  common  species  of  the  Upper  Coal-measures,  which  is  found  also  in  Europe. 
Fig.  637,  Cyclopteris  eleyans  Lsqx.,  found  in  the  Shamokin  Coal-bed,  Pennsylvania. 

In  Arctic  America,  on  Melville  Island,  impressions  of  a  Sphenopteris  have  been  ob 
served  in  connection  with  the  coal. 

4.  Calamit'uls.  —  Fig.  641  represents  C.  cannceformis  Schloth  ,  one  of  the  Lower  Coal- 
measure  species;  641  a,  surface  markings,  at  a  joint;   C.  Cistii  Brngt.  and  C.  nodosus 
Schloth.   are   other  American  Lower-coal   species,  as  well  as  foreign;   C.  jiachyderma 
Brngt.  is  found  only  in  the  Millstone  grit  (Lesquereux). 

5.  Asterophyllitids.  —  Fig.  639,  Asterophyll/tes  sublevis  Lsqx. ;  Fig.  638,  A.  oralis  Lsqx., 
with  the  nutlets  in  the  axils  of  the  leaves;  Fig.  640,  Sphenophyllum  Schlotheimii  Brngt., 
from  Pennsylvania,  Salem  and  Gate  veins,  and  Pomeroy  beds,  Ohio. 

6.  Gymnosperms.  —  Cordaites  borassifnliit,  Ung.  is  one  of  the  common   species  of  the 
Coal-measures.     Fig.  642  A,  Cordiocarpm  elonyotus  Xewb.,  from  Ohio;  642  B,  C.  bisec- 
tus  Dn.,  from  Nova  Scotia;  642  C,  C.  samircefnrmi*  Newb.,  from   Ohio;  644  ct,  b,  c. 
Triyonocarpus  tricuspidatus  Newb.,  from  Ohio,  representing  the  rind,  the  nut,  and  the 
kernel;  645,  nut  of  another  Ohio  species,  figured  by  Xewberry,  but  not  described;  646, 
T.  ornatus  Newb.,  from  Ohio;  646  a,  view  of  extremity,  showing  the  radiating  ribs; 
646  A,  Cardiocarpus  bicitspidatus'Kewb.,  from  Ohio. 

Fig.  643  represents  the  seed  of  the  Weltvitschia,  now  living  in  southern  Africa.  The 
Wdwltschia  is  an  embryonic  form  of  Conifer;  it  having  (1)  only  two  leaves,  the  coty- 
ledonous,  these  being  persistent,  and  increasing  in  width  and  length  with  the  age  of  the 
plant,  and  (2)  growing  to  a  height  of  only  one  or  two  feet,  but  spreading  sometimes  to 
a  diameter  of  four  feet,  without  bark;  and  (3)  bearing  a  group  of  large  and  beautifully 
regular  cones.  It  would  seem  to  be,  as  Bentham  has  suggested,  a  type  of  Conifer 
handed  down  from  early  geological  time.  But  no  such  trunks  have  been  found  in  the 
Carboniferous  or  later  beds.  Although  probably  unlike  Cordnites  in  its  embryonic 
features,  it  shows  what  leaves  and  fruit  are  consistent  with  the  type  of  Conifers. 

Whittleseya  elegans  Newb.,  striated  leaves  over  ail  inch  wide  and  twice  as  long,  is 
probably  Coniferous,  and  related  to  Cordaites. 


CARBONIFEROUS   AGE.  331 

The  Sternbergice,  which  are  abundant  in  Ohio,  and  at  Pictou,  Nova  Scotia,  have  been 
shown  by  Dawson  and  Williamson  to  be  casts  of  the  pithy  or  open  cellular  interior  of 
either  Conifers  or  Lepidodendrids.  They  are  thick,  cylindrical  stems,  much  wrinkled 
circularly,  consisting  of  the  same  arenaceous  material  as  the  rock  in  which  the}'  occur 
buried.  Occasionally,  they  have  a  carbonaceous  exterior,  which  is  the  woody  part  of 
the  former  tree.  In  Nova  Scotia  specimens,  as  well  as  those  of  England,  a  coniferous 
structure  has  sometimes  been  observed  in  the  coaly  exterior,  and  also  a  very  open  cel 
lular  structure  through  the  sandstone  interior.  One  of  the  Coal-measure  species,  from 
Pictou,  is  not  distinguishable,  in  its  microscopic  structure,  according  to  Dawson,  from 
the  P inites  (Dadoxylon)  Brandlingi  of  Witham. 

7.  Cryptogams.  —  Seaweeds  are  rare  in  the  Coal-measures.  A  Spirophyton,  like  S. 
Cftuda-galli  (p.  254),  has  been  reported  by  Lesquereux  as  occurring  in  sandstone,  prob 
ably  of  this  era,  or  of  the  Subcarboniferous,  in  Crawford  County,  Arkansas.  Species 
of  the  genus  Caulerpites  have  been  observed  in  Pennsylvania,  Illinois,  Indiana,  Mis 
souri,  in  both  the  Lower  and  the  Upper  Coal-measures.  Chondrites  Collet  ti  Lsqx.  was 
obtained  near  Lodi,  Indiana,  overlying  a  thin  coal-bed  at  the  base  of  the  Coal-measures. 
Lesquereux  remarks  that,  although  the  ironstone  concretions  have  preserved  the  most 
delicate  parts  of  Ferns  and  Insects,  no  trace  of  a  Fungus  or  Lichen  has  been  found  in 
them. 

Characteristic  Species  of  some  of  the  Subdivisions  of  the  Carboniferous. 

Lesquereux  enumerates  the  following,  among  the  species  characteristic  of  the  groups 
below  mentioned  :  — 

(a.)  Millstone  Grit. — Lepidodendron,  six  species;  SigiUaria,  two;  Catamites,  two; 
Stigmaria ;  and  the  Ferns,  Pecopteris  velutina  Lsqx.,  P.  nervosa  Brngt.,  Neuropteris 
jiexuosa  Brngt.,  N.  hirsuta  Lsqx.,  Anmdaria  sphenophylloides  Ung.,  Odontopteris  crenu- 
lata  Brngt.,  Hymenophyllitesfurcatus  Brngt.,  Spfienopteris  latifolin  Brngt.,  which  occur 
also  higher,  to  at  least  Coal-bed  No.  1  B. 

(b.)  Mammoth  Bed  (No.  1  B).  —  A  great  number  of  fruits,  including  nearly  all  of  the 
Coal-measures,  of  the  genera  Trigonocarpus,  Cardiac -irpus,  Rhabdocarpus,  and  Carpo- 
lithes;  numerous  Lepidodendra  (eighteen  species);  Alethopteris  lonchitica  and  A.  mar- 
ginata  Gopp.,  not  known  above,  and  species  of  Cnllipteris,  with  few  of  the  finer  forms 
of  the  family,  of  the  genus  Pecopteris  ;  among  which  few  there  are  the  Pecopteris  velu 
tina  Lsqx.,  P.  Sillimani  Brngt.,  P.  plumosa  Brngt. ;  Sphenopteris  family  numerously 
represented,  —  e  g.,  S.  laiifoUa  Brngt.,  S.  obtusiloba  Brngt.,  S.  ylamhdosa  Lsqx.,  8. 
polyphytta  L.  &  H.,  S.  Newberryi  Lsqx  ,  S.  artemisicefolia  Brngt.,  and  Hymenophyllites 
Hildrethi  Lsqx.  and  //.  spinostts  G<  pp.,  all  peculiar  to  it;  all  the  American  species  of 
Odontopteris,  except  0.  crenulnta  Brngt.,  found  also  in  the  Millstone  grit.  Many  Sigil- 
lar'm,  as  8.  stettata  Lsqx..  S.  Serin  Brngt.,  £.  tesselata  Brngt.,  S.  Brochanti  Brngt., 
8.  alveolaris  Brngt.,  and  others,  not  found  above.  The  most  abundant  species  are  the 
omnipresent  Neuropteris  hirsuta  and  N.flexuosa.  There  are  also  species  of  Annularia, 
Sphenophyllum,  AsteropJtyllites,  and  Calfimites ;  and  everywhere  Stiymaria  ficoides. 

(c.)  Con/ No.  4.  —This  bed  is  characterized  by  small  Ferns.  There  are  no  Lepido 
dendra,  but  some  SiyillnruK  ;  and  numerous  species  of  the  Pecopteris  familv ;  also  species 
of  Asterophyllites,  many  of  Neuropteris,  and  several  of  Sphenopteris. 

(d.)  Coal  No.  8,  the  Pittsbury  Co<d-bed.  -There  are  Neuropteris  hirsuta  Lsqx.,  Cor- 
daites  borassifolin  Ung.,  Neuropteris  ftexuosa  Brngt.,  Pecopteris  poly 'morpha  Brngt.,  P. 
arborescens  Brngt.,  P.  cyathea  Brngt.,  Sphenophyllum  emarginatum  Brngt.;  Catamites, 
three  species;  Siyillaria,  one  species;  Lepidodendron,  none.  Neuropteris  Moorii  Lsqx. 
begins  here,  and  has  some  resemblance  to  an  Oolytic  species. 

2.  Animals. 

The  animal  life  of  the  Carboniferous  period  included,  besides 
marine  Invertebrates,  terrestrial  Mollusks,  and  a  large  variety  of 
terrestrial  Articulates,  as  Insects,  Spiders,  Myriapods ;  and,  among 


332 


PALEOZOIC   TIME. 


Fig.  646  B. 


Vertebrates,  besides  Fishes  and  Amphibians,  a  higher  range  of  life, 
in  true  Reptiles.  No  evidence  has  been  obtained  of  the  existence 
then  of  Birds  or  Mammals. 

Among  PROTOZOANS,  of  the  Rhizopod  tribe,  the  little  Fusulina, 
related  to  the  Nummulites  of  a  later  period,  was  a  characteristic  kind. 
The  shell,  as  shown  in  the  annexed  figure  (Fig.  646), 
had  nearly  the  shape  and  size  of  a  kernel  of  wheat.  Fig. 
646  a  shows  the  form  as  seen  in  a  transverse  direction. 
Internally,  it  contains  a  large  number  of  minute  cells,  like 
other  foraminifers.  In  Europe,  it  is  found  only  in  the 
Subcarboniferous. 

The  RADIATES  comprised  Corals  and  Crinoids,  but  of 
less  numbers  than  in  the  Subcarboniferous. 
Among  MOLLUSKS,   Brachiopods    still  far  outnumbered  all  other 
kinds  ;  and  with  them  there  were  some  species  of  Orthoceras,  Nautilus, 
and  Goniatites,  and  other  kinds  of  Paleozoic  type.     But  with   these 
there  were  land-snails,  allied  to  the  modern  Pupa.     Some  of  the  Bra- 
Figs.  647-650. 


BRACHIOPODS.  —  Fig.  647,  Productus  Nebrascensis  ;  648,  Chonetes  mesoloba  ;  649,  Spirifer  camera- 
tus  ;  650,  Athyris  subtilita. 


Figs.  651,  652. 


(if/J 


LAMELLIBRANCHS.  —Fig.  651,  Macrodon  carbonarius;  652,  Allorisma  subcuneata. 


chiopods  are  represented  in  Figs.  647  to  650 ;  among  them,  species  of 
the  genera  Productus  (Fig.  647;  and  Spirifer  (Fig.  649)  were  common. 


CARBONIFEROUS   AGE. 


333 


Lamellibranchs  were  of  many  kinds.    Two  are  shown  in  Figs.  651, 
652. 

The  following  are  figures  of  some  of  the  Gasteropods,  one  excepted, 


Figs.  653-057. 
655 


GASTEROPODS.  — Fig.  653,  Pleurotomaria  tabulati ;  654,  Bellerop'ion  curbonarius  ;  655,  Pleuroto- 
maria  sphferulata ;  656,  Macrocheilus  (?)  fusiformis ;  657,  Dentalium  obsoletum. 


Fig.  654  representing  a  floating  shell  of  the  old  Lower  Silurian  genus 
BeUerophori)  of  the  tribe  of  Heteropods. 

One  of  the  small  land-snails,  or  Pulmonates, 
is  represented,  a  little  enlarged,  in 


Figs.  658-600. 
6*9 


Fig.  658,  —  a  species  found  in  the 


Fig.  661. 


Fig.  658,  Pupa  vetusta  ( X  % ) ! 
659,  P.  Vermilionensi?  ;  660, 
Dawsonella  Meeki. 


Spirorbis 
carbonarius. 


Nova  Scotia  Coal-measures ;  and 
Figs.  659,  660,  show  the  forms  of 
two  others,  from  the  Carboniferous 
of  Illinois. 

Among  ARTICULATES,  the  con 
tinental,  rather  than  oceanic,  char 
acter    of  the    era   is  well   shown.      The  class  of  Worms  included  a 
very  small  species,  having  a  spiral 
shell   (Fig.    661),    and    therefore 
called  Spirorbis,  which  lived  at 
tached  to  the  leaves  and  stems  of 
the  submerged  plants  ;  and,  there 
fore,  since  the  plants  are  not  ma 
rine,  in  the  fresh-water  or  brackish- 
water  basins  of  the  continent.   The 
shell  is  closely  like  that  of  modern 
species  of  the  genus  Spirorbis. 

The  CRUSTACEANS  of  the  era 
included  a  few  Trilobites.  But 
there  were  also  other  kinds  of 
modern  aspect.  Fig.  662  repre 
sents  one,  closely  related  to  the 

modern  Limulus,  or    Horse-shoe  Eupro..ps  Dana> 

Crab,  a  species  of  which  (often  a 


334  PALEOZOIC    TIME. 

foot  long,  apart  from  its  tail  spine)  is  common. on  the  Atlantic  coast 

Figs.  663-667. 


CRUSTACEANS.— Fig.  663,  Acanthotelson  Stimpsoni ;   664,  Palaeocans  typus  (x3);  665,  Anthra- 
palaemon  gracilis.     MYRIAPODS  :  666,  Xylobius  sigillariae ;  667,  Euphoberia  armigera. 


Figs.  668,  668  A. 


Fig.  668,  Eoscorpius  carbonarius;  668  A,  Arthrolycosa  antiquus. 

of  North  America,  south  of  Cape  Cod.     The  specimen  here  figured  is 


CARBONIFEROUS   AGE. 


335 


from  Illinois.  Other  Illinois  species,  of  more  advanced  type,  were 
allied  to  the  Shrimps',  or  Macrural  Decapods ;  Figs.  G64,  GG5  repre 
sent  two  of  this  kind.  Fig.  663  is  a  species  of  Tetradecapod. 

The  MYRIAPODS,  or  Centipedes,  were  of  the  same  tribe  with  the 
modern  lulus,  or  the  cylindrical  Myriapods,  having  two  pairs  of  feet 
to  each  segment  of  the  body.  Fig.  666  represents  a  species  from 
Nova  Scotia,  and  Fig.  667,  one  of  very  large  size,  from  Illinois. 

Figs.  669-671. 


NEUROPTEROUS  INSECTS.— Fig.  669,Miamia  Bronsoni  (x  2);  670, Miamia  Danae.     ORTHOPTERS.  — 
671,  Blattina  venusta. 

SPIDERS  were  represented  by  Scorpions,  and  also  by  true  Spiders. 
One  of  the  Scorpions,  from  Morris,  Illinois,  is  shown  in  Fig.  668,  and 
a  Spider  from  the  same  locality,  in  Fig.  668  A. 

The  INSECTS,  as  gathered  from  American  rocks,  comprised  species 
related  to  the  May-fly  and  others,  among  Neuropters  ;  Cockroaches, 
among  Orthopters.  Fig.  669  represents  one  of  the  Neuropters  related 


336 


PALEOZOIC    TIME. 


to  the  May-flies,  twice  the  natural  size,  from  Morris,  Illinois  ;  and  Fig. 
670,  two  wings  of  another  related  species.  Figure  671  represents 
one  of  the  posterior  wings  of  a  Cockroach,  from  Arkansas.  Morris, 
Illinois,  and  Pennsylvania,  also,  have  afforded  specimens  of  the  Cock 
roach  family.  Other  insects  have  been  found  in  Nova  Scotia.  One, 
called  Haplophlebium  by  Scudder,  resembles  much  that  of  Fig.  599, 
both  in  the  nervures  of  the  wing,  and  in  size  ;  the  expanse  of  wing, 
observes  Dawsou,  was  seven  inches,  —  indicating  a  species  of  May -fly 
much  larger  than  any  now  living.  May-flies  are  the  kind  of  insect 
most  likely  to  be  preserved  in  rock  deposits,  because  they  frequent  wet 
places. 

Passing  to  Vertebrates,  the  class  of  FISHES  had  only  Selachians 
and  Ganoids,  as  in  the  Devonian  ;  and  the  Ganoids  had  still  the  an 
cient  feature  of  vertebrated  tails.  Two  of  these  Ganoids,  one  with  the 

Figs.  673-677. 


GAXOIPS.  — Fig.  673,  Eurylepis  tuberculatus  ;  674,  Coelacanthus  elegans.  SELACHIANS.  —  Fig.  675, 
Petalodus  destructor ;  Fig.  676,  Fin-spine  ;  Fig.  677  a,  b,  Dermal  tubercles  of  Petrodus  occi- 
deiitalL-i. 

vertebral  column  extending  along  the  middle  of  the  tail,  are  illustrated 
in  Figs.  673,  674  ;  they  are  from  a  black  shale  of  the  Coal-measures, 
at  Linton,  Ohio,  where  fossil  species  have  been  found  in  large  numbers. 
Many  teeth  and  fin-spines  of  sharks  occur  in  the  rocks.  A  tooth  of 
one  of  them,  Petalodus  destructor,  of  the  tribe  of  Petalodonts  (so 
named  from  the  broad  leaf-like  form),  is  shown,  one  third  the  natural 
size,  in  Fig.  675  :  it  is  from  Illinois.  A  portion  of  the  fin-spine  of 
another  is  represented  in  Fig.  676.  At  localities  of  this  spine,  there 
are  frequently  bony  pieces.  Figs.  677  «,  b,  which  are  regarded  as  the 
bony  tubercles  with  which  the  surface  of  the  body  was  armed.  Both 
spine  and  tubercles  have  been  referred  to  the  same  species,  Petrodus 
occidentalism 

Among  REPTILES  l  there  were  both  Amphibians  and  true  Reptiles ; 
but  the  former  were  much  the  most  numerous. 


1  The   following   are   the   general    characteristics  of    Reptiles  and   of    their  subdi 
visions  :  — 

Reptiles  are  cold-blooded  animal.-;,   like    Fishes,   but  air-breathing,  like  Birds  and 


CARBONIFEROUS    AGE.  337 

The  Amphibians  were  not  of  the  naked-skinned  kind  of  modern 
time,  but  had  scales,  like  the  Ganoid  Fishes,  and  also  like  most  true 


Mammals.  Unlike  Fishes,  as  stated  by  Gill,  they  have  a  sternum;  a  shoulder-girdle, 
represented  by  a  scapula  and  its  appendages;  two  lungs,  instead  of  an  air-bladder,  each 
with  a  special  canal  communicating  with  the  pharynx;  and  the  lower  jaw  articulated 
with  the  skull  by  the  intervention  of  a  special  bone,  the  <>s  quadratum.  They  are  of 
low  vital  activity,  with  the  temperature  variable  and  in  general  directly  related  to  that 
of  the  surrounding  medium.  The  vertebrae  differ  from  those  of  Mammals,  in  being- 
convex  and  concave  at  the  opposite  ends,  and  in  a  few  cases  concave  at  both  extrem 
ities,  approximating,  in  this  last  case,  to  those  of  Fishes.  The  teeth,  when  set  in  sock 
ets,  never  have  more  than  one  prong  of  insertion,  while  those  of  Mammals  may  have 
two  or  more.  They  are  of  two  types,  which  are  so  fundamentally  distinct  that  they 
require  the  division  of  the  class  into  two  sub-classes. 

I.  AMPHIBIANS.  — Breathing  when  young  (or  in  the  tadpole  state)  by  means  of  gills, 
and.  with  a  few  exceptions,  undergoing  a  metamorphosis  in  which  they  become  gill- 
less.     Heart  with  three  cavities. 

II.  REPTILES.  —  Having  no  gills  at  any  period  of  life,  and  undergoing  no  metamor 
phosis.    Heart  with  three  or  four  cavities. 

I.  AMPHIBIANS  (BATRACIIIANS  of  most  authors). 

In  the  Amphibians,  the  skeleton  is  distinguished  by  having  (1)  two  occipital  condyles, 
for  the  articulation  of  the  head  with  the  body,  one  placed  either  side  of  the  foramen; 
(2)  the  ribs  very  short,  or  rudimentary,  or  wanting;  (3)  the  skull  flat  and  usually 
broad,  and  of  a  loose  and  open  structure.  The  body  in  living  species  is  covered  with  a 
soft  skin,  with  sometimes  minute  scales,  as  in  the  Ccecilians.  In  an  extinct  group,  there 
are  distinct  scales;  and  these  species  in  this  and  other  ways  approach  the  true  Reptiles. 

There  are  three  tribes  among  living  species,  and  a  fourth  of  extinct  species,  if  not 
also  a  fifth. 

1.  CCECILIANS,  or  Snake-like  Amphibians.  —  Body  having  the  form  of  a  snake ;  no  feet. 

2.  SALAM ANDROIDS,  or  Batrachia  Urodela,  —  Body  usually  lizard-like,  or  resembling 
in  form  a  tadpole;  having  short  legs,  as  in  the  Salamanders;  sometimes,  as  in  Siren, 
only  the  two  fore-feet  developed ;  ribs  short.     They  graduate  downward  into  species 
that  keep  their  gills  through  life,  which,  while  perfect  .animals,  are  representatives  of  the 
embryonic  or  young  state  of  the  higher  Amphibians.    In  others,  of  intermediate  grade, 
the  gill-opening  is  retained,  but  not  the  gills.     But,  in  the  large  majority,  the  gills  and 
gill-openings  both  disappear.      Some  species,  like  the  Siredon  or  Axolotl,  of  Mexico, 
Siren  and  Nectvnu  of  the  United  States,  and  Proteus  of  the  Adelsberg  Cave,  Carniola, 
retain  their  gills  through  life. 

The  Menopoma  of  the  Alleghany  region,  like  some  others,  retains  the  gill-openings, 
but  not  the  gills;  the  animals  are  large,  broad  and  flat,  sometimes  over  two  feet  long. 
The  Amphiumn  of  the  Southern  States  also  retains  the  gill-openings.  The  Megalo- 
batrachus  (or  Sieboldia),  of  Japan,  is  closely  related,  although  the  gill-openings  become 
closed  up:  it  is  the  largest  of  the  existing  tailed  Amphibians,  having  a  length  exceed 
ing  three  feet.  The  fossil  Andrias  Scheuchzeri  Tschudi,  of  the  Tertiary,  is  related  to  it. 

The  ordinary  Salamandrids  are  without  gills  or  gill-openings,  in  the  adult  state. 

In  most  of  the  North  American  Salamandrids,  there  are  teeth  on  the  vomer,  and  no 
parotid  gland ;  while  the  species  of  Europe  want  these  vomerine  teeth,  and  have  parotid 
glands. 

3.  BATKACHOIDS  (so  named  from  the  Greek  Barpa^o?,  a  frog),  or  Batrachia  Anoura. 
Body  having  four  long  legs  (the  hinder  the  longer)  and  no  tail,  as  in  the  Toads  and 
Frogs.    The  teeth  are  small,  and  mostly  on  the  roof  of  the  mouth  on  the  vomer,  with 
none  in  the  lower  jaw;  the  vertebrae  are  typically  ten,  but  sometimes  coalesce  so  as  to 
appear  fewer,  the  apparent  number  seldom  exceeding  eight;  the  ribs  are  wanting. 

4.  LABYKINTHODONTS.  —  The  species  of  this  group  of  extinct  Amphibians  resemble 

22 


338  PALEOZOIC   TIME. 

Reptiles.  These  teeth,  moreover,  have  the  labyrinthine  internal  texture 
of  the  teeth  of  Ganoids  (p.  521) ;  and  hence  they  are  called  Labyrin- 

the  Batrachoids,  in  having  (1)  double  occipital  condyles;  (2)  teeth  on  the  vomer;  (3) 
short,  if  any,  ribs;  (4)  usually  large  palatine  openings:  and  they  approach  Saurians  in 
having  (1)  the  teeth  stout  and  conical,  and  set  in  sockets;  (2)  the  body  covered  with 
plates  or  scales;  (3)  the  size  sometimes  very  great.  The  teeth  have  the  labyrinthine 
arrangement  of  the  dentine  and  cement  that  characterizes  the  Sauroid  fishes  among 
Ganoids  (see  Fig.  521),  and  which  is  still  continued  in  that  group  among  the  living 
Gars ;  and  hence  the  name  Labyrinthodonts. 

The  GAHOCEPHALA  are  supposed  to  be  Labyrinthodonts,  while  approaching  Ganoid 
fishes  in  the  sculptured  bony  plates  which  covered  the  head,  and  in  some  other  char 
acters. —  Ex.,  Ai  ctteyosaurus  and  Apateon. 

II.  TRUE  REPTILES. 

The  skeleton  in  the  true  Reptiles  has  (1)  but  one  occipital  condyle  below  the  foramen; 

(2)  a  series  of  ribs;  (3)  a  covering  of  scales  or  plates,  with  rare  exceptions. 
The  existing  species,  and  part  of  the  extinct,  belong  to  three  tribes :  — 

1.  SNAKES,  or  OPHIDIANS.  —  (1)  Body  without  legs,  with  rare  exceptions;  (2)  no 
sternum;  (3)  eyes  without  lids;  (4)  no  external  ear. 

2.  SAUIUANS.  —  Body  (1)  without  a  carapax,  and  with  a  tail;  and  having  (2)  four 
feet  (rarely  two,  or  none);  (3)  a  sacrum  corresponding  to  two  united  vertebra?,  sometimes 
more;  (4)  eyes  with  lids,  or  seldom  without;  (5)  usually  an  external  ear-opening. 

3.  TURTLES,  or  CHELONIANS.  —  Body  having  (1)  a  carapax,  or  shell,  made  of  several 
pieces  firmly  united  ;  (2)  a  very  large  sternum,  forming  the  under  surface  of  the  body; 

(3)  a  horny  beak,  instead  of  teeth;  (4)  an  external  ear  opening;  (5)  neck  and  limbs  very 
flexible. 

Saurians.  —  The  Saurians  vary  in  length  from  a  few  inches  to  fifty  or  more  feet. 
In  some,  the  teeth  are  set  in  sockets,  as  in  the  Thecodont  Saurians  (so  named  from  #T;KT/, 
a  cose,  and  66oC?,  tooth)  and  Crocodilians.  In  others  (Pleurodonts),  the  teeth  are  im 
planted  in  a  groove,  the  outer  border  of  which  projects  more  than  the  inner;  in  others 
(Acrodonts),  they  are  soldered  firmly  to  the  salient  part  of  the  jaw-bone. 

The  prominent  tribes  are  the  following,  beginning  with  the  highest  in  rank:  — 

1.  DINOSAURS  (Seizes,  terrible,  and  <raCpos,  lizard). — Reptiles  of  great  size,  all  now 
extinct,  having  some  mammalian  and  many  bird-like  characteristics:  (1)  the  long  bones 
have  a  medullary  cavity;  (2)  the  pelvic  arch  and  the  hind-feet  are  nearly  as  in  Birds; 
(3)  the  sacrum  consists  of  at  least  four  vertebrae,  a  mammalian  feature;  (4)  the  cervical 
vertebra?  are  convexo-concave,  as  in  Mammals;  (5)  the  lower  jaw  in  some  species  has 
lateral   motion,  for   trittiration.     They  include   the  Meyalosaur  (p    445),   Hykeosaur, 
lyuanodon,  Hadrosaur,  etc. 

2.  CROCODILIANS,  or  Cuirassed  Saurians.  —  Body  having  (1)  a  cuirass,  made  of  bony 
plates:    (2)  large,   conical   teeth,    in   sockets,   in   a  single   row;    (3)  one  jugale;   two 
premaxillary  bones;  (4)  sacrum  formed  in  general  of  two  vertebrae;  (5)  heart  with  four 
cavities;  external   nostrils   at  the  extremity  of  the  snout.     The  modern  species  have 
concavo-coni'tx  vertebra1, — that  is,  the   anterior  face  is  concave  and  the  posterior  con 
vex;  in  others,  of  the  Teleosaur  group,  including  the  extinct  Teleosaurs,  Ilyposaurs, 
etc.,  they  are  biconcave. 

8.  LACERTIANS,  or  Scaly  Saurians. —  Body  having  (1)  corneous  scales;  (2)  the  teeth 
rarely  in  sockets;  (3)  no  jugale;  one  ventricle;  one  premaxillary  bone;  (4)  sacrum 
consisting  of  two  vertebra?,  at  the  most.  The  Lizards,  lyuunas,  and  Monitors  are  the 
types  of  the  tribe. 

A  few  extinct  species  characterized  by  small  scales  are  Thecodonts,  like  the  Croco 
diles,  so  that  they  stand  apart  from  the  Lacertians,  and  are  intermediate  between  them 
and  Crocodilians.  Such  are  the  Thecoduntosaur,  Paleosaitr  and  Proferosaur  (Fig.  697, 
p.  373),  —  among  the  earliest  of  true  Reptiles,  and  the  precursors  of  the  Crocodiles  and 
Dinosaurs. 


CARBONIFEROUS   AGE.  339 

thodont  Amphibians,  or  Labyrintltodonts.  Morris,  Illinois,  has  afforded 
several  specimens  ;  and  one  of  them  is  represented,  twice  the  natural 
size,  in  Fig.  678.  It  had  the  elongated  tail  of  a  Salamander.  The 
orbits  are  very  large,  and  the  teeth  numerous.  The  scales  over  the 
body  were  not  overlapping,  and  appear  to  have  been  most  crowded 
over  the  posterior  part  of  the  body.  Other  related  species  have  been 
detected  among  the  remains  at  Linton,  Ohio  ;  one  is  represented  in 
Fig.  679,  and  some  of  the  vertebras  and  ribs  of  another  species,  in 
Fig.  680.  The  Coal-measures  of  Nova  Scotia  have  afforded  several 
species  of  related  kinds.  One  of  them,  Baphetes  planiceps  Owen,  had 
a  skull  seven  inches  broad. 

The  locality  at  Morris,  Illinois,  from  which  so  many  of  the  species 
above  described  —  both  Articulates  and  Vertebrates  —  were  obtained, 
abounds  in  iron-stone  concretions  of  a  flattened  lenticular  shape;  and 
the  specimens  are  contained  within  the  concretions,  each  having  served 
as  a  nucleus,  about  which  the  concreting  action  went  forward.  The 
figures  of  these  Illinois  species,  with  the  exception  of  Figs.  668  A 
and  669,  are  from  Worthen's  Geological  Report  of  Illinois. 

In  Nova  Scotia,  remains  of  several  of  the  Amphibians  have  been 
found  at  the  Joggins,  in  the  interior  of  Siyillaria  stumps,  which  had 
become  partly  hollowed  out  by  decay  and  afterward  filled  by  sand 
and  mud,  in  the  marsh  or  forest  where  they  stood,  before  their  final 
burial  by  the  deposits  that  were  increasing  around  them.  Figure  614, 
on  page  312,  represents  a  section  of  the  part  of  the  Coal-measures  in 
which  the  stump  was  found  that  gave  up  the  first  three  species  of 
Amphibians.  The  discovery  was  made  by  Dawson  and  Lyell  in  1851. 
Along  with  mineral  charcoal  derived  from  the  wood,  and  the  bones 
of  the  Reptiles,  there  were  taken  from  this  stump  more  than  fifty 
shells  of  the  land-snail  Pupa  vetusta  (Fig.  658),  and  a  Myriapod 

4.  The  Mosfisaurs  (p.  465),  on  the  contrary,  although  of  large  size  (forty  or  more  feet 
long),  had  the  teeth  in  sockets,  four  paddles,  and  the  body  covered  with  bony  scutes. 

Besides  these  tribes,  there  are  two  extinct  groups :  — 

5.  ENALIOSAURS  (from  e^aAio?.  marine,  etc.),  or  Swimming  Saurians.  —  (1)  Furnished 
with  paddles  for  swimming;  (2)  having   the  vertebrae  biconcave,  —  another  fish-like 
characteristic;  (3)  teeth  large,  and  set  in  a  groove.     Ichthyosaur  and  Plesiosaur  were 
the  most  common  genera.     (See  pp.  442,  443.) 

5.  PTEROSAURS  (from  nrepov,  a  wing,  etc.),  or  Flying  Saurians.  —  The  most  common 
genus  was  Pterodactylus,  p.  446.  By  the  excessive  elongation  of  the  little  linger  of  the 
fore-feet,  support  AVES  afforded  to  a  membrane  which  extended  to-  the  tail,  and  made  a 
wing  for  flying.  The  remaining  fingers  were  short,  and  furnished  with  claws.  The 
long,  slender  jaws  were  set  with  a  large  number  of  teeth  in  sockets.  The  bones  were 
hollow  and  light,  as  in  Birds.  They  had  the  habits  of  Bats,  and  wings  of  a  similar 
character.  But,  in  Bats,  all  the  fingers  of  the  hand  but  the  thumb  are  elongated  for  the 
purpose  of  the  wing;  and  the  thumb  alone  is  used  for  clinging. 

Cheloniaiis.  —  The  Turtles,  or  Chelonians,  are  of  two  tribes:  — 

1.  The  Sea-Turtles,  —  furnished  with  paddles,  instead  of  feet. 

2.  The  Land-Turtles,  —  furnished  with  feet. 


340 


PALEOZOIC    TIME. 


Figs.  678-681. 


AMPHIBIANS.  —Fig.  678,  Amphibamus  grandiceps  (X2);  679,  Raniceps  L}-ellii ;  680,  vertebrae  and 
ribs  of  another  species.     ENALIOSAUR.  —  Figs.  681,  681  a  Eosaurus  Acadianus,  vertebra  ( XK)- 


CARBONIFEROUS    AGE.  341 

(Fig.  666),  besides  fragments  of  many  other  specimens  of  the  Pupa, 
and  a  few  individuals  of  the  small  Spirorbis,  represented  in  Fig  661, 
on  page  333.  Dawson  observes  that  the  shells  were  probably  the 
food  of  the  Reptiles,  adding  that  he  has  found,  in  the  stomach  of  a 
recent  Menolranchus  (M.  lateralis  Harlan),  as  many  as  eleven  un 
broken  shells  of  the  fresh-water  snail  PJtysa  heterostropha. 

Such  a  congregation  of  animals  in  a  single  stump  proves,  as  Dawson 
states,  that  the  species  of  the  tribes  represented  were  not  rare  in  the 
marshes  and  forests  of  Carboniferous  Acadia. 

FOOTPRINTS  of  Labyrinthodonts  have  been  found  in  the  Coal- 
measures  of  Pennsylvania,  Indiana,  Illinois,  Kansas,  and  Nova  Scotia  ; 
and  others,  apparently  of  true  Reptiles,  have  been  reported  from 
Kansas. 

TRUE  REPTILES  were  represented,  according  to  specimens  of  ver 
tebrae  from  Nova  Scotia,  by  the  tribe  of  Enaliosaurs,  or  Sea-saurians 
as  the  word  means ;  swimming  species  that  had  paddles  instead  of 
feet.  (Jurassic  kinds  are  represented  in  the  figures  on  pages  442, 
443.)  Fig.  681  a  shows  the  biconcave  form  of  the  vertebrae,  a  fish- 
like  feature,  characterizing  this  tribe  of  Saurians. 

Characteristic  'Species. 

1.  Protozoans — Rl/izopods. — Fig.  646  R,Fusulina cylindnca  Fischer;  F.  gracilis 
M.,  and  F.  robusta  M. ;  considered  varieties  of  one  species  by  Meek.     The  foraminifers 
occur  in  vast  numbers,  almost  making  up  the  limestones  in  some  places,  and  have  been 
observed  in  Ohio,  Indiana,  Illinois,   Missouri,  Nebraska,  and  Kansas.     In  the  United 
States,  the  genus  Fusulina  is  confined  to  the  Coal-measures;  but  in  Russia  it  occurs  also 
in  the  upper  part  of  the  Subcarboniferous  rocks. 

2.  Radiates. —  (a.)  Polyps.  —  The  Corals  Lophophyllum  proliferum  McChesney, 
from  Illinois,     Syrinyupora  mitlt-attenuata  McChesney,  Cftmpophyllnm  torquium  Ow. 
(b.)  Acalephs. —  Ckcetetei    milleporacvus.     (c.)  Echinoderms.  —  Crinoids,  of  the  genera 
Poteriocrimis,  Actinocrinus,  Cyathocrimis,  Zeacrinits,  Erisocrinus,  Scaphiocrinus,  Eupa- 
chycrinus,  Aycissizucrimiz,  etc.;  Echinoidt,  of  the  Paleozoic  genus  Archceocidaris. 

3.  Mollusks.  —  (a.)  Bi'ftchiopocls.  —  Fig.  649,  Spirifer  cnmeratus  Mort.  (S.  Meuse- 
backamtt  R.),  from  the  Lower  and  Upper  Coal-measures,  and  occurring  in  Ohio,  Ken 
tucky,  Indiana,  Illinois,  Missouri,  Iowa,  Kansas,  Texas,  New  Mexico,  and  Utah.     This 
species  is  closely  allied  to  S.  striatus  Sow.  (Figs.  221,  222,  p.  171),  and  is  regarded  by 
some  as  only  a  variety  of  it;  but  it  belongs  exclusively,  in  this  country  at  least,  to  the 
Coal-measures,  and  not  to  the  Subcarboniferous,  in  which  the  S.  striatus  is  found  well 
marked.     Fig.    647,    Productiu   Nebrascensis   Ow.,    from   Illinois,    Kansas,   and    New 
Mexico;  Fig.   648,    Chonetes  mesoloba  N.  &  P.,  a  common  species;  Fig.  650,  Atlnjris 
(Spiriyera)  subtilita  Newb.,  very  common  in  the  Coal-measures,  and  not  known  in  the 
American  Subcarboniferous,  although  reported  from  the  latter  in  England;  there  are, 
however,  Subcarboniferous  forms  distinguishable  with  difficulty  from  it.     Spiriferina 
KentncJcensis  is  an  Upper  Coal-measure  species,  from  Illinois,  Kentucky,  Missouri,  and 
near  Pecos   village,    New   Mexico;    Spiriftr  llneatus    Phill.,    Meekella  strict  to -costala 
White  and  St.  John,  from  Illinois,  Missouri,  and  Iowa;  Syntrielasnia  hemipUcnta  M.  & 
W.,  Illinois  and  Utah;    Orthis  carbonnria  Swallow;  Terebratulfi  bovidens  Mort. ;  Jfemi- 
pronites  crasszis  M.  &H. ;  Cryptacanthia  (  Waldheimia)  compacta  White  &  St.  John. 

The  following  first  appeared  in  the  Subcarboniferous,  and  are  continued  into  the 
Carboniferous:  Proditctus  2^nctatus  (Fig.  596,  p.  300),  P.  com,  P.  muriattus,  P.  semi- 
reticulatus  (Fig.  239,  p.  173),  Spiriftr  lineatus. 


342  PALEOZOIC   TIME. 

(b.)  La mellibranchs.  —  Fig.  051 ,  Macrodon  carbonarius  M.,  Upper  Coal-measures  of 
Kentucky;  Fig.  652,  Allorisma  subcuneata  M.  &  H.,  Kansas;  Aviculopecten  rectilute- 
raria  Cox,  Upper  and  Lower  Coal-measures,  Avicula  ( Gervillia)  longa  M.,  Nuculana 
bellistri'ita  M..  Cardiomorpha  Hfissouriensis  Shum.,  Solenomya  radiata,  Myalina  per- 
attenuata  M.  &  W.,  M.  recurvirostris  M.  &  W.,  Schizodus  amplus  M.  &  \V.,  all  from 
Illinois;  Astartella,  etc.  Entolium  aviculatum  M.,  Kansas;  Pinna  peracutn  Shum., 
Missouri,  Kansas;  Lima  retifera  Shum.,  Kansas;  Mytilus  [Jfodiola  (?)]  Shawneensis 
Shum.,  Kansas;  species  of  Jtfonapteria,  Pseudomonotis,  Placunopsis,  etc.;  Modiola  Wy- 
ominyensis  Lea,  Wyoming,  Pa.;  Naiadites  (Anthracofttera)  carbonaria  Dn.,  Nova 
Scotia;  N.  elonyata  Dn.,  Nova  Scotia;  N.  levis  Dn.,  Nova  Scotia. 

(c. )  Gasteropods. —  Fig.  654,  Bellerophon  carbonarius  Cox  (often  referred  to  B.  Urii 
Fleming),  Upper  Coal.  Kentucky;  Fig.  653,  Pleurotomaria  tabulata  Con. ;  Fig.  655,  P. 
sphcerulata  Con.;  P.  carbonaria,  N.  &  P.,  P.  Grayvillensis  N.  &  P.;  Fig.  656,  Macro- 
cheilus  (?)  fusiformis  II.,  M.  Neicberryi  Stevens,  M.  ventricosus  H.,  Illinois:  Marchi- 
sonia  minima  Swallow,  Missouri;  Fig.  657,  Dentalium  obsoletum  H.,  D.  Meekianum 
Gein.,  from  Nebraska  and  Illinois;  Chiton  carbonarius  Stevens,  Euomphalus  subruyosus 
M.  &  W.,  Loxonema  semicostatum  M.,  Aclis  robusta  Stevens,  Strept«cis  Wldtfitldi  M., 
all  from  Illinois;  Naticopsis  sp.  Also  the  Lund-snail  (Helix  family),  Pupa  vetusta  Dn. 
(Fig.  658),  half  an  inch  long,  from  the  Coal-measures  of  the  Joggins,  Nova  Scotia; 
Fig.  659,  Pupa  Vermi/ionensis  Bradley,  from  Vermilion  County,  Illinois,  in  a  concre 
tionary  limestone ;  Fig.  660,  Dawsonelln  Meeki  Bradley,  from  same  locality. 

(d. )  Cephalopods.  —  Nautilus  Missottriensis  Shum.,  Lower  Coal-measures;  N.  pluni- 
volvus  Shum.,  Upper  Coal-measures;  Goniatites  politus  Shum.,  near  Middle  Coal-meas 
ures;  G.parvus  Shum.,  Upper  Coal-measures;  Orthoceras  aculeatum  Swallow,  Upper 
Coal-measures ;  0.  moniliforme  Swallow,  Upper  Coal  measures,  —  all  from  Missouri : 
0.  faishense  McChesney,  Indiana  and  Illinois;  Nautilus  1'itus  M.  &  W.,  N.  Winslowi 
M.  &  W.,  N.  Lasalltnsis  M.  &  W.,  Goniatites  comjmctus  M.  &  W.,  all  from  Illinois. 

4.  Articulates. — (a.)  Worms.  — Yig.  661,  Spirorbis  carbonarius  Dn.  (Micro- 
clioncJius  carbonarius  Murch.,  Gyromyces  ammonis  Giipp),  attached  to  leaves  and  stems 
of  plants,  in  the  measures  of  all  the  Coal-fields;  Palasodampa  anthrax  M.  &  AV.,  Morris, 
Illinois. 

(b.)  Crustaceans.  —  Phyllopods:  Dithyrocaris  carbonarius  M.  &  W.,  Cera tiocaris  sin u- 
atus  M.  &  W.,  both  from  Illinois.  Trilobites:  Phillipsia  Missouriensis,  P.  major,  P. 
Cliftonensis,  —  all  described  by  Shumard,  —  from  the  Upper  Coal-measures  of  Missouri; 
P.  scitula  M.  &  W.,  common  in  Illinois  and  Indiana.  LlmuUds :  Fig.  662,  Euproops 
Dance  M.  &  W.,  Morris,  Illinois.  Eurypterids:  Diplustylus  Dawsoni  S.,  Nova  Scotia; 
Eurypterus  MazonensisM.  &  W.,  from  Morris,  Illinois.  Osfracoids:  Beyricliia  Americana 
Shum.,  from  Missouri;  Leaia  tricarinata  M.  &  W.,  from  Upper  Coal-measures, 
Illinois.  Tetradecapods :  Fig.  663,  Acanthotelson  Stimpsoni  M.  &  W.,  Morris,  Illinois; 
A.  Eveni  M.  &  W.,  Morris,  Illinois.  Decapods:  Fig.  664,  Pakeocaris  typits  M.  &  W., 
Morris,  Illinois;  Fig.  665,  Anthrapalaimon  aracilis  M.  &  \V.,  Morris,  Illinois. 

(c.)  Myriapods.  —  Fig.  666,  Xylobius  SiyillaricR  Dn.,  from  the  Coal-measures  of  Nova 
Scotia,  and  related  to  the  modern  lulus;  a,  organ  (labrum?}  pertaining  to  the  mouth, 
with  its  palpus,  enlarged:  the  species  must  have  burrowed  into  the  interior  of  the  Siyil* 
laria  trunk  in  which  it  was  found  (Dawson);  X.  similis  Scud.,  ibid.;  X.fractus  Scud., 
ibid.;  X.  Dawsoni  Scud.,  ibid.;  Archiulus  xylobioides  Scud.,  ibid.;  Fig.  667,  Eitpho. 
beria  armif/era  M.  &  W.,  Morris,  Illinois;  E.  major  M.  &  W.,  Morris,  Illinois;  An- 
thracerpes  ty/ntsM.  &  W.,  Morris,  Illinois. 

(d. )  Spiders.  —  Fig.  668,  Eoscorpins  carbonarius  M.  &  W.,  Morris,  Illinois;  a.  Comb- 
like  organ;  Mazmiia  Woodiana  M.  &  W.,  Morris,  Illinois;  Architarbus  rotundatus  Scud, 
allied  to  the  Phalnnyidce,  Morris,  Illinois;  Fig.  668  A,  Arthrolycosa  antiqims  Harger,  a 
spider,  from  Morris,  Illinois,  allied  to  the  Protolycosa  of  Rcemer  in  having  a  jointed 
abdomen  and  in  other  points;  the  generic  name,  signifying  a  jointed  Lycosa  or  Taran 
tula,  alludes  to  this  Paleozoic  feature. 

(e.)  Insects. — 1.  Orthopters,  related  to  the  Cockroach  (Blatta).  Fig.  671.  Bluttlnn 
venusta  Lsqx.,  from  the  Coal-measures,  at  Frog  Bayou,  Arkansas;  a  similar  wing, 


CARBONIFEROUS  AGE.  343 

possibly  the  same  species,  has  been  found  by  Moore,  near  Pittsburgh,  Pennsylvania. 
Archimylacris  Acadicus  Scud  ,  East  River,  Pictou,  Nova  Scotia;  Mylacris  anthracopliila 
Scud.,  Morris,  Illinois. 

2.  Neuropters.  —  Yig.  669,  Miamia  Bronsmii  D.,  twice  the  natural  size,  Morris,  Illi 
nois;  Fig.  670,  M.  l}nnce  Scud.,  Morris,  Illinois;  flemeristia  occidentals  D.,  ibid.; 
Ilaplophlefnum  Barnes'd  Scud.,  Little  Glace  Bay,  Cape  Breton,  Nova  Scotia;  Chrestotes 
lapidea  Scud.,  Morris,  Illinois;  Megathtntomum  pustulatum  Scud.,  a  delicate  wing,  two 
inches  in  breadth,  from  Morris,  Illinois;  Eupheme^ltes  simplex  Scud.,  E.  yiyas  Scud., 
and  E.  affinis  Scud.,  from  Morris,  Illinois. 

5.  Vertebrates.—  (a.)  Fishes.  —  Fig.  673,  Eurylepis  tuberculatus  Newb.;  and 
Fig.  674,  Ccelacanthus  elegans  Newb.,  —  both  Ganoids  from  the  Coal-measures  at  Linton> 
Ohio :  the  latter  is  remarkable  for  not  having  the  tail  heterocercal,  although  strictly 
vertebrated.  Eight  other  species  of  Eurylepis,  two  of  Caslocanthus,  and  three  of  Rhizo- 
dus,  have  been  described  by  Newberry  from  Linton.  Other  Ganoids  occur,  of  the 
genera  Megalichthys,  Palceoniscus,Amblypterus<  and  Pyyoptcrus,  in  the  Coal  measures  of 
the  United  States  and  Nova  Scotia. 

Among  Selachians,  the  following  European  genera  have  been  recognized  in  the  Coal- 
measure  limestones  of  Pennsylvania,  Ohio,  Indiana,  Illinois,  etc.,  — the  species  being 
generally  distinct  from  those  of  the  Old  World  :  1.  HYBODOXTS:  genera  Dlplodus  and 
Cladodus ;  Dlplodus  compressus  Newb.,  Linton,  Ohio;  D.  latus  Newb.,  ibid.;  D.  yracilis 
Newb.,  ibid.  ;  2.  PETALODOXTS:  genera  Petalodus,  Ctenoptycliius,  Chomatodus ;  Fig. 
675,  Petalodus  destructor  N.  &  W.,  from  Illinois ;  677  a,  677  b,  Petrodus  occidentalis  N. 
&  W.  from  Illinois,  Indiana,  etc.;  676,  lin-spine  found  associated  with  the  scales  of 
Petrodus  occidentalis,  and  referred  by  F.  H.  Bradley  to  the  same  species.  Also  Ortha- 
cnnthus  arcuatus  Newb.,  Linton;  Co-mpsacanthus  levis  Newb.,  Linton;  Drepanacanthus 
anceps  N.  &  \V.,  from  Springfield,  Illinois. 

(b.)  Reptiles. — Amphibians. — Fig.  679,  Raniceps  Lyellii  Wyman,  found  by  Dr. 
Newberry,  along  with  fossil  fishes,  at  Linton,  Ohio:  Fig.  678,  Amphibamus  grandiceps 
Cope,  from  Morris,  Illinois;  Fig.  680,  vertebrae  and  ribs,  of  a  species  figured  by 
Wyman,  but  not  named,  from  Linton,  Ohio.  £aphetesplaniceps  Owen,  from  Pictou, 
Nova  Scotia;  the  specimen  is  a  portion  of  the  skull,  seven  inches  broad;  Dendrerpeton 
Acadianum,  found  in  the  stump  of  a  Siyillaria  at  the  Joggins  (p.  339),  probably  about 
two  and  a  half  feet  long,  and  having  the  body  covered  Avith  scales,  and  the  whole  sur 
face  of  the  cranium  sculptured;  D.  Otveni  Dn.,  ibid.;  Hylonomus  Lyelli  Dn.,  ibid.; 
H.  aciedentatusDn..  ibid.;  H.  WymaniDn.,  ibid.;  Hylerpeton  Dawsoni  Owen,  ibid. 

Amphibian  footprints  have  been  observed  in  the  Coal-measures  of  Pennsylvania, 
Kansas,  Indiana,  and  Nova  Scotia.  Near  Westmoreland,  Pa.,  in  a  layer  situated  about 
100  feet  below  the  horizon  of  the  Pittsburg  coal,  Dr.  A.  T.  King  counted  twenty-three 
consecutive  steps  of  one  individual,  which  he  named  Thendrojws  heterodactylus ;  the 
tracks  of  the  hind-feet  five-toed,  and  of  the  fore  feet  four-toed, — the  former  five 
and  a  half  inches  long,  and  the  latter  four  and  a  half  inches;  and  the  distance  between 
the  successive  tracks  six  to  eight  inches,  and  between  the  two  lines  about  the  same. 
Another  species  from  the  same  region  is  the  Cheirotherium  Reiteri  of  Moore. 

Enaliosaurs.  —  Fig.  681,  vertebra  of  Eosnurus  Acadinnus  Marsh,  reduced  to  one  half 
the  natural  size,  being  one  of  two  united  vertebrae  found  by  Marsh  at  the  Joggins, 
Nova  Scotia,  5,000  feet  below  the  top  of  the  Coal -measure  series;  681  a,  transverse 
section  of  same,  showing  its  biconcave  character.  The  resemblance  to  the  vertebra  of 
an  Ichthyosaurus  (Fig.  807,  p.  442),  is  close;  and,  from  the  depth  of  its  concavities,  the 
animal  is  supposed  by  Marsh  to  have  been  one  of  the  most  fish-like  of  the  tribe.  Hux 
ley  has  suggested,  in  view  of  the  characters  of  the  Antlimcosaurus  Russelli  of  the  Brit 
ish  Coal  fields,  described  by  him,  that  the  animal  may  have  been  a  Labyrinthodont  with 
biconcave  vertebrae.  Marsh  has  given  reasons  for  holding  to  his  first  opinion  that  the 
species  was  an  Enaliosaur. 


344 


PALEOZOIC    TIME. 


2.  COAL-MEASURES  OF  FOREIGN  COUNTRIES. 
I.  Distribution  of  the  Coal-measures. 

The  Coal-formation   in  Europe  has   great  thickness  of  rocks   and 
coal  in  Great  Britain,  much  less  in  Spain,  France,  and  Germany,  and 

Fig.  681  A. 


Fig.  681  A,  Geological  Map  of  England.  The  areas  lined  horizontally  and  numbered  1  are  Silurian. 
Those  lined  vertically  (2),  Devonian.  Those  cross-lined  (3),  Subcarboniferous.  Carboniferous 
(4),  black.  Permian  (5).  Those  lined  obliquely  from  right  to  left,  Triassic  (6),  Lias  (7a),0blyte 
(7 b),  Wealden  (8),  Cretaceous  (9).  Those  lined  obliquely  from  left  to  right  (10,  11),  Tertiary.  A 
is  London,  B,  Liverpool,  C,  Manchester,  D,  Newcastle. 

a  large  surface,  with  little  thickness  or  coal  in  Russia.     It  exists,  also, 


CARBONIFEROUS   AGE.  345 

and  includes  workable  coal-beds,  in  China,  and  also  in  India  and 
Australia ;  but  part  of  the  formation  in  these  latter  regions  may  prove 
to  be  Permian.  No  coal  of  this  era  has  yet  been  found  in  South 
America,  Africa,  or  Asiatic  Russia. 

The  proportion  of  coal-beds  to  area  in  different  parts  of  Europe 
has  been  stated  as  follows :  in  France,  1-1 00th  of  the  surface  ;  in 
Spain,  l-50th;  in  Belgium,  l-20th  ;  in  Great  Britain,  1-1  Oth.  But, 
while  the  coal-area  in  Great  Britain  is  about  12,000  square  miles, 
that  of  Spain  is  4,000,  that  of  France  about  2,000,  and  that  of  Bel 
gium  518. 

The  distribution  of  the  Coal-measures  over  England  is  shown  on  the  accompanying 
map,  the  black  areas,  numbered  4,  representing  them.  The  Coal-measures  appear  over 
a  broad  region  running  north-northeast  across  from  South  Wales  to  the  northeast  coast, 
where  is  the  Newcastle  basin.  The  principal  regions  are  the  South  Wales,  000,000 
acres  in  area,  and,  in  nearly  the  same  latitude,  the  Forest  of  Dean,  west  of  the  Severn, 
and  the  region  about  Bristol,  east  of  the  Severn;  the  small  patches  in  central  England, 
in  Worcestershire,  Shropshire  (Coalbrook  Dale),  Warwickshire,  Leicestershire,  and  Staf 
fordshire;  north  of  these,  the  great  Lancashire  region,  east  of  Liverpool,  with  the 
basin  of  Flintshire  on  the  Dee,  the  whole  together  over  500,000  acres;  a  little  to  the 
east,  the  Derbyshire  coal  region,  between  Nottingham  and  Leeds,  and  adjoining  Shef 
field  (covering  parts  of  Nottinghamshire,  Derbyshire,  and  Yorkshire),  550,000  acres  in 
area;  farther  north,  a  patch  on  the  western  coast,  in  Cumberland,  about  Whitehaven, 
etc.;  and,  on  the  eastern  coast,  the  great  region  of  Newcastle,  500,000  acres  in  area. 

In  Scotland,  the  beds  cover  an  area  of  about  two  thousand  square  miles,  and  lie  be 
tween  the  Grampian  range  on  the  north  and  the  Lammermuirs  on  the  south. 

In  Ireland,  there  are  several  large  coal-regions,  —  that  of  Ulster,  to  the  north,  esti 
mated  at  500,000  acres;  of  Connaught,  also  in  the  north,  200,000;  of  Leinster  (Kil 
kenny),  in  the  southeast,  150,000;  of  Minister,  on  the  west,  south  of  Galway  Bay, 
1,000,000. 

Ramsay  observes  that  all  the  coal-areas  of  England  were  once  one 
great  coal-field  ;  in  other  words,  that  they  were  made  in  one  con 
tinuous  area  of  marshes  and  inland  lakes.  He  also  thinks  it  probable 
that  the  coal-area  of  the  lowlands  of  Scotland  was  originally  part 
of  the  same  great  basin. 

The  first  stratum  in  the  Carboniferous  series,  over  the  Subcarbon- 
iferous,  is  the  Millstone-grit,  —  as  in  Pennsylvania. 

In  South  Wales,  the  thickness  of  the  Coal-measures  is  7,000  to 
12,000  feet,  with  more  than  one  hundred  coal-beds,  seventy  of  which 
are  worked:  that  of  the  Millstone-grit  is  400  to  1,000  feet. 

In  the  Fore st-of- Dean,  the  Coal-measures  have  a  thickness  of  2,400 
feet,  and  include  at  lea^t  twenty-three  coal-beds,  and  the  Millstone- 
grit  455  feet :  while  in  the  Bristol  coal-iield,  the  other  side  of  the 
Severn,  there  are  5,090  feet  of  Coal-measures,  with  eighty-seven  coal- 
beds,  according  to  Prestwich  ;  but  a  middle  portion,  called  the  Pennant 
series,  1,725  feet  thick,  consists  largely  of  sandstone,  and  contains  only 
five  coal-beds.  Below,  there  are  nearly  1,000  feet  of  Millstone-grit, 
which  is  partly  red  sandstone. 


346  PALEOZOIC   TIME. 

In  the  Lancashire  Coal-region,  which  reaches  nearly  to  Liverpool, 
the  Coal-measures  are  stated  to  have  a  thickness  of  7,200  feet,  and  to 
include  over  forty  beds  of  coal  over  one  foot  in  thickness,  and  the 
Millstone-grit  of  3,500  to  5,500  feet. 

The  Lancashire  area,  and  the  Cumberland,  farther  north,  lie  on  the 
west  side  of  an  anticlinal  ridge,  mostly  of  Subcarboniferous  and  Lower 
Carboniferous  rocks,  called  the  Pennine  chain,  in  some  points  2,000 
feet  high,  which  extends  north  to  the  Cheviot  Hills,  between  England 
and  Scotland.  The  Derbyshire  and  Newcastle  areas  are  to  the  east 
of  this  anticlinal.  In  the  former,  the  thickness  of  the  Coal-measures 
is  less  than  4,000  feet,  of  which  nineteen  beds  are  of  coal,  and  that  of 
the  Millstone-grit  is  about  350  feet.  In  the  latter,  the  Coal-measures 
are  about  2,000  feet  thick,  and  include  about  sixty  feet  of  coal,  and 
the  Millstone-grit  is  a  little  over  400  feet  thick  :  the  beds  afford  about 
a  fourth  of  the  coal  of  England. 

In  the  south  of  Ireland,  the  Coal-measures  contain  300  feet  of 
Lower  shales,  500  of  the  flagstone  series,  and  1,800  of  shales,  sand 
stones,  etc.,  with  coal ;  and,  in  the  north  of  England,  there  are  500 
feet  of  Millstone  grit,  beneath  2,000  of  Coal-measures. 

Ramsay  has  stated  that,  under  Permian  and  Triassic  strata,  north 
of  the  Bristol  coal-field,  there  may  probably  be  about  55,000  millions 
of  tons  of  coals  available,  at  all  events  at  less  than  4,000  feet  in 
depth  ;  and  to  this  Mr.  Prestwich  has  added  400  millions  of  tons  for 
the  Severn  valley,  on  the  south  side  of  the  estuary. 

The  coal-workings  are  carried  on  in  most  of  the  British  mines  by  a  regular  system  of 
deep  mining.  At  Whitehaven,  the  mines  reach  out  far  under  the  sea.  All  coal-beds,  a 
foot  thick  and  within  4,000  feet  of  the  surface,  are  regarded  by  Ramsay  as  economically 
workable;  and,  on  this  as  a  basis,  he  calculates  that  the  amount  of  coal  available  is 
80,000,000,000  of  tons.  In  1870,  110,000,000  tons  of  coal  were  raised. 

It  is  believed,  with  apparently  good  reason,  that  the  Coal-measures,  with  their  many 
coal-beds,  may  exist  beneath  the  region  of  Permian  rocks  numbered  6  in  the  map  on 
page  344,  and  perhaps  farther  to  the  southeastward. 

The  coal  of  England,  Scotland,  and  Ireland  is  mainly  bituminous  or  semi-bituminous. 
Anthracite  occurs  in  South  Wales,  especially  its  western  part,  and  also  in  the  mines  of 
southern  Ireland  (Cork.  Kerry,  Limerick,  and  Clare);  but  this  variety  is  in  general  less 
hard  and  more  inflammable  than  that  of  Pennsylvania. 

The  following  are  the  principal  coal-mines  of  the  countries  of  Europe:  — 

FKANCE.  —  Basin  of  the  Loire  (St.  Etienne);  containing  eighteen  beds  of  bituminous 
coal,  and  also  some  anthracite;  Moselle  (Saarbriick);  Burgundy;  Languedoc;  Pro 
vence;  Limousin;  Auvergne;  Brittany. 

BELGIUM.  —  Liege  Coal-field,  —  the  eastern  division,  about  100,000  acres;  Hainault 
Coal-field,  —  the  western  division,  200,000  acres. 

GERMANY.  — Basin  of  the  Saar,  tributary  to  the  Moselle,  on  the  borders  of  France 
(the  Saarbriick  Coal-field);  Basin  of  the  Ruhr,  tributary  to  the  Rhine,  near  Dusseldorf 
(Dortmund  and  Westphalian  Coal-fields),  —  the  eastern  extension  of  the  Belgian  region. 
In  Saxony,  near  Zwickau  and  Dresden. 

AUSTRIA.  —  Bohemia,  south  of  the  Erzgebirge  and  Riesengebirge,  and  reaching  into 
Silesia. 


CARBONIFEROUS   AGE.  847 

SPAIN.  —  In  the  Asturias  (largest);  near  Cordova;  Catalonia  (small). 

PORTUGAL.  —  Near  Coimbra. 

RUSSIA.  —  The  Millstone-grit,  according  to  Murchison,  occurs  along  the  west  flank  of 
the  Ural,  and  to  the  southward  in  the  region  of  Donetz,  where  there  is  some  coal.  But 
the  great  Carboniferous  area  of  Russia  is  mainly  a  region  of  Subcarboniferous  lime 
stone;  and  the  true  Coal-measures  are  almost  wholly  wanting  beneath  the  wide  spread 
Permian  beds.  The  Permian,  Carboniferous,  Devonian,  and  Silurian  beds,  which  are 
spread  out  nearly  horizontally  over  the  vast  Russian  plains,  are  folded  up  in  the  Urals 
and  partly  metamorphosed,  the  making  of  these  mountains  having  taken  place  after 
the  Permian  era. 

Prestwich  observes,  with  regard  to  a  close  parallelism  in  the  several 
coal-beds,  between  the  different  British  coal-fields,  and  between  these 
and  European  coal-fields,  that,  while  this  is  not  to  be  looked  for,  some 
general  relations  may  be  made  out.  The  great  dividing  mass  of  rock, 
2,000  to  3,000  feet  thick,  called  Pennant,  exists  in  both  the  Welsh 
and  Bristol  coal-fields  ;  and  the  total  thickness  is  not  very  different 
in  the  two  —  about  10,500  feet  in  one  and  8,500  in  the  other,  with 
seventy-six  coal-beds  in  Wales,  arid  fifty-five  in  Somerset.  In  the 
Hainault  (or  Mons  and  Charleroi)  basin,  the  measures  are  9,400  feet 
thick,  with  one  hundred  beds  of  coal ;  in  the  Liege  basin,  7,600  feet, 
with  eighty-five  beds  ;  in  Westphalia,  7,200  feet,  with  one  hundred 
and  seventeen  beds.  Prestwich  adds,  further,  that  the  earliest  British 
coal-beds  are  to  the  north,  where  they  occur  low  down  in  the  Subcar 
boniferous  limestone  ;  but  there  the  later  are  wanting ;  while  to  the 
south,  coal-beds  appear  first  above  the  Millstone-grit,  and  the  mak 
ing  of  coal-bed  debris  continued  long  after  it  had  ceased  to  the  north. 
Moreover,  in  Britain,  the  northern  Coal-measures,  excepting  the  Lan 
arkshire,  are  not  half  the  thickness  of  the  southern,  and  for  the  most 
part  hardly  one-fourth. 

II.  Life. 
1.  Plants. 

The  same  genera  of  plants  are  represented  among  the  European 
coal-beds  as  occur  in  America  ;  and  very  many  of  the  species  are  iden 
tical.  In  this  respect,  the  vegetable  and  animal  kingdoms  are  in  strong 
contrast ;  for  the  species  of  animals  common  to  the  two  continents  have 
always  been  few. 

The  following  table  contains  the  number  of  species  of  the  different 
genera  of  coal-plants  peculiar  to  each  continent,  North  America  and 
Europe  (Britain  included),  and,  in  another  column,  those  common  to 
both. 


348 


PALEOZOIC    TIME. 


Genera  of  Coal-Plants. 

Species  peculiar 
to  the 
Uuited  States. 

Species  peculiar 
to  Europe. 

Species  common 
to  both 
Continents. 

I.  Equisetites  Sternb. 

4 

3 

1 

Calamites  Suck. 

1 

6 

Asterophyllites     Brngt.   (Calamo- 

3 

5 

Calamostachys  Schp. 

1 

3 

3 

Huttonia  Sternb  

1 

Macrostach\rs  Schp.   . 

1 

TV  rni'i    f?ihti 

1 

1 

1 

Sphenophyllum  Brngt. 

2 

tt 

Annularia  Brnyt.  .... 

2 

4 

II.  Sphenopteris  Brngt.  . 

14 

48 

22 

Eremopteris  Schp. 

1 

Steffensia  Gopp. 

1 

Adiantites  Gopp.   .... 

5 

1 

Neuropteris  Brngt. 

20 

8 

16 

Odontopteris  Brngt. 

9 

3 

6 

Lescuropteris  Sctip.    . 
Callipteris  Brngt  
Cyclopteris     Gopp.      (Palreopteris 

1 
1 

2 

'  Schp.,  Noeggerathia  Lsqx.  ) 

5 

2 

3 

Triphyllopteris  Schp. 

1 

Rhacopteris  Schp. 

1 

Pecopteris  Brnyt. 

15 

37 

25 

Goniopteris  Presl.  .... 

1 

5 

Phyllopteris  Dn. 

1 

Alethopteris  Sternb. 

10 

5 

5 

Neriopteris  Neiab. 
Beinertia  Gopp,      .... 

1 

1 

1 

Staphylopteris  Presl. 

5 

Asterocarpus  Gopp. 
Oligocarpia  Gopp. 

1 

1 

1 
1 

Hawlea  Corda        .... 

1 

Dictyopteris  Gutb. 

2 

3 

1 

Lonchopteris  Brngt. 

1 

5 

Schizopteris  Brngt.    . 

1 

Rhacophyllum  Schp. 

5 

1 

5 

Pachypteris  Brngt.     . 

1 

Rhizomopteris     Schp.     (Stigmari- 
oides  Lsqx.)       .... 

8 

2 

Caulopteris  L.  tf  H.  . 

3 

Stemmatopteris  Cordci  . 

5 

2 

Megaphytum  Art. 

4 

4 

Psaronius  l  Coitd  .... 

10? 

2 

III.  Lycopodites  Auct. 

3 

8 

1 

Lepidodendron  Sternb.  . 

21 

30 

7 

Ulodendron  Rhode     . 

1 

6 

2 

Knorria  Sternb  

2 

Lepidophloios  Sternb. 

8 

3 

1 

Halonia  L.  cf  H.    . 

1 

6 

1 

Cyclocladia  Goldenb. 

1 

Lepidostrobus  Brngt. 

14 

9 

4 

Lepidophyllum  Brngt. 

7 

1 

4 

1 

Antholithes  L.  cf  H.   . 

5 

3 

Psilophyton  Dn.     .... 

1 

Psilotites  Goldenb. 

1 

Sigillaria  Brngt.    .... 

18 

44 

23 

Sigillarioides  Lsqx.     . 

2 

Stigmaria  Brngt  

(> 

3 

Pinnularia  L.  d-  It.     . 

7 

1 

1  American  species  are  not  as  yet  positively  studied:  from  specimens  collected  in  large 
numbers  ten  to  fifteen  species  are  recognized  (not  described).    (Lesquereux.) 


CARBONIFEROUS   AGE. 


349 


Genera  of  Coal  Plants. 

Species  peculiar 
to  the 
United  States. 

Species  peculiar 
to  Europe. 

Species  common 
to  both 
Continents. 

Diploxylon    Corda 

1 

2 

IV.  NceggeVathia  Sternb. 
Whittleseya  Newb. 

1 

1 

4 

1 

Cordaites"   Uny.     (Pycnophyllum 
Brnyt.,  Flaoellaria  Mernfr.)    . 

3 

1 

2 

Trigonocarpus  Brnyt.     . 

16 

4 

7 

Rhabdocarpus  Gopp.  $  Bert/.     . 

10 

11 

5 

Cardiocarpus  Brnyt.      . 

13 

3 

1 

Ptilocarpus  Lsqx. 

3 

Carpolithtis  Sternb. 

14 

4 

1 

Polysporia  Newb. 
Walchia  Sternb  

1 
2 

Araucaroxylon  Kraus  (Dadoxylon 

Endlingtr)      .... 

3 

10 

V.  Spirangium     Sclip.       (Palaeoxvris 

Brnyt.}        .         .         .         .         . 

3 

1 

The  genera  Calamites,  Sphenopteris,  Pecopteris,  Lepidodendron.  and 
SigiUaria  have  much  the  largest  number  of  species  in  Europe. 

According  to  this  table,  — for  which  the  work  is  indebted  to  Professor  L.  Lesquereux, 
—  there  are  in  all,  exclusive  of  fruits,  about  four  hundred  and  thirty-four  known  Amer 
ican  species,  and  four  hundred  and  fort}'  European  (and  British);  and,  of  these,  one 
hundred  and  seventy-six  are  common  to  the  two  continents.  In  other  words,  about  two 
jtfths  of  all  the  American  species  were  growing  also  in  the  Carboniferous  forests  of  the 
other  continent. 

The  type  of  Cycads  was  represented  in  Europe  by  pinnate  leaves 
of  Mesozoic  genera.  Geinitz  has  described  one  species,  near  Ptero- 
phyllnm  inflexum  Eichw.,  as  occurring  near  Barnaoul,  in  the  Altai, 
along  with  the  Carboniferous  plants,  Lepidodendron  Serlii  Brngt., 
Nceggerathia  cequalis  Gopp.,  N.  distans  Gopp.,  Sphenopteris  anthrisci- 
folia  Gopp.,  etc.  lie  proposes  for  it  the  name  Pt.  Altaense.  Another 
related  Pterophyllum  has  been  announced  by  Sandberger  as  found 
in  the  Upper  Carboniferous  rocks  of  the  Schwarzwald,  in  Baden, 
Germany. 

2.   Animals. 

The  most  important  additions  to  the  facts  already  stated,  furnished 
by  the  European  rocks,  are  those  relating  to  the  classes  of  Insects  and 
Spiders.  Besides  Cockroaches,  there  were  probably  Weevils,  as  well 
as  other  kinds  of  Beetles,  species  related  to  the  May-fly  and  Dragon 
fly,  and  also  to  Termites.  The  class  of  Spiders  (or  Arachnids)  was 
represented  by  Scorpions,  Pseudo-scorpions,  and  true  Spiders,  as  in 
America. 

The  Vertebrates  were  similar  in  type  to  the  American,  the  fishes 
being  Ganoids  and  Selachians,  and  the  Reptiles  mainly  Labyrintho- 
donts. 

A  number  of  European  Subcarboniferous  species  are  identical  with,  or  closely  related 
to,  forms  common  in  the  American  Coal-measures.  Thus  it  is  with  the  following  : 


350 


PALEOZOIC    TIME. 


Athyris  subtilita,  Retzia  radians  Morr.,  Spirifer  lineatus,  8.  Urii  Flem.,  Productus  longi- 

spinus  Sow.,  P.  scabriculus  Sow.,  P.  costatus  Sow.,  Fusulina  cylindrica,  and  F.  robust  a. 

The  following  figures  represent  some  of  the  remains  of  Articulates  :  (a. )  Crustaceans, 

-No  species  of  Trilobites  are  reported  from  the  foreign  Coal-measures, —showing, 

apparently,   the  complete  extinction  of  this  ancient  tribe.     Fig.  683,  Prestwichia  ro- 

Figs.  682-686. 


Fig.  682,  Gampsonyx  fimbriatus  ;  683,  Prestwichia  rotundata    ( X>£) ;  684,  Cyclophthalmus  senior ; 
685,  Dictyoneura  anthracophila ;  686,  Blattina  primseva. 

Fig.  686  A. 


Anthrapalaemon  Salteri. 

tundata  Woodw.,  reduced  one  half,  Coalbrook  Dale;  P.  anthrax 
Woodw.,  Coalbrook  Dale;  Belinui-us  triloUtoides  Woodw.,  Ireland 
and  Coalbrook  Dale;  B.  regince  Baily,  Ireland;  B.  arcuatns  Daily, 
Ireland.  Fig.  682,  Gampsonyx  (Enronectes)  jtmbriatits  Jordan,  a 
Schizopod.  Fig.  686  A,  Anthrapakemon  Salteri,  from  Lanarkshire, 
Scotland.  A.  duUus  S.  and  A.  Grossarti  S.  are  other  species  re 
ferred  to  this  genus,  the  former  from  Coalbrook  Dale  (includes  the  Glyphea  (?)  dubia  S., 
and  Apus  dubivs  M.-Edw.),  and  the  latter  from  Lanarkshire;  but  the  broad  flattened 
carapax  indicates  a  nearer  relation  to  sEylea  and  Galathea  than  to  Palcemon.  Pygoceph- 
alus  Couperi  Hux.  is  the  name  of  a  Schizopod  from  near  Manchester,  England. 

(b.)  Myriapods.  —  Euphoberia  Brownii  Woodw.,  from  Glasgow,  E.  anthrax  Woodw., 
from  Coalbrook  Dale,  Xylobius  siyillarice  Dn.,  from  Glasgow  and  Huddersfield. 


CARBONIFEROUS    AGE.  351 

(c. )  Spiders. —  (1.)  Scorpions:  Fig.  684,  Cyclo/Jithahnus  senior  Corda,  a  Scorpion  from 
Chomle,  Bohemia.  (2.)  Pseudo-scorpions:  Microlabis  Sternberyi  Corda,  from  Bohemia. 
Eophrymus  Prestiritchii  Woodw.,  from  Dudley;  Architarbus  subovalis  Wood w.,  Lanca 
shire,  very  near  the  Illinois  species  (p.  342).  (3.)  True  Spiders:  Protolycosa  anthra- 
cophila  R.,  from  Silesia;  an  Aranea,  from  Bohemia. 

((/.)  Insects.  —  Remains  of  Insects  have  been  found  at  several  localities,  and  especially 
at  Saarbriick  and  Wettin.  (1.)  Xeuropters:  Dictyoneura  cinthracopliila  Goldb.,  Saar- 
briick;  D.  Humboldti'ina  Goldb.,  ib. ;  D.  libellulo'ules  Goldb..  ib. ;  Corydalis  Bronyniarti 
Mant.,  Coalbrook  Dale.  (2.)  Orthopters:  Fig.  683,  Blattina  priinceoa  Goldb.,  Saarbriick, 
besides  two  other  Blattince  from  Saarbriick,  and  several  from  Westphalia;  Gryllacris 
lithanthraca  Goldb.  (Locust),  from  Saarbriick;  Termes  Heeri  Goldb.,  and  other  species, 
from  Saarbriick.  (3.)  Coleopters:  Troxites  Germari  Goldb.,  Saarbruck;  Curculioides 
Ansticii  Buckl.,  Coalbrook  Dale. 

(e.)  Fishes.  —  The  Fishes  of  the  Carboniferous  age  are  found  most  abundantly  in  the 
Subcarboniferous  limestones,  as  these  were  wholly  of  marine  origin;  still,  a  consider 
able  number  of  species  occur  in  the  Coal-measures.  The  Selachians  are  of  the  genera 
Ctenodus,  Ctenoptychins,  Gyracanthus,  etc.,  and  also  Helodus,  Clndodus,  Orodus,  Ctena- 
canthus,  etc.,  which  are  mostly  Subcarboniferous.  The  most  common  Coal-measure 
genera  of  Ganoids  are  Palwomscus,  Amblyptenu,  and  IMopty  chins. 

(/.)  Reptiles. —  A  few  Reptilian  remains  have  been  observed  in  Europe  and  Britain, 
similar  in  general  character  to  those  of  America,  and  indicating  the  existence  of  Laby- 
rinthodonts.  Loxomma  Allmanni  Hux.,  Edinburgh,  the  skull  ten  inches  wide  and  four 
teen  long;  Anthracosaurus  Russelli  Hux.,  Lanarkshire;  Parabatrachus  Colei  Owen, 
British  Coal-measures;  Anthracerpeton  crassosteum  Owen,  Glamorganshire;  Archeyo- 
saurus  Decheni  Goldfuss,  Saarbriick,  three  and  one-half  feet  long:  A.  minor  Meyer, 
Saarbriick;  Apateon  pedestris  H.  v.  Meyer,  from  near  Miinsterappel,  on  the  Bavarian 
Rhine;  Urocordylus  Wandesford'd  Hux.,  Kilkenny,  the  tail  very  long,  having  seventy- 
five  vertebras ;  Ophiderpeton  Brownriyyii  Hux.,  Kilkenny,  snake-like,  three  feet  long; 
Septerpeton  Dobbs'd  Hux.,  Kilkenny. 

3.  GENERAL  OBSERVATIONS. 

1.  Source  of  Coal.  —  (1.)  Goal  derived  from  Vegetation.  —  As  the 
coal-beds  and  accompanying  strata  abound  in  the  impressions  of  leaves 
and  stems,  and  the  coal  also  consists  largely  of  vegetable  fibre  (p.  318), 
the  vegetable  origin  of  coal  is  beyond  all  reasonable  doubt. 

(2.)  Plants  of  the  Coal.  — The  plants  that  have  contributed  most  to 
the  formation  of  the  great  beds  of  vegetable  debris,  which  were  after 
ward  converted  into  coal,  are  the  Sigillarids,  Calamites,  Ferns,  and 
Oordaites,  with  the  Lepidodendrids  for  the  beds  of  the  Lower  Coal- 
measures. 

The  Sigillarids  and  Calamites  were  probably  for  the  most  part  con 
fined  to  the  wet  grounds  or  marshes,  and  the  islands  of  floating  plants ; 
while  the  Lepidodendrids  and  Tree-ferns,  judging  from  recent  Lyco- 
pods  and  Ferns,  were  plants  both  of  the  wet  plains  and  of  the  dry  hills. 
Conifers  must  have  been  associated  with  these  last  in  the  drier  forests 
of  the  continent ;  but,  if  the  Cordaites  are  the  leaves  of  any  of  the 
species,  they  also  spread  over  the  wet  regions,  and  took  part  in  the 
construction  of  the  floating  islands.  The  nature  of  the  plants  found 
in  the  coal-beds,  and  of  the  associated  animal  life,  is  proof  that  the 
coal  is  not  made  even  partly  of  marine  species. 


352  PALEOZOIC  TIME. 

2.  Climate,  Atmosphere.  —  The  growth  of  the  Carboniferous  vege 
tation  was  dependent,  as  now,  on  the  climate  and  the  condition  of  the 
atmosphere. 

(1.)  Temperature  of  the  Ocean  and  Air.  —  In  the  animal  life  of  the 
waters,  we  have  a  safe  criterion  for  the  temperature  of  the  oceans. 
Among  the  species,  there  was  the  large  coral,  Lithostrotion,  common 
in  both  Europe  and  the  United  States.  One  such  species  is  almost 
sufficient  to  prove  a  similar  temperature  for  the  ocean  over  these  three 
distant  regions.  This  Lithostrotion  was  found  by  Beechey  on  the 
northwest  Arctic  coast,  between  Point  Barrow  and  Kotzebue  Sound  ; 
and  with  it  occurred  other  corals,  and,  among  the  Brachiopods,  Produc- 
tus  semireticulatus,  well  known  in  lower  latitudes.  The  Arctic  was, 
therefore,  at  that  time  a  reef-growing  sea ;  and,  if  the  distribution  of 
corals,  forming  coral-reefs,  was  limited  by  the  same  temperature  then 
as  now,  the  waters  were  at  no  part  of  the  year  below  66°  F.  Besides 
the  above  species,  there  have  been  identified,  in  the  Arctic,  the  Euro 
pean  species  Productus  sulcatus  Sow.,  Atrypa  aspera  Dalm.,  A.  fallax 
Sow.  These  were  found  on  Bathurst  and  the  neighboring  islands,  in 
latitudes  75°  and  77°. 

The  small  diversity  in  the  oceanic  temperature  of  the  globe  is  fur 
ther  shown  by  the  occurrence  of  the  following  Carboniferous  species 
in  the  Bolivian  Andes :  Productus  semireticulatus,  P.  longispinus  Sow., 
Athyris  subtilita,  and  a  Bellerophon,  resembling  B.  Urii  Flem. 

The  coal-beds  of  Arctic  regions  are  evidence  of  a  profuse  growth  of 
vegetation  over  an  extended  area,  and  protracted  through  a  long  period. 
The  conditions,  between  the  latitudes  70°  and  78°,  were,  therefore, 
analogous  to  those  over  the  United  States,  from  Pennsylvania  to  Ala 
bama,  and  from  Illinois  to  Texas.  While  a  general  resemblance  to  the 
ancient  flora  of  the  United  States  and  Europe  is  apparent  from  the 
observations  which  have  been  •  made,  but  few  species  have  yet  been 
identified.  The  plants  were  not  mosses  of  peat  swamps,  such  as  now 
extend  far  north.  If  we  draw  any  conclusion  from  the  facts,  it  must 
be  that  the  temperature  of  the  Arctic  zone  differed  but  little  from  that 
of  Europe  and  America.  Through  the  whole  hemisphere  —  and,  we 
may  say,  world  —  there  was  a  genial  atmosphere  for  one  uniform  type 
of  vegetation,  and  there  were  genial  waters  for  Corals  and  Brachio 
pods. 

(2.)  Moisture  of  the  Atmosphere.  —  A  warm  state  of  the  globe 
would  necessarily  imply  a  very  much  larger  amount  of  evaporation 
than  now.  The  climate  would  be  insular  throughout ;  and  heavy  mists 
would  rest  over  the  land,  making  the  air  and  land  moist.  The  com 
paratively  small  diversity  of  climate  between  the  equator  and  poles 
would  probably  be  attended  with  fewer  storms  than  now,  and  with  a 
less  rapid  movement  in  the  general  circulation. 


CARBONIFEROUS   AGE.  353 

(3.)  Impurity  of  the  Atmosphere.  —  In  the  present  era,  the  atmos 
phere  consists  essentially  of  oxygen  and  nitrogen,  in  the  proportion  of 
23  to  77  parts  by  volume.  Along  with  these  constituents,  there  are 
about  four  parts  by  volume  of  carbonic  acid,  in  10,000  parts  of  air. 
Much  more  carbonic  acid  would  be  injurious  to  animal  life.  To  vege 
table  life,  on  the  contrary,  it  would  be,  within  certain  limits,  promotive 
of  growth  ;  for  plants  live  mainly  by  means  of  the  carbonic  acid  they 
receive  through  their  leaves.  The  carbon  they  contain  comes  princi 
pally  from  the  air. 

This  being  so,  it  follows,  as  has  been  well  argued,  that  the  carbon 
which  is  now  coal,  and  was  once  in  plants  of  different  kinds,  has  come 
from  the  atmosphere,  arid,  therefore,  that  the  atmosphere  now  contains 
less  carbonic  acid  than  it  did  at  the  beginning  of  the  Carboniferous 
period,  by  the  amount  stowed  away  in  the  coal  of  the  globe. 

Volcanoes  contribute  at  the  present  time  a  little  to  the  carbonic  acid  of  the  atmos 
phere;  and  it  may  be  that  some  of  the  carbon  in  coal  is  from  this  source.  But  this  car 
bonic  acid  is  given  out  only  where  the  heat  of  the  volcanic  vent  has  limestone  to  act 
upon ;  and,  if  this  is  a  rare  case  now,  it  was  even  less  common  in  Paleozoic  time,  when 
volcanoes  were  probably  far  less  numerous.  Moreover,  the  carbon  in  the  limestone 
(carbonate  of  lime)  of  the  globe,  while  it  was  taken  directly  from  the  earth's  waters 
(p.  130),  came  in  part  from  the  atmosphere,  the  rains  cany  ing  it  down  to  the  ocean. 
If,  then,  the  limestones  robbed  the  atmosphere,  as  well  as  the  coal,  the  amount  of  Car 
boniferous  coal  in  the  earth's  rocks  does  not  probably  represent  more  carbonic  acid  than 
the  atmosphere  of  the  Carboniferous  age  lost. 

Such  an  atmosphere,  containing  an  excess  of  carbonic  acid  as  well 
as  of  moisture,  would  have  had  greater  density  than  the  present ;  con 
sequently,  as  urged  by  E.  B.  Hunt,  it  would  have  occasioned  increased 
heat  at  the  earth's  surface,  and  this  would  have  been  one  cause  of  a 
higher  temperature  over  the  globe  than  the  present. 

During  the  progress  of  the  Carboniferous  period  there  was,  then, 
(1)  a  using  up  and  storing  away  of  the  carbon  of  the  superfluous  car 
bonic  acid,  and,  thereby,  (2)  a  more  or  less  perfect  purification  of  the 
atmosphere,  and  a  diminution  of  its  density.  In  early  time,  there  was 
no  aerial  animal  life  on  the  earth ;  and,  so  late  as  the  Carboniferous 
period,  there  were  only  Reptiles,  Myriapods,  Spiders,  Insects,  and  pul- 
monate  Mollusks.  The  cold-blooded  Reptiles,  of  low  order  of  vital 
activity,  correspond  with  these  conditions  of  the  atmosphere.  The 
after-ages  show  an  increasing  elevation  of  grade  and  variety  of  type 
in  the  living  species  of  the  land. 

(4.)  Influence  of  the  Climate  on  the  Growth  of  Plants.  —  A  moist 
warm  climate  produces  exuberant  growth  in  plants  that  are  fitted  for 
it.  The  plants  of  the  Coal  period  were  made  for  the  period.  The 
Sigittarids  and  Calamites  manifest,  by  their  characters  and  mode  of 
occurrence,  that  they  could  flourish  only  in  a  moist  region  ;  and  the 
23 


354  PALEOZOIC    TIME. 

Ferns  of  the  tropics  are  most  luxuriant  in  moist  woods.  The  Lepi- 
dodcndrids,  by  their  association  with  the  Sigillarids  and  Ferns,  show 
that  the  same  conditions  (as  is  now  the  case  with  their  kin,  the  Ly- 
copodia)  favored  their  development.  In  fact,  Lycopods,  Equiseta, 
and  most  Ferns,  are  plants  that  like  shady  as  well  as  moist  places. 
Adding,  then,  the  prevalent  moisture  and  warmth  to  the  excess  of 
carbonic  acid  in  the  atmosphere,  we  should  be  warranted  in  conclud 
ing  that,  even  if  there  were  less  sunshine  than  at  the  present  time, 
vegetable  growth  must  have  been  more  exuberant  than  it  is  now,  es 
pecially  in  the  colder  temperate  zones.  This  exuberance  would  not 
have  shown  itself  in  thick  rings  of  growth,  in  trees  made  for  those 
very  conditions,  but,  as  through  the  existing  tropics  under  a  moist  cli 
mate,  in  the  great  denseness  of  the  jungles  and  forests,  many  plants 
starting  up  where  but  one  would  have  flourished  under  less  favorable 
circumstances.  Our  peat  swamps  are  often  referred  to,  as  a  measure 
for  the  growth  of  plants  in  the  Coal  era.  But  while  they  illustrate 
well  the  mode  of  making  beds  of  vegetable  debris,  their  rate  of  prog 
ress  may  be  no  safe  criterion  as  to  the  rate  in  Carboniferous  swamps. 
The  peat- plants  of  the  present  day  are  species  of  the  temperate  and 
colder  zones,  and  are  too  different  in  kind  to  warrant  a  comparison. 

3.  Geographical  Conditions  over  North  America,  during  the  Prog 
ress  of  the  Carboniferous  Period.  —  The  Subcarboniferous  was  a 
period  of  submerged  continental  regions  ;  and  the  Carboniferous  of  as 
extensive  an  emergence ;  not  continuous  emergence,  but  prolonged 
and  repeated  emergences  with  little  change  of  level,  alternating  with 
slight  or  partial  subsidences. 

The  conglomerate,  called  Millstone-grit,  with  whose  formation  the 
Coal-period  began,  marks  the  transition  from  the  marine  to  the  terres 
trial  period.  The  area  that  had  been  covered  with  fields  of  Crinoids 
was  swept  during  this  epoch  by  currents  and  waves,  which  left  the 
surface  under  a  great  depth  of  pebbles  and  sand.  The  coarseness  of 
the  beds  along  the  Appalachian  region,  in  Pennsylvania,  points  out 
that  this  was  the  border-reef  of  the  continent ;  and  the  great  thick 
ness  of  the  deposits,  —  1,100  feet,  —  that  it  was  a  region  also  of  pro 
found,  though  slowly  progressing,  subsidence.  The  more  sandy  char 
acter  of  the  beds  of  this  border  in  Virginia  harmonizes  with  the 
general  fact  in  earlier  time  ;  and  so  also  do  the  little  thickness  and 
finer  character  of  the  beds  of  Ohio  and  eastern  Kentucky,  —  a  region 
on  the  inner  margin  of  the  subsiding  Appalachian  era,  not  participating 
so  fully  in  the  great  change  of  level. 

The  coal-beds  of  the  Millstone-grit  also  show  that  the  continent 
was  in  this  semi-emerged  condition ;  for  every  such  bed  is  proof  that 
areas  of  land  were,  for  a  long  time,  above  the  ocean,  where  plants 
could  grow. 


CARBONIFEROUS    AGE.  355 

When  the  era  of  the  Coal-measures  had  fairly  set  in,  the  great 
Interior  region  of  the  Continent,  even  from  the  eastern  limits  of  the 
Appalachian  region  to  the  western  borders  of  Kansas  and  Nebraska, 
as  the  extent  of  the  Coal-formation  shows,  slowly  emerged ;  and  the 
continent  then,  for  the  first  time,  extended  from  the  remote  Arctic 
zone,  south  to  Alabama.  West  of  Kansas,  there  were  limestones  of 
the  Coal-measure  era  in  progress,  instead  of  coal-beds ;  and  these 
indicate  that  the  old  sea  of  the  Interior  region  still  covered  the  slopes 
and  summits  of  the  Rocky  Mountains ;  and  over  these  meridians  the 
waters  may  have  connected  with  the  Arctic  ocean.  The  limestones 
of  Point  Barrow,  at  the  farther  extremity  of  the  Rocky  Mountain 
range,  may  be  of  the  same  age. 

This  emergence,  giving  so  great  extent  to  the  young  continent,  was 
not  complete  until  the  first  of  the  great  beds  of  vegetable  debris 
began  to  form.  Then  North-  America,  within  the  limits  stated,  was 
one  vast  forest,  except  where  fresh  waters  lay  too  deep  for  forests  to 
grow  ;  and  the  lakes  probably  had  islands  of  shrubbery  and  forest 
vegetation  floating  over  the  waters,  as  is  now  true  of  some  of  the 
tropical  lakes  of  India. 

Since  single  coal-beds  in  the  earlier  part  of  the  series  appear  to 
have  had  a  very  wide  range,  it  is  safe  to  conclude  that  the  great  In 
terior  region  had  nearly  a  common  level,  —  that  it  was  a  vast  plain, 
with,  at  the  most,  only  gentle  undulations  in  the  surface,  and  with 
the  higher  land  mainly  over  the  Archaean  and  Silurian  lands  to  the 
north.  There  were  no  Alleghanies ;  for  this  very  region  was  a  part 
of  the  great  coal-making  plain  :  there  were  no  Rocky  Mountains,  for 
these,  as  the  Carboniferous  limestones  prove,  were  mainly  under  the 
sea.  The  Appalachian  region  and  the  Interior  basin,  both  east  and 
west  of  the  Mississippi,  were  merged  in  one  great  continental  basin, 
all  making  together  one  nearly  level  country,  the  low  Cincinnati  ridge 
being  the  only  land  west  of  New  York  that  projected  above  the  level 
of  the  marshes.  Being  thus  level,  there  could  have  been  no  great 
Mississippi  or  Ohio  ;  the  continent  would  have  had  no  sufficient  drain 
age,  and  the  wide  plains  would  necessarily  have  been  marshy,  and 
spotted  with  shallow  lakes. 

This  Continental  basin,  as  stated  on  page  146,  was  separated  from 
the  Eastern-border  region,  by  the  Green  Mountains,  —  a  range  which 
had  stood  as  a  low  barrier  between  New  England  and  New  York, 
from  the  close  of  the  Lower  Silurian.  Both  the  Nova  Scotia  Coal- 
measures  and  those  of  central  Pennsylvania  are  almost  destitute  of 
true  marine  fossils ;  and  hence  the  true  raised  border  of  the  continent 
was  some  miles,  or  scores  of  miles,  to  the  eastward  of  the  most  eastern 
Carboniferous  limits.  The  Nova  Scotia  and  New  Brunswick  beds 


356  PALEOZOIC   TIME. 

were  laid  down  in  a  great  estuary  constituting  the  mouth  of  the  St. 
Lawrence,  then  the  greatest  river  of  the  continent ;  and  this  estuary 
appears  to  have  spread  southward  along  the  Bay  of  Fundy,  and  north 
ward  and  northeastward,  over  the  St.  Lawrence  bay,  to  Newfound 
land  ;  for  the  coal-rocks  cover  even  the  extreme  northern  portion  of 
the  peninsula  of  Nova  Scotia.  Hence  the  raised  continental  border 
in  this  part  probably  lay  as  far  out  as  eastern  Newfoundland,  from 
which  it  may  have  stretched  far  enough  southwestward  to  have  shut 
in  also  the  Rhode  Island  region.  The  dip  of  the  Nova  Scotia  Coal- 
beds,  and  their  great  thickness  at  Pictou,  on  the  shores  of  the  Gulf, 
show  that  only  a  small  part  of  the  originally  great  area  is  now  above 
the  sea-level. 

Over  these  marshes,  then,  grew  the  clumsy  S/gillarids  and  Calamites, 
and  the  more  graceful  Tree-ferns,  Lepidodendrids,  and  Conifers,  with 
an  undergrowth  of  Ferns,  and  upon  the  dry  slopes  near  by,  forests  of 
Lepidodendrids,  Conifers,  and  Tree-ferns  ;  and  the  luxuriant  growth 
was  prolonged  until  the  creeping  centuries  had  piled  up  vegetable 
debris  enough  for  a  coal-bed.  Trees  and  shrubs  were  expanding,  and 
shedding  their  leaves  and  fruit,  and  dying,  making  the  accumulation 
of  vegetable  remains.  Islands  of  vegetation,  floating  over  the  lakes, 
may  have  contributed  largely  to  the  vegetable  debris.  Stumps  stood 
and  decayed  in  the  swamps,  while  the  debris  of  the  growing  vegeta 
tion,  or,  in  some  cases,  the  detritus  borne  by  the  waters,  accumulated 
around  them ;  and  their  hollow  interiors  received  sands,  or  leaves,  or 
bones,  or  became  the  haunts  of  reptiles,  as  was  their  chance.  Logs 
were  floated  off  over  the  lakes,  to  sink  and  become  buried  in  the 
accumulating  vegetable  debris,  or  in  deposits  of  detritus  ;  and  some 
of  these  transported  stumps  may  have  had  aboard  large  stones,  which 
they  finally  dropped,  and  so  put  an  occasional  "  bowlder  "  into  the 
forming  beds. 

As  already  explained,  there  is  no  reason  to  suppose  that  the  vege 
tation  was  confined  to  the  lower  lands  :  it  probably  spread  over  the 
whole  continent,  to  its  most  northern  limits.  It  formed  coal  only 
where  there  were  marshes,  and  where  the  deposits  of  vegetable  debris 
afterward  became  covered  by  deposits  of  sand,  clay,  or  other  rock- 
material. 

The  condition  of  the  continent  just  described  represents  only  one 
phase  in  the  Carboniferous  period.  The  rocks  register  a  succession  of 
changes  ;  for  coal-beds  are  succeeded  by  sandstones,  or  shales,  or  lime 
stones,  or  iron-ore  beds,  and  many  alternations  of  these  beds,  to  a 
thickness  fifty  times  as  great  as  that  of  the  coal-beds.  These  inter 
vening  strata,  moreover,  were  sometimes  of  fresh-water  origin  ;  and  at 
others,  of  marine :  in  the  one  case,  containing  fresh-water  shells,  or 


CARBONIFEROUS    AGE.  357 

other  inland  species ;  in  the  other,  full  of  Crinoids  and  Brachiopods, 
the  life  of  the  sea.  The  great  extent  of  the  continent,  wherever  these 
strata  occur,  underwent,  therefore,  continued  oscillations  of  level,  or 
the  sea  as  unceasing  changes  of  water-level.  After  a  period  of  verdure, 
there  followed  a  desolation  as  complete  as  that  when  the  subjacent 
Millstone-grit  was  spread  over  the  surface,  —  either  a  subsidence  of 
the  interior,  or  some  other  change,  that  led  to  a  general  submergence 
beneath  fresh-waters,  or  a  similar  subsidence,  or  else  a  removal  or 
sinking  of  barriers,  that  placed  the  whole  beneath  salt  water  ;  in  either 
case,  the  former  vegetation  gave  way  to  aquatic  life  again. 

The  broken  relics,  that  were  a  result  of  the  catastrophe,  are  often 
packed  together  in  the  first  deposits  that  ensued.  Lesquereux  states 
that,  in  the  roof-shale  of  the  coal-bed  at  Carbondale,  Pa.,  there  was 
found  an  impression  of  the  bark  of  a  Lepidodendron,  two  feet  wide 
and  seventy-five  feet  in  length.  Andrews  mentions  that  thousands  of 
the  trunks  of  the  Fern,  Pecopteris  arborescens  Lsqx.,  are  found  in  the 
shale  over  the  Pomeroy  Coal-bed ;  and  that  at  one  place  the  trunk  of 
a  Sigillaria  was  traced  by  him  for  more  than  forty  feet. 

The  oscillations  must  have  been  exceedingly  various,  to  have  pro 
duced  all  the  alternations  of  shales,  sandstones,  limestones,  and  ore- 
beds. 

The  movements,  moreover,  must  have  been  slow  in  progress  :  mo 
tion  by  the  few  inches  a  century  accords  best  with  the  facts.  When 
under  terrestrial  vegetation,  and  receiving  vegetable  debris  for  coal- 
beds,  it  must  have  lain  for  a  long  period  almost  without  motion  ;  for 
only  a  very  small  change  of  level  would  have  let  in  the  salt  water  to 
extinguish  the  life  of  the  forests  and  jungles,  or  have  so  raised  the 
land  as  to  dry  up  its  lakes  and  marshes.  Hence  the  grand  feature  of 
the  period  was  its  prolonged  eras  of  quiet,  with  the  land  little  above 
the  sea-limit,  —  a  condition  that  made  coal-beds  also  in  later  geo 
logical  ages.  Again,  for  the  making  of  the  shales  or  sandstones, 
the  continent  may  have  rested  long  near  the  water's  surface,  just 
swept  by  the  waves.  It  may  have  been  long  a  region  of  barren 
marshes  ;  and,  in  this  condition,  it  might  have  received  its  iron-ore  de 
posits,  as  now  marshes  become  occupied  by  bog-ores.  It  must  have 
been  long  in  somewhat  deeper  waters,  and  covered  with  a  luxuriance 
of  marine  life,  in  order  to  have  received  its  beds  of  limestone.  Finally 
the  land  slowly  emerged  again  from  the  waters,  and  the  old  vegetation 
spread  rapidly  across  the  great  plains,  commencing  a  new  era  of  coal- 
making  vegetable  debris ;  or  the  escape  was  only  partial,  and  coal- 
plants  took  possession  of  one  part,  and  made  limited  coal  deposits, 
while  the  sea  still  held  the  rest  beneath  it :  for  uniform  oscillations  of 
level  in  all  cases,  through  so  great  an  area,  are  not  probable  ;  and 


358  PALEOZOIC   TIME. 

therefore  the  former  continuity  of  a  single  coal-bed  through  the  East 
and  West  requires  strong  proof,  to  be  admitted. 

The  coal-beds  are  thin,  compared  with  the  associated  rocks.  But 
the  time  of  their  accumulation,  or  the  length  of  all  the  periods  of 
verdure  together,  may  have  far  exceeded  the  time  that  was  given  up 
to  the  accumulation  of  sands  and  limestones.  If  there  were  but  100 
feet  of  coal  in  all,  it  would  correspond  to  between  500  and  1000  feet 
in  depth  of  vegetable  debris.  The  sands  and  clays  came  in  after  each 
time  of  verdure,  to  store  away  the  product  for  a  future  age. 

These  submergences,  although  quietly  carried  forward,  sometimes  let 
in  currents  or  waves  of  great  force,  as  shown  not  only  by  the  forma 
tion  of  coarse  gravel  beds  (now  conglomerates),  but  also  by  the 
erosion  of  the  rock-deposits,  and  also  of  the  beds  of  vegetable  debris. 
In  Vermilion  County,  Illinois,  as  observed  by  F.  H.  Bradley,  a  por 
tion  of  the  Upper  Coal-measures,  including  shales,  argillaceous  lime 
stones,  and  two  coal-beds,  were  carried  away  to  a  depth  of  sixty  feet , 
and,  in  the  depression  thus  made,  a  sandstone,  which  belongs  at  the  top 
of  the  series,  was  laid  down  so  as  to  fill  and  overlie  it.  Also,  on  the 
same  authority,  in  Vermillion  County,  Indiana  (adjoining  the  county 
just  mentioned),  the  Millstone-grit  (here  a  pebbly  sandstone),  under 
the  Coal-measures,  is  cut  off  short,  and  followed  horizontally  by  shale 
and  limestone  ;  as  if  the  grit  stood  as  a  bluff  in  the  waters,  in  which 
the  latter  rocks  were  deposited.  Other  evidences  of  erosion  have  been 
described  from  these  States,  and  also  from  Ohio. 

In  Nova  Scotia,  the  changes  during  the  Carboniferous  period  (or 
Carboniferous  and  Permian)  went  on  until  14,570  feet  of  deposits 
were  formed  ;  and,  in  that  space,  as  has  been  stated,  there  are  seventy- 
six  coal-seams  and  dirt-beds,  indicating  as  many  levels  of  verdant 
fields,  between  the  others  when  the  waters  prevailed.  In  Pennsyl 
vania,  there  are  nearly  3,000  feet  of  rocks  in  the  series,  above  the  Mill 
stone-grit,  and  60  to  120  feet  of  coal. 

In  the  Nova  Scotia  Coal-measures,  there  is  evidence  in  the  fossils 
that  the  waters  were  to  a  large  extent  fresh  or  brackish.  The  oc 
currence  of  a  SpirorUs  along  with  the  Papa  and  Reptilian  remains, 
in  the  Sigillaria  stump,  has  been  considered  as  evidence,  in  this  par 
ticular  case,  of  the  presence  of  brackish  water  during  the  burial  of  the 
stump.  Only  one  bed  in  the  Nova  Scotia  Coal-formation,  above  the 
Subcarboniferous  portion,  is  known  to  contain  marine  fossils.  The 
land-snail  (Pupa)  occurs  also  in  abed  —  an  under-clay  —  over  1,200 
feet  below  the  level  of  the  stump  in  which  it  was  first  found  ;  and  in 
this  interval  there  are  twenty -one  coal-seams,  showing,  as  Dawson  ob 
serves,  that  the  species  existed  during  the  growth  and  burial  of  at 
least  twenty  forests. 


CARBONIFEROUS   AGE.  359 

In  the  Interior  Continental  region,  the  submergence  attending  the 
formation  of  these  intervening  rocks  was  mostly  or  wholly  marine  ; 
for  all  the  fossils  thus  far  observed  are  those  of  marine  species  ;  and 
they  occur  in  many  strata  of  limestone,  sandstone,  and  shale,  through 
out  the  Coal-measures.  In  Central  Pennsylvania,  the  evidences  of  ma 
rine  life  are  uncertain.  Over  the  great  Mammoth  bed  of  Wilkesbarre, 
are  shales  (in  the  township  of  Hanover)  containing  bivalve  shells;  but 
these  may  be  of  the  fresh- water  type  of  Unionidce.  The  thinner  shales, 
among  the  coal-beds  of  the  Interior  basin,  and  the  limited  arenaceous 
layers  may  have  been  formed  when  the  marshes  became  flooded  with 
fresh  waters  ;  while  the  great  sandstones  and  limestones  and  thicker 
shales  arc  all  evidence  that  the  former  fresh-water  marsh  was  followed, 
through  submergence,  by  a  flood  of  marine  waters.  The  extermina 
tion  of  the  Lepidodendrids  of  the  Lower  Coal-measures  was  probably 
connected  with  such  a  submergence.  The  marine  waters  probably 
came  in  from  the  Interior  basin  to  the  southwest,  and  not  from  the 
ocean  on  the  east. 

The  Lower  Coal-measures  extend  to  the  most  eastern  limits  of  the 
anthracite  in  Pennsylvania,  and  contain  but  little  limestone,  either  in 
the  east  or  west.  The  Upper,  above  the  Pittsburg  bed,  extend  only 
over  the  western  portion  of  that  State.  This  more  western  limit  of 
the  Upper  than  the  Lower  section  shows  plainly  that  a  rising  of  the 
country  had  taken  place  more  to  the  east,  to  a  height  that  was  too 
dry  for  the  marsh-vegetation  of  which  coal  was  made.  We  observe, 
further,  that  limestones  occur  in  the  Upper  Coal-measures,  and  increase 
much  on  going  westward  over  the  Interior  basin ;  and,  finally,  as  has 
been  stated,  they  prevail  extensively  over  the  larger  part  of  the  Rocky 
Mountain  region. 

The  coal-bed  itself  bears  evidences  of  alternations  of  condition,  in  its  own  lamination, 
or  even  in  the  alternations  in  its  shades  of  color.  A  layer  an  eighth  of  an  inch  thick 
corresponds  to  an  inch,  at  least,  of  the  accumulating  vegetable  remains;  and  hence  the 
regularity  and  delicacy  of  the  structure  are  not  surprising.  Alternations  are  a  conse 
quence  of  (1)  the  periodicity  in  the  growth  of  plants  and  the  shedding  of  leaves;  (2) 
the  periodicity  of  the  seasons,  the  alternations  of  the  season  of  floods  with  the  season  of 
low  waters,  or  comparative  dryness;  (3)  the  occurrence,  at  intervals  of  several  years,  of 
excessive  floods.  Floods  may  bring  in  more  or  less  detritus,  besides  influencing  the  fall 
and  distribution  of  the  vegetation.  In  some  conditions,  there  would  be  a  long  steeping 
of  the  vegetation  in  the  waters,  before  it  was  put  under  the  pressure  of  beds  of  clay  of 
sand;  and  the  precise  quality  of  the  coal  would  be  varied  thereby,  the  decomposition 
of  the  vegetation  depending  on  the  amount  of  water,  the  composition  of  that  water, 
and  the  length  of  time  exposed.  Newberry  has  suggested  that  bituminous  coal  has 
taken  the  form  of  Cannel  when  the  vegetation  was  reduced  to  a  perfect  pulp  at  the 
time  of  the  change  to  coal. 

The  Coal  period  was  a  time  of  unceasing  change,  —  eras  of  uni 
versal  verdure  alternating  with  others  of  wide-spread  waters,  destruc 
tive  of  all  the  vegetation  and  other  terrestrial  life,  except  that  which 


360  PALEOZOIC   TIME. 

covered  regions  beyond  the  Coal-measure  limits.  But  yet  it  was  an 
era  in  which  the  changes  for  the  most  part  went  forward  with  so  ex 
treme  slowness,  and  with  such  prevailing  quiet,  that,  if  man  had  been 
living  then,  he  would  not  have  suspected  their  progress,  unless  he  had 
records  of  some  thousands  of  years  past  to  consult.  According  to  the 
reading  of  the  records,  it  was  a  time  of  great  forests  and  jungles,  and 
of  magnificent  foliage,  but  of  few  or  inconspicuous  flowers ;  of  Aero- 
gens  and  Gymnosperms,  with  no  Angiosperms  ;  of  marsh-loving  In 
sects,  Myriapods,  and  Scorpions,  as  well  as  Crustaceans  and  Worms, 
representatives  of  all  the  classes  of  Articulates,  but  not  the  higher 
Insects,  that  live  among  flowers ;  of  the  last  of  the  Trilobites,  and 
the  passing  climax  of  the  Brachiopods  and  Crinoids  ;  of  Ganoids  and 
Sharks,  but  no  Teliosts  or  Osseous  Fishes,  the  kinds  that  make  up 
the  greater  part  of  modern  tribes ;  of  Amphibians  and  some  inferior 
species  of  True  Reptiles,  but  no  Birds  or  Mammals ;  and  therefore 
there  was  no  music  in  the  groves,  save  that  of  Insect  life  and  the 
croaking  Batrachian.  Thus  far  had  the  world  progressed,  by  the  close 
of  the  Carboniferous  period. 

The  special  history  of  the  Coal-period  of  Europe  and  Britain  might 
be  followed  out,  as  has  been  done  for  North  America.  But  the  de 
tails  would  illustrate  no  new  principles,  and  would  be  more  appropriate 
in  a  general  treatise  than  in  a  text-book.  More  facts  are  to  be  ascer 
tained,  before  their  history  will  be  as  clearly  deciphered. 

4.  Formation  of  Mineral  Coal.  —  From  the  analyses  on  page  316, 
it  is  seen  (1)  that  mineral  coal  consists  chiefly  of  carbon;  (2)  that, 
also,  hydrogen  and  oxygen  are  always  present;  (3)  that  Anthracite 
contains  usually  2  to  5  per  cent,  of  oxygen  and  hydrogen  ;  and  the 
Bituminous  coals  often  12  per  cent,  in  weight  of  oxygen,  and  4  to  6 
of  hydrogen  ;  while  Brown  Coal,  the  bituminous  coal  of  later  forma 
tions  (which  ordinarily  gives  a  brownish -black  powder),  contains  20 
per  cent,  or  more  of  oxygen,  with  5  or  6  of  hydrogen. 

Mineral  coal,  therefore,  is  not  carbon,  but  a  compound,  or  a  mixture 
of  two  or  more  compounds,  of  carbon,  hydrogen,  and  oxygen,  asso 
ciated  probably  with  some  free  carbon  in  anthracite,  and  possibly  in 
some  or  all  bituminous  coal.  In  this  view,  coals  are  mainly  oxydized 
hydrocarbons,  or  mixtures  of  them.  As  stated  on  page  314,  they  are 
scarcely  acted  on  by  ether  or  benzine,  and  hence  contain  no  mineral 
oil,  or  only  a  trace  of  any  soluble  hydrocarbon ;  but,  at  a  high  temper 
ature,  hydrocarbons  (compounds  of  hydrogen  and  carbon)  are  given 
out,  in  the  forms  of  either  mineral  oil,  tar,  or  gas. 

The  coal,  as  has-been  shown,  is  derived  from  the  alteration  of  vege 
table  material.  This  vegetable  material  is  (a)  woody  fibre  ;  (b)  cel 
lular  tissue  ;  (c)  bark ;  (d)  spores  of  Lycopods  (Lepidodendrids,  etc.) ; 


CARBONIFEROUS   AGE.  361 

(e)  resins  and  associated  substances.  The  following  is  the  composition 
of  (1)  dried  wood  in  the  mass  ;  (2)  cork  (the  bark  of  Quercus  suber)  . 
(3)  the  spores  of  Lycopods  ;  (4,  5,  6)  the  common  kinds  of  mineral 
coal ;  and  (7)  peat  or  vegetable  material,  partly  altered  to  the  coal- 
like  condition. 


I. 

Woody  Ingredients. 
1.  Wood        '  .  -     '-..  ' 

Carbon. 
.'•iViiTrrv-V-   .        49-66 

Hydrogen. 
6-21 

Oxygen. 
43-03 

Nitrogen. 
1-10 

2.  Cork       . 

.     6573 

8-33 

24-44 

1-50  =  100 

II. 

3.  Lycopocl  Spores 
Coal  "Products. 

64-80 
.     95-0 

8-73 
2-5 

20-29 
2-5 

6-18  =  100 

5.  Bituminous  Coal 

81-2 

5-5 

12-5 

0-8 

6.  Brown  Coal    . 

.     68-7 

5-5 

25-0 

0-8 

7.  Peat    . 

59-5 

5-5 

33-0 

2-0 

From  this  table,  it  appears  that,  in  the  change  of  woody  fibre  to 
anthracite,  the  diminution  in  the  amount  of  oxygen  and  hydrogen  is 
about  ninety  per  cent.,  and  that  of  the  oxygen  above  ninety-five  per 
cent. ;  in  that  to  bituminous  coal,  the  percentage  of  hydrogen  is  not 
very  much  altered,  but  that  of  the  oxygen  is  reduced  over  seventy  per 
cent.  ;  in  that  to  brown  coal,  the  percentage  of  the  hydrogen  is  the 
same  nearly  as  in  bituminous,  but  that  of  the  oxygen  is  reduced  only 
forty  to  forty-five  per  cent. 

The  relations  of  these  woody  materials  and  coals  are  still  better, 
exhibited  in  the  following  table,  giving  the  atomic  proportions  of  the 
constituents,  carbon  being  made  one  hundred  ;  the  atomic  equivalents 
of  carbon,  hydrogen,  and  oxygen  being  respectively  12,  1,  16. 


Carbon. 

Hydrogen. 

Oxygen  . 

1.  Wood         

.     100 

150 

65 

2.  Cork        

100 

150 

30 

3.  Lycopod  Spores          . 

.     100 

166 

24 

4.  Anthracite       ..... 

100 

33 

2 

5.  Bituminous  Coal         . 

.     100 

83 

12 

6.  Brown  Coal     

100 

96 

27 

7.  Peat    . 

,     100 

112.5 

40 

There  was  littlo  ordinary  bark  in  the  beds  of  vegetable  debris,  since 
the  cortical  part  of  Lycopods,  Ferns,  and  Calamites  is  not  of  this 
nature :  although  nearer  coal  in  constitution  than  true  wood,  bark 
resists  alteration  longer,  and  is  less  easily  converted  into  coal.  The 
spores  of  Lycopods  often  retain  their  amber-yellow  color  in  the  coal, 
although  undoubtedly  changed  in  constitution.  Resins,  which  are  still 
nearer  coal  in  the  amount  of  carbon,  but  hold  less  oxygen,  are  found 
mostly  as  resins  in  coal,  especially  when  they  are  in  lumps  or  grains, 
but  of  somewhat  altered  composition. 

The  composition  given  above  for  dried  wood  is  the  mean  of  many  analyses,  by  Pe- 
tersen  and  Schbdler  (Liebig's  Annalen,  xvii.  141),  as  deduced  by  Bischof,  corrected  by 


362  PALEOZOIC   TIME. 

deducting  1-10  from  the  oxygen  and  making  it  nitrogen.  Pure  woody  fibre  and  cellular 
tissue  (cellulose)  consist  of  Carbon  4444,  hydrogen  6-17,  oxygen  49-39  =  100;  but, 
through  the  presence  of  resinous  and  other  matters,  the  average  composition  of  wood  is 
as  stated.  The  mean  composition  for  the  wood  of  three  common  species  of  Pines 
(Finns  larix,  P.  abies,  and  P.  picea)  differs  little  from  the  average,  it  being  (the  nitrogen 
included  with  the  oxygen)  Carbon  49'84,  hydrogen  6'37,  oxygen  43 -75  =  100.  From 
Chevandier's  various  analyses  (Ann.  Ch.  Phys.,  III.  x.  129),  the  average  constitution 
of  wood  is,  Carbon  51-21,  hydrogen  0-21,  oxygen  41/45,  nitrogen  1-10  =  100.  His  re 
sult  differs  from  the  preceding,  mainly  in  the  separation  of  the  nitrogen  from  the 
oxygen. 

The  ultimate  analysis  of  Cork,  on  the  preceding  page,  is  by  Mitscherlich.  Cork  (one 
of  the  purest  of  barks)  includes  about  ten  per  cent,  of  substances  soluble  in  absolute 
alcohol,  one  of  which  contains  over  eighty  per  cent,  of  carbon,  with  little  oxvgen,  and 
hence  the  low  percentage  of  oxygen  in  the  analysis  of  cork  above  cited.  Bark  also 
contains,  on  an  average,  twelve  per  cent,  of  tannic  acid  (a  compound  of  Carbon  52-4  per 
cent.,  hydrogen  3'6,  oxygen  44-0);  and  the  rest  of  it  is  supposed  to  be  impure  cellulose. 

Dawson  has  suggested,  in  view  of  the  many  Sigillaria  stumps  hollowed  out  bv  decay, 
and  flattened  stems  of  other  trees,  tilled  with  shale  or  sandstone,  found  in  the  Coal- 
measures,  that  the  vegetable  debris  from  which  the  coal  has  proceeded  was  largely  bark, 
or  material  of  that  general  nature.  But  the  occurrence  of  such  stumps  and  stems  outside 
of  the  coal-beds,  while  proof  that  the  interior  wood  of  the  plants  was  loose  in  texture  and 
verv  easily  decayed,  is  no  evidence  that  these  trees  contributed  only  their  cortical  portions 
to  the  beds  of  vegetable  debris.  Moreover,  the  cortical  part  of  Lepidodendrids  (under 
which  group  the  Sigillarids  are  included  by  the  best  authorities)  and  of  Ferns  also,  is 
made  of  the  bases  of  the  fallen  leaves,  and  is  not  like  ordinary  bark  in  constitution;  and 
Equiseta  have  nothing  that  even  looks  like  bark.  This  cortical  part  was  the  firmest  part 
of  the  wood;  and  for  this  reason  it  could  continue  to  stand,  after  the  interior  had  decayed 
away,  — an  event  hardly  possible  in  the  case  of  a  bark-covered  Conifer,  however  decom 
posable  the  wood  might  be.  Further,  trunks  of  Conifers  are  often  found  in  the  later  geo 
logical  formations,  changed,  throughout  the  interior,  completely  to  Brown  coal  or  Lignite. 

Lycopods  and  Equiseta  have,  like  Ferns  and  Mosses,  the  same  constitution  with  ordi 
nary  wood.  The  following  are  the  results  of  anatyses  of  species  of  these  plants  by  Mr. 
George  "W.  Hawes,  and  also  of  a  Sphagnum  (Peat-swamp  moss)  by  Websky,  the  ash 

excluded:  — 

Carbon.      Hydrogen.     Oxygen.        Nitrogen. 

1.  Lycopodium  dendroideum  .  48-70  6 -61  43 -25  1-44  Hawes. 

2.  Lycopodium  complanatum  .     48-43  6'61  43-02  1-94  Hawes. 

3.  Equisetum  hyemale    .        .  47 '50  6'68  44-49  1-27  Hawes. 

4.  Sphagnum    ".  49'88  6'54  42-42  1-16  =  100  Websky. 

As  the  Sphagnum  is  made  of  cellular  tissue,  the  analyses  show  that,  in  Lycopods,  the 
cellular  and  vascular  portions  are  essentially  alike  in  constitution. 

The  fact  that  the  spores  of  Lycopods  retain  an  amber-like  color,  in  the  coal,  proves 
that  they  do  not  yield  to  change  so  easily  or  thoroughly  as  the  ordinary  woody  tissues, 
but  approximate  in  this  respect  to  particles  of  resin. 

In  the  decomposition  of  wood  and  leaves  in.  the  air,  the  carbon 
and  hydrogen  combine  with  oxygen,  —  both  external  oxygen  and  that 
of  the"  plant,  —  and  the  ultimate  products  are,  as  in  the  combustion 
of  wood,  carbonic  acid  (CO2)  and  water  (H2O),  with  nothing  left 
behind.  Thus  it  is,  essentially,  with  the  leaves  and  stems  that  fall 
to  the  ground  over  the  drier  portions  of  the  continent. 

When  the  vegetable  material  is  under  water,  the  atmospheric  oxy 
gen  is  excluded,  except  the  small  part  contained  in  water ;  and  this 
oxygen,  with  some  proceeding  from  the  growing  plants  in  the  waters, 


CARBONIFEROUS   AGE.  363 

is  all  that  comes  from  external  sources.  Under  this  diminished  supply, 
part  of  the  carbon  and  hydrogen  escape  oxydation,  and  a  coaly  product 
is  left  behind.  This  covering  of  water  prevents  a  complete  combustion 
of  the  material,  just  like  the  covering  of  earth  over  burning  wood, 
when  charcoal  is  made.  The  air  might  also  be  partly  or  wholly  ex 
cluded  from  vegetable  debris,  by  a  covering  of  clay  or  earth  ;  and  this 
is  generally  what  happened,  sooner  or  later,  in  the  Carboniferous  period. 
The  changes  attending  the  ultimate  decomposition  under  these 
circumstances  depend  on  the  affinity  of  (1)  the  carbon  for  oxygen, 
making  carbonic  acid  ;  (2)  of  hydrogen  for  oxygen,  producing  water  ; 

(3)  of  carbon  for  hydrogen,  making  carbo-hydrogen  gas  or  oil  ;  and 

(4)  on  the  tendency  of  the  carbon  and  hydrogen,  under  certain  pro 
portions,  to  form,  with  a  portion  of  the  oxygen,  the  stable  compounds 
included  under  the  term  Coal.     The  carbonic  acid  and  water   escape, 
and  also  the  carbo-hydrogen  gas ;  and,  consequently,  under  the  most 
favorable  circumstances,  the  wood  loses,  in   the   change,  much   carbon 
and  hydrogen  as  well  as  oxygen.     It  is  probable  that,  in  the  making 
of  bituminous  coal,  at  least  three-fifths  of  the  material  of  the  wood 
are  lost;    and,  in    the  making  of  anthracite,  three-fourths.     Besides 
this  reduction  to  two-fifths  and  one-fourth  by  decomposition,  there  is 
a  reduction  in  bulk  by  compression  ;  which,  if  only  to  one-half,  would 
make  the  whole  reduction  of  bulk  to  one-fifth  and  one-eighth.      On 
this  estimate,  it  would  take  five  feet  in  depth  of  compact  vegetable 
debris  to  make  one  foot  of  bituminous   coal,  and  eight  feet  to   make 
one  of  anthracite.     For  a  bed   of  pure  anthracite    thirty  feet  thick, 
(like  that  at  Wilkesbarre),  the  bed  of  vegetation  should  have  been  at 
least  240  feet  thick. 

Anthracite  coal  is  a  result,  as  remarked  upon  beyond,  of  the  action 
of  heat  on  bituminous  coal,  under  pressure,  attending  an  upturning  of 
the  rocks,  the  heat  driving  off  nearly  all  volatile  matters  it  could  de 
velop,  and  so  leaving  a  coke  (the  anthracite)  behind.  Made  in  this 
way,  the  reduction,  in  the  case  of  anthracite,  would  be  to  about  one 
eighth,  as  above  estimated.  The  average  amount  of  ash  in  anthracite 
ought,  consequently,  to  be  nearly  half  greater  than  in  bituminous  coal. 

If  the  vegetable  debris  were  so  buried  that  no  external  oxygen  were  concerned  in 
the  change  attending  the  decomposition,  and  if  all  the  oxygen  of  the  wood  went  to 
form  carbonic  acid  with  part  of  the  carbon,  the  result  would  be  a  kind  of  mineral  oil; 
for  dry  wood  has  approximately  the  composition  C6H!1O4;  removing  from  twice  this, 
C12H18Q8,  4C02  (which  would'take  off  all  the  oxygen),  there  would  be  left  GSRis, 
the  composition  of  a  species  of  the  naphtha  group.  So  also,  animal  oils,  on  the  simple 
separation  of  carbonic  acid,  may  become  mineral  oils.  Warren  &  Storer  obtained,  by 
the  destructive  distillation  of  the  oil  of  the  white-fish,  after  its  saponification  by  lime, 
the  various  oils  of  the  marsh-gas  group,  besides  others  of  the  ethylene  and  benzole 
series.  It  is  well  known,  also,  that  similar  oils  are  obtained  by  the  destructive  distilla 
tion  of  wood. 


364  PALEOZOIC   TIME. 

But  the  change  could  not  be  as  simple  as  here  indicated,  since  (1)  there  is  some 
nitrogen  present  in  plants;  (2)  the  plants  would  have  undergone  some  change  before 
the  complete  burial:  (3)  some  water  and  carbo-hydrogen  might  also  be  made  and 
escape,  though  it  is  not  probable  that  the  amount  would  be  large.  The  facts  still 
illustrate  a  possible  mode  of  transformation.  But  since  part  of  the  oxygen  remains  in 
all  coals,  only  part  of  the  oxygen  of  the  wood  has  gone  to  produce  carbonic  acid;  and, 
moreover,  external  oxygen  has  taken  some  part  in  making  this  gas,  or  the  water  that 
is  given  off.  The  amount  of  oxygen  present  is  much  the  largest  in  Brown  coal,  and 
probably  because  external  oxygen  was  more  concerned  in  the  transformation  than  in 
the  making  of  Carboniferous  bituminous  coal. 

Bischof  has  calculated  that,  if  the  escaping  product  is  carbonic  acid  and  water, 
derived  from  the  elements  of  the  wood  (which  might  be  the  case  if  external  oxygen 
were  completely  excluded),  the  amount  of  coal  left,  in  the  case  of  bituminous  coal, 
would  be  about  54  per  cent.  If  the  escaping  gases  were  carbonic  acid  and  hydrogen, 
the  latter  combining  with  external  oxygen  to  form  water,  the  amount  of  bituminous 
coal  left  would  be  about  42  per  cent. 

It  h  also  to  be  noted,  that,  in  the  derivation  of  coal  from  vegetable  matters,  there 
may  be.  as  suggested  by  S.  W.  Johnson,  a  process  carried  forward  of  molecular  con 
densation,  such  as  organic  chemistry  affords  many  examples  of,  which  may  account 
for  the  increased  density  of  the  product,  and  for  the  occurrence  of  the  maximum 
density  in  anthracite. 

In  the  formation  of  peat, — the  first  step  toward  Brown  coal,  —  both  carbonic  acid 
and  water  escape,  with  also  a  little  carbo-hydrogen  gas  (marsh-gas)  and  nitrogen;  and 
the  peat,  which  results,  is  chiefly,  according  to  late  experiments,  humic  acid.  Brown 
coal  also  contains  probably  some  humic  acid,  as  is  indicated  by  the  brown  color  it  gives 
to  a  solution  of  potash  when  heated  with  it.  No  such  color  is  obtained  with  bituminous 
coal  or  anthracite. 

The  gas  bubbling  up  from  a  marsh  afforded  Websky:  Carbonic  acid  (CO2)  2-97, 
marsh-gas  (CH4)  43-30,  nitrogen  53'67  =  100.  The  carbonic  acid  is  proportionally  small ; 
because  it  is  soluble  in  water,  and  also  because  it  may  enter  into  combination  with 
earthy  ingredients  present  in  the  ash.  The  amount  of  escaping  nitrogen  shows  that 
coal  retains  but  little  of  that  in  the  vegetable  and  animal  life  of  the  marsh. 

See,  further,  on  the  making  of  Coal  and  Peat,  Bischof 's  "Chemical  Geology" 
Websky,  in  the  Jour.  f.  pr.  Chem.,  xcii. ;  Hunt,  in  Am.  Jour.  Sci.,  II.  xxxv.,  and  the 
Canadian  Naturalist,  vi.  241;  S.  W.  Johnson,  on  "  Peat  and  its  Uses." 

Impurities  of  the  Coal.  —  The  impurities  of  the  coal  are  in  part 
derived  from  the  wood. 

1.  Silica  is   present  in  the  exterior  part  of  the  stems  of  Equiseta 
(the  representatives  of  the  ancient  Calamites),  to  such  an  extent  that 
the  plants   sometimes  afford  25  per  cent,  of  ash,  with  half  this   silica. 
that  is,  100  Ibs.  of  the  dried  plants  contain  12J  Ibs.  of  silica  ;  and  it 
exists  in  smaller  proportions  in  the  interior  of  all  plants. 

2.  Alumina,  while  absent  from  most  plants,  constitutes  22  to  50 
per  cent,  of  the  ash  of  some  modern  species  of  Lycopods. 

3.  Lime  and  Magnesia  are  present  in  small  proportions  in  the  ash 
of  all  plants.     In   Cliara,  species   that   existed  in   the  Carboniferous 
era,  and  which  afford  30  per  cent,  or  more,  of  ash,  95  per  cent,  are 
carbonate  of  lime. 

4.  Oxyd  of  iron  is  present  in  many  plants.     The  ash  of  one  Lyco- 
pod  afforded  6  per  cent,  of  this  oxyd ;  and  the  same  is   true  of  a 
Sphagnum. 


CARBONIFEROUS   AGE.  365 

5.  Potash  is   present  in  all  terrestrial  vegetation,   and  soda  more 
sparingly  ;  but,  as  the  salts  of  these   alkalies  are  soluble,  they  would 
mainly  disappear  in  the  course  of  the  decomposition. 

6.  Traces  of  sulphur  occur  in  wood,  as  well  as  in   animal  matters, 
which  therefore  would  be  present   in   the  accumulating  beds.     This 
sulphur,   by  combination   with   iron,  would   have   formed  pyrite,  —  a 
common  impurity  in  coal-beds.     But  it  seems  also  to  exist  in  coal  in 
a   resin  or  some  other  organic  compound.      Nitrogen   is  present  in 
coals,  but  under  what  condition  is  not  known. 

Impurities  were  also  introduced,  as  earth  or  clay,  by  waters,  as  the 
occasional  intercalations  of  shale  show.  Even  the  winds  transport 
dust,  and  may  have  contributed  to  the  earthy  ingredients  of  the  coal. 

Waters  may  also  have  carried  in  other  ingredients  in  solution,  as 
oxyd  of  iron,  in  combination  with  either  carbonic  acid,  sulphuric  acid, 
or  some  organic  acid;  for  iron  is  carried  in  these  ways  (mainly  the 
last)  into  all  marshy  or  low  regions,  from  the  hills  around,  being 
derived  from  the  decomposition  of  iron-bearing  minerals.  Sulphate 
of  iron  would  lose  its  oxygen  from  contact  with  decomposing  vegeta 
tion,  and  become  sulphid  of  iron  ;  and  this  is  another  source  of 
pyrite.  In  the  change,  the  oxygen  takes  carbon  from  the  coal  or  de 
composing  plants,  and  forms  carbonic  acid,  which  escapes,  and  leaves 
only  sulphur  and  iron,  to  make  sulphid  of  iron,  or  pyrite.  The 
carbonic  acid  made  in  the  change  of  wood  to  coal  was  in  part  utilized 
by  its  combination  with  iron  in  the  protoxyd  state,  making  carbonate 
of  iron,  the  ordinary  constituent  of  the  iron  ore  of  coal  regions. 
Sesquioxyd  of  iron,  in  contact  with  decomposing  vegetation,  becomes 
protoxyd,  which  then  unites  with  the  escaping  carbonic  acid. 

The  following  are  analyses  of  the  ash  of  Lycopods  (1,  2),  Ferns  (3  to  6),  Equiseta 
(7,  8),  Conifer  (9),  Moss  of  the  genus  Sphagnum  (10),  and  Chnra  (11). 


KO 

NaO 

CaO 

MgO 

Fe203 

MnSQ' 

'     A  12Q3 

PQ5 

SQ3 

SiQ2 

Cl 

1.  Lye.  clavatum  . 

31-90 

2-68 

413 

5-89 

6-00 

- 

22-20 

7-30 

3-55 

13-01 

- 

2.  Lye.  clavatum  . 

25-69 

174 

7-93 

.6-51 

230 

253 

26-65 

536 

4-90 

13-94 

313 

3.  Aspl.  filix      .     . 

45-5 

5-2 

7-9 

7-4 

1-5 

- 

- 

20-0 

68 

22 

4-6 

4.  Aspid.  filix   .     . 

39-80 

531 

18.74 

8-28 

0-97 

- 

- 

2-56 

5-40 

4-38 

14-72 

5.  Osm.  spicant     . 

23-65 

3-33 

4-09 

6-47 

1-17 

- 

- 

1-76 

1-29 

53-00 

5-82 

6.  Pteris  aquilina  . 

19-35 

4-78 

12-55 

2-30 

3-94 

- 

- 

515 

1-77 

43-65 

6-20 

7.  Eq.  arvense  .     . 

19-16 

0-48 

1720 

2-84 

0-72 

- 

- 

2-79 

10-18 

4173 

6-26 

8    Eq.  Telmateia    . 

8-01 

0-63 

8-63 

1-81 

1-42 

- 

- 

1-37 

283 

70-64 

5-59 

9.  Pinus  abies  .     . 

12-84 

5-64 

58-27 

2-81 

160 

tr. 

tr. 

260 

1-60 

12-55 

2-06 

10.  Sphag.  commune  8'02 

12-40 

3-17 

4-92 

635 

tr. 

589 

106 

4-33 

41-69 

12-09 

11.  Chara  foetida     . 

0-85 

1-44 

95-35 

0-99 

0-67 

- 

- 

0.54 

0-42 

1-22 

0-16 

Analysis  1,  is  by  Ritthnusen  ;  2,  Aclerholt;  3,  A.  Weinhold;  4,  Struckmann;  5,  6,  9, 
Malaguti  &  Dtirocher;  7,  8,  E.  Wittig;  10,  H.  Vohl.;  11,  Schulz-Fleet. 

In  the  analyses  that  have  been  made  of  Lycopods,  the  amount  of  ash  is  3-2  to  6  per 
cent,  in  weight  of  the  dried  plant;  of  Ferns,  2-75  to  7-56  per  cent.  :  of  Equisetum  arvense, 
18-71  per  cent.  ;  of  Eq.  Telmateia,  26*75  per  cent.  ;  of  Conifers,  mostly  less  than  2  per 
cent.  ;  of  Chara  foetida,  31-33  per  cent.  ;  of  Fungi,  3*10  to  9'5  per  cent.  ;  of  Lichens, 


366  PALEOZOIC  TIME. 

1*14  to  17  per  cent,  (the  last  in  Cladonia).  but  mostly  between  1*14  and  4-30  per  cent. 
In  Lycopodium  dendroideum,  Hawes,  in  his  analyses  (p.  362),  found  3*25  per  cent,  of 
ash;  in  L.  complanatum,  5'47  per  cent.,  and  in  Equisetum  hyemale,  11*82  per  cent. 

Lycopodium  chamcecyparissus  afforded  Aderholt  51-85  per  cent,  of  alumina:  or,  when 
without  spores,  57*36  percent.;  while  Ritthausen  obtained  39*07  alumina  for  this  species, 
and  37*87  for  L.  complanatum.  In  Lycopods,  the  silica  constitutes  10  to  14  per  cent,  of 
the  ash.  In  the  ash  of  Mosses  have  been  found  8  to  23 '58  per  cent,  of  potash,  4  to  16 
of  silica,  1*06  to  6*56  of  phosphoric  acid,  4*9  to  10'7  of  magnesia.  Among  Ferns,  the 
amount  of  ash,  so  far  as  determined,  varies  from  5  to  8  per  cent. 

The  ash  of  Funyi  affords  21  to  54  per  cent,  of  potash,  0*36  to  11*8  of  soda,  1*27  to  8 
of  magnesia,  15  to  60  of  phosphoric  acid,  and  0  to  15*4  of  silica.  Among  Lichens,  the 
ash  of  Cludoni'i  rangiferina  contains  70*34  percent,  of  silica;  of  other  species,  less, 
down  to  0*9  per  cent. 

Trapa  natans,  of  bogs,  in  Europe,  affords  13  to  25  per  cent,  of  ash ;  and  25  per  cent, 
of  this  are  oxyd  of  iron  (Fe203)  with  a  little  oxyd  of  manganese.  Of  the  ash  of  the 
fruit  scales,  over  60  per  cent,  are  oxyd  of  iron. 

Since,  according  to  the  average  composition  of  Lycopods,  the  dried 
plant  affords  5  pounds  of  ash  to  100  of  the  plant,  and  40  per  cent, 
of  this  is  alumina  and  silica  (27  alumina  and  13  silica),  these  two 
ingredients  make  up  2  per  cent,  of  the  plants.  Ferris,  with  the  same 
amount  of  ash,  afford,  as  the  average,  27  per  cent,  of  silica,  with  no 
alumina.  Equiseta  afford,  on  an  average,  20  per  cent  of  ash,  and  50 
per  cent,  of  this  may  be  silica.  Supposing,  now,  that  Lycopods  (Lepi- 
dodendrids,  etc.)  afforded  one  half  the  material  of  the  coal-beds,  and 
the  other  plants  the  rest,  and  that  the  silica  and  alumina  of  the  former 
averaged  40  per  cent.,  and  of  the  latter  only  27  per  cent.,  this  being 
all  silica,  then  the  amount  of  these  ingredients  afforded  by  the  vegeta 
tion  would  be  1'66  per  cent,  of  the  whole  weight  when  dried.  This 
would  make  the  amount  of  silica  and  alumina,  in  the  bituminous  coal 
made  from  such  plants  (supposing  three  fifths  of  the  material  of  the 
wood  lost  in  making  the  coal,  as  estimated  on  page  363),  4  per  cent. ; 
and  the  whole  amount  of  ash  about  4*75  per  cent.  At  the  same  time, 
the  ratio  of  silica  to  alumina  would  be  nearly  3  to  2. 

Now  many  analyses  of  the  bituminous  coal  of  the  Interior  basin 
have  obtained  not  over  3  per  cent,  of  ash,  or  impurity,  although  the 
general  average,  excluding  obviously  impure  kinds,  reaches  4-5  to  6 
per  cent.;  being,  for  the  coals  of  the  northern  half  of  Ohio,  5-12,  and 
for  the  southern  half  4.72. 

It  hence  follows  that  (1)  the  whole  of  the  impurity  in  the  best  coals 
may  have  been  derived  from  the  plants ;  (2)  the  amount  of  ash  in  the 
plants  was  less  than  the  average  in  modern  species  of  the  same  tribes ; 
(3)  the  winds  and  waters  for  long  periods  contributed  almost  no  dust 
or  detritus  to  the  marshes  ;  and  (4)  the  ash,  or  else  the  detritus,  was 
greatest  in  amount  toward  the  borders  of  the  Interior  marsh-region. 
In  that  era  of  moist  climate  and  universal  forests,  there  was  almost  no 
chance  for  the  winds  to  gather  dust  or  sand  for  transportation. 


PERMIAN    PERIOD.  367 


3.   PERMIAN  PERIOD  (15). 

The  Permian  period,  the  closing  era  of  the  Carboniferous  age,  was 
a  time  of  decline  for  Paleozoic  life,  and  of  transition  toward  a  new 
phase  in  geological  history. 

The  term  Permian  was  given  by  Murchison,  De  Verneuil,  and  Key- 
serling,  after  the  ancient  kingdom  of  Permia,  in  Russia,  which  included 
the  existing  governments  of  Perm,  Viatka,  Kazan,  Orenburg,  etc., 
where  the  formation  exists.  In  America,  no  division  of  the  Permian 
period  into  epochs  has  been  recognized. 

1.  AMERICAN. 
I.  Rocks:   kinds  and  distribution. 

The  Permian  rocks  are  confined  to  the  Interior  Continental  basin, 
and  occur  in  the  portion  of  it  west  of  the  Mississippi,  —  especially  in 
Kansas,  and  perhaps  other  parts  of  the  eastern  slope  of  the  Rocky 
Mountains.  They  overlie  conformably  the  Carboniferous  ;  and,  as  the 
rocks  make  one  continuous  series,  it  is  difficult  to  determine  the  limit 
between  the  two  formations. 

The  rocks  are  limestones,  sandstones,  red,  greenish,  and  gray  marl- 
ytes  or  shales,  gypsum  beds,  and  conglomerates,  among  which  the  lime 
stones  in  some  regions  predominate. 

In  Kansas,  they  outcrop  along  the  western  border  of  the  Carboniferous  region,  and 
also  in  patches  to  the  east  of  this  range.  On  the  map,  p.  144,  the  Permian  is  dis 
tinguished  by  light  dots  on  a  dark  ground.  The  beds  occur  also  about  the  Black  Hills 
(near  lat.  44°  N.  and  long.  104°  W.),  on  the  eastern  slope  of  the  Big  Horn  Mountains, 
and,  according  to  Shumard,  in  the  Guadalupe  Mountains  in  New  Mexico. 

The  whole  thickness  made  out  by  Swallow  &  Han*n  is  about  820  feet;  and  203  feet 
of  this  are  called  by  them  the  Upper  Permian,  and  the  rest  the  Lower.  Meek  &  Hay- 
den  refer  the  Lower  division,  with  good  reason,  and  also  a  part  of  the  Upper,  to  the 
Upper  Coal-measures.  The  limestones  are  usually  impure,  and  also  magnesian,  like 
most  of  the  limestones  of  the  same  region  of  older  date.  They  are  generally  rather 
soft  or  irregular  in  structure,  and  much  interlaminated  with  clayey  or  arenaceous  beds. 
Some  of  the  layers  contain  hornstone.  In  a  review  of  the  Nebraska  Carboniferous 
fossils,  Meek  refers  all  to  the  Upper  Coal-measures,  although  they  contain  a  few  genera 
and  species  that  are  especially  characteristic  of  the  European  Permian.  (Havden's 
Rep.  on  Nebraska,  1872.) 

II.  Life. 

Nothing  is  yet  known  respecting  the  American  Permian  flora. 
In  the  beds  admitted  by  all  to  be  probably  Permian,  there  are  only 
a  few  Mollusks. 

The  species  here  figured  occur  in  the  uppermost  beds  (Permian  of  Meek  &  Hayden). 
Fig.  687,  Pseudomonotis  Hawnii  M.  &  H.,  cast  of  the  outside  of  the  left  valve; 
687  «,  cast  of  the  interior  of  the  right  vulve  of  the  same.  The  genus  Pseudomonotis 


368 


PALEOZOIC    TIME. 


is  related  to  Avicula:  it  has  an  opening  below  the  beak,  for  the  passage  of  the  byssuc, 
as  shown  in  the  figure.  Fig.  G88,  Myalina  perattenuata  M.  &  H.;  Fig.  689,  Bakeiceliia 
parva  M.  &  H. ;  Fig.  690,  Pleurophorus  subcuneatm  M.  &  H. ;  Fig.  691,  shell  of  a  small 
undetermined  Gasteropod. 


.  687-691. 


687a 


MOLLUSKS.—  Figs.  687,  687  a,  Pseudomonotis  H.awnii ;  688,   Myalina  perrattenuata :  689,   Bake- 
wellia  parva  ;  690,  Pleurophorus  subcuneatus  ;  691,  an  undetermined  Gasteropod. 

Among  the  species  of  Mollusks  from  the  beds  referred  to  the  Permian  by  Swallow, 
75  in  number,  nine  tenths  occur  also  in  the  Carboniferous  beds  below. 

III.  General  Observations. 

We  observe  the  following  facts  connected  with  the  period:  (1.) 
The  beds  are  apparently  all  marine  strata,  for  the  fossils  are  marine. 
(2.)  The  numerous  alternations,  between  impure  limestones  and  clays 
and  some  sand  deposits,  indicate  oscillations  through  the  period  in  the 
depth  of  water,  between  moderate  depths  and  very  shallow  waters. 
(3.)  The  absence  of  coal  beds  is  proof  that  there  were  no  fresh-water 
Carboniferous  marshes  in  the  regions  where  the  rocks  have  thus  far 
been  examined.  (4.)  The  non-occurrence  of  these  marine  strata  over 
the  region  east  of  the  Mississippi  seems  to  show  that  this  eastern  part 
of  the  continent  was  dry  land.  Early  in  the  Carboniferous  period, 
the  Pennsylvania  region  was  raised,  and  became  dry  even  of  its  old 
marshes;  for  only  the  Lower  Coal-measures  occur  there  ;  and,  in  the 
Permian  period,  as  it  appears,  the  dry  region  had  extended  so  as  to 
include  all  the  country  east  of  the  Mississippi.  (5.)  The  beds  occur 
within  the  same  region,  or  on  the  borders  of  the  same  region,  in 
which  the  Coal-formation  during  the  Carboniferous  period  was  repre 
sented  by  limestones  ;  that  is,  in  the  great  interior  sea  which  had  so 
long  existed  as  the  Paleozoic  representative  of  the  Gulf  of  Mexico,  — 
a  comparatively  shallow,  but  extensive,  inland  sea,  stretching  north 
ward.  The  present  western  limit  of  the  Gulf  is  nearly  in  a  north-and- 
south  line  with  the  western  boundary  of  the  State  of  Kansas.  The 
existence  of  these  Permian  deposits  was,  then,  owing  to  a  continuation 
of  the  conditions  that  characterized  the  Carboniferous  period.  That 


PERMIAN   PERIOD.  869 

era,  limestone-making  over  these  western  regions,  was  prolonged  into 
another,  when  the  limestones  formed  still,  but  with  numerous  inter 
ruptions  by  clay-depositions.  The  beds  are  continuous  with  the  Car 
boniferous,  without  interruption  or  uncouformability,  and  yet  are 
referred  to  the  Permian,  because  they  probably  belong  to  the  Permian 
period  in  geological  time,  or,  at  least,  its  earlier  portion. 

2.   FOREIGN  PERMIAN. 
I.  Rocks:  kinds  and  distribution. 

The  Permian  strata  of  England  outcrop  along  the  borders  of  the 
several  coal  regions,  excepting  that  of  South  Wales.  They  occupy  a 
small  area  in  Ireland,  about  the  Lough  of  Belfast.  They  consist  of  red 
sandstone  and  marlytes,  along  with  magnesian  limestone.  In  Europe, 
the  Permian  beds  in  like  manner  border  directly  upon  the  Coal- 
measures  ;  and  the  rocks  are  similar  in  general  character  to  those  of 
England. 

The  Permian  beds,  before  their  relations  were  correctly  made  out,  were  included, 
along  with  part  of  the  Triassic,  under  the  name  "New  Red  Sandstone." 

They  occur,  over  small  areas,  in  central  Germany,  from  southern  Saxony  along  the 
Erz  Mountains,  over  the  adjoining  small  German  States,  west  to  Hesse  Cassel,  and 
north  to  the  Hartz  Mountains  and  Hanover.  Within  this  area,  Mansfeld  is  one  noted 
locality,  situated  in  Prussian  Saxony,  not  far  from  Eisleben ;  another  is  on  the  south 
west  borders  of  the  Thuringian  forest  (Thiiringerwald),  in  Saxe-Gotha,  a  line  which 
is  continued  on  to  the  northwest,  by  Eisenach,  toAvard  Miinden  in  southern  Germany. 

In  Thuringia  and  Saxony,  the  subdivisions  of  the  rocks,  beginning  below,  are  (1)  the 
Rothlieyende  or  Red  beds  (called  also  Todtlieyende),  consisting  of  red  sandstone,  and 
barren  of  copper  ores;  near  the  town  of  Eisenach,  about  4,000  feet  thick.  (2.)  The 
Zechstein  formation,  or  magnesian  limestone,  consisting  of  (a)  the  Lower  Zechstein,  a 
gray,  earthy  limestone,  overlying  the  Kupferschiefer,  or  copper-bearing  shales,  and  the 
still  lower  Weisslieyende  or  GrctttUegende,  or  white  or  gray  beds;  (b)  the  Middle  Zech 
stein,  magnesian  limestone,  called  the  Rmch-ioacke  and  RauhTcalk;  (c)  the  Upper 
Zechstein,  or  the  Plattendolomit,  and  including  the  impure  fetid  limestone  called  Stink- 
stein.  The  formation  to  the  southward  loses  its  limestone.  The  whole  Permian  has 
been  called,  in  Germany,  the  Dyas,  from  the  Greek  for  two,  in  allusion  to  the  two 
principal  strata  of  which  it  there  consists.  (For  an  account  of  it,  see  Murchison's 
"  Siluria,"  and  also,  especially  for  its  fossils,  Geinitz's  "  Dyas,"  in  4to,  Leipzig, 
1861,  18620 

In  Durham,  England,  there  is  (1)  a  Lower  Red  Sandstone,  200  feet  thick  (corre 
sponding  to  the  Rothliegende  of  Germany);  then  (2),  a,  60  feet  of  marl-slate  (corre 
sponding  to  the  Kupferschiefer);  b,  two  strata  of  magnesian  limestone,  the  lower  500, 
and  the  upper  100  feet  thick,  separated  by  200  feet  of  gypseous  marlvte,  and  overlaid 
by  100  feet  of  the  same.  The  magnesian  and  other  limestones  disappear  to  the  south, 
near  Nottingham.  In  Northwestern  England,  the  Lower  Permian  includes  3,000  feet  of 
marlytes  and  sandstones;  the  Middle,  only  10  to  30  feet  of  magnesian  limestone;  the 
Upper,  600  feet,  similar  to  the  Lower.  The  red  sandstones  of  Rhone  Hill,  near  Dun- 
gannon,  Tyrone,  Ireland,  are  supposed  to  be  Permian.  There  are  detached  Permian 
areas  in  Dumfriesshire,  Ayrshire,  etc.,  in  Scotland.  In  Ayrshire,  they  cover  the  Coal- 
measures,  and  have  some  beds  of  igneous  rock  at  base. 

In  Russia,  the  two  German  divisions  are  recognized,  (1)  magnesian  limestones  inter- 
laminated  with  sandstones  of  true  marine  origin,  (2)  overlving  marlvtes  of  various 
24 


370 


PALEOZOIC   TIME. 


colors,  of  marsh  origin,  with  some  gypsum.  There  is  an  occasional  thin  seam  of  coal. 
The  strata  cover  a  region  over  the  interior  of  Russia  more  than  twice  as  large  as  all 
France,  including  the  greater  part  of  the  governments  of  Perm.  Orenburg,  Kazan, 
Nijni  Novgorod,  Yaroslavl,  Kostroma,  Viatka,  and  Vologda  (Murchison).  The  de 
posits  are  flanked  and  underlaid  on  nearly  all  sides  by  different  members  of  the  Car 
boniferous  formation  containing  comparatively  little  coal. 

The  coincidence  is  worth  noting,  that  the  Permian  rocks  of  Russia,  or  interior 
Europe,  lie  between  its  great  river,  the  Volga,  and  the  summit  of  the  Ural  Mountains, 
just  as,  in  interior  North  America,  they  occur  between  its  great  river,  the  Mississippi, 
and  the  Rockv  Mountain  summits.  It  may  be  that,  on  both  continents,  the  region 
between  the  great  river  and  the  ocean  had  been  raised  above  the  sea  during  the  pre 
ceding  changes. 

The  Permian  has  also  been  recognized  near  Bell  Sound  in  Spitzbergen;  and  Von 
Koninck  has  described  several  fossils  from  it. 

The  coal  formation  of  Illawarra  and  Hunter's  River,  Australia,  is  probably  Permian, 
as  stated  by  the  author  in  his  notes  on  Australian  Geology,  Geol.  Rep.  Wilkes'  Expl. 
Exped.,  4to,  1849. 

The  lower  part  of  the  Lower  Permian  of  England  contains,  in  some  places,  beds  of 
coarse  conglomerate,  containing  angular  masses  of  rock  of  great  size ;  and  Ramsay 
attributes  the  transportation  of  the  blocks  to  floating  ice. 

II.  Life. 
1.  Plants. 

The  Permian  plants  are  closely  related  to  those  of  the  Upper  Coal- 
measures.  They  are  mostly  of  the  same  genera,  and  in  part  of  the 
same  species.  There  are  Calamites,  JSquiseta,  ferns,  including  Tree- 


Figs.  692-695. 


Figs.  692,  693,  Neuropteris  Loschii ;  694,  694  a,  Annularia  carinata;  695,  Walchia  piniformis. 

ferns,  and  a  number  of  Conifers  and  Cycads ;  yet  the  prevalence  of 
some  new  kinds  gives  a  somewhat  different  aspect  to  the  flora.  Among 
Lycopods,  the  genus  Walchia  (Fig.  695)  is  most  characteristic. 

The  Ferns  were  of  the  genera  Neuropteris,  Sphenopteris,  Pecopteris,  Alethopteris,  etc. ; 
and  there  were  also  species  of  AsternjtJti/llites  and  Annularia,  as  well  as  Calamites,  Coal- 
measure  genera.  Catamites  yiyas  Brngt.  is  a  large  and  common  species.  On  the  other 


PERMIAN   PERIOD.  371 

hand,  there  were  few  SiffiOaride.  The  Conifers  were  more  varied:  they  included  species 
of  Dddoxylon,  Pinites,  Ullmannia,  etc.  The  genus  Wulch'ui,  characterized  by  lax  and 
very  short  spreading  leaves,  began  near  the  close  of  the  Carboniferous  period,  but  is 
much  more  numerous  in  species  during  the  Permian.  It  has  been  considered  a  Conifer; 
but  the  fruit,  according  to  Geinitz,  is  that  of  a  Lycopod.  Tree-ferns  of  the  genus  Psa- 
ronius  were  common,  as  in  the  Upper  Coal-measures.  Fruits  are  described,  by  Geinitz, 
of  the  genus  Gidivlmites,  which  he  supposes  to  be  of  the  Palm  tribe. 

Fig  092,  pinnule  or  branchlet  of  a  large  frond  of  Neu ropier 'is  Loschii,  a  species  com 
mon  to  the  Permian  and  Coal-measures,  as  well  also  as  Pecopteris  arborescens,  P.  similis, 
and  some  other  plants;  093,  a  portion  showing  the  venation.  Fig.  694,  a  small  part  of 
a  specimen  of  Anmdaria  carinata  Sternberg;  the  stem  is  jointed,  as  in  the  Equiseta,  and 
gives  off  branchlets  at  the  articulations;  these  branchlets  are  also  jointed,  and  have 
whorls  of  leaf-like  appendages  at  the  articulations.  In  694,  only  the  first  joint  and  its 
whorl  are  shown,  of  natural  size;  in 694 a,  a  branch  is  shown  (of  reduced  size),  consisting 
of  its  several  joints  and  whorls,  but  the  natural  termination  is  wanting.  Fig.  695,  Wal- 
chia  piniformis  Sternberg.  The  figures  arc  from  the  work  of  Geinitz  and  Gutbier  on. 
the  "Dyas  "  of  Saxony. 

2.   Animals. 

Corals  of  the  Cyathophyllum  family,  Brachiopods  of  the  genera  Pro- 
ductus,  Spirifer,  and  Orthis,  Pteropods  of  the  genus  Cvnularia,  Ceph- 
alopods  of  the  genus  Orthoceras,  and  Ganoid  fishes  with  vertebrated 
tails,  give  a  Paleozoic  character  to  the  Fauna.  But  there  are  many 
new  features :  among  these,  the  most  prominent  is  the  appearance  of 
Crocodilian  Reptiles  of  the  tribe  of  Thccodonts — species  having  the 
teeth  set  in  sockets,  as  the  name  (from  the  Greek)  implies. 

This  transition-character  is  apparent  also  in  the  number  of  old  ani 
mal  as  well  as  vegetable  types  that  here  nearly  or  quite  fade  out,  —  for 
it  is  the  period  of  the  last  of  the  species  of  Productus,  Orthis,  Murchi- 
sonia  ;  nearly  the  last  of  the  extensive  tribe  of  Cyathophylloid  corals, 
which  made  coral  reefs  of  far  greater  extent  than  those  of  modern 
seas  ;  nearly  the  last  of  the  extreme  vertebrate-tailed  (heterocercal) 


Fig.  696. 


Palaeoniscus  Freieslcbeni  (X 


Ganoid  fishes.  These  groups  had  already  dwindled  much,  before  the 
Permian  period  ;  for  some  prominent  Carboniferous  genera,  as  the 
Goniatites,  do  not  reach  into  it.  The  old  or  Paleozoic  world  was  pass 
ing  by,  while  within  it  new  types  had  come  forth,  prophetic  of  the 
earth's  brighter  future. 


372  PALEOZOIC  TIME. 


Characteristic  Species. 

1.  Radiates.  —  (a.}  Polyps.  —  Cyathophylloid  Corals,    (ft.)  Acalephs.  —  Corals  of 
the  genus  Stenopora.     (c.)  Echinoderms. —  Crinoids  near  Cyathocrinus ;    Echinoids  of 
the  genus  Eocidaris,  near  the  Paleozoic  Archceocidaris. 

2.  Mollusks.  —  (a.)  Bryozoans. —  Fenestella  retiformls  Vern.,  found  in  the  Per 
mian  of  Russia,  England,  and  Germany,  besides  a  dozen  other  related  species. 

(b.)  Brachiopods.  —  Spirifer  alatus  Schloth.,  from  England,  Lower  Zechstein  in  Sax 
ony, —  some  specimens  2^  in.  broad;  Spiriferina  cristata  Dav.,  from  the  Zechstein, 
Germany;  Productus  horridus  Sow.,  from  England  and  Germany,  characteristic  par 
ticularly  of  the  Lower  Zechstein,  and  occurring  also  in  the  Kupferschiefer;  Stropkalosia 
excavata  Gein  ,  England,  Germany;  the  species  of  the  genera  Productus  and  Sfropha- 
losia  are  exceedingly  abundant  in  individuals;  Camarophoria  Schlotheinil  Von  Buch, 
from  Russia,  Germany,  and  England;  the  genus  is  related  to  Terebraivfa  and  Pen- 
tamewts,  and  is  peculiar  to  the  Carboniferous  and  Permian;  Camarophoria  superstes, 
Russia. 

(c.)  Lamellibranchs. —  Pseudomonotis  speluncarin  Bevr.,  England,  Russia,  and  Ger 
many  in  the  Lower  Zechstein;  Clidophorus  Pallasi  Gein.,  Russia  and  Germany;  Mya- 
lina  squamosa  Sedg.,  Russia,  England;  Aviculn  KazanensisVern.,  Russia;  Bakewellia 
antiqua  King,  England,  Russia,  Germany;  Schizodus  dvbius  M.,  a  very  common  species 
in  England,  Germany,  and  Russia;  Scl/izodus  Schlotheimii  Gein.,  /S.  obscurus  Sow.,  and 
S.  truncatus  King.  The  genus  Schizodus  is  of  the  same  family  with  Triyonia,  a  charac 
teristic  genus  in  the  Reptilian  age:  it  commenced  in  the  Devonian. 

(d.)  Gasteropods  are  rare  fossils  in  the  Permian.  There  arc  a  few  species  of  Murchi- 
sonia  and  Straparvllus,  Paleozoic  genera,  besides  some  others. 

(e.)  Pteropods  of  the  genera  demand  Conularia. 

(f-)  Ctsphalopodi  existed,  and  among  them  two  or  three  species  of  Orthoceras. 

3.  Articulates. — No   Trilobites  are  known.     Ostracoids  are  common.     Under 
Tetradecapods,  occurs  here  the  Amphipod,  Protoponu&u  problematicus,  from  the  Per 
mian  of  Durham,  England,  first  described  by  Schlotheim,  but  recently  explained  by 
Bates.     Decapods  of  the  order  of  Macrourans  appear  to  have  commenced  in  the  Coal 
formation.     But  the  first  of  the  Brachyurans  is  announced  from  the  Permian  by  Yon 
Schauroth,  who  names  it  Hemitrochiscus  paradoxus.     It  is  an  eighth  of  an  inch  long. 
Geinitz  regards  it  as  related  to  the  Pinnotheres  family. 

4.  Vertebrates.  —  (a.}  Fishes.  —  Fig  096,  Pafaont'scus  Freieslebeni  Agassiz,  one- 
third  the   natural   size;  common  in  the  Kupferschiefer,  and  also  found  in  the  Coal- 
measures  in  England,  at  Ardwick.     Over  forty  species  of  fishes  have  been  described. 
The  more  characteristic  genera  are  Palceoniscus,  Platysomus,  Acrolepis,  Pyyopterus,  and 
Xenacanthus,  but  they  are  also  all  Carboniferous.    Besides  the  above,  the  species  include 
Palceoniscus  elegam  Sedgw.,  P.  comptus  Ag.,  Platysomus  macrurus  Ag.,  PL  yibbosus  Bl., 
Acrolepis  SedywicUi  Ag.,  Pyyopterus  mandibularis  Ag.,  Ccelacanthus  yranulatus  Ag.,  etc. 
lanassa  Utuminosn  Miinst.    and  Wodnika  striatula  Miinst.   are    species  of  Cestraciont 
sharks  from  the  Kupferschiefer.     Menaspis  armata  Ewald,  from  the  Kupferschiefer, 
has  been  regarded  as  a  Cephalaspid  related  to  Pteraspis,  but  also  as  the  head  or  tail 
shield  of  a  Crustacean. 

(b.)  Reptiles.  —  A  number  of  species  have  been  described,  belonging  to  the  tribes  of 
Labyrinthodonts  and  Thecodonts.  Fig.  697,  Proterosaurus  Speneri  Meyer,  regarded  as 
a  Thecodont.  It  was  3|  feet  long,  and  is  from  the  copper-slate  (Kupferschiefer)  of  Ger 
many  and  Saxony.  Two  species  of  the  same  genus  have  been  found  in  the  marl-slate 
of  Durham,  England,  along  with  others  of  Labyrinthodonts.  Dasyceps  Buckkindi  Hux 
ley  is  a  Labyrinthodont, from  Kenilworth,  England,  the  only  specimen  a  cranium  10 
inches  long  and  9}  broad. 

These  Permian  Reptiles  had  biconcave  vertebra1,  like  the  inferior  swimming  reptiles, 
but  the  socket-teeth  of  the  Crocodiles.  The  teeth  were  flattened,  and  creuulate  at  the 


GENERAL    OBSERVATIONS. 


373 


margins.    The  fingers  in  the  Proterosaurus  call  to  mind  those  of  the  Pterodactyl,  as 
Geinitz  suggests.     The  name  Proterosaurus  is  from  n-porepos,  first,  and  aavpos,  lizard. 

Fig.  697. 


Proterosaurus  Speneri. 

Various  footprints  of  Reptilians  and  Labyrinthodonts  have  been 
found  in  the  Permian  of  Germany;  among  the  latter,  Saurichnites 
salamandroides  Gein.,  and  among  the  former,  S.  lacertoides  Gein., 
feet  with  arcuate  finger-impressions.  Coprolites,  or  fossil  excrements, 
of  Reptiles  or  Fishes,  have  been  found  near  Zwickau  and  Mansfeld. 

The  Paleozoic  character  of  the  life  of  the  Permian,  as  already 
shown,  is  strongly  marked.  Geinitz  observes,  further,  that  the  Tere- 
bmtula  elonyata  Schlot.  of  the  Zechstein  approaches  a  Devonian 
form  ;  Cmnaroplioria  Schlotheimi  Kg.  (Zechstein)  is  near  the  Car 
boniferous  C.  crumena  Mart. ;  Spirifer  Cl'tnnyanus  Dav.  (Zechstein), 
the  Carboniferous  S.  Urii;  Sjnriferina  cristata,  the  Carboniferous 
S.  octoplicata.  The  genus  Schizodus  ends  with  the  Permian,  as  well 
as  Ortlus,  Camarophoria,  Producing,  and  Strophalosia. 


IV.  GENERAL  OBSERVATIONS  ON  THE  PALEOZOIC  AGES. 

I.  Rocks. 

1.  Maximum  thickness.  —  The  maximum  thickness  of  the   Silurian 
rocks  of  North  America  is  at  least  25,000  feet ;    of   the   Devonian, 
about  14,400  feet;  and  of  the  Carboniferous,  nearly  16,000  feet. 

2,  Diversities  of  the  different  Regions  of  the  continent  with  regard 
to  the  kinds  of  rocks.  —  The   rocks    of  the   Appalachian  region   are 
mainly  fragmental,  the  limestones  forming  only  a  fourth  of  the  whole 
thickness.     The  strata  of  the  Interior  Continental  basin   are   mostly 
limestones,  these  constituting  full  two-thirds  of  the  series.     Although 
New  York  is  situated  mostly  within  the  Interior  basin,  it  still  adjoins 
the  Appalachian  region,  and  partly  lies  within  its  border.     Some  idea 


374 


PALEOZOIC   TIME. 


of  the  contrast  between  the  two  regions  may  be  gathered  from  a  com 
parison  of  the  section  of  the  New  York  rocks,  on  p.  142,  with  the 
general  section  of  the  formations  in  the  Mississippi  valley  here  pre 
sented. 

In   the   Lower   Silurian  of   this  section,  the  Calciferous    beds    are 
mainly  of  limestone,  as  well  as  the  Trenton  and  the  greater  part  of 


Fig.  G98. 


{  PERMIAN 
I 


CARBONIFEROUS 


[  SUBCARBOXIFEROUS-{ 

t  CHEMUNG   .     .  . 

!  HAMILTON  .     .  .  j 

(  CORNIFEROUS    .  .  i 

NIAGARA     .     .  .  J 

CINCINNATI  .  .  .  j 

j  TRENTON  .  .  .  J 

CANADIAN  .  .  .  i 

I  POTSDAM  .  .  .  ) 


Permian. 
Coal-measures. 

Conglomerate. 
Subcarboniferous  limestone. 
Subcarboniferous  sandstone. 

Black  shale  (Huron). 

Cliff  limestone. 

Blue  limestone  and  shale. 

Trenton  limestone  :  Galena  limestone  ; 
Black  River  limestone. 

Lower  Magnesian   limestone. 
Potsdam  sandstone. 


Section  of  the  Paleozoic  rocks  in  the  Mississippi  basin. 

the  Cincinnati  Group.  The  Upper  Silurian  contains  little  but  lime 
stone  ;  the  Lower  Devonian  and  the  Subcarboniferous  are  also  mainly 
limestone.  Moreover,  many  limestone  beds  intervene  in  the  Coal  meas 
ures  ;  and,  west  of  the  Mississippi,  over  a  considerable  portion  of  the 
Rocky  Mountain  slope,  the  Carboniferous  beds  are  mainly  limestones. 
The  rocks  of  the  northern  border  of  the  Interior  Continental  basin, 
toward  the  Archaean,  contain  a  much  smaller  proportion  of  limestone 
than  those  of  the  central  portion. 

The  contrast  between  the  Appalachian  region  and  the  Interior  will  become  more  ap 
parent  from  a  few  general  sections.  The  first  here  given  is  from  the  State  of  Penn 
sylvania,  which  lies  within  the  Appalachian  region;  it  is  from  the  Geological  Report  of 
H.  D.  Rogers;  the  second  is  a  section  of  the  Ohio  rocks,  lying  on  the  eastern  border  of 
the  Interior  basin,  from  the  Geological  Reports  of  J.  S.  Newberry;  the  third  is  a  sec 
tion  of  the  Michigan  rocks,  lying  on  the  northern  side  of  the  basin,  by  A.  "Winchell : 
the  fourth,  of  Iowa,  which  is  also  on  the  northern  side,  by  C.  A.  White  ;  the  ffth  and 
sixth,  of  Illinois  and  Missouri,  which  are  near  its  centre, — the  former  by  A.  H. 
Worthen,  the  latter  by  G.  C.  Swallow,  but  with  changes  from  more  recent  informa 
tion;  the  seventh,  of  Tennessee,  of  which  the  eastern  part  is  in  the  Appalachian  region, 
and  the  middle  and  western  in  the  Interior,  by  J.  M.  Safford.  In  each  case,  the 
section  begins  below. 


GENERAL    OBSERVATIONS.  375 

1.  Pennsylvania  Section, 

Lower  Silurian. 

PRIMORDIAL,  Potsdam  Epoch.  —  "  Primal  Series  "  of  Rogers,  — sandstones  and  slates 

3,000-4,000  feet. 
CANADIAN,  Calciferous  Epoch.  —  "Auroral  "  calcareous  sandstone,  250  feet. 

Quebec  and    Chazy  Epochs.  —  "Auroral"   magnesian  limestone,  with  some 

cherty  beds,  5,400  feet. 

TRENTON,  Trenton  Epoch.  —  "Matinal  "  limestone,  with  blue  shale,  550  feet. 
Utica  Epoch.  —  "  Matinal  "  bituminous  shale,  400  feet. 

Cincinnati  Epoch.  —  "  Matinal  "  blue  shale  and  slate,  with  some  thin  gray  cal 
careous  sandstones,  1,200  feet. 

Upper  Silurian. 

NIAGARA,  Oneida  Epoch.  —  "  Levant  Gray  "  sandstone  and  conglomerate,  700  feet. 

Medina  Epoch.  —  "  Levant  Red  "  sandstone  and  shale,  1,050  feet;  and  "Le 
vant  White  "  sandstone,  with  olive  and  green  shales,  760  feet:  total,  1,810 

feet. 
Clinton  Epoch.  —  "  Surgent  Series,"  shales  of  various  colors,  both  argillaceous 

and  calcareous,  with  some  limestones,  ferruginous  sandstones,  and  iron-ore 

beds,  2,000  feet. 
Niagara   Epoch.  —  Not  well  defined;    possibly  corresponds  with  part  of  the 

"  Surgent "  series. 
SALINA,  Saliferous  Epoch. — "Scalent"  variegated  marls  and  shales,   some  layers  of 

argillaceous  limestone,  1,650  feet. 
LOWER  HELD  ERIJERG. —  "Scalent"   limestone,   thin-bedded,   with   much   chert,  350 

feet;  " Pre-meridian  "  encrinal  and  coralline  limestone,  250  feet;  total,  600 

feet. 
ORISKANY,    Oriskany  Epoch.  —  "Meridian"    calcareous  shales,   and  calcareous  and 

argillaceous  sandstone,  520  feet. 

Devonian. 

CORNIFEROUS,   Cauda-galli  Epoch.  —  "  Post-meridian  "    silico-calcareous  shales,  200- 

300  feet. 

Corniferous  Epoch.  —  "  Post-meridian  "  massive  blue  limestone,  80  feet. 
HAMILTON,  Marcellus  Epoch.  —  "Cadent."  Lower  black   and  ash-colored   slate,  with 

some  argillaceous  limestone,  800  feet. 

Hamilton  Epoch.  —  "Cadent"  argillaceous  and  calcareous  shales  and  sand 
stone,  1,100  feet. 

Genesee  Epoch.  —  "  Cadent  "  Upper  black  calcareous  slate,  700  feet. 
CHEMUNG,  Portage  Epoch. —  "Vergent"    dark-gray,  flaggy  sandstones,  with  some 

blue  shale,  1,700  feet. 
Chemung  Epoch.  —  Vergent"  gray,  red,  and  olive  shales,  with  gray  and  red 

sandstones,  3,200  feet. 
CATSKILL.  —  ';  Ponent "  red  sandstone  and  shale,  with  some  conglomerate,  6,000  feet. 

Carboniferous. 

SUBCARBOXIFEROUS,  Loioer.  —  "Vespertine"  coarse,   gray  sandstones  and  siliceous 
conglomerate  at  the  eastward,  becoming  line  sandstones  and  shales  at  the 
westward,  2,660  feet. 
Upper. —  "  Umbral  "   fine  red  sandstones  and  shales,  with  some  limestone, 

3,000  feet. 
CARBONIFEROUS,    Millstone- Grit    Epoch.  —  "  Serai  "    siliceous  conglomerate,   coarse 

sandstone  and  shale,  including  coal-beds,  1,100  feet. 
Coal-measures.  —  2,000-3,000  feet. 


376  PALEOZOIC   TIME. 

2.    Ohio  Section. 

Lower  Silurian. 

PRIMORDIAL,  Potsdam  Epoch.  —  Whitish  calcareous  sandstone,  316  feet  or  more—  (at 

bottom  of  the  "  State  House  well  "). 
CANADIAN,  Caldferous  Epoch.  —  Drab,  sandy,  magnesian  limestone,  475  feet  —  (passed 

through  in  boring  the  "  State  House  well  "). 
TRENTON,  Trenton,  Utica,  and  Cincinnati  Epochs.  —  Limestones  and  calcareous  shales 

and  marly tes,  blue  and  green  below,  gray,  brown,  and  red  above,  1,220  feet, 

(the  lower  250  found  only  in  deep  borings.) 

Upper  Silurian. 

NIAGARA,  Clinton  Epoch.  —  Cream  to  salmon-colored,  semi-crystalline,  crinoidal  lime 
stone,  10  to  40  feet. 
Niaf/ara  Epoch.  —  Shales,  60  to  100  feet,  overlaid  by  buff  and  blue  arenaceous 

and  magnesian  limestones,  90  to  180  feet. 

Salina  Epoch.  —  Limestones,  with  beds  of  gypsum,  1  to  16  feet. 
LOWER  HELDERHEKG. —  "  Waterlime  "  group:  gray  and  yellow,  coarse-grained  and 

massive  limestones,  70  to  100  feet. 
ORISKANY,  Oriskany  Epoch.  —  Coarse  saccharoidal  sandstone,  3  to  10  feet. 

Devonian. 

CORNIFEROUS,  Corniferous  Epoch.  —  Buff  massive  limestone,  15  to  100  feet. 
HAMILTON,  Hamilton  Epoch.  —  Bluish  marly  limestone,  10  to  20  feet  near  Sandusky, 

elsewhere  wanting. 

Genesee  Epoch. — Black,  bituminous    "Huron"  shale,  with  numerous  large 
calcareous  concretions,  250  to  330  feet.     Partly  Portage  ? 

(  "  Erie  "  green,  gray,  and  blue  shales,  with  few  thin  lay- 

CHEMUNG,  Portage  Epoch.  —  j   ers  of  sandstone  and  limestone :  1,000  feet  in  the  eastern 
Chemuny  Epoch.  —  \    counties,  500  to  400  in  the  central  ones,  and  thinning 
[  southward  until  no  longer  recognized. 

Carboniferous. 

SUBCARBONIFEROUS,  Lower.  —  "  Waverly  "  shales  and  sandstones;  in  the  northern 

counties,  320  feet ;  640  feet,  on  the  Ohio  River. 
Upper.  —  "  Maxville  »  limestone,  10  to  20  feet. 

CARBONIFEROUS,  Millstone  Grit  Epoch.  —Conglomerate  and  sandstones,  10  to  130  feet. 
Coal-measures.  —  Shales,  sandstones  and  limestones,  with  bands  of  iron  ore 
and  twelve  workable  seams  of  coal,  2,000  feet. 

3.  Michigan  (Lower  Peninsula)  Section. 

Lower  Silurian. 

PRIMORDIAL.  — No  formation  certainly  identified. 

CANADIAN.  —  " Lake  Superior"  sandstone,  mottled,  reddish,  or  dark  and  shaly,  at 

Sault  St.  Mary,  18  feet;  more  to  the  westward,  250  feet. 
TRENTON,  Trenton  Epoch. —  Blue  argillaceous  limestone,  with  shale,  30  feet 

^Cincinnati  Epoch.  —  Argillaceous   limestone,  bluish-gray  below,  18    feet  or 

more. 

Upper  Silurian. 

NIAGARA,  Clinton  Epoch.  —  Argillaceous  and  calcareous  limestones,  51  feet. 
Niagara  Epoch.  —  White  and  gray  limestones,  97  feet. 


GENERAL    OBSERVATIONS,  377 

SALINA,  Saliferous  Epoch.  — Brown  and  gray  argillaceous  limestones,  calcareous  clay, 

and  variegated  gypseous  marls,  37  feet. 
ORISKANY,  Oriskany  Epoch.  —  Cherty,  sometimes  agatiferous  conglomerate,  3  feet. 

Devonian. 

CORNIFEROUS,  Corniferous  Epoch.  —  Brecciated  limestone,  250  feet;  overlaid  by  oolitic, 
arenaceous,  and  bituminous  limestones,  104  feet. 

HAMILTON,  Marcellus  (?)  Epoch.  —  Black,  bituminous  limestone,  15  feet. 

Hamilton  Epoch.  —  Argillaceous   limestones,    17    feet;    crystalline  limestone, 
with  included  lenticular  clayey  masses,  23  feet;  total,  40  feet.     Contains  a 
bed  of  coal,  on  Little  Traverse  Bay. 
Genesee  (?)  Epoch.  —  Black,  bituminous  shale,  20  feet. 
CHEMUNG,  Portaye  Epoch. —  "Huron  "  shales,  190  feet. 

Carboniferous. 

SUBCARBONIFEROUS,  Lower.  —  "Huron"  and  "Marshall"  grit-stones,  and  reddish, 
yellowish,  and  greenish  sandstones  and  conglomerates,  173  feet;  "Napoleon 
sandstone,"  generally  micaceous,  with  clay  beneath,  123  feet;  "Michigan 
Salt-group,"  carbonaceous  and  argillaceous  shales,  magnesian  and  arena 
ceous  limestones,  and  thick  beds  of  gypsum,  184  feet;  total,  480  feet. 
Upper.  —  Limestones,  arenaceous  below,  66  feet. 

CARBONIFEROUS,  Millstone  Grit  Section  —  "Parma"  thick-bedded  sandstone,  in  some 

places  conglomerate,  105  feet. 

Coal-measures.  —  Bituminous  shales  and  fire-clays,  with  occasional  thin  sand 
stones  and  limestones,  123  feet;  "Woodville"  sandstone,  79  feet;  total, 
202  feet. 

4.  Iowa  Section. 

Lower  Silurian. 

PRIMORDIAL,  Potsdam  Epoch.  —  Sandstone,  with  thin,  calcareous  layers,  300  feet. 
CANADIAN,  Calciferous  Epoch.  —  '•  Lower  Magnesian  "  limestone,  250  feet. 

Chazy  Epoch.  —  "  St.  Peter's  Sandstone,"  8'J  feet. 
TRENTON,  Trenton  Epoch.  —  "Buff,"   "Blue,"  and  "Galena"  magnesian  limestones, 

with  some  shaly  portions  in  the  lower  layers,  450  feet. 

Cincinnati  Epoch.  —  Siliceous  and  argillaceous  "  Maquoketa  "  shales,  mostly 
bituminous,  80  feet. 

Upper  Silurian. 

NIAGARA,  Clinton  and  Niagara  Epochs.  —  Light  yellowish-gray,  compact  magnesian 
limestone,  with  much  chert.  350  feet. 

Devonian. 

HAMILTON,  Hamilton  Epoch.  —  Shales  and  magnesian  limestones,  200  feet. 

Carboniferous. 

SUBCARBONIFEROUS.  —  Consisting  of  —  1st,  "Kinderhook"  beds,  175  feet;  2d,  "Bur 
lington"  limestone,  190  feet;  3d,  "  Keokuk  "  limestone,  with  thin  beds  of 
shale,  90  feet;  4th,  "St.  Louis"  limestone,  commonly  brecciated  and  con 
cretionary,  in  some  parts  compact,  75  feet:  total.  530  feet. 

CARBONIFEROUS.  —  Lower  Coal-measures,  200  feet;  Middle,  200  feet;  Upper,  200  feet. 


378  PALEOZOIC   TIME. 

5.  Illinois  Section. 
Lower  Silurian. 
CANADIAN,  Calciferous  Epoch.  —  "  Lower  Magnesian  limestone,"  100  to  120  feet. 

Chazy  Epoch. —  u  St.  Peter's  "  sandstone,  150  feet. 
TRENTON,  Trenton  Epoch.  — "  Trenton  "  and  "  Galena  "  brown  magnesian  limestones, 

200  to  300  feet. 

Cincinnati  Epoch.  —  Shales,  shaly  sandstones,  and  dark-blue  limestone.  60  to 
250  feet, 

Upper  Silurian. 

NIAGARA.  —  Buff  and  gray  magnesian  limestone,  some  cherty  beds,  250  to  300  feet. 
LOWER  HELDERBERG  ?  —  "  Clear  Creek  "  limestone,  300  to  350  feet. 
ORISKANY.  —  Quartzose  sandstone,  becoming  locally  calcareous,  50  feet. 

Devonian. 

CORNIFEROUS  ?  —  Limestone,  10  to  120  feet. 

HAMILTON,  Hamilton  Epoch.  —  "  Black  shale,"  30  to  GO  feet. 

Carboniferous. 

SUBCARBONIFEROUS. —Consisting  of  — 1st,  "Kinderhook"  group,  100  to  150  feet; 
2d,  "Burlington"  limestones,  with  chert,  25  to  200  feet;  3d,  "  Keokuk  " 
group,  100  to  150  feet;  4th,  "  St.  Louis"  group,  50  to  200  feet;  5th, 
"  Chester  "  group,  500  to  800  feet. 

CARBONIFEROUS,  Millstone  Grit  and  Coal-measures,  600  to  1,200  feet. 

6.  Missouri  Section. 

Lower  Silurian. 

CANADIAN,  Calciferous  and  Quebec  Epochs. —  "  Lower  Magnesian  "  limestones,  1,300- 

1,500  feet. 
TRENTON,  Trenton  Epoch.  — Bluish -gray  and  drab  compact  limestone,  and  some  blue 

shale,  435  feet;   overlaid  by   "  Receptaculite  "  argillaceous  subcrystalline 

limestone,  130  feet;  total,  565  feet. 
Cincinnati  Epoch. — Two  beds  of  argillaceous  magnesian  limestone,  60  feet, 

separated  by  shales,  60  feet;  total,  120  feet. 

Upper  Silurian. 

NIAGARA,  Niagara  Epoch.  — Magnesian  and  argillaceous  limestone,  150  feet. 
LOWER  HELDERBERG.  — Light-gray  magnesian  limestone,  100  feet. 
ORISKANY.  —  Light-gray,  nearly  pure  limestone,  —thickness  not  given. 

Devonian. 

CORNIFEROUS.  —  Gray,  compact,  earthy  limestone,  with  chert  and  some  sandstone ;  in 
some  parts,  a  hard  white  oolyte.  75  feet. 

HAMILTON,  Hamilton  Epoch.  —  Blue  argillaceous  shale,  with  thin  layers  of  concretion 
ary  limestone,  50  feet. 
Genesee  Epoch.  —  "  Black  shale,"  6  feet. 

Carboniferous. 

SUBCARBONIFEROUS.  —  1st,  Light-drab,  fine-grained,  compact,  "Lithographic  "  siliceous 
limestone,  70  feet;   2d,  buff  sandstone,  with  some  magnesian  limestone, 


GENERAL    OBSERVATIONS.  379 

underlaid  by  shale,  100  feet;  3d,  fine-grained,  compact  limestone,  overlaid 
by  brown  silico-magnesian  limestone,  70-120  feet;  4th,  "  Encrinital,"  brown, 
buff,  gray  and  white,  coarse  crystalline  heavy-bedded  limestones,  every 
where  containing  chert,  500  feet;  5th,  "Archimedes  "  gray  and  drab,  crys 
talline  and  compact  limestones,  with  some  silico-argillaceous  limestones 
and  blue  shales,  200  feet;  6th,  "St.  Louis"  hard,  crystalline,  gray,  cherty 
limestone,  with  thin  beds  of  argillaceous  shale,  250  feet;  7th,  "Ferru 
ginous  "  brown  and  red,  coarse,  friable  sandstone,  in  some  parts  white  and 
"  saccharoidal,"  200  feet:  total,  1,150  feet. 

CARBONIFEROUS,  Coal-measures.  —  Blue  and  gray  compact  limestones,  with  black, 
blue  and  purple  bituminous  and  calcareous  shales,  and  a  few  thin  beds  of 
coarse  sandstone,  2,000  feet  or  more. 

7.  Tennessee  Section. 

Lower  Silurian. 

PRIMORDIAL,    Acadian  Epoch   (?).  —  "  Ocoee "   slates   and  conglomerates,  8,000    to 

10,000  feet. 

Potsdam  Epoch. —  "Chilhowee"  sandstones  and  sandy  shales,  at  least  2,000 
feet  in  East  Tennessee. 

CANADIAN,  Calciferous  and  Quebec  Epochs.  —  "  Knox  Group,"  fine-grained  sandstones 
and  shales,  with  magnesian  limestone:  sandstone  member  (lowest),  800-1.000 
feet  in  East  Tennessee,-  shales,  1,500-2,000  feet;  limestone,  3,500  to  4,000 
feet. 

TRENTON,  Trenton  Epoch.  —  Blue  and  dove-colored  limestones,  gray  and  mottled  mar 
bles  and  shales,  1,500-2,000  feet  in  East  Tennessee  ;  Trenton  and  lower  part 
of  "Nashville  Group,"  500  feet  in  Middle  Tennessee. 

Utica  and  Cincinnati  Epochs.  — Upper  part  of  "  Nashville  Group,"  calcareous 
shales  and  argillaceous  limestones,  including  beds  of  fine  marble,  500-1,000 
feet  in  East  Tennessee  ;  500  feet  in  Middle  Tennessee. 

Upper  Silurian. 

NIAGARA,    Medina  Epoch.  —  "Clinch  Mountain"   white   and   gray  sandstone,  and 

"White  Oak  Mountain  "  brown  sandstones  and  shales,  800-1,000  feet. 
Clinton  Epoch.  —  "  Dyestone  Group,"  variegated  calcareous  shales,  with  some 
sandstone  and  bands  of  "dyestone  "  iron-ore,  100-300  feet  in  East  Tennessee. 
Niagara  Epoch.  —  "  Meniscus  "  gray  limestone,  150-200  feet. 

LOWER  HELDERBERG.  —  Gray  crinoidal  limestone,  75-100  feet  in  Middle  Tennessee ; 
absent  elsewhere  ( ?). 

Devonian. 

HAMILTON  (  ?),  Genesee  Epoch.  —  "  Black  shale,"  a  brownish-black  shale,  often  pyrit- 
iferous  and  bituminous,  with  a  layer  of  phosphatic  nodules  at  top,  and  a 
dark  gray,  fine-grained  bituminous  fetid  sandstone  at  bottom,  100  feet  or 
more. 

Carboniferous . 

SUBCARBONIFEROUS,  Loiver.  —  "Siliceous  Group,"  shales  and  sandstone,  varying  to 

blue  and  gray  limestones,  mostly  cherty,  with  some  shale,  300-550  feet. 
Upper.  —  "Mountain"    limestone,    blue,    thick-bedded,    and    in   great   part 
oolitic,  500-700  feet  in  Middle  Tennessee. 

CARBONIFEROUS.  —  Sandy  conglomerates,  sandstones  and  shales,  with  six  or  more 
workable  coal-beds,  2,500  feet  or  more. 


380  PALEOZOIC    TIME. 

In  the  Eastern-border  region,  about  the  Gulf  of  St.  Lawrence 
(which  was  probably  an  interior  basin  like  the  Interior  Continental), 
there  were  limestones  forming  almost  continuously,  from  the  Calcif- 
erous  epoch  in  the  Lower  Silurian  to  the  close  of  the  Clinton  epoch 
in  the  Upper  Silurian,  which  is  the  last  of  the  formations  there 
observed.  With  regard  to  other  parts  of  the  Eastern-border  region, 
our  knowledge  is  yet  imperfect,  and  in  great  measure  because  the 
crystallization  which  the  rocks  have  undergone  has  obliterated  most 
of  their  original  features.  This  is  the  case  over  New  England  and 
the  border  of  the  continent  south  of  New  York.  Besides  this,  a  strip 
of  land  some  eighty  miles  wide,  constituting  the  eastern  margin  of  the 
continental  plateau,  is  still  under  water  (p.  11).  The  map,  Fig.  735, 
gives  a  general  view  of  the  breadth  and  depth  of  this  plateau,  off  the 
coast  of  New  Jersey. 

3.  Diversities  in  the  different  regions  as  to  the  thickness  of  the  rocks. 
—  The   maximum  thickness   of  the  North  American  Paleozoic  rocks 
is  55,000  feet.     About  45,000  feet  of  this  thickness  occur  in  the  Ap 
palachian    region    of   Pennsylvania,   the  rest  being  made  up  by  the 
excess  of  the  Carboniferous  formation  in  Nova  Scotia.    All  this  45,000 
feet  is  not  found  in   any  one  place  ;  for  some  of  the  formations  are 
thickest  along  the  middle  of  the  region,  others  on.  the  western  side, 
and   still  others  on  the  eastern.     The  general  thickness  over  the  Ap 
palachian  regions  is  40,000  feet,  according  to  Hall.     Each  of  the  suc 
cessive  formations  in   the   Appalachian   region  is  remarkable  for  its 
great  thickness,  from  the  Potsdam  upward. 

In  the  central  portions  of  the  Interior  Continental  basin,  the  thick 
ness  varies  from  3,500  (and  less  on  the  north)  to  6,000  feet.  It  is,, 
therefore,  from  one  seventh  to  one  twelfth  that  in  the  Appalachian 
region. 

Another  region  of  unusual  thickness  lies  on  the  north  side  of  the 
Interior  basin,  near  the  Archaean.  Along  Lakes  Superior  and  Huron, 
the  fragmental  Huronian  beds  of  the  closing  part  of  the  Archaean  age 
accumulated  to  a  thickness  of  10,000  to  20,000  feet ;  and,  in  the  course 
of  the  Canadian  period,  the  sedimentary  beds,  in  some  places  about 
the  former  lake,  reached  a  thickness  of  3,000  to  4,000  feet.  Again, 
in  the  region  of  the  St.  Lawrence,  about  Ottawa,  the  Potsdam  beds 
have  twice  the  thickness  they  exhibit  in  the  State  of  New  York  ;  and 
the  Trenton  beds  in  Canada  are  three  times  as  thick,  or  nearly  1,000 
feet. 

In  Missouri,  during  the  Calciferous  and  Quebec  epochs,  the  accumu 
lations  had  the  great  thickness  of  1,300  feet,  —  an  exception  to  the 
usual  fact  in  the  Interior  Continental  region. 

4.  Relative  duration  of  the    Paleozoic  ages.  —  The    thicknesses  of 


GENERAL    OBSERVATIONS.  381 

the  series  of  rocks  pertaining  to  the  several  ages  affords  some  data  for 
estimating  tlieir  time-ratios.  The  results  are  necessarily  uncertain, 
since  the  increase  of  a  rock  is  often  directly  connected  with  the  subsi 
dence  there  in  progress,  as  has  been  elsewhere  explained.  Still,  the 
conclusions  are  sufficiently  reliable  to  be  here  presented. 

Taking  the  maximum  thickness,  along  the  Appalachians,  of  the  suc 
cessive  formations  (the  limestone  and  fragmental  beds  in  each  case 
from  the  same  region),  we  find  for  the 

Fragmental  rocks.        Limestones. 

1.  Potsdam  period 7,000  200 

2.  Rest  of  Lower  Silurian   .     .     .  18,000  6.000 

3.  Lower  Silurian  era     ....  25,000  6,200 

4.  Upper  Silurian  era      ....     6,760  600 

5.  Devonian  Age 14,300  100 

6.  Carboniferous  Age     ....  16,000  125 

Limestones  increase  with  extreme  slowness,  as  explained  in  the 
chapter  on  coral  islands.  From  five  to  ten  feet  of  fragmental  deposits 
will  accumulate  while  one  of  limestone  is  forming.  This  conclusion 
is  sustained  by  the  ratio,  in  any  given  period,  between  the  fragmental 
rocks  of  the  Appalachians  and  the  limestones  of  the  Interior  basin. 

Taking  the  ratio  as  5  to  1,  and  making  the  substitution  accordingly, 
the  numbers  are,  respectively,  (1)  8,000;  (2)  48,000;  (3)  56,000; 
(4)  0,760;  (5)  14,800;  (6)  16,625.  These  numbers  have  nearly  the 
ratio  1  :  6  :  7  :  1 J  :  2  :  2.  Hence,  for  the  Silurian,  Devonian,  and  Car 
boniferous  ages,  the  relative  duration  will  be  8^ :  2 :  2,  or  not  far  from 
4 :  1:1.  Or,  the  Silurian  age  was  four  times  as  long  as  either  the  De 
vonian  or  Carboniferous  ;  and  the  Lower  Silurian  era  nearly  six  times 
as  long  as  the  Upper  Silurian. 

In  the  Silurian  age,  the  ocean  worked  almost  alone,  in  the  wear  and 
accumulation  of  rock  material,  while  in  the  Carboniferous,  at  least 
about  Nova  Scotia,  where  the  Carboniferous  rocks  are  nearly  three 
times  as  thick  as  elsewhere,  river-action  aided  greatly  in  the  result. 
Hence  the  ratio  4:1:1  would  seem  to  give  the  relative  length  of  the 
Carboniferous  age  too  high.  Yet,  as  the  eras  of  the  several  coal  beds 
must  have  been  each  of  great  length,  the  ratio  can  hardly  need 
change  on  this  account. 

II.  Life. 

1.  System  of  progress.  —  The  Animal  kingdom  began  with  Proto 
zoans,  then  followed  Radiates,  Mollusks,  and  water- Articulates ;  it 
included  Fishes,  the  lower  Vertebrates,  in  the  closing  Silurian ;  and 
Amphibian  Reptiles  in  the  commencing  Carboniferous  age.  With 
each  period,  the  progress  was  upward,  toward  a  fuller  and  higher  dis 
play  of  the  system  of  life,  though  not  beginning  always  in  the  lowest 
species  of  a  group. 


382  PALEOZOIC   TIME. 

It  is  important  to  observe,  in  this  connection,  that  the  length  of  the 
Age  of  Invertebrates,  or  Silurian  age,  as  just  shown,  was  at  least 
four  times  that  of  either  the  Devonian  or  the  Carboniferous. 

The  following  are  some  of  the  principles  bearing  on  the  progress  of 
life,  which  have  been  exemplified  in  Paleozoic  history. 

( 1 .)    The  earlier  species  were  aquatic,  and  all  of  them  marine. 

Protozoans,  Radiates,  Mollusks,  and  the -water-Articulates,  comprise 
all  known  species  of  animals,  and  Sea- weeds  all  the  fossil  plants,  to 
the  close  of  the  Lower  Silurian  ;  and  the  Upper  Silurian  adds  only 
Fishes,  or  aquatic  Vertebrates,  and  terrestrial  Cryptogams.  In  all 
divisions  of  the  kingdoms  of  life,  the  species  made  for  the  water  are  of 
inferior  grade.  As  already  stated,  there  were  probably  exceptions,  in 
the  existence  of  Lichens  and  Fungi  even  before  the  Silurian,  and  of 
Insects  and  Spiders  before  the  Devonian ;  but  direct  proof  of  this  is 
wanting. 

(2.)  Many  of  the  earlier  types  were  comprehensive  types,  that  is,  they 
combined  the  characteristics  of  two  or  three  groups  of  the  same  or 
later  time.  Thus,  the  Bracldopods,  the  most  common  of  all  the  kinds 
of  life,  combined  characteristics  of  both  the  Mollusks  and  the  Worms, 
and  so  decidedly  that  a  recent  writer,  Mr.  E.  S.  Morse,  takes  the 
ground  that  they  are  more  closely  related  to  Worms  than  to  Mollusks. 

Crinoids,  and  especially  the  Cystids,  combine  the  flexible  arms  of 
Star-fishes  with  much  of  the  box-like  structure  and  other  characters  of 
Echini.  Trilohites  have  intermediate  characters  between  those  of 
Entomostracans  and  those  of  Tetradecapods,  although  apparently  be 
longing  to  the  former  of  these  groups. 

Neuropterous  Insects  of  the  Devonian  and  Carboniferous  eras  were 
in  general  not  purely  Neuropters,  but  combined  characters  of  Orthop- 
ters  also,  showing  it  in  their  wings  and  other  parts,  one  even  having  a 
stridulating  arrangement,  which  at  present  is  peculiarly  the  property  of 
Orthopters. 

Ganoid  fishes  are  well  called  Reptilian  fishes  by  Agassiz,  they  hav 
ing  the  teeth  of  the  ancient  Labyrinthodont  Reptiles,  a  cellular  air- 
bladder  approximating  to  a  lung,  and  a  flexible  articulation  between 
the  head  and  neck  —  points  not  known  among  the  ordinary  Osseous 
fishes. 

The  CephaJaspids,  the  earliest  Ganoids,  were  intermediate  in  some 
respects  between  Ganoids  and  the  Sharks,  the  other  fishes  of  the  De 
vonian. 

The  Amphibian  ^Reptiles  of  the  Carboniferous  were  mainly  if  not 
wholly  Labyrinthodonts,  species  that,  along  with  the  ordinary  charac 
ters  of  the  Amphibians,  had  the  scaly  skin,  strong  teeth,  etc.,  of 
Lizards,  or  true  Reptiles. 

The  Lepidodendrids  of  the  Coal  era,  while  true  Acrogens,  have  the 


GENERAL   OBSERVATIONS.  383 

aspect  and  foliage  of  the  Pine  tribe.  The  Cycads  have  the  habit  of 
foliage  nearly  of  a  Palm,  the  vernation  of  a  Fern,  the  leaf  uncoiling  iii 
its  development,  along  with  the  wood,  flowers,  and  fruit,  and  hence  the 
essential  structure,  of  a  Conifer. 

Thus  it  was  true  of  many  of  the  grand  divisions  that  they  embraced 
a  wider  range  of  characters  than  belongs  to  the  divisions  which  after 
ward  appeared.  In  some  cases,  these  comprehensive  types  occurred 
along  with  the  groups  of  which  they  were  in  a  sense  the  combination, 
as  in  the  case  of  the  Lepidodendrids  with  the  Ferns  and  Pine-tribe, 
during  the  Devonian  and  Carboniferous  ages.  In  other  cases,  they 
were  prophetic  of  one  or  two  groups  yet  to  exist,  as  with  the  Ganoids, 
which  foreshadowed  reptile  life  long  before  it  appeared,  and  also  the 
purer  fish  type. 

3.  Many  of  the  Paleozoic  species  were  much  larger  than  later  species 
of  the  same  groups.     Among  Crustaceans,  there  were  Trilobites  larger 
than  any  living  Crustacean  ;  species  of  the  Eurypterus  group  five  feet 
long,  while  the  nearest  existing  species  are  not  an  inch  long  ;  Ostra- 
coids  of  ten  times  the  length  and  a  thousand  times  the  bulk  of  modern 
kinds  ;  and  so  also  with  the  Phyllopods. 

Among  Insects,  there  were  Neuropters  whose  wings  were  over  three 
inches  long  and  two  wide,  vastly  beyond  the  size  of  any  recent  May 
fly.  Among  Fishes,  there  were  Sharks  at  least  thirty  feet  long,  or 
near  the  size  of  the  largest  living  species.  Among  Reptiles,  the  an 
cient  Amphibians  were  gigantic,  compared  with  the  frogs  and  salaman 
ders  of  the  present  day  ;  the  earliest  known  had  its  fore-foot  four 
inches  broad.  Among  Plants,  the  ancient  Lepidodendrids  were  great 
trees  ;  while  the  modern  Lycopodia,  to  which  they  are  related,  are  two 
feet  or  less  in  height. 

The  Entomostracans  (Trilobites,  Phyllopods,  Ostracoids,  Eurypte- 
rids,  etc.)  made  their  grandest  display  in  the  Silurian  and  Devonian 
ages,  and  Cryptogamous  plants  their  best  in  the  Carboniferous  age. 

4.  Many  of  the  Paleozoic  species  were  multiplicate  forms,  the  body 
containing  more  than  the   normal   number  of  divisions.     In  normal 
Crustaceans,  the  number   of  segments,  or  rings,  of  which  the  thorax 
and  abdomen  consist,  is  fourteen  ;  but,   in   the  great  majority  of  the 
Paleozoic  species,  including  all  the  Phyllopods  and  many  of  the  Tri 
lobites,  the  number  was  indefinite.     Again,  in  the  Echinoids,  of  Post- 
carboniferous  time,  the  number  of  vertical  series  of  plates  was  more 
than  twenty,  the  normal  number. 

5.  Very  many  of  the   earlier  Paleozoic  animals  were  fixed  species 
with  stems  or  other  mode  of  attachment,  like  flowers.     The  Crinoids  are 
examples  among  Echinoderms  ;  the  Graptolites,  among  Acalephs  ;  the 
Corals,  among  Polyps  ;  Bryozoans  and  Brachiopods,  among  Mollusks  ; 


384  PALEOZOIC   TIME. 

and  these  made  up  a  very  large  part  of  the  animal  life  of  the  Lower 
Silurian. 

6.  Harmony  in  the  life  of  an  era.  —  The  forests  of  the  Devonian 
and  Carboniferous  were  made  up  of  Acrogens,  or  the  highest  of  Cryp 
togams,  and  Conifers,  the  lowest  of  Phenogams  ;  and  among  the  for 
mer  there  were  the  pine-like  Lepidodendrids  and  Sigillarids,  having 
the  foliage  of  the  Conifers,  and  somewhat  also  of  their  form  of  fructi 
fication.     In  the  Silurian,  when  the  bivalved  Mollusks  were  the  most 
abundant  of  species,  Ostracoids,  or  bivalve  Crustaceans,  were  also  ex 
ceedingly  common. 

7.  Exterminations.  —  At  the  close  of  each  period  of  the  Paleozoic 
ages,  there  was  an  extermination  of  a  large  number  of  living  species. 
Again,  as  each  epoch  terminated,  there  was  an  extermination  of  life, 
but  in  most  cases  less  general.     With  the  transitions  between  strata  of 
different  kinds,  in  the  course  of  an  epoch,  there  were  usually  some  ex 
terminations  ;  and,  even  in  the  passage  from  layer  to  layer,  there  is 
often  evidence  of  the  extinction  of  some  species.     In  a  corresponding 
manner,  there  were  often  one  or  more  new  species  with  each  new  kind 
of  layer,  and  generally  several  with  each  change  in  the  strata ;  while 
many  appeared  with   the   opening  of  an   epoch,  and   a  whole  fauna, 
nearly,  with  the  commencement  of  a  period.     Hence,  the  introduction 
and  extinction  of  species  were  going  on  through  the  whole  course  of 
the  history,  instead  of  being  confined  to  particular  points  of  time ;  but, 
at  the  close  of  long  periods  and  epochs,  there  were  more  general  ex 
terminations.    As  the  rocks  from  which  the  facts  come  are  Continental 
rocks,  the  conclusion  with  regard  to  the  completeness  of  extermina 
tions  cannot  be   regarded  as  applying  necessarily  to  the  life   of  the 
deeper  parts  of  the  ocean. 

8.  Extinction  of  whole  tribes,  families,  or  genera  of  species.  —  Among 
the  tribes  of  land-plants  of  the  Carboniferous  age  that  became  extinct 
at  its  close,  there  are  those  of  the  Sigillarids  and  Lepidodendrids. 

The  races  of  animals  that  were  most  prominent  in  giving  a  special 
character  to  the  Paleozoic  fauna  were  the  following :  — 

Among  Radiates,  Crinoids  and  Cyathophylloid  Corals ;  among  Mol- 
lusl'S,  Brachiopods  and  Orthocerata  ;  among  Articulates,  Trilobites ; 
among  Vertebrates,  the  vertebrate-tailed  Ganoid  fishes.  Of  these,  the 
group  of  Trilobites  became  extinct  with  the  close  of  the  Paleozoic, 
and  the  vertebrate-tailed  Ganoids  very  nearly  so  ;  and  Cyathophylloid 
Corals,  Crinoids,  Brachiopods,  and  Orthocerata  lost  their  preeminence 
in  numbers  of  species  and  individuals,  in  their  respective  sub-kingdoms. 

The  following  are  a  few  other  examples  of  the  last  appearance 
among  fossils  of  prominent  Paleozoic  groups  :  — 

Graptolites,  which  culminated  in  the  Lower  Silurian,  became  rare 
before  the  close  of  the  Upper  Silurian,  and  ended  with  the  Carbonif- 


GENERAL    OBSERVATIONS.  385 

erous  ;  Cystideans,  which  culminated  also  in  the  Lower  Silurian,  and 
had  their  last  species  in  the  early  Devonian,  though  not  their  last  spe 
cies  in  fact,  since  the  depths  of  the  Atlantic  Ocean  still  contain  Cys- 
tids;  Goniatites,  which  began  in  the  Hamilton  period  of  the  Devonian, 
and  are  unknown  after  the  Carboniferous  age.  Many  other  instances 
are  given  in  the  table  beyond.  The  causes  of  such  extinctions  were 
connected  with  a  higher  principle  than  that  of  mere  physical  catas 
trophe. 

The  following  table  presents  to  the  eye  the  history  of  many  of  the 
genera,  families,  and  tribes  of  Paleozoic  species,  showing,  by  means  of 
the  narrow  dark  areas,  the  time  of  their  commencement;  the  time  of 
their  culmination  (by  the  greatest  breadth  of  the  area)  ;  and  the  time 
of  their  extinction  in  the  course  of  the  Paleozoic  ages,  or  the  fact  of  their 
continuing  to  survive  in  after-time.  Thus,  opposite  the  word  Polyps, 
the  area  commences  near  the  beginning  of  the  Silurian,  and  increases 
through  the  Paleozoic,  but  does  not  terminate  there,  since  they  exist 
afterward  ;  the  Cyathophylloid  Corals  begin  with  the  Lower  Silurian, 
have  their  maximum  in  the  Devonian,  and  only  a  few  are  known  after 
the  Carboniferous.  At  the  top  of  the  columns,  P.  Pd.  stands  for  Pri 
mordial  Period ;  and  S.,  C.,  P.,  for  Subcarboniferous,  Carboniferous, 
and  Permian. 

9.  Genera  of  the  present  time  dating  from  the  Paleozoic  era.  —  The 
number  of  lines  connecting  the  past  with  the  present  is  considerably 
increased  in  the  Carboniferous  age.  These  lines  are,  however,  only 
long-lived  genera,  not  species.  The  following  are  those  which  appear 
to  be  determined  with  a  good  degree  of  certainty :  — 

Lingula  (?),  Discina,  Crania,  Nautilus,  Pleurotomaria,  Rhyncho- 
nella,  Terebratula,  Ostrea,  Avicula,  Pinna,  Lima,  Solemya,  Leda,  Nu- 
cula,  Dentalium,  Chiton.  They  are  all  Molluscan.  The  first  five 
commenced  in  the  Lower  Silurian.  It  is  to  be  acknowledged  that 
there  may  have  been  greater  differences  between  the  existing  and 
modern  species  of  these  genera  than  the  shells  have  given  reason  to 
suspect.  In  view  of  this,  the  older  Lingulce  have  been  of  late  called 
Lingulellce,  sufficiently  great  differences  existing  to  excite  the  belief 
that  the  animals  were  generically  different.  'It  is  a  remarkable  fact 
that  there  are  no  Radiate  genera  in  this  list. 

Besides  the  above,  the  genera  Area  and  Astarte  have  been  referred 
to  the  Paleozoic ;  but  the  species  probably  belong  to  other  genera. 
There  are  no  genera  of  Articulates,  unless  it  be  the  genus  Spirorbis, 
about  which  there  is  reason  for  much  doubt. 

There  are  modern  genera  of  Protozoans  in  the  Paleozoic,  and  prob 
ably  also  of  Diatoms  ;   and  the  number  of  such  genera  among  these 
protozoan   and  protophyte  forms  will  probably  be  greatly  increased, 
when  the  species  are  further  investigated. 
25 


386 


PALEOZOIC   TIME. 


RADIATES. 

Polyps 

Cyathophyllum  Family 

Favosites,  of  the  Madrepore  Tribe.  . . 
Halysites 


Oculina  Tribe 

Astrsea  Tribe .  . . 


Acalephs 

Graptolites 

Chaetetes 

Echinoderms 

Cystideans 

Crinideans 

Blastideans  (Pentremites,  etc.) 

Star-fishes 

Palaeechinoids  (including  Archaeocidaris) 

Cidaris,  Spatangids,  etc 


MOLLUSKS. 

Brachiopods 

Lingula  Family,  gen.  Lingulella 

Obolus,  Obolella 

Discina  Family,  gen.  Discina 

Siphonotreta 

Orthis  Family,  gen.  Orthis 

Leptaena 

Strophomena 

Rhynchonella  Family,  gen.  Rhynchonella,  etc. 

Pentamerus 

Camarophoria 

Productus  Family,  gen.  Chonetes 

Productus 

Spirifer  Family,  gen.  Atrypa. , 

Spirifer 

Athyris 


GENERAL    OBSERVATIONS. 


387 


Terebratula  Family,  gen.  Terebratula.  . . 
Stringocephalus,  Rensselaeria.  . 

Other  Terebratulids 

Crania  Family,  gen.  Crania. 

Bryozoans 

Acephals 

LAMELLIBRANCHS 

Monomyaries 

Dimyaries  without  a  siphon 

Dimyaries  having  a  siphon 

Cephalates 

PTEROPODS  

GASTEROPODS 

Shell  without  a  beak 

Shell  beaked 

Cephalopoda 

Nautilus  tribe,  including  Orthoceras,  etc. . 
Ammonite  tribe,  gen.  Goniatites. . 
Ammonite  Tribe,  gen.  Ammonites 

ARTICULATES. 
Worms 

Crustaceans 

ENTOMOSTRACANS 

Ostracoids 

Trilobites  .  . , 


Paradoxides . . 
Bathyurus 


Asaphus,  Remopleurides 

Calymene,  Ampyx,  Illaenus,  Acidaspis, 
and  Ceraurus 


388 


PALEOZOIC   TIME. 


SILURIAN. 

DEV 

CARD 

LO\VER.                     UPPER. 

P.  Pd.  | 

S    C.  P. 

Homalonotus  and  Lichas  
Phillip'ia   Grifflthides 

. 

• 

{       1 
i 

Phyllopods  

i 

-^^*- 

Cyclops  Tribe  (Eurypterus,  etc.)  
TETRADECAPODS  
Isopods        

BBBBH 

mmmtm 

- 

Avnphipods  

DECAPODS         .                         

j 

1      j 

ijl 

i 

i 

1  ^ 

Myriapods        •        

i 

i    1 

i  . 

Insects                                  .           

i  fl 

j 

BEETLES             .        .        

LEPIDOPTERS,  DIPTERS,  HYMEN  OPTERS,  etc  

VERTEBRATES. 
Fishes                         

I 

j 

-1  —       

1                                                        __m 

In 

Hybodonts                  

i 

I  II 

ep 

1 
1 

1  

i  1 

ORDINARY  

i   .  ..    _ 

i     \\ 

•     .  i 

1     M 

i  

i  ~~n 

i  n 

i  U 

i 

..-i  4-j 

1            ! 

GENERAL    OBSERVATIONS.  389 

III.  American  Geography. 

1.  General  course  of  progress.  —  Through  the  Paleozoic  ages,  the 
dry  land  of  the  closing  A.rchaean  age  (map  on  p.  149)  gradually  ex 
tended  southeastward,  southward,  and  southwestward.  At  the  end  of 
the  Silurian,  the  limit  of  the  dry  land  appears  to  have  crossed  New 
York,  near  the  central  east-and-west  line  of  the  State ;  and,  at  the 
close  of  the  Devonian,  it  lay  not  far  from  its  southern  border. 
Westward,  beyond  Michigan,  in  Illinois,  Iowa,  and  Minnesota,  there 
was  a  like  expansion  to  the  south  and  west  of  the  Wisconsin  Archaean. 
Michigan  long  continued  to  be  a  part  of  the  oscillating  Interior  basin, 
the  Paleozoic  formations  being  continued  there,  even  to  the  close  of 
the  Coal  period. 

Along  the  St.  Lawrence,  the  Ottawa  basin  was  nearly  obliterated 
at  the  close  of  the  Lower  Silurian  (p.  216).  At  the  same  time,  the 
folding  and  crystallization  of  the  rocks  of  the  Green  Mountains,  —  the 
northern  portion  of  the  Appalachian  chain,  —  took  place  ;  and  the 
region  of  the  mountains  became  dry  land,  and  part  of  the  terra  firma 
of  North  America.  In  the  latter  half  of  the  Upper  Silurian,  the 
river  opened  into  a  St.  Lawrence  gulf  over  the  site  of  Montreal,  and 
a  Lower  Helderberg  limestone  was  formed  in  its  waters,  upon  the  up 
turned  Lower  Silurian.  The  same  waters  extended  southward  along 
Lake  Champlain  and  the  Hudson  River  valley  ;  and  in  them  Lower 
Helderberg  limestones  were  formed,  on  both  sides  of  the  Hudson 
River.  In  the  Devonian  age,  the  head  of  the  St.  Lawrence  gulf  was 
probably  in  the  vicinity  of  Quebec,  and  opened  southward  over  central 
New  England  ;  for  coral  reefs  were  growing  in  the  region  of  Lake 
Memphremagog,  and  in  the  Connecticut  valley,  at  Littleton,  N.  II., 
during  the  earlier  Devonian  (p.  256)  ;  and  Crinoids  in  the  same  valley, 
in  Massachusetts  (p.  237),  in  the  Lower  or  Upper  Ilelderberg  era. 

Still  farther  south,  over  part  of  Rhode  Island,  lay  the  Carbon 
iferous  marshes  or  coal-making  area  of  the  New  England  basin  ;  while, 
to  the  northeast,  over  part  of  Nova  Scotia  and  New  Brunswick,  the 
region  of  the  St.  Lawrence  Gulf,  and  bordering  portions  of  New 
foundland,  there  were  the  far  larger  marshes  of  the  Acadian  basin. 
The  two  belong  geographically  to  the  same  great  region  —  then  low 
—  between  the  St.  Lawrence  and  the  ocean,  but  were  probably  in 
part  separated  by  the  Archaean  rocks  of  northeastern  Massachusetts. 

At  the  same  time,  over  the  rest  of  the  continent,  the  dry  land 
had  expanded  nearly  to  its  present  extent,  and  became  covered  with 
forests,  jungles,  and  marshes  of  Carboniferous  vegetation.  This  con 
dition  oscillated  with  that  of  marine  submergence,  many  times  in  the 
progress  of  the  Coal  period.  But  the  dry  land  appears  to  have  reached 


390  PALEOZOIC   TIME. 

a  degree  of  permanence,  in  the  Appalachian  region,  after  the  Pittsburg 
Coal  series,  and  to  a  still  wider  extent,  throughout  the  whole  interior 
east  of  the  Mississippi,  after  the  Upper  Coal  beds  (p.  368)  ;  so  that, 
when  the  Carboniferous  period  closed,  the  continent  in  this  its  eastern 
half  was  almost  complete.  Over  the  whole  surface,  including  New 
England,  Canada,  and  the  British  possessions  eastward,  no  rocks 
occur  between  the  Paleozoic  and  Cretaceous,  excepting  small  strips  of 
Mesozoic  in  the  Eastern-border  region,  east  of  the  Alleghanies,  and 
also  in  the  Connecticut  valley  and  Nova  Scotia. 

The  interior  sea,  which  in  Silurian  and  Devonian  periods  had 
spread  from  the  Gulf  of  Mexico  over  the  whoje  Interior  Continental 
basin,  and  northward  on  the  west  side  of  the  Arch^an  nucleus  to  the 
Arctic  Ocean,  after  many  variations  eastward  and  westward  in  its  ex 
tent  through  the  whole  Paleozoic,  was  at  last  mostly  limited  to  the 
region  west  of  the  Mississippi ;  for  here  are  located  all  the  marine 
sedimentary  deposits  of  the  Interior,  formed  in  later  time. 

2.  Mountains.  —  The  mountains   of  the  Paleozoic   continent  were 
mainly  those   of  the  Archa3an, — the  Adirondack,  of  northern   New 
York;  other  heights,  in   British  America;  ridges   in   the  line  of  the 
Highlands  of  New  Jersey,  and  the  Blue  Ridge  of  Virginia ;  probably 
the  Black  Mountains  of  North  Carolina ;  the  Black  Hills,  Wind  River 
Mountains,  and  other  ridges  in  the  seas  of  the  Rocky  Mountain  region, 
etc.     The  Carboniferous  marshes  covered  a  large  part  of  the  site  of 
the  Alleghanies ;  and  a  sea,  in  which  Carboniferous  limestones   were 
forming,    a    considerable    portion  —  perhaps    all    but    the    Archrean 
heights  —  of  the  area  of  the  Rocky  Mountains. 

Moreover,  after  the  close  of  the  Lower  Silurian,  the  Green  Moun 
tain  region  appears  to  have  been  above  the  sea  (pp.  212,  305),  and 
divided  the  New  England  or  Eastern-border  region  from  the  Interior. 
Consequently,  the  subsequent  progress  of  the  dry  land  over  New 
England  was  from  the  Green  Mountain  region  eastward,  as  well  as 
from  the  St.  Lawrence  southward.  In  other  words,  the  Devonian 
beds,  which  stretch  from  Gaspe  to  Vermont,  stretch  also  over  much  of 
Maine.  But  nearly  all  the  interior  of  New  England  was  probably 
dry  land,  after  the  close  of  the  Lower  Devonian,  since  rocks  of  the 
Upper  Devonian  are  confined  to  the  Atlantic  border  of  Maine  and 
New  Brunswick.  At  the  close  of  the  Devonian,  another  mountain- 
making  epoch  passed  over  the  Eastern-border  region  (p.  289)  ;  and 
probably  the  upturning  and  crystallization  of  the  Devonian  and  Upper 
Silurian  rocks  of  New  England,  as  well  as  of  Eastern  Canada,  Nova 
Scotia,  and  New  Brunswick,  dates  from  this  time. 

3.  Rivers.  —  The  rivers  of  the   early  Paleozoic  were  only   small 
streams,  such  as  might  have  gathered  on  the  limited  Archaean  lands. 


GENERAL   OBSERVATIONS.  391 

In  the  later  Devonian  and  the  Carboniferous,  they  included  the  Hud 
son  and  St.  Lawrence  (p.  287),  and  probably,  during  the  Carbon 
iferous,  the  Connecticut.  But,  even  to  the  last,  the  region  of  the 
great  streams  of  the  Rocky  Mountains  was  still  a  part  of  the  interior 
sea ;  the  Mississippi  had  but  a  part  of  its  length,  and  this  only 
temporarily,  as  the  country  was  often  submerged.  The  valley  of  the 
Ohio  River  was  in  part  the  region  of  the  interior  Carboniferous 
marshes :  as  the  mountains  in  which  it  rises  were  not  yet  raised,  the 
river  cannot  have  existed.  Moreover,  the  Cincinnati  uplift  (p.  212), 
which  stretched  southwestward  into  Kentucky  and  Tennessee,  and 
may  date  from  the  beginning  of  the  Upper  Silurian,  probably  divided 
the  great  interior  marshes  about  the  upper  Ohio  region  from  those  of 
the  lower. 

IV.  Oscillations  of  level.  —  Dislocations  of  the  strata. 

1.  General  subsidence.  —  The  earliest  Silurian  beds,  in  the  Appa 
lachian  region  and  New  York,  —  the  Primordial,  —  bear  abundant 
proof,  in  ripple-marks,  sun-crack?,  and  wind-drjfts,  of  their  formation 
near  the  water-level.  Many  of  the  succeeding  strata  of  the  Silurian 
and  Devonian  periods  contain  the  same  evidence,  and  lead  to  the  same 
conclusion  for  each ;  and  later,  in  the  Carboniferous  formation,  many 
layers  show  in  a  similar  manner  that  they  were  spread  out  by  the 
waves,  or  within  their  reach.  Consequently,  when  these  last  layers 
of  the  Paleozoic  in  the  Appalachian  region  were  at  the  ocean's  level, 
the  Potsdam  beds  —  though  once  also  at  the  surface  —  were  about 
seven  miles  below  (p.  380)  ;  for  this  is  the  thickness  of  the  strata  that 
intervene ;  seven  miles  of  subsidence  had,  therefore,  taken  place  in 
that  region,  during  the  progress  of  the  Paleozoic  ages. 

From  analogous  facts,  it  is  learned  that  the  subsidence  in  the  In 
terior  Continental  basin  may  not  have  exceeded  one  mile.  In  the 
lower  peninsula  of  Michigan,  measuring  it  by  the  thickness  of  the 
rocks,  it  was  at  least  2,500  feet ;  in  Illinois,  3,000  to  4,000  feet ;  in 
Missouri,  5,000  to  6,000  feet. 

On  the  northern  border  of  the  Interior  basin,  near  the  Archaean, 
the  thickness  of  the  Lower  Silurian  indicates  a  great  subsidence  in 
that  era,  which  was  not  afterward  continued.  Thus,  in  the  vicinity  of 
the  Great  Lakes,  the  10,000  or  20,000  feet  of  the  Huronian  in  the  last 
part  of  the  Archaean  age,  and  the  4,000  of  the  early  Lower  Silurian, 
teach  that,  near  the  beginning  of  Paleozoic  time,  this  was  a  region 
of  unusual  subsidence ;  and  the  igneous  rocks  that  intersect  and  inter- 
laminate  the  sedimentary  strata  evidently  came  up  through  the 
fractures  that  accompanied,  or  were  occasioned  by,  the  subsidence. 

In  Western   Canada,  between  the  stable  Archa3an  of  Canada  and 


392  PALEOZOIC    TIME. 

New  York,  the  1,000  feet  of  Trenton  limestone  and  700  feet  of  Cal- 
ciferous  and  Potsdam  beds  prove  that  there  was  a  great  subsiding 
also  in  that  region,  during  the  Lower  Silurian,  while  little  occurred 
on  the  south  side  of  the  New  York  Archaean  region. 

In  Nova  Scotia,  the  subsidence  in  the  Carboniferous  age  alone  was 
almost  three  miles,  or  nearly  half  the  seven  estimated  for  the  Appa 
lachians  ;  and  the  question  of  such  a  subsidence  is  placed  beyond  doubt, 
by  finding  root-bearing  clay-beds  and  coal-beds  at  different  levels  in 
the  series,  marking  approximately  the  successive  water-levels  as  the 
slow  subsidence  went  forward. 

All  the  numbers  here  given  are  probably  below  the  actual  fact ; 
for  the  strata,  in  many  cases,  —  especially  along  the  Appalachian  re 
gion  -r-  may  have  lost  much  of  their  original  thickness  by  denudation, 
either  before  or  after  they  were  consolidated.  This  loss  may  have 
been  one  fourth  the  whole  ;  but,  whatever  its  extent,  it  probably  has 
not  altered  the  proportion  of  subsidence  between  the  Appalachian 
region  and  the  Interior. 

2.  Oscillations.  —  The  successions  of  sandstones,  shales,  and  lime 
stones  in  the  Paleozoic  series  have   been  explained   to   be  indications 
of  as  many  changes  in  the  water-level  of  the  continent.     The  preva 
lence  of  limestones  over   the   Interior   basin    points   out  the  region 
as  an  extensive  reef-growing  sea,  opening  south  into  the  Atlantic  by 
the  Mexican  Gulf  region,  and  perhaps   also  into  the  Pacific,  for  the 
larger  part  of  Paleozoic  time.     But  there  were   slow   oscillations  in 
progress,  that  changed  the  limits  of  the  formations  to  the  eastward  or 
westward,  and  northward  or  southward,  as  the  periods   succeeded  one 
another. 

Until  the  close  of  the  Subcarboniferous  period,  the  oscillations  had 
that  wide  continental  range  which  was  eminently  characteristic  of  the 
American  Paleozoic.  In  the  period  following,  the  Carboniferous,  the 
continent  for  prolonged  periods  stood  raised  just  above  the  ocean,  at 
a  nearly  uniform  level,  —  so  low  that  its  interior  was  covered  with 
immense  fresh-water  marshes,  and  for  so  long  eras  that  the  vegetable 
accumulations  attained  the  thickness  sufficient  for  great  coal-beds 
(p.  358)  ;  but  these  emergences  had  their  alternations  with  submerg 
ences.  The  system  of  oscillations,  though  slower  in  movement,  was 
still  continued  ;  yet  the  movements  were  less  general ;  and  it  is  there 
fore  difficult  to  make  out  a  parallelism  in  the  beds  of  coal  and  inter 
vening  rock-strata  through  the  East  and  West. 

3.  Uplifts  and  dislocations.  —  The  only  mountain-region,  along  the 
course  of   existing  chains,  which  can   now  be  pointed   to  as  having 
emerged  during  the  Paleozoic  ages,  is  that  of  the  Green  Mountains. 

In  Nova  Scotia,  New  Brunswick,  and  parts  of  the  St.  Lawrence 


GENERAL    OBSERVATIONS.  393 

valley  and  New  England,  there  were  dislocations  of  the  strata  and 
extensive  uplifting  at  the  close  of  the  Devonian,  making  high  ridges, 
but  no  true  mountain  range.  But,  in  general,  over  the  Continental 
Interior,  and  along  the  Appalachian  region  south  of  New  York,  the 
strata  from  the  bottom  of  the  Silurian  to  the  top  of  the  Carboniferous 
make  an  unbroken  series,  with  no  unconformability  except  the  slight 
want  of  parallelism  by  overlap,  which  the  great  oscillations  at  times 
occasioned  (p.  305).  The  extent  of  the  series,  and  the  vast  length  of 
time  occupied  by  those  passing  ages,  make  this  exemption  from  great 
disturbances  a  subject  of  profound  importance  in  American  geological 
history. 

4.  Direction  of  Oscillations.  —  The  direction  of  the  oscillations  of 
the  continent  may  be  learned  from  the  course  of  the  region  along 
which,  through  the  successive  periods,  the  greatest  amount  of  change 
of  level  took  place.  One  such  region  is  the  Appalachian,  in  which  the 
subsidence,  as  has  been  shown,  amounted  in  some  parts  to  seven  miles 
or  more,  while  parallel  with  it,  in  the  Interior  basin,  the  average  was 
comparatively  small.  The  review  of  the  limits  of  the  successive  for 
mations,  on  p.  389,  shows  that  even  the  minor  changes  took  place 
under  the  influence  of  oscillations  having  this  general  course. 

The  Lower  Silurian  uplift,  from  Lake  Erie  to  central  Tennessee, 
conforms  to  this  system.  In  accordance  also  with  it,  the  Coal-measures 
in  Pennsylvania,  to  the  top  of  the  Pittsburg  series,  were  elevated,  so 
that  their  marshes  became  dry,  before  the  higher  beds  were  laid  down ; 
and  these  upper  beds,  with  the  whole  region  west  to  the  Mississippi, 
before  the  Permian  (p.  368). 

The  Appalachian  region  lies  parallel  with  one  great  branch  of  the 
Archaean  dry  land,  C  C,  on  map,  p.  149,  and  also  with  the  Atlantic 
Ocean.  The  Appalachian  oscillations  therefore  conformed  in  direction 
with  one  of  the  two  Archaean  systems  (p.  160):  they  were  but  a  con 
tinuation  of  the  series  that  prevailed  while  the  Archaean  age  was  in 
progress. 

With  regard  to  the  region  west  of  the  Archaean,  our  information  is 
yet  scanty  :  sufficient,  however,  is  known  to  make  it  apparent  that  the 
increase  of  dry  land  was  from  the  Archaean  to  the  southwest,  or  cor 
responding  to  oscillations  parallel  to  the  Rocky  Mountains.  The  direct 
effect  of  such  oscillations  is  manifest  in  the  Illinois  uplifts  preceding 
the  Coal-measures,  for  they  are  parallel  to  the  Rocky  Mountain  chain 
and  the  Pacific  coast-line.  This,  then,  was  a  second  grand  direction  of 
oscillations.  It  was  parallel  with  the  northwestern  branch  of  the 
Archaean, B  B,  on  map,  p.  149,  and  corresponded  to  the  second  of  the 
two  series  that  prevailed  during  the  Archaean  age. 

It  is  hence   apparent  that,  whatever  the  forces  at  work  in  Archaean 


394  PALEOZOIC   TIME. 

time,  they  continued  to  act  in  the  same  general  direction  throughout 
the  Paleozoic.  The  action  of  the  two  systems  of  forces  together 
evidently  produced  the  great  amount  of  subsidence  adjoining  the 
Canada  Archaean,  where  the  thick  deposits  of  the  Huronian  and  Lower 
vSiluriari  periods  were  formed,  and  where,  finally,  the  basins  of  the  Great 
Lakes  were  made.  These  and  many  other  lakes  of  North  America  lie 
near  the  limit  between  the  oscillating  part  of  the  continent  and  the 
stable  Archaean  area,  and  to  this  fact  owe  their  formation. 

5.  Cotemporaneous  movements  in  the  American  and  European  con 
tinents.  —  The  fact  that  the  continent  of  Europe  was  above  the  ocean, 
and  in  that  condition  which  was  characteristic  of  the  Coal  period,  at 
the  same  time  with  North  America,  shows  a  cotemporaneousness  in 
the  oscillations  of  the  crust  on  the  opposite  sides  of  the  Atlantic 
Ocean.  This  concordance  will  be  better  apprehended,  when  it  is  con 
sidered  that  the  land  must  have  been  but  little  elevated,  and  quite 
uniformly  so,  —  enough  to  drain  the  great  salt  marshes  of  their  salt, 
and  not  so  high  as  to  turn  them  into  dry  fields.  It  was  not  sufficient 
that  there  should  be  land  and  Carboniferous  vegetation  ;  for,  without 
the  wet,  swampy  lands,  —  wet  with  fresh  waters,  and  very  wide  in  ex 
tent,  —  the  great  accumulations  of  vegetation  and  immense  coal  fields 
would  not  have  been  made. 

There  is  a  similarity  between  the  continents,  also,  in  the  character  of 
the  oscillations  which  occurred  in  the  course  of  the  Carboniferous 
period,  which  submerged  the  land  after  material  for  a  coal  bed  had 
accumulated,  and  buried  it  for  long  keeping  beneath  sands,  muds,  or 
clays,  and  then  brought  it  again  to  the  surface  for  renewed  verdure 
and  another  coal  bed ;  and  so  on,  in  many  successions. 

The  Millstone  grit,  which  preceded  the  Coal-measures  in  Europe  as 
well  as  America,  is  evidence  of  a  degree  of  correspondence  in  that 
upward  movement  of  the  continents  through  the  wraves  which  ushered 
in  the  epoch  of  the  Coal-measures  ;  and  the  prevalence  and  wide  dis 
tribution  of  the  limestone  of  the  Subcarboniferous  period,  which  next 
preceded,  mark  another  cotemporaneous  movement,  —  a  very  general 
submergence,  preceding  the  emergence  just  alluded  to.  Moreover,  in 
both  continents,  some  thin  coal  beds  were  formed  in  the  Subcarbon 
iferous  period. 

Contrast  between  America  and  Europe.  —  While  the  two  continents 
were  at  times  concordant  in  their  general  movement,  there  was  ap 
parently  a  contrast  during  the  Coal  period  in  the  moisture  of  the  two, 
which  may  in  part,  at  least,  be  attributed  to  climate.  This  is  apparent 
in  the  vastly  larger  coal  fields  of  America.  Guyot  has  called  America 
the  forest-continent,  a  character  it  now  bears  because  of  its  moist  climate, 
or  more  abundant  rains  ;  and  it  is  probable  that  it  presented  this 
peculiarity  with  the  first  appearance  of  vegetation  over  its  surface. 


GENERAL   OBSERVATIONS.  395 

V.  DISTURBANCES  CLOSING  PALEOZOIC  TIME. 
1.  AMERICAN. 

An  account  of  the  Green  Mountain  revolution,  closing  the  Lower 
Silurian,  has  been  given  on  pages  212-216.  In  the  succeeding  eras, 
through  the  Paleozoic, —  eras  of  prolonged  quiet,  —  there  were  slow 
oscillations  in  progress  over  the  continent,  and,  at  the  close  of  the  De 
vonian,  some  great  displacements  of  strata,  producing  metamorphism,  in 
the  northeast ;  but  no  upturning  took  place  over  the  Appalachian  re 
gion  southeast  of  New  England,  until  the  m  Carboniferous  age  was  ap 
proaching,  or  had  reached,  its  end.  This  epoch  of  disturbance  even 
rivalled  that  of  the  .Middle  Silurian,  in  the  extent  of  the  region  in 
volved,  and  forms  a  historical  boundary  between  Paleozoic  and  Meso- 
zoic  time.  The  upturning  after  the  Lower  Silurian  affected  the  Green 
Mountain  region  and  some  other  parts  of  New  England,  folding  and 
crystallizing  the  rocks,  besides  raising  the  mountains  above  the  sea  and 
addino-  them  to  the  stable  land  of  the  Continent.  In  the  disturbance 

O 

closing  the  Paleozoic,  all  of  the  Appalachian  region  southwest  of  the 
Green  Mountains  was  concerned  ;  and  the  Alleghany  Mountains  were 
among  the  grand  results.  A  portion  of  eastern  New  England,  and  of 
New  Brunswick  and  Nova  Scotia  to  the  northeast,  partook  in  the 
changes.  It  was  a  time  of  growth  for  the  Continent;  for,  besides  mak 
ing  the  Appalachians,  nearly  all  the  region  east  of  the  Mississippi  be 
came  part  of  the  essentially  stable  land. 

The  effects  of  the  disturbance  were  like  those  of  the  Silurian  revo 
lution.  There  were  (1)  flexures  and  upturnings  of  the  strata  ;  (2) 
faults  ;  and  (3)  alterations  of  rocks. 

1.  Flexures. —  The  Coal-measures  of  Pennsylvania,  Rhode  Island, 
and  Nova  Scotia,  which  were  originally  spread  out  in  horizontal  beds 
of  great  extent,  are  now  tilted  at  various  angles,  or  rise  into  folds ; 
and  the  strata  are  broken  and  faulted  on  a  grand  scale.  Some  of  the 
folds  are  scores  of  miles  in  breadth,  and  are  in  many  successions 
over  the  region,  wave  succeeding  wave.  Moreover,  not  only  the  Coal- 
measures,  but  the  Devonian  and  Silurian,  with,  in  some  regions  at 
least,  part  of  the  Archaean  beds  beneath,  are  involved  together  in  this 
majestic  system  of  displacements.  The  following  facts  on  this  subject 
are  mainly  from  the  Memoirs  and  Geological  Reports  of  the  Profes 
sors  Rogers. 

The  general  character  of  the  flexures  is  illustrated  in  the  annexed 
sections.  Fig.  699  (by  Taylor)  is  from  the  anthracite  strata  of  the 
Mauch  Chunk  region,  Pennsylvania.  The  great  coal  bed  is  folded 
and  doubled  on  itself;  and  part  of  the  inclosing  strata  are  nearly  ver 
tical.  In  Fig.  700  (by  Rogers),  from  Trevorton,  Pa.,  the  folding  is  of 


396 


PALEOZOIC    TIME. 


a  more  gentle  kind  :  eight  coal  seams  are  contained  in  this  section, 
each  of  the  dark  lines   representing  one.     These  are  examples  of  the 


Fig.  699. 


Section  of  the  Coal-nieasuru.s,  near  Nesquehoumg,  Pa. 

condition  of  the  whole  anthracite  region.  The  patches  into  which  it  is 
divided,  as  shown  on  the  map,  p.  310,  illustrate  other  effects  of  the 
foldings  ;  for  the  whole,  in  all  probability,  was  originally  one  great 
area,  continuous  with  that  of  western  Pennsylvania. 

Fig.  700. 


Section  of  the  Coal  measures,  half  a  mile  west  of  Trevorton  Gap,  Pa. 

The  sections  represented  in  Figs.  701,  702  illustrate  the  flexures  of 
the  Paleozoic  rocks,  showing  that  the  whole  participated  in  the  system. 

Fig.  701. 


Section  on  the  Schuylkill,  Pa. ;   P.  Pottsville,  on  the  Coal-measures. 

Fig.  701  (by  Lesley)  is  a  section  from  the  Schuylkill,  along  by  Potts 
ville:  the  formations  included  in  it  embrace  from  the  Potsdam  sand- 
Fig.  702. 


vi  v    iv  ill     n        DJ  iv 

Section  from  the  Great  North  to  the  Little  North  Mountain,  through  Bore  Springs.  Va.  ;  t,  t, 
positions   of  thermal  springs. 

stone  (2)  to  the  Coal  formation  (14)  :  the  numbers  indicate  the  for 
mations.  The  section  in  Fig.  702  (by  Rogers)  extends  from  the 
Great  North  to  the  Little  North  Mountain,  through  the  Bore  Springs, 
in  Virginia :  it  has  been  partly  explained  on  pa<res  93,  97.  The  for 
mations  are  numbered  —  II.  the  Calciferous  ;  III.  Trenton;  IV.  Cin 
cinnati  ;  V.  Oneida ;  VI.  Clinton  and  Lower  Helderberg ;  VII.  Oris- 
kany  sandstone  and  Cauda-galli  grit. 


GENERAL    OBSERVATIONS. 


397 


The  mountains  of  Pennsylvania  as  well  as  Virginia  are  full  of  such 
sections.  In  fact,  they  present  the  common  features  of  the  Appa 
lachians,  from  Alabama  to  New  Jersey.  It  is  here  obvious  that  not 
only  the  Coal-measures  but  the  whole  Paleozoic  has  been  forced  by 
some  agency  out  of  its  originally  horizontal  condition  into  this  con 
torted  state.  The  folds  were  mountains  themselves  in  extent ;  but, 
through  the  extensive  denudation  to  which  they  have  since  been  sub 
jected,  they  have  been  worn  off  and  variously  modified  in  external 
shape,  until  now,  as  explained  on  page  9G,  it  is  often  extremely  dif 
ficult  to  trace  out  the  original  connections. 

The  folds  are  most  abrupt  to  the  eastward ;  to  the  west,  they 
diminish  in  boldness,  and  become  gentle  undulations ;  yet  there  is  often 
a  sudden  transition  to  these  gentler  bendings,  along  lines  of  great 

Fig.  703. 


Map  of  Pennsylvania,  showing  the  positions  of  the  axes  of  the  folds  in  the  strata. 

faults.  It  would  be  an  error  to  suppose  that  the  number  of  folds  is 
uniform,  through  the  length  of  the  Appalachians.  On  the  contrary, 
all  along  their  course,  there  are  folds  rising  and  others  disappearing ; 
they  may  continue  on  for  a  few  miles  or  scores  of  miles,  and  some  for 


398  PALEOZOIC   TIME. 

much  greater  distances,  and  then  gradually  disappear,  while  others, 
more  to  the  east  or  west,  take  their  places.  Thus,  in  the  Appalachian 
chain,  there  is  a  complexity  of  flexures  following  a  common  direction. 
This  character  is  well  shown  in  Fig.  703,  —  a  map  prepared  for  this 
work  by  J.  P.  Lesley,  who,  in  connection  with  other  assistants  in  the 
Geological  Survey  of  Pennsylvania,  has  done  much  toward  working 
out  the  facts  here  presented.  It  gives  a  general  view  of  the  direction 
and  number  of  the  folds  through  Pennsylvania.  Each  line  stands  for 
the  axis  of  a  flexure.  Without  claiming  absolute  accuracy,  it  gives  a 
correct  general  idea  of  the  number  arid  positions  of  the  folds  in  this 
part  of  the  Appalachian  region. 

The  following  are  some  of  the  most  important  facts  established  with 
regard  to  these  Appalachian  flexures  :  — 

1.  They  occupy  the  whole  Appalachian  and  Eastern-border  regions 
of  the  continent,  nearly  or  quite  to  the  Atlantic  Ocean. 

2.  They  are  parallel  with  the  general  course  of  the  mountains,  and 
nearly  with  the  Atlantic  coast. 

3.  They  are   most  crowded  and  most  abrupt  over  the  part  of  the 
regions  which  is  toward  the  ocean,  —  that  is,  the  southeast   side   (Fig. 
702. 

4.  The  steepest  slope  of  a  fold  is  that  which  faces  the  northwest, 
or  away  from  the  ocean  (Figs.  701,  702). 

5.  They  are  in  numerous  ranges  ;  but,  while  some  are  of  very  great 
length,  there  is   in  general  a  commingling  of  shorter  flexures  ;  and 
often  they  are  in  groups  of  overlapping  lines  (Figs.  12  to  17),  as  ex 
plained,  with  reference  to  the  arrangement  of  the  parts  of  mountains, 
on  pages  19  and  20. 

6.  Although  many  of  the  folds  were  like  mountains  in  dimensions, 
they  have  been  so  worn   and  removed  by  denuding  waters  —  either 
those  of  the  ocean,  or  rivers,  or  both  —  that  the  higher  parts  of  the 
folds  do  not  generally  form  the  summits  of  existing  elevations.     The 
fissures  of  the  broken  mountains  would  have  been  deepest  and  most 
numerous  in  the  axes  of  the  folds  ;  and  hence  denudation  has  been 
most  destructive  along  the  more  elevated  portions. 

2.  Faults.  —  Besides  the  remarkable  plication  of  the  earth's  crust 
in  this  Appalachian  revolution,  numberless  fractures  and  faults  or  dis 
locations  occurred  over  the  whole  region,  as  was  natural  under  the 
contortions  and  uplifts  in  progress.  Some  of  the  faultings  were  of 
great  extent,  lifting  the  rocks  on  one  side  of  the  line  of  fracture 
5,000  or  10,000  feet  above  the  level  on  the  other  side.  The  faults 
mentioned  on  p.  214  are  of  this  character ;  and  part  of  the  series  there 
alluded  to  was  probably  made  at  this  time.  There  is  one  of  these 
great  faults  west  of  the  eastern  range  of  the  Cumberland  Mountains, 


GENERAL    OBSERVATIONS.  399 

in  eastern  Tennessee,  well  shown  in  the  map  and  sections  of  Safford. 
In  southwestern  Virginia,  there  are  faults,  according  to  Rogers,  of 
seven  or  eight  thousand  feet.  One  remarkable  line  of  this  kind  ex 
tends  along  the  western  margin  of  the  Great  Valley  of  Virginia, 
throughout  the  chief  part  of  its  length,  along  by  the  ridge  (on  the 
northwest  side  of  the  valley)  named,  in  its  different  parts,  the  Little 
North  Mountain,  North  Mountain,  and  Brushy  Ridge.  In  some  parts, 
as  in  the  annexed  section,  Fig.  704  (by  Lesley),  the  Lower  Silurian 

Fig.  704. 


Section  of  the  Paleozoic  formations  of  the  Appalachians,  in  southern  Virginia,  between  Walker's 
Mountain  and  the  Peak  Hills  (near  Peak  Creek  Valley) :  F,  fault ;  a,  Lower  Silurian  limestone; 
b,  Upper  Silurian  ;  c,  Devonian  ;  rf,  Subcarboniferous,  with  coal  beds. 

limestone  is  brought  into  conjunction  with  beds  but  little  below  the 
Subcarboniferous  limestone  ;  so  that  there  is  a  transition  from  the 
lower  strata  to  the  upper,  in  simply  crossing  the  fault.  In  some 
places,  there  is  an  inversion  of  the  strata,  so  that  a  bed  of  semi- 
bituminous  coal  of  the  upper  beds  is  found  under  the  Lower  Silurian 
limestone  and  conformable  to  it  in  dip.  This  fault  continues  on  for 
eighty  miles.  (W.  B.  &  H.  D.  Rogers.) 

Several  such  examples  might  be  cited  from  Pennsylvania  as  well 
as  Virginia.  One  occurs  near  Chambersburg,  Pa.,  and  is  thus  de 
scribed  by  Lesley  in  his  "  Manual  of  Coal  and  its  Topography " 
(p.  147).  "The  western  side  of  the  anticlinal  'cove-canoe'  has  been 
cut  off  and  carried  down  at  least  twenty  thousand  feet  into  the  abyss, 
along  a  fracture  twenty  miles  in  length  ;  the  eastern  side  must  have 
stood  high  enough  in  the  air  to  make  a  Hindoo  Koosh ;  and  all  the 
materials  must  have  been  swept  into  the  Atlantic  by  the  denuding 
flood.  The  evidence  of  this  is  of  the  simplest  order,  and  patent  to 
every  eye.  Portions  of  the  Upper  Devonian  wall  against  the  lowest 
portions  of  the  Lower  Silurian.  The  thickness  of  the  rocks  between 
is,  of  course,  the  exact  measure  of  the  downthrow,  which  is  therefore 
twenty  times  as  great  as  the  celebrated  Pennine  Fault  in  England. 
Yet  a  man  can  stand  astride  across  the  crevice,  with  one  foot  on 
Trenton  limestone  and  the  other  on  Hamilton  slates,  and  put  his 
hand  upon  some  great  fragments  of  Shawangunk  grit,  caught  as  they 
were  falling  down  the  chasm,  held  fast  in  its  jaws  as  it  closed,  and 
revealed  by  the  merest  accident  of  lying  suspended  in  the  crack  just 
where  the  plane  of  denudation  happened  to  cut  it." 


400  PALEOZOIC   TIME. 

At  the  west  base  of  the  Chilhowee  Mountain,  near  Montvale 
Springs,  Blount  County,  Tennessee,  Subcarboniferous  shales  are 
brought  into  contact  with  the  "  Ocoee  "  conglomerate  of  the  Acadian 
epoch,  by  a  fault  and  displacement  of  more  than  10,000  feet.  (Saf- 
ford.) 

Lesley,  after  explaining  the  relations  of  the  eastern  or  Blue  Ridge,  the  Great  Valley 
next  west,  the  Appalachian  or  middle  chain,  and  the  Alleghany  or  western,  and  men 
tioning  that  the  eastern  escarpment  of  the  last,  "overlooking  the  Appalachian  ranges 
with  their  narrow  parallel  interval-valleys,  is  the  so-called  Backbone  Alleghany  Moun 
tain,"  and  separates  the  headwaters  of  nearly  all  the  Atlantic  and  Western  rivers, 
observes  that  New  River,  in  southern  Virginia,  divides  the  northern  region  of  plica 
tions  from  the  southern  of  great  faults;  and  this  river  is  remarkable  for  cutting 
through  the  Appalachians,  and  taking  its  rise  even  as  far  east  as  the  Blue  Ridge.  lie 
adds,  concerning  this  southern  district,  "The  Paleozoic  zone,  included  between  the 
Great  Valley  and  the  Backbone  escarpment,  is  occupied  by  as  many  pairs  of  parallel 
mountains  as  there  are  great  parallel  faults;  and,  as  these  faults  range  in  straight 
lines,  at  nearly  equal  distances  from  each  other,  these  mountains  run  with  remarkable 
uniformity  side  by  side  for  a  hundred  or  two  hundred  miles,  and  are  finally  cut  off, 
either  by  short  cross-faults,  or  by  slight  angular  changes  in  the  courses  of  the  great 
faults."  This  strip  of  country  is  thirty  to  forty  miles  wide;  and  the  intervals  between 
the  fractures  or  faults  are  from  five  to  six  miles  wide.  All  the  ranges  show  southeast 
dips;  a  portion  of  the  Carboniferous  formation  forms  the  southeastern  brow  of  each, 
overlooking  to  the  southeast  Lower  Silurian  limestone,  and  resting  on  Devonian  and 
Silurian,  which  come  into  view  to  the  northwest. 

According  to  the  Professors  Rogers,  these  faults  in  southwestern  Virginia,  which 
were  early  described  by  them,  occur  along  the  axes  of  plications,  instead  of  in  mono- 
clinal  strata.  (Trans.  Amer.  Assoc.  Geol.  Nat.,  p.  494.) 

Thus,  the  whole  Continental  border,  from  Alabama  to  Newfound 
land,  participated  in  these  grand  movements. 

3.  Alterations  of  rocks.  —  The  alterations  which  the  rocks  under 
went  at  the  time  of  these  disturbances  are  as  follow  :  — 

1.  Consolidation.  —  Strata  were  consolidated  ;  for  the  rocks  of  the 
Coal-measures,  the  conglomerates  and  sandstones  especially,  are  often 
very  hard  and  siliceous,  where  the  beds  have   been   most  folded  or 
disturbed. 

2.  DeUtuminization  of  Coal  —  The  coal  is   not  bituminous,  or  is 
true  anthracite,  where  the  rocks  are  most  disturbed  ;  and,  going  west 
ward,  into  regions  of  less  disturbance,  the  proportion  of  bitumen  or 
volatile  substances  increases  quite  regularly  (Rogers).     It  appears  as 
if  the  debituminization  of  the  coal  had  taken  place  from  some  cause 
connected  with   the  uplifting.     In  Rhode  Island,  the   effects  are  still 
more  marked,  the  coal  being  altered  not  simply  to  an  excessively  hard 
anthracite,  but  in  part  to  graphite. 

3.  Crystallization  or  Metamorphism.  —  In  some  districts,  the  rocks 
are  changed  to  gneiss,  mica  schist,  or  slates,  and  granular  limestone 
(marble). 

4.  Characteristics    of    the    force    engaged.  —  As    in    the    Medio- 


GENERAL    OBSERVATIONS.  401 

Silurian,  or  Green  Mountain,  revolution,  the  cause  of  the   upturning 
had  the  following  characteristics  :  — 

1.  The  force  acted  at  right  angles  to  the  general  direction  of  the  At 
lantic  coast,  the  flexures  being  approximately  parallel  to  the  coast-line. 

2.  It  acted  from  the  direction  of  the  ocean,  the  flexures  and  meta- 
morphism  being  greatest  on  the  oceanic   side,  and  fading  out  toward 
the  interior. 

3.  It  was  slow  in  action  and  long  continued,  a  result  of  movement 
at  the  rate  of  a  few  feet  or  yards  in   a  century,  the  flexures  having 
taken  place  without   obliterating,  and  hardly  obscuring,  the  stratifica 
tion.     There  may  have  been  sudden  starts,  and  earthquakes  beyond 
modern  experience ;   but  the  general  course  of  progress  must  have 
been  quiet. 

4.  Heat  was  concerned  in  the  changes,  or  produced  by  the  move 
ment  ;  for  several  thermal  springs  exist  in  Virginia,  situated,  accord 
ing  to  Rogers,  along  the   axes  of  the   Appalachian  folds,  as  if  some 
traces  of  the  heat  still  remained. 

5.  The  force  was   the  same  in  kind,  and  also  in   direction,  judging 
from   the  identity  of  results,  with  that  which  produced  the  flexures 
and  other  changes  that  closed  Archasan  time  (p.  155),  as  well  as  those 
of  the  Medio-Silurian  disturbance,  and  caused  the  oscillations  through 
the   progressing  Paleozoic  ages  required    for  the   completion  of  the 
succession  of  rocks ;  the  same   that  occasioned  the  deep   subsidences 
along  the  Appalachian  region.     When   the  Appalachian  subsidences 
were  about  to  cease,  then  began  the   new  movement  that  flexed  and 
stiffened  the  rocks  of  the  Atlantic  border. 

Although  there  is  no  proof,  in  the  flexures  or  the  metamorphism, 
of  any  emergence  of  the  strata  from  the  ocean  during  their  progress, 
there  is  sure  evidence  that,  when  the  revolution  ceased,  it  left  the 
Appalachian  chain  with  nearly  the  present  elevation.  The  evidence 
of  this  final  result  of  the  moving  forces  is  afforded  by  the  strata  of 
Mesozoic  time,  which  come  next  under  consideration. 

In  North  America,  from  the  close  of  the  Paleozoic,  there  was  a 
great  change  in  the  scene  of  geological  progress,  so  that  the  regions 
are  no  longer  the  Eastern  Border,  the  Appalachian,  and  the  great  In 
terior  Continental;  but,  instead,  the  Atlantic  Border,  the  Gulf  Border, 
the  Western  Interior,  or  interior  west  of  the  Mississippi,  and  the  Pacific 
Border.  The  Appalachian  region  and  the  eastern  part  of  the  Interior 
basin  no  longer  participate  in  the  rock-making.  The  new  regions  co 
alesce  ;  the  third  is  but  a  continuation  of  the  Gulf  region  to  the 
northwest,  over  the  area  of  the  Rocky  Mountains,  which  was  still  low 
or  submerged,  and  it  is  probable  that  it  communicated  directly  with 
the  Pacific. 

26 


402  PALEOZOIC   TIME. 

2.  DISTURBANCES   IN  FOREIGN  COUNTRIES. 

The  disturbances  through  the  course  of  the  Paleozoic  ages  in  Europe 
appear  to  have  been  more  numerous  and  diversified  than  in  America. 
But  they  were  inferior  in  extent  to  those  that  attended  its  close. 
Murchison  remarks  that  the  close  of  the  Carboniferous  period  was 
specially  marked  by  disturbances  and  upliftings.  He  states  that  it  was 
then  "  that  the  coal  strata  and  their  antecedent  formations  were  very 
generally  broken  up,  and  thrown,  by  grand  upheavals,  into  separate 
basins,  which  were  fractured  by  numberless  powerful  dislocations."  In 
the  north  of  England,  as  first  shown  by  Sedgwick,  and  also  near 
Bristol,  and  hi  the  southeastern  part  of  the  Coal-measures  of  South 
Wales,  there  is  distinct  unconformability  between  the  Carboniferous 
and  lowest  Permian.  Elie  de  Beaumont  has  named  this  system  of 
dislocations  the  system  of  the  North  of  England.  Between  Derby  and 
the  frontier  of  Scotland,  the  mountain-axis  is  of  this  date,  and  trends 
between  north  and  north-northwest ;  the  region  is  remarkable  for  its 
immense  faults.  The  great  dislocations  of  North  Wales  may  be  of 
the  same  epoch. 

Yet,  while  it  is  manifest  that  the  period  between  the  close  of  the 
Carboniferous  and  the  beginning  of  the  Triassic  was  one  of  enormous 
disturbances,  it  is  not  always  clear  to  what  time  in  this  interval  par 
ticular  uplifts  should  be  referred.  In  the  Dudley  coal  field,  the  Per 
mian  beds,  according  to  Murchison,  are  conformable  to  the  Carbonifer 
ous  ;  but,  at  the  close  of  the  Permian  (or  at  least  before  the  middle  of 
the  Trias),  there  were  great  dislocations.  In  other  coal  regions,  as 
those  of  France  and  Belgium,  and  of  Bohemia  about  Prague,  there  is 
other  evidence  of  physical  changes,  in  the  absence  of  Permian  beds ; 
while,  also,  in  many  places,  the  beds  of  the  coal  regions  are  much 
contorted.  De  Beaumont's  System  of  the  Netherlands  includes  disloca 
tions  of  Permian  beds,  along  the  foot  of  the  Hartz  Mountains,  and  in 
Nassau  and  Saxony,  which  preceded  the  deposition  of  the  Triassic. 
He  distinguishes  examples  of  this  system  of  disturbances  in  France 
and  some  other  parts  of  Europe,  and  also  prominently  in  South  Wales. 
To  his  System  of  the  Rhine,  he  refers  dislocations  and  elevations  of  the 
Permian  sandstone  of  the  Vosges  (Gres  de  Vosges),  along  the  moun 
tains  of  the  Vosges,  the  Black  Forest,  and  the  Odenwald,  and  shows 
that  they  antedate  the  Triassic  period. 

In  Russia,  as  well  as  England,  there  are  tracts  where  the  Permian 
strata  follow  on  after  the  Carboniferous  without  unconformability.  It 
was  in  this  closing  part  of  the  Paleozoic  era,  either  after  the  Car 
boniferous  or  after  the  Permian,  that  the  rocks  of  the  Urals  were 
folded  and  crystallized  ;  for  Carboniferous  rocks  are  flexed  and  altered 
in  the  same  manner  as  in  the  Alleghany  region. 


TRIASSIC   PERIOD.  403 


III.    MESOZOIC    TIME. 

The  Mesozoic  or  Mediaeval  time  in  the  Earth's  history  comprises  a 
single  age  only,  —  the  REPTILIAN. 

REPTILIAN  AGE. 

The  Age  of  Reptiles  is  especially  remarkable  as  the  era  of  the  cul 
mination  and  incipient  decline  of  two  great  types  in  the  Animal  King 
dom,  the  Reptilian  and  Molluscan,  and  of  one  in  the  Vegetable  King 
dom,  the  Oycadean.  It  is  also  remarkable  as  the  era  of  the  first  Mam 
mals, —  the  first  Birds,  —  the  first  of  the  Common  or  Osseous  Fishes, 
—  and  the  first  Palms  and  Angiosperms. 

The  age  is  divided  into  three  periods.  Beginning  with  the  earliest, 
they  are :  1.  The  TRIASSIC  PERIOD  ;  2.  The  JURASSIC  PERIOD  ; 
3.  The  CRETACEOUS  or  CHALK  PERIOD. 

These  periods  are  well  defined  in  European  Geology.  But  in  North 
American  the  separation  of  the  first  and  second  has  not  yet  in  all 
regions  been  clearly  made  out. 

1.  TRIASSIC   PERIOD  (16). 

The  name  Triassic,  given  to  this  period,  alludes  to  a  threefold 
division  which  this  formation  presents  in  Germany.  This  division  is 
local  and  unessential :  it  does  not  occur  in  other  remote  parts  of 
Europe,  or  in  England,  and  is  not  to  be  looked  for  in  distant  con 
tinents. 

1.  AMERICAN. 

The  formation  referred  to  the  Triassic  in  Eastern  North  America 
may  belong  in  part  to  the  Jurassic  period.  It  is  not  supposed  to 
reach  back  into  the  Permian,  because  there  are  no  Paleozoic  forms 
among  the  plants  or  animals. 

I.  Rocks  :    kinds  and  distribution. 

The  rocks  are  met  with  in  three  distinct  regions  :  1,  in  the 
Atlantic-border  region,  between  the  Appalachians  and  the  coast ;  2,  in 
the  Western  Interior  region,  over  part  of  the  slopes  of  the  Rocky  Moun 
tains  ;  3,  on  the  Pacific  Border. 

1.  On  the  Atlantic  Border,  the  beds  occur  in  long  narrow  strips, 
parallel  with  the  mountains  or  the  coast-line,  and  occupy  valleys  that 


404  MESOZOIC    TIME. 

were  formed  in  the  course  of  the  folding  of  the  Appalachians,  or 
earlier.  The  formation  may  be  partly  Jurassic,  although  no  line  of 
division  can  be  made  out,  either  through  transitions  in  the  rocks  or  by 
means  of  fossils.  They  lie  unconformably  on  the  folded  crystalline 
rocks,  and  thus  show  that  they  are  subsequent  to  them  in  age.  On  the 
map,  page  144,  the  harrow  areas  are  obliquely  lined  from  the  right  to 
the  left.  The  principal  of  them  are  :  — 

(1.)  The  Acadian  area,  situated  along  the  western  margin  of  the 
peninsula  of  Nova  Scotia,  and  about  150  miles  long;  also  in  Prince 
Edward's  Island. 

(2.)  The  Connecticut  Valley  area,  extending  from  New  Haven  on 
Long  Island  Sound  to  Northern  Massachusetts,  having  a  length  of 
110  miles  and  an  average  width  of  twenty  miles. 

(3.)  The  Palisade  area,  commencing  along  the  west  side  of  the  Hud 
son  River,  in  the  southeast  corner  of  New  York,  near  Piermont,  and 
stretching  southwestward  through  Pennsylvania,  as  far  as  Richmond, 
Virginia,  about  350  miles  long. 

(4.)  The  North  Carolina  area,  commencing  near  the  Virginia  line, 
and  extending  through  North  Carolina,  over  the  Deep  River  region, 
120  miles  long. 

There  are  also  a  few  smaller  areas  parallel  to  these. 

The  map  of  Pennsylvania,  on  p.  310,  shows  the  position  of  the  area 
in  that  State,  it  being  distinguished  by  the  same  oblique  lining  as  on 
the  general  map.  It  takes  the  same  westward  bend  with  the  Appala 
chians  of  the  State,  retaining  that  parallelism  with  the  mountains  which 
characterizes  the  areas  elsewhere. 

Kinds  of  rocks.  —  The  rock  is  in  general  a  red  sandstone;  it  passes 
at  times  into  a  shale,  and  in  others  to  a  conglomerate.  Occasionally 
it  includes  beds  of  impure  limestone.  The  sandstone  is  largely  a 
granytic  sand-rock,  it  usually  containing  grains  of  feldspar  and  quartz 
commingled,  as  if  made  of  pulverized  granyte  or  gneiss.  There  are 
often  sudden  transitions  from  sandstone  to  coarse  conglomerate ;  and, 
in  many  places,  thin  layers  of  large  stones  lie  in  the  finer  beds. 
Many  layers  are  obliquely  laminated,  in  a  coarse  style,  showing,  like 
the  occurrence  of  the  conglomerate,  the  action  of  powerful  currents 
in  the  deposition  of  their  material ;  while  other  portions  are  thinly 
laminated  and  somewhat  clayey,  indicating  regions  of  still  waters  or 
eddies  ;  and  still  others  are  fine,  even-grained,  brownish-red  sand-rock, 
making  an  excellent  building  stone,  and  often  called  freestone  —  as  the 
rock  at  Portland  on  the  Connecticut,  and  near  Newark,  New  Jersey. 
Near  Richmond,  Va.,  and  along  Deep  River,  in  North  Carolina,  there 
are  valuable  beds  of  bituminous  coal. 


TRIASSIC   PERIOD.  405 

Markings  on  the  rocks.  —  In  many  regions,  the  layers  of  rock  are 
covered  with  ripple-marks  and  raindrop-impressions  or  mud-cracks,  — 
evidences  in  part  of  exposure  above  the  water,  during  the  progress  of 
the  beds. 

In  the  Connecticut  valley,  and  to  a  less  extent  in  New  Jersey  and 
Pennsylvania,  the  surfaces  of  the  beds  are  sometimes  marked  with  the 
footprints  of  various  animals,  as  insects,  reptiles,  and  birds ;  and  over 
12,000  tracks,  averaging  100  tracks  for  each  species  of  animal,  have 
been  taken  out. 

2.  On  the  Gulf  Border,  there  are  no  Triassic  rocks,  excepting  such 
as  may  possibly  be  buried  beneath  later  formations. 

3.  The  formation  supposed  to  be  Triassic,  between  the  Mississippi 
and  the  summit  of  the  Rocky  Mountains,  consists  of  sandstones  and 
marly  tes  of  usually  a  brick-red   color,  and   often  contains   gypsum.     It 
covers   a  large  area  between  the  meridians  of  90°  and  102°  W.,  in 
cluding  the  Indian  Territory,  parts  of  Kansas  and  Northern  Texas, 
and  a  portion  of  New  Mexico.     It  outcrops  at  the  base  of  the  eastern 
ridges  of  the  Rocky  Mountains.      Over  the  Rocky  Mountain  region, 
between  the    eastern    Archa3an    ranges    and   the  Sierra  Nevada,  the 
Triassic  enters  largely  into  the  constitution  of  various  mountain  ridges, 
as  those  of  the  Elk,  Wahsatch,  Uintah,  and  Humboldt  ranges.     It  con 
stitutes    a  considerable   part   of  the    auriferous  slates    of   the  Sierra 
Nevada,  affording  fossils  in  some  places.     It  spreads  over  much  of  the 
Colorado  valley,  and  occurs  also  near  the  coast  in  British  Columbia 
and  Alaska. 

(a.)  AREAS  ox  THE  ATLANTIC  BORDER.  —  1  The  Acadian  areas.  —  (1. )  A  region 
in  Nova  Scotia,  forming  the  east  side  of  the  Bay  of  Fundy,  and  northeastward  in  this 
line,  along  the  northern  border  of  the  Basin  of  Mines.  (2.)  Prince  Edward's  Island, 
covering  nearly  all  of  it. 

2.  The  Connecticut  River  area. 

3.  The  Souihbury  area. — A  small  parallel  region  in  Connecticut,  more  to  the  west 
ward,  in  the  towns  of  Southbury  and  Woodbury. 

4.  The  Palisade  area.  —  This,  the  longest  continuous  line,  extends  from  Rockland  on 
the  Hudson  River,  through  New  Jersey,  Pennsylvania,  and  Virginia,  east  of  the  Blue 
Ridge,  being  thirty  miles  wide  in  some  places  in  New  Jersey,  twelve  on  the  Susque- 
hanna,  and  six  to  eight  on  the  Potomac.     It  crosses  the  Delaware  between  Trenton  and 
Kintnerville,  the  Susquehanna  at  Bainbridge,  and  the  Schuylkill  twelve  miles  below 
Reading.     The  map  (p.  310)  gives  the  position  of  the  beds  in  Pennsylvania,  indicated 
by  oblique  lines. 

5  and  6.  Short  areas  in  Virginia,  parallel  to  the  last,  and  more  to  the  eastward.  The 
easternmost,  or  Richmond  area,  commences  on  the  Potomac,  a  few  miles  below  Wash 
ington,  and  continues  to  Richmond  and  twenty-five  or  thirty  miles  beyond.  The  other 
lies  twenty-five  miles  west  of  the  Richmond  range. 

7.  The  North  Carolina  area.  — It  begins  near  Oxford,  in  Granville  County,  and  fol 
lows  nearly  the  line  of  the  Richmond  range  (of  Virginia),  crossing  Orange  and  Chatham 
counties,  westward  of  Raleigh,  passing  Deep  River,  where  it  contains  coal,  and  extend 
ing  into  South  Carolina.  On  the  Neuse,  it  is  twelve  miles  broad;  between  Raleigh  and 
Chapel  Hill,  eighteen  miles ;  on  the  Cape  Fear,  not  over  eight  miles. 


406  MESOZOIC    TIME. 

As  the  several  regions  are  isolated  from  one  another,  they  naturally  differ  widely  in 
the  succession  of  beds  and  in  the  character  of  the  rocks.  They  cannot,  therefore,  be 
brought  into  parallelism  by  reference  to  mineral  characters. 

In  the  Connecticut  River  region,  in  Massachusetts,  according  to  Hitchcock,  these  beds 
consist,  beginning  below,  of  — 

1.  Thick-bedded  sandstone  through  nearly  half  the  thickness,  in  some  parts  a  con 
glomerate.  2.  Micaceous  sandstone  and  shale,  with  fine-grained  sandstone.  This  shale 
sometimes  contains  very  thin  coal  seams'  and  fossil  fishes.  3.  A  coarse  gray  conglom 
erate,  the  stones  sometimes  a  foot  or  more  through. 

The  material  has  come  from  the  crystalline  rocks  adjoining,  —  the  granyte,  gneiss, 
mica  schist,  etc.,  and  has  not,  in  general,  been  much  assorted  by  the  action  of  currents 
or  waves.  The  thickness  has  not  been  satisfactorily  ascertained,  owing  to  the  extent  to 
which  the  beds  are  covered  by  the  stratified  Drift  and  alluvium  of  the  valley,  conceal 
ing  all  faults:  it  cannot  be  less  than  3,000  feet,  and  may  be  more  than  double  this. 

At  Southbury  and  near  Middlefield,  Ct.,  and  near  Springfield,  Mass.,  there  is  an  im 
pure  gray  or  yellowish  limestone,  fitted  for  making  hydraulic  lime. 

In  Virginia,  the  rocks  consist,  as  in  New  England,  of  the  debris  of  the  older  crystal 
line  rocks  with  which  they  are  associated.  Near  Richmond,  where  the  beds  are  800 
feet  thick,  there  are  20  to  40  feet  of  bituminous  coal,  in  three  or  four  seams,  alternating 
with  shale;  and  in  some  places  the  coal  shales  directly  overlie  granyte  and  gneiss.  The 
coal  is  of  good  quality,  and  resembles  the  bituminous  coal  of  the  Carboniferous  era.  It 
contains,  according  to  Hubbard  (Am.  J.  Sci.,  xlii.  371,  1842),  30  to  35  per  cent,  of  vola 
tile  ingredients. 

In  North  Carolina,  the  beds  rest  on  the  crystalline  rocks,  and  have  been  derived  from 
their  wear.  Emmons  divides  them  into  three  groups,  beginning  below:  1.  The  Lower 
red  sandstone  and  its  underlying  conglomerate,  estimated  at  1,500  to  2,000  feet  in  thick 
ness.  2.  The  Coal  measures,  including  shales  and  drab-colored  ripple-marked  sand 
stones,  in  some  places  1,200  feet  thick.  3.  The  Upper  red  or  mottled  sandstones  and 
marlytes,  separated  at  times  from  the  bed  below  by  a  conglomerate. 

There  are  five  seams  of  coal  at  the  Deep  River  mines,  —  the  first  (or  upper)  and  best, 
6|  feet  thick.  The  coal  resembles  that  of  Richmond,  and  is  valuable  for  fuel.  Emmons 
obtained  28  to  31  per  cent,  of  volatile  ingredients.  The  beds  below  the  coal  are  of 
much  less  thickness  in  the  Dan  River  coal  region  than  in  that  of  Deep  River.  Good 
argillaceous  iron-ore  abounds  in  the  coal  region  of  North  Carolina;  so  that  in  almost 
every  respect  there  is  a  close  resemblance  to  the  coal  regions  of  older  date.  Both  at 
Richmond  and  in  North  Carolina,  there  are  numerous  coal  plants  in  the  beds;  and  many 
stems  or  trunks  stand  as  they  grew,  penetrating  the  successive  layers. 

(1.)  "\VESTERN  INTERIOR  REGION.  —  There  is  still  some  doubt  as  to  the  age  of  the 
beds  of  the  Rocky  Mountains  referred  to  the  Triassic  period.  Although  very  widely 
distributed  over  the  eastern  slope,  south  of  the  parallel  of  38°,  they  seldom  contain  fos 
sils;  and  the  few  found  —  occasional  pieces  of  fossil  wood  —  are  not  sufficient  to  settle 
the  question.  The  beds  are  known  to  underlie  unquestionable  Jurassic  beds,  at  the 
Black  Hills  in  Dakota  and  the  Red  Buttes  on  the  North  Platte,  and  hence  to  occupy  a 
position  between  the  Jurassic  and  Carboniferous.  They  therefore  belong  either  to  the 
Triassic  or  to  an  inferior  part  of  the  Jurassic  formation. 

(c.)  ROCKY  MOUNTAIN  REGION  AND  PACIFIC  BORDER.  —  In  the  Elk  Mountains,  of 
the  western  part  of  the  Colorado  territory,  several  of  whose  peaks  are  over  14,000  feet 
high,  the  upper  part,  for  several  thousand  feet,  consists  of  Triassic,  or  Triassic  and  Ju 
rassic,  sandstones  and  marlytes,  nearly  horizontally  stratified,  overlying  Carboniferous 
strata  (Hayden).  The  high  Wahsatch  and  Uintah  Mountains,  east  of  the  great  Salt 
Lake,  are  also  largely  Triassic  and  Jurassic  over  Carboniferous,  and  so  are  part  of  the 
Humboldt  ranges  west  of  this  lake :  in  the  AVahsatch,  the  beds  consist  of  sandstones  and 
dolomitic  limestones,  1,800  feet  thick  (King).  The  Triassic  of  the  Sierra  Nevada  has 
been  observed  in  California,  according  to  Whitney,  in  El  Dorado  Count}-,  at  Spanish 
Flat,  in  Plumas  County,  near  Gifford's  Ranch,  etc.;  also  in  Owen's  Valley,  along  the 
western  flanks  of  the  Invo  and  White  Mountains. 


TRIASSIC   PERIOD. 


40T 


Rocks  of  the  Upper  Colorado,  according  to.Xewberry,  lie  between  the  Carboniferous 
and  the  Cretaceous;  and  the  whole  thickness  is  2,000  to  2,500  feet.  But  it  is  not  yet 
known  whether  all  these  beds  are  of  the  Triassic,  or  whether  they  cover  both  the  Tri- 
assic  and  Jurassic  periods. 

The  Triassic  has  been  identified  by  fossils  also  in  British  Columbia  ( ?),  and  near  the 
entrance  of  Pavalouk  Bay,  etc.,  in  Alaska  (Am.  J.  Sci.,  III.  v.  473) ;  also  near  Sonora, 
Mexico.  Whitney  states  that  the  Triassic  of  California  and  also  that  of  Alaska  is  Upper 
Triassic,  or  the  equivalent  of  the  St.  Cassian  beds  of  Central  Europe,  which  is  that  of 
the  Middle  Keuper. 

II.  Life. 

The  American  Triassic  formation  of  the  Atlantic  Border  is  remark 
able  for  the  paucity  of  all  evidences  of  distinctively  marine  life. 

The  same  is  true  of  the  Triassic  rocks  of  the  Western  Interior.  But 
the  beds  of  the  Pacific  slope,  in  the  Ilumboldt  Mountains  and  north 
ern  California  and  Mexico,  contain  many  marine  fossils. 

Figs.  705-709. 


Fig.  705,  Podozamites  lanceolatus  ;  706,  Pterophyllum  graminioides  ;  707,  Clathropteris  rectiuscu- 
la;  708,  Pecopteris  (Lepidopteris)  Stuttgartensis ;   709,  Cyclopteris  linmeifolia. 

On  the  Atlantic  Border,  extensive  coast-accumulations  may  have 
been  formed,  containing  marine  fossils,  as  on  the  Pacific  side  and  in 
Europe  ;  but  none  such  are  now  exposed  to  view. 

1.  Plants. 

The  vegetation  of  the  Triassic  period  included  neither  Sigillarids 
nor  Lepidodendrids,  characteristic  groups  of  the  Carboniferous  era ; 


408  MESOZOIC   TIME. 

but,  instead,  there  were  Cycads,  along  with  many  new  forms  of  Ferns, 
Equiseta,  and  Conifers.  Figures  705  to  709  show  this  contrast  be 
tween  the  floras  of  the  Carboniferous  and  Triassic  eras.  Figs.  705 
and  706  represent  the  remains  of  leaves  of  some  of  the  Cycads  ;  Figs. 
737  and  738,  a  foreign  species  of  one  of  the  Conifers,  a  Voltzia  re 
lated  to  the  Cypress ;  and  Figs.  707,  708,  and  709  are  species  of  ferns. 
Trunks  of  Conifers  occur  occasionally  in  the  sandstone.  One,  found 
near  Bristol,  Conn.,  was  over  fifteen  feet  long  and  a  foot  in  diameter. 
No  species  of  grass  or  moss  have  been  met  with.  The  remains  of 
plants  are  sufficient  to  show  that  the  forest  vegetation  consisted  mainly 
of  Conifers,  Tree-ferns,  and  Cycads.  As  the  Cycads  were  the  most 
characteristic  trees  of  the  early  and  middle  Mesozoic,  a  figure  of  a 


Cycas  circinalis  (X 

common  species,  of  the  Moluccas  (where  it  grows  to  a  height  of  thirty 
or  forty  feet),  is  here  annexed.  (1.)  The  habit  is  that  of  a  Palm. 
(2.)  The  manner  in  which  the  leaves  are  developed  is  like  that  of 
most  Ferns,  they  coming  forth  coiled  up,  and  uncoiling  as  they  expand. 
But,  while  thus  comprising  some  fern-like  and  palm-like  characteris 
tics,  (3.)  the  Cycads  are  fundamentally,  that  is  in  their  fruit  and  wood, 
true  Gymnosperms,  or  related  to  the  Pine  tribe.  The  wood  has  a 


TRIASSIC   PERIOD.  409 

very  large  pith,  abounding  in  starch,  surrounded  by  one  or  more  rings 
of  wood,  each  the  result  of  several  years  growth. 

Characteristic  Species. 

Conifers.  —  The  genus  Voltzia  contained  cypress-like  trees,  having  lax  leaves,  the 
terminal  often  longer  than  the  others ;  and  the  fruit-branchlet  consisted  of  broad  and 
short  leaves  or  scales.  A  species  near  V.  heterophylla  Schimp.  (Fig.  737)  has  been  found 
in  the  American  rocks,  at  the  Little  Falls  of  the  Passaic,  in  New  Jersey.  Several  Fir 
cones,six  inches  long.have  been  found  at  Phoenixville,  Pa.;  and  a  small  one  from  the 
Massachusetts  beds  has  been  figured  by  Hitchcock. 

Cycads.  —  Pterophyllum  longifolium  Braun,  from  North  Carolina  and  Pennsylvania, 
characteristic  of  the  Upper  Trias  in  Europe,  resembles  much  Fig.  739 ;  P.  graminioides 
Emmons,  Fig.  706,  from  North  Carolina.  Fig.  705,  Podozamites  lanceolatus  Emmons, 
from  the  same  locality. 

Acroyens. —  Fig.  707,  Clathropteris  rectiuscula  Hk.,  from  Easthampton,  Mass.,  near 
the  middle  of  the  Sandstone  formation:  in  one  specimen  there  were  seventeen  such 
fronds  radiating  from  one  stem.  Fig.  708,  Pecopteris  (Lepidopteris)  Stuttgartensis 
Brngt.,  a  fern  with  the  fruit,  from  the  Richmond  Coal-beds,  found  also  in  the  Trias 
of  Europe.  Fig.  709,  Neuropteris  (?)  KnnceifoUa  Bunbury,  from  Richmond.  Other  ferns 
are  the  Acrostichites  oblonyus  Gopp.,  and  Laccopteris  falcata  Emmons,  both  from  North 
Carolina.  Equisetum  Rogersii  Schimp.  occurs  at  Richmond,  Va.,  and  in  Pennsylvania. 
One  or  two  Catamites  have  been  found  in  North  Carolina. 

The  vegetation  of  the  beds  is  decidedly  Triassic  in  character.  Pecopteris  Stuttgart- 
ends  and  Pterophyllum  longifolium  are  Upper  Triassic  in  Europe ;  Laccopteris  falcata 
closely  resembles  L.  yerminans  Giipp.,  an  Upper  Triassic  species;  Neuropteris  linncei- 
folin  is  near  N.  pachyrachis  Schimp.,  also  Upper  Triassic;  Clathropteris  and  Voltzia,  are 
Triassic  or  Jurassic.  The  prevalence  of  Cycads  is  decidedly  Mesozoic,  and  not  Per 
mian.  Calamites  and  species  of  Neuropteris  occur  in  the  European  Trias,  as  well  as  in 
the  Permian  and  Carboniferous. 

2.  Animals. 

On  the  Atlantic  Border,  the  Triassic  rocks  have  afforded  no  traces 
of  Radiates,  and  but  few  of  Mollusks.  This  singular  fact  is  partly 
accounted  for  through  another,  already  stated,  —  that  the  beds  are 
either  fresh-water  or  brackish-water  deposits. 

On  the  Pacific  Border,  in  California  and  Nevada,  the  beds  have 
afforded  many  marine  fossils.  Among  them  are  species  of  the  Paleo 
zoic  genera  Spirifer,  Orthoceras,  and  Goniatites ;  besides  others  that 
are  as  strikingly  Mesozoic,  such  as  Lamellibranchs  of  the  genera 
Monotis,  Myophoria,  etc.,  and  Ammonites  of  the  genus  Ceratites,  etc. 
(Figs.  710  A-D),  and  others. 

A  foreign  species  of  Triassic  Myophoria  is  represented  on  page  426. 

The  Devonian  Goniatites  were  the  earliest  known  representatives 
of  the  Ammonite  group  of  Cephalopods,  the  prominent  characteristics 
of  the  shells  of  which  are  that  the  siphuncle  is  dorsal,  and  the  trans 
verse  partitions  are  flexed  at  the  margin  so  as  to  make  there  a  series 
of  pocket-shaped  cavities  opening  upward.  Figs.  710  A.  B  are  dif- 


410 


MESOZOIC   TIME. 


ferent  views,  in  profile,  of  a  species  of  Ceratites,  one  of  the  genera  of 
the  Ammonite  group;  and  710  Ca  second  species,  reduced  in  size 
one  third.  The  partitions  are  not  seen  over  the  exterior  of  the  shell, 
and  hence  nothing  of  them  is  shown  in  Fig.  710  C.  In  710  A,  a  few 


Fig.  710  A,  B,  C,  D. 

B    |       1  C 


inr 


AMMONITE  FAMILY.  —Fig.  710  A,  Ceratites  Haidingeri ;    B,  same  in  profile  ;    C,  Ceratites  Whitneyi 
D,  same  showing  form  of  pockets. 

are  represented,  to  exhibit  their  character.  Each  downward  flexure 
corresponds  to  a  depression  or  pocket-like  cavity ;  and,  as  in  other 
species  of  Ceratites,  these  pockets  are  quite  simple  in  form,  and  nu 
merous.  Fig.  710  D  represents  two  of  the  pockets  of  710  C.  Fig. 
744,  p.  426,  represents  a  foreign  Ceratites  ;  and  Fig.  746,  another  of 
the  Ammonite  group,  in  which  the  openings  of  the  pockets  around  the 
margin  of  the  outer  chamber  of  the  shell  are  shown.  The  mantle  of 
the  living  Cephalopod  (whose  body  filled  the  outer  chamber)  descended 
into  the  pockets,  and  thus  aided  the  animal  in  holding  to  its  shell. 
Fig.  845,  p.  463,  represents  another  species  of  the  Ammonite  group, 
of  later  age,  which  has  the  pockets  very  complex,  as  seen  in  Fig.  8455, 
showing  the  outline  of  several  of  them. 

Figs.  711-712. 


Figs.  711,  a,  b,  Estheria  ovata  ;  712,  Palephemera  mediaeva  ( X}£). 

Articulates  were  represented  in  eastern  America  by  both  Crusta 
ceans  and  Insects.     The  Crustacean  remains  are,  with  a  single  excep- 


TRIASSIC   PERIOD.  411 

tion,  Ostracoids  ;  and  some  of  the  species  occurred  in  great  numbers. 
Three  varieties  of  them  are  represented  in  Figs.  711,  a,  b.  The  only 
fossil  Insect  observed  is  the  larve  (or  ex u via  of  the  larve)  of  a  Neu- 
ropter  (Fig.  712)  related  to  the  genus  Ephemera,  from  Turner's  Falls, 
on  the  Connecticut ;  it  is  about  three-quarters  of  an  inch  long. 

But,  although  relics  of  Insec  ts  and  of  Crustaceans  other  than  Ostra 
coids  were  rare,  several  species  of  these  classes  of  Invertebrates,  and 
also  of  Worms,  are  indicated  by  the  tracks  which  they  left  on  the  fine 
mud,  that  is  now  shale.  Figs.  713-717  represent  some  of  these  foot- 


Figs.  713-717. 
713          XX        714  715     I         716V          v 


*-       '\          -v     ,,,     /'         s     s        \    nT 

*,!C  A     /    v/  u       v     \        / 

/',    '  \     '     \'  w    \  v    \      / 
rs   v  w  \         / 

(    u  w    \  ^    N        / 
^  14    v  \  \       / 

Figs.  713-715,  Tracks  of  Insects ;  716,  717,  Tracks  of  Crustaceans  (?). 

marks.  Those  of  Insects  were  probably  made  by  larves  which  lived 
in  water,  like  those  of  many  Neuropters.  Nearly  thirty  species  of 
Articulates  have  been  named  by  Hitchcock  from  the  tracks. 

The  Vertebrates  thus  far  made  known,  by  their  fossils  and  foot 
prints,  outnumber  all  other  known  kinds  of  animal  life  ;  and  many 
were  of  remarkable  size.  They  included  not  only  Fishes  and  Reptiles, 
but  also  the  first  of  Mammals,  and  probably  also  the  first  of  JBirds. 
Thus  the  sub-kingdom  of  Vertebrates  had,  from  this  earliest  period  of 
the  Mesozoic,  all  its  grander  subdivisions  or  classes  represented. 

The  Fishes  were  all   Ganoids  (Fig.  718).     Unlike   the  Paleozoic, 

Fig.  718. 


Fig.  718,  GANOID,  Catopterus  gracilis  (XM) ;  a>  Scale  of  same,  natural  size. 

they  include,  along  with  species  having  vertebrated  tails,  others  that 
have  the  tails  only  half-vertebrated,  or  not  vertebrated  at  all ;  and  this 


412  MESOZOIC    TIME. 

is  the  last  period  in  which  this  old  Paleozoic  characteristic  appeared. 
Thus,  as  Agassiz  first  observed,  the  progress  of  the  ages  was  marked 
in  the  tails  of  the  fishes. 

The  Reptiles  were  very  diversified  in  form  and  size.  But,  although 
fragments  of  the  skeletons  of  several  species  have  been  found,  a  much, 
larger  number  are  known  only  from  their  footprints,  Figs.  719—730. 

Figs.  719-724. 


Fig.  719,  Macropterna  divaricans  ( X%) ;  720,  Apatichnus  belltis  (XK) ;  721,  Anomoepus  Fcambus, 
fore-foot  (X3^);  721  a,  hind  foot  of  same ;  722.  Anisopus  Deweyan us,  fore  foot  (x>a);722a, 
hind  foot  of  same ;  723,  A.  gracilis,  fore  foot  (X%) ;  723  a,  hind  foot  of  same  ;  724  Otozoum 
Moodii,  fore  foot ;  724  a,  hind  foot  of  same  (both  X-j^-). 

Their  fossil  bones  have  been  discovered  in  Prince  Edward's  Island, 
Massachusetts,  Connecticut,  Pennsylvania,  and  North  Carolina.  One 
of  the  most  interesting  localities  is  at  Phrenixville,  Pa.,  where  there  is 
literally  "  a  bone-bed,"  as  described  by  Wheatley.  The  footprints 
like  those  referred  to  birds  are  most  numerous  in  the  Connecticut  val 
ley  area. 

The  reptiles  were  of  the  following  kinds  :  — 

1.  Amphibians,  of  the  order  of  Labyrintkodonts,  whose  tracks  are 
four-toed  or  five-toed  and  often  hand-shaped.  There  were  two  kinds  of 
them.  One,  the  ordinary  Labyrinthodonts,  which  were  quadruped-like 
in  locomotion,  the  fore-feet  being  ordinarily  used  in  walking;  the  other, 
virtually  bipeds,  the  fore-feet  or  hands  seldom  coming  to  the  ground. 
Figs.  722  represents  the  track  of  the  forefoot  of  one  of  the  former, 
and  722  «,  that  of  the  hind  foot,  both  half  the  natural  size.  Figs.  723, 
723  a,  are  the  tracks  of  the  fore  and  hind  feet  of  another  species,  two- 
thirds  the  natural  size.  Of  the  bipeds,  Figs.  719  represent,  of  re 
duced  size,  three  consecutive  tracks  —  right  foot,  left  foot,  right  foot 
—  of  one  kind,  the  length  of  each  about  three  inches.  Fig.  724  a 


TRIASSIC    PERIOD.  413 

represents,  reduced,  the  track  of  the  hind  foot  of  the  most  gigantic  of 
these  biped  Labyrinthodonts,  the  Otozoum  Moodii.  The  actual  length 
of  the  track  was  twenty  inches,  and  the  stride  three  feet ;  and  hence  the 
legs  of  the  animal  were  long  and  stout.  Eleven  consecutive  tracks 
have  been  observed  on  a  single  slab  of  sandstone.  The  right  and  left 
tracks  follow  one  another  at  equal  distances ;  and  hence  the  animal 
walked  or  ran,  and  did  not  leap.  The  fore  feet  were  sometimes,  though 
very  rarely,  brought  to  the  ground ;  and  the  form  of  the  impression  is 
shown  in  Fig.  724.  No  impression  of  a  tail  has  been  observed  on 
any  of  the  slabs ;  and  hence  this  appendage  must  have  been  short  or 
wanting  altogether ;  and,  if  the  latter,  the  Otozoum  was  much  like  a 
gigantic  long-legged  biped  Batrachian,  —  tall  enough  to  look  over  a 
twelve-foot  wall,  —  and  furnished,  in  all  probability,  with  scales  like  a 
Saurian,  and  with  teeth  three  or  more  inches  long. 

Others  of  these  amphibian  bipeds  were  quite  small,  some  having  left 
tracks  not  over  a  fourth  of  an  inch  in  length.  Professor  Hitchcock  has 
described  over  fifty  species,  from  the  tracks  in  the  sandstone  of  the 
Connecticut  valley. 

2.  Dinosaurs.  —  The  Dinosaurs  of  the  Triassic,  while  having  the  fore 
feet  four-toed,  had  the  hind  feet  three-toed,  like  those  of  Birds.  More 
over,  the  toes  had  the  same  number  of  joints  as  in  Birds.  Fig.  721 
represents  the  fore-foot,  and  721  «,  the  hind-foot  track,  from  Turner's 
Falls  on  the  Connecticut.  The  latter  has  a  prolonged  heel,  arising 
from  the  preceding  or  tarsal  joint  coming  to  the  ground  in  walking. 
The  animal  was  able  to  raise  its  body  erect,  bird-like,  yet  often  used 
its  fore  feet  in  locomotion.  Only  a  very  few  specimens  of  this  kind 
have  been  found. 

The  bones  of  a  Triassic  animal,  u  as  large  as  a  hound,"  were  found 
near  Springfield,  Mass.,  and  named  by  Hitchcock  Megadactylus,  from 
its  long  fingers.  Cope  regards  it  as  a  Dinosaur.  But  its  fore  feet 
were  nearly  as  long  as  its  hind  feet;  and  it  differed  therefore  from  that 
which  made  the  tracks  just  referred  to,  in  being  quadrupedal  in  locomo 
tion.  Its  leg  bones  were  slender  and  hollow,  like  those  of  Birds,  and 
had  thin,  dense  walls.  A  squarish  impression  accompanies  in  some 
cases  the  three-toed  Reptilian  footprints,  which  appears  as  if  made  by 
a  blunt  extremity  of  the  body  ;  but  Cope  has  shown  that  the  two 
ischial  bones  (the  lower  and  posterior  part  of  the  pelvis)  were  pro 
longed  backward,  as  in  Birds,  and  terminated  behind  side  by  side ;  and 
that  hence  the  impression  might  well  have  been  made  by  their  blunt 
extremity. 

Bones  of  another  species,  called  Clepsysaurus,  have  been  found  in 
Pennsylvania  by  Lea,  and  also  in  North  Carolina  by  Emmons.  Fig. 
727  represents  a  tooth  of  the  species,  showing  that,  while  bird-like 


414 


MESOZOIC   TIME. 


Figs.  725-728. 


in  some  points,  it  was  decidedly  not  so  in  its  more  fundamental  char 
acteristics. 

Bones  found  in  the  red  sandstone  near  "Windsor,  Connecticut,  be 
longed  either  to  another  Dinosaur  or  to  a  Bird ;  in  either  case,  probably 
to  one  of  the  track-makers. 

Fig.  725  represents,  reduced,  a  tooth  from  Prince  Edward's  Island, 
of  a  species  called  Bathygnathus  by  Leidy,  which  Cope  observes  may 

have  belonged  to  another  Dinosaur. 
The  teeth  are  four  inches  long. 

Lacertians,  Rhynchosanrs. —  Figs. 
726,  728,  represent  teeth  referred 
to  a  species  of  the  Triassic  genus 
Belodon.  Bones,  found  at  Phrenix- 
ville,  Pa.,  that  were  formerly  referred 
to  a  Pterosaur  or  flying-lizard,  are 
now  regarded  by  Cope  as  those  of 
a  Rhynchosaur,  a  Saurian  having 
the  beaked  mouth  of  a  turtle. 

Enaliosaurs  or  Swimming  Sau- 
rians.  —  Leidy  has  described  a  spe 
cies  of  Enaliosaur  (or  Sea-saurian, 
as  the  word  signifies),  from  the 
Triassic  rocks  of  Humboldt  County, 
sis-  Nevada. 

Birds.  —  The  evidence  with  regard  to  the  existence  of  Birds  at 
this  period  has  been  shaken  by  the  discovery  of  the  three-toed  reptile- 
tracks  ;  and  it  is  not  impossible,  as  was  early  suspected,  that  all  the 
supposed  bird-tracks  may  turn  out  to  be  Reptilian.  Still,  while  three- 
toed  tracks  have  been  found  by  thousands,  the  occurrence  of  accom 
panying  impressions  of  the  anterior  feet  is  rare.  It  is  altogether  prob 
able  that  there  were  Birds  as  well  as  Reptiles. 

The  Birds,  if  any  existed,  must  have  been  very  numerous  and  varied 
in  kind  and  size.  The  tracks  prove,  by  the  length  of  stride,  that  the 
species  were  mostly  long-legged,  like  the  Waders  and  the  Ostrich  ; 
and,  by  the  regularity  of  stride,  that  they  were  not  leaping  animals. 
None  were  web-footed.  The  existence  of  Birds  is  probable,  from  the 
fact  that,  in  the  same  era,  there  were,  beyond  question,  species  of  Mam 
mals,  the  highest  division  of  the  Animal  Kingdom  ;  and  also  by  the 
discovery  of  the  bones  and  feathers  of  a  Bird  in  the  European  Jurassic, 
—  possibly  a  cotemporary,  since,  as  already  stated,  the  Connecticut 
River  sandstone  may  be  partly  Jurassic.  If  any  birds  existed,  it  is 
pretty  certain  that  they  had  long  vertebrated  tails,  as  this  was  the  case 
with  the  Jurassic  bird  of  Solenhofen  (p.  446). 


Fig.  725,  Bathygnathus  borealis  (  X  %) :  726 
726  a,  Belodon  priscus  ;  727,  Clepsysaurus 
Pennsylvanicus  ;  728,  Belodon  Carolinen- 


TRIASSIC   PERIOD. 


415 


The  largest  of  the  tracks  was  nearly  two  feet  long ;  and,  from  its 
depth  and  the  great  length  of  stride,  it  is  evident  that  the  animal  was 
tall  and  heavy,  —  probably  fourteen  feet  high,  exceeding  the  Ostrich  of 
our  day,  and  even  the  huge  Moa  of  New  Zealand  (p.  580).  If  the  tracks 
of  this  animal  are  those  of  a  Dinosaur,  instead  of  a  Bird,  the  height  of 
the  biped  Reptile  could  hardly  have  been  less  than  that  here  stated. 

Smaller  species  were  common,  and  many  have  been  described.     Fig. 


Fig.  729. 


r 


Fig.  730. 


,  s   PH 

~"3-3-_.W 


A 


>X    \  / 

Brontozoum  giganteur 


Slab  of  sandstone,  with  tracks  of 
Birds  and  Reptiles  (X^)' 


730  (from  Hitchcock)  represents  a  large  slab,  with  its  lines  of  tracks, 
showing  that  a  number  of  these  three-toed  animals  (a,  b,  c)  and  at 
least  one  Amphibian  (d)  passed  over  the  muddy  surface  during  the 
same  day,  or  before  the  tides  or  freshets  made  new  depositions  of  de 
tritus  :  the  tracks,  a,  a,  are  enlarged  views  of  J,  and  still  are  only  one 
tenth  of  the  natural  size. 

Mammals.  —  The  only  Mammal  thus  far  discovered  in  the  Ameri 
can  rocks  was  made  known  by  Professor  Emmons.     The   specimens 

Fig.  731. 


Dromatherium  sylvestre. 


are   two  jaw-bones   (Fig.  731),  found  in  North  Carolina.     According 
to  Professor  Owen,  they  belonged  to  an  Insectivorous  (insect-eating) 


416  MESOZOIC    TIME. 

Marsupial l  near  the  modern  genus  Myrmecobius  of  Australia.2  The 
species  has  been  named,  by  its  discoverer,  Dromatherium  sylvestre. 
Mammals  of  similar  kinds  probably  spread  over  the  continent,  and  may 
have  been  of  many  species. 

Characteristic  Species. 

1.  Mollusks.  —  Lamellibranchs, — Myacites    Pennsylvanicus    Conrad,    from    the 
black  slate  of  Phoenixville,  Pa.     Two  other  species  occur  at  the  same  locality. 

In  California  or  Nevada,  are  Orthoperas  Blake i  Gabb,  Goniatitts  (Ammonites)  levidor- 
satus  Hauer,  Ceratites  (Goniatites)  Haidinyeri  Hauer,  C.  Whitneyi  Gabb,  Ammonites 
Blakei  Gabb,  A.  Ausseanus  Hauer,  A.  Billinysianus  Gabb,  Ifalobia  dubia  (?)  Gabb, 
Monotis  subcircularis  Gabb,  Posidonomya  stella  Gabb,  Myophoria  alta  Gabb,  Spiriftr 
Homfrayi  Gabb,  besides  other  species. 

2.  Articulates — (a.)  Crustaceans. — Ostracoids:    Fig.    711,  Estlieria  ovata    Lea 
(Posidonia  minuta),   from  Richmond,   Va.,  and  Phoenixville,   Pa.,  resembles   the  P. 
minuta  of  the  European  Trias;  Fig.  711  a,  E.ovalis  Emmons,  from  North  Carolina,  and 
Fig.  711  b,    E.  parva  Lea,   Phoenixville,  Pa.,  are   both  E.  ovata,  according  to  T.  R. 
Jones.     Two  species  of  Cypris,  one  smooth,  and  the  other  granulate,  occur  at  Phoenix 
ville  and  Gwynned,  Pa.     Figs.  716,  717  represent  tracks  referred   by  Hitchcock  to 
Macrotiraii  Crustaceans. 

(b.)  Insects. — Fig.  712,  exuvia  of  a  Neuropterous  larve,  related  to  Ephemera, 
according  to  J.  L.  Le  Conte:  the  appendages  along  the  sides  are  probably  branchiae 
attached  to  the  abdomen.  Tracks  of  different  insects  are  shown  in  Figs.  713-715,  from 
Hitchcock.  On  comparing  especially  Figs.  713,  714  with  the  footprints  of  some  living 
Insects,  Dr.  Deane  found  a  close  resemblance  between  them. 


1  Mammals.  —  The  highest  group  of  Vertebrates  are  of  two  grand  divisions :  — 

I.  The  Ordinary  or  True  Viviparous  Mammals,  such  as  the  Monkey,  Lion,  Elephant, 
Ox,  Bat,  Mouse,  Whale,  etc. 

II.  The  Semi-oviparous   Mammals,  which    are,  with  one   exception,   Marsupial.  — 
Birth  takes  place  before  the  ordinary  degree  of  maturity  in  the  embryo  is  attained, 
and  they  thus  approximate  to  oviparous  vertebrates.     The  immature  young  in  these 
Marsupials  are  passed  into  a  pouch  (marsupium),  situated  over  the  venter  of  the  mother, 
in  which  they  are  nourished  from  her  teats, until  the  degree  of  maturity  required  for 
independent  existence  is  attained.     They  are  the  lowest,  and  geologically  the  earliest, 
of  Mammals. 

2  A  view  of  the  Myrmecobius  is  here  given. 


732,  Myruiecobius  fasciatus  (X 


TRIASSIC   PERIOD.  417 

3.  Vertebrates.  —  («.}  Fishes.  —  Fig.  718,  Catopterns  gracWs  Redfielcl  (reduced 
one  half),  from  Middletield,  Ct.:  also  found  in  North  Carolina  and  at  Phoenixville, 
Pa.;  718  «,  scale  of  same,  natural  size.  There  are  also  other  species  of  Catopterns; 
also  species  of  Ischypterus  and  of  Turseodus  Leidy  (related  to  Btkmostomus  or  Eu- 
f/nathus).  In  the  last,  the  tail  is  not  at  all  vertebrated.  Radiolepis  speciosus  Emmons 
is  another  Ganoid,  from  North  Carolina  and  Pennsylvania. 

The  best  localities  of  fossil  fishes  are  Sunderland,  Mass. ;  Middlefield  Falls  and 
Southbury,  Ct. ;  Richmond  Coal-beds,  Va. ;  Phoenixville,  Pa. 

(b.)  Reptiles. —  (1.)  Amphibians. — Fig.  723,  Anisopus  yradlis  Hk.,  reduced  one 
third.  Fig.  722,  Anisopus  Deivey/tnus  Hk.,  half  natural  size.  Fig.  719,  Macropterna 
divaricans  Hk.  (reduced'  to  one  sixth).  Fig.  724,  Otozoum  Moodii  Hk.,  one  eighteenth 
natural  size.  Portions  of  the  skeleton  of  Labyrinthodont  Amphibians  have  been  de 
tected  by  Leidy  among  the  fossils  of  Gwynned,  Pa,  twenty  miles  north  of  Philadel 
phia,  and  also  among  those  found  at  Phoenixville ;  and  Emmons  has  figured  a  portion 
of  the  head  of  a  fine  species  from  North  Carolina. 

(c.)  Dinosaurs.  —  Figs.  721,  721  a,  tracks  of  fore  and  hind  feet  of  Anomoepus  scam- 
bus  Hk. ;  725,  tooth,  reduced  one-half,  of  Bathygnathus  borealis  Leidy,  from  a  jaw  found 
in  the  rocks  of  Prince  Edward's  Island,  referred  to  the  Amphibians  by  Leidy,  to  the 
Thecodonts  by  Owen,  and  to  the  Dinosaurs  by  Cope. 

(d.)  Lacertians. — Fig.  727,  tooth,  natural  size,  of  the  Cfepsyaawnu  Pennsylvanicus 
Lea,  the  edge  sharp-denticulate,  from  North  Carolina,  and  Phoenixville,  Pa. ;  726,  one  of 
the  back  set' of  teeth  of  Belodon  priscus  Leidy,  from  North  Carolina;  726^,  ?ection 
of  same ;  728,  one  of  the  front  set  of  teeth  of  B.  Carolinensis  Cope,  from  North  Caro 
lina,  and  Phoenixville,  Pa.;  B.  Leaii  Cope,  from  North  Carolina;  B.  lepturus  Cope, 
from  Phcenixville.  Also  the  Rhynchosaur  (according  to  CopQ),RhabdopeHx  longispmit 
Cope,  from  Phoenixville,  formerly  regarded  as  a  Pterosaur. 

Coprolites  are  abundant  in  the  shales  of  Phcenixville. 

(e.)  Birds  (?).  —  Fig.  729,  Brontozoum  yiganteum  Hk.,  reduced  to  one-sixth  natural 
size.  Fig.  730,  part  of  a  slab  of  sandstone  figured  by  Hitchcock,  one-thirtieth  natural 
size:  a,  b,  c,  three  kinds  of  bird-like  tracks;  a  and  c,  of  the  genus  Brontozoum  Hk. ;  a, 
a,  same  as  b,  but  drawn  larger,  to  show  the  articulations  of  the  toes.  Figs,  d,  e,  two 
kinds  of  Reptilian  tracks,  of  the  genus  Anisopus  Hk.,  d,  Anisopus  Deweyanus  Hk. 
Natural  length  of  ft,  4  inches;  of  b,  8  to  9  inches;  of  c,  3|  inches;  of  d  and  e,  1  to  1^ 
inches.  The  best  localities  of  tracks  of  birds  and  other  animals  are  at  Greenfield  and 
Turner's  Falls,  Mass. ;  Portland,  Conn. 

(f. )  Mammals. — Fig.  731,  Dromatlierium  sylvestre  Emmons,  from  North  Carolina. 
Owen  says  of  the  species  that  "  this  Triassic  or  Liassic  Mammal  would  appear  to  find 
its  nearest  living  analogue  in  Myrmecobius,  Fig.  732,  p.  416;  for  each  ramus  of  the 
lower  jaw  contained  ten  small  molars  in  a  continuous  series,  one  canine  and  three 
conical  incisors,  —  the  latter  being  divided  by  short  intervals." 

III.   Disturbances.  —  Igneous  action.  —  Trap  rocks. 

Trap  ridges  and  dikes  accompany  this  formation  on  the  Atlantic 
border.  The  rocks  constituting  them  are  of  igneous  origin,  and  were 
ejected  in  a  melted  state,  through  fissures  in  the  earth's  crust.  It  is 
remarkable  that  these  fractures  should  have  taken  place  in  great  num 
bers  just  where  the  Triassic  beds  exist,  and  only  sparingly  east  or  west 
of  them  ;  and  also  that  the  igneous  rock  should  be  essentially  the  same 
throughout  the  thousand  miles  from  Nova  Scotia  to  North  Carolina. 
The  igneous  and  aqueous  rocks  are  so  associated  that  they  necessarily 
come  into  the  same  history.  Mount  Tom  and  Mount  Holyoke,  of 
Massachusetts,  are  examples  of  these  trap  ridges  ;  also  East  Rock  and 

27 


418 


MESOZOIC  TIME. 


"West  Rock,  near  New  Haven,  and  the  Hanging  Hills,  near  Meriden, 
in  Connecticut ;  the  Palisades  along  the  Hudson,  in  New  York  ;  Ber 
gen  Hill  and  other  elevations  in  New  Jersey. 

In  Nova  Scotia,  trap  ridges  skirt  the  whole  red  sandstone  region, 
and  face  directly  the  Bay  of  Fundy ;  Cape  Blomidon,  noted  for  its 
zeolitic  minerals,  lies  at  its  northern  extremity,  on  the  Bay  of  Mines. 

In  Connecticut,  the  ridges  and  dikes  are  exceeding  numerous,  show 
ing  a  vast  amount  of  igneous  action.  The  following  map  (Fig.  733), 

Fig.  733. 


Map  of  part  of  the  region  in  central  Connecticut,  from  Xew  Haven,  northward.  The  lines  wm,  op 
show  the  outlines  of  the  Triassic  area  ;  N.  H.,  New  Haven  ;  N.,  Micldletown  ;  H.,  Hartford  ; 
M.,  Meriden,  west  of  which  are  the  "  Hanging  Hills  ;  "  w.,  West  Rock  ;  c.,  East  Rock. 


TRIASSIC   PERIOD.  419 

from  a  more  complete  one  of  the  State,  by  Percival,  gives  some  idea 
of  their  number  and  position.  They  commence  near  Long  Island 
Sound,  at  New  Haven,  where  they  form  some  bold  eminences,  and 
extend  through  the  State,  and  nearly  to  the  northern  boundary  of 
Massachusetts.  Mounts  Holyoke  and  Tom  are  in  the  system.  The 
general  course  is  parallel  with  that  of  the  Green  Mountains. 

Although  the  greater  part  of  the  dikes  are  confined  to  the  sand 
stone  regions,  there  are  a  few  lines  outside,  intersecting  the  crystalline 
rocks,  and  following  the  same  direction  ;  and  part,  at  least,  of  these 
belong  to  the  same  system. 

Even  the  little  Southbury  Triassic  region,  lying  isolated  in  western 
Connecticut,  has  a  large  number  of  trap  ridges,  and  such  a  group  of 
them  as  occurs  nowhere  else  in  New  England,  outside  of  the  Triassic. 
Their  direction  and  positions  in  overlapping  series  are  the  same  as  in 
the  Connecticut  valley. 

The  trap  usually  forms  hills  with  a  bold  columnar  front  and  sloping 
back ;  when  nearly  north  and  south  in  direction,  the  bold  front  is  to 
the  westward  in  the  Connecticut  valley,  and  to  the  eastward  in  New 
Jersey.  It  has  come  up  through  fissures  in  the  sandstone,  which 
varied  from  a  few  inches  to  300  feet  or  more  in  breadth.  In  many 
cases,  it  has  made  its  way  out  by  opening  the  layers  of  sandstone ; 
and  in  such  cases  it  stands  with  a  bold  front,  facing  in  the  direction 
toward  which  it  thus  ascended. 

The  proofs  that  the  trap  was  actually  melted  are  abundant.  For 
the  sandstone  rocks  have  in  many  places  been  baked  to  a  hard  grit  by 
the  heat,  arid  at  times  so  blown  up  by  steam  as  to  look  scoriaceous  ; 
and  such  layers  have  been  actually  taken  in  some  cases  for  beds  of 
scoria.  In  some  places,  the  uplift  has  opened  spaces  between  the 
layers,  where  steam  has  escaped  and  changed  a  fine-grained  clayey 
sandstone  into  a  very  hard  rock  looking  like  trap.  Occasionally,  crys 
talline  minerals,  as  epidote,  tourmaline,  specular  iron  (hematite),  gar 
net,  and  chlorite,  are  among  the  results  of  the  heat  or  hot  vapors.  The 
evidences  of  heat,  moreover,  diminish  as  we  recede  from  the  ridges. 
There  is  no  doubt  that  the  sandstone  in  many  places  owes  its  escape 
from  denudation  to  the  firm  consolidation  it  derived  from  the  heat  and 
vapors  rising  with  the  eruptions,  and  to  the  waters  of  hot  springs  then 
set  in  action. 

In  all  the  several  regions  along  the  Atlantic  border,  the  sandstone  strata  are  in  most 
parts  much  tilted.  In  North  Carolina,  there  is  generally  a  dip  of  10°  to  22°  to  the 
southwest  (Emmons) ;  in  Virginia,  Maryland,  Pennsylvania,  and  New  Jersey,  the  dip 
is  to  the  northwest  or  north-northwest  (Rogers);  in  Connecticut  and  Massachusetts,  to 
the  east  or  southeast,  the  amount  seldom  exceeding  23°. 

Some  of  the  dikes  of  trap  and  fissures  in  the  sandstone,  in  Con- 


420  MESOZOIC   TIME. 

necticut  and  New  Jersey,  contain  copper-ore  (copper-glance,  erubescite 
and  malachite) ;  and  there  is  little  doubt  that  the  copper  veins  and  the 
barite  (sulphate  of  barium),  which  is  often  the  gangue  of  the  vein, 
originated  in  the  same  period  of  eruption.  The  red  color  of  the 
sandstone  —  a  consequence  of  the  oxydation  of  iron  present  in  it  — 
appears  to  have  had  its  origin  in  the  same  cause. 

This  history  of  the  Triassic  of  the  Atlantic  border  and  its  trap 
dikes  appears  to  be  a  repetition  of  what  took  place  long  before,  during 
both  the  Huronian  and  the  Lower  Silurian  eras,  in  the  Lake  Superior 
region,  where  a  similar  subsidence  (at  least  10,000  feet  in  the  former, 
and  3,000  or  4,000  in  the  latter)  and  similar  igneous  eruptions  accom 
panied  the  formation  of  the  beds. 

IV.   General  Observations. 

General  Progress.  —  The  following  points  bear  upon  the  history  of 
this  period  in  Eastern  North  America  :  — 

I.  The  position  of  the  rocks  in  linear  ranges,  parallel  with  the  moun 
tains,  and  therefore  along  depressions  in  the  surface   that  existed  when 
the  period  opened.  —  The  Connecticut  valley  is  one  of  the  great  depres 
sions.     Such  areas  would  naturally  have  become  inlets  of  the  sea,  or 
estuaries,  river-courses,  lakes,  or  marshes,  and  would  have  received  the 
debris  of  the  hills  brought  in  by  streams. 

II.  The  absence  of  Radiates,  the  paucity  of  Mollusks,  and  the  presence 
of  few  species  that  are  properly  marine.  —  These  facts  prove  that  the 
ocean  had  imperfect  access,  where  any,  to  the  regions  ;  that  the  beds 
were  therefore  estuary  or  lacustrine,  and  not  sea-shore  formations  like 
the  Cretaceous  and  Tertiary  of  later  times.     The  occurrence  of  vege 
table  remains  and  of  the  coal  beds  sustains  this  conclusion. 

III.  Tlie  mud-cracks,  raindrop-impressions  and  footprints.  —  These 
show,  wherever  they  occur,  that  the  layer  was  for  the  time  a  half- 
emerged  mud-flat  or  sand-flat ;  and,  as  they  extend  through  much  of 
the  rock,  there  is  evidence  that  the  layers  in  general  were  not  formed 
in  deep  water.     They  abound  especially  in  the  upper  half  of  the  Con 
necticut-valley  strata. 

IV.  The  occurrence,  in  some  parts  of  the   Connecticut  valley,  of 
coarse  conglomerate,  some  of  the  stones  of  which  are  very  large,  and 
of  a  coarse  kind  of  oblique  lamination  in  much  of  the  rock,  is  evi 
dence  that  some  of  the  beds  were  deposited  by  a  flood  of  waters  pour 
ing  violently  down   this  valley ;    and  they  seem  also  to  indicate  that 
floating  ice  must  have  been  concerned  in  part  of  the  deposition.     The 
granytic  and  unassorted  character  of  the  sands  looks  as  if  the  material 
had  been  made  by  the  disintegration  of  New  England  rocks,  through  a 


TRIASSIC   PERIOD.  421 

long  era,  and  finally,  in  the  Triassic  era,  had  been  swept  off  from  the 
land  into  the  valley,  by  the  flood  referred  to. 

V.  The  thickness,  —  3,000  to  5,000  feet  or  more.  —  We  learn  from 
this  thickness,  in  connection  with  the  fact  just  stated,  that  the  areas 
underwent  a  gradual  subsidence  of  3,000  to  5,000  feet  or  more  ;  con 
sequently,  that  these  oblong  depressions  made  at  the  time  of  the  fold 
ings  were   slowly  deepening,  and  continued  to  deepen  until  the  last 
layer  was  laid  down. 

VI.  The  tilted  condition  of  the  beds,  without  evidence  of  folds.  —  The 
tilting  must  be  a  result  of  mechanical  force  ;  and,  as  the  bedding  is 
well  preserved,  while  joints  are  common,  it  follows  that  the  force  was 
very  gradual  in  its  action.     Under  V.,  a  profound  subsidence  is  stated 
to  have  been  in  progress,  in  the  regions  of  depression  occupied  by  the 
strata.     Such  a  subsidence  would  have   brought   a   strain   upon  the 
rocks  of  the  trough  below,  and  sooner  or  later  would  have  produced 
fractures  and  disturbance  ;  and,  if  one  side  or  part  of  the  depression 
were  undergoing  more  subsidence  than  the  opposite,  it  would  have 
caused  that  oblique  pushing  of  the  beds  that  would  have   ended  in 
faulting  and  tilting  them.    The  direction  of  the  dip  and  strike,  in  such 
a  case,  would  depend  on  the  relative  positions,  with  reference  to  the 
whole  basin,  of  the  parts  undergoing  greatest  and  least  subsidence. 

VII.  The  sandstone  strata  intersected   by   dikes   of  trap.  —  These 
dikes  are  proofs  that  fractures  took  place.     The  subsidence  of  such  a 
region  would  have  brought  increasing  tension  or  strain  upon  the  rocks 
below,  tending  to  produce  fractures,  especially  about  the  axial  region 
of  the  depression ;  arid  these  would  have  opened  the  way  for  ejections 
of  melted  rocks.     Thus  the  tilting,  fractures,  joints,  and  ejections  are 
parts  of  one  system  of  events. 

The  manner  in  which  the  trap  at  its  eruption  has  sometimes  sep 
arated  the  layers  of  sandstone,  and  in  this  way  escaped  to  the  surface, 
instead  of  coming  up  through  the  fissures  simply,  shows  that  the  rock 
had  been  tilted  extensively  before  the  ejection. 

In  the  north-and-south  ridges  of  the  Connecticut  valley,  the  trap  which  thus  escaped 
now  shows,  as  already  observed,  a  bold  front  to  the  westward,  the  dip  of  the  sandstone 
being  to  the  eastward.  Now,  in  this  bold  columnar  front,  the  angle  of  inclination  in 
the  columns  is  just  the  angle  of  dip  in  the  sandstone,  the  columns  being  at  right  angles 
to  the  layers  of  sandstone.  Hence,  the  inclination  in  the  sandstone  layers  existed  before 
the  time  of  ejection,  and  determined  the  position  of  the  columns;  for  the  columnar 
structure  of  trap  is  always  at  right  angles  to  the  cooling  surfaces;  and  these  surfaces 
were  those  of  the  opened  layers  of  sandstone.  We  have  proof  therefore  that  there  was 
a  tilting  of  the  strata  in  progress,  before  the  final  breaking  and  ejections. 

Era  of  the  Eruptions  of  trap.  — As  the  trap  dikes  intersect  the  later  beds  of  the  for 
mation,  the  igneous  ejections  must  either  have  been  among  the  closing  events  of  the 
sandstone  period,  or  have  occurred  in  a  succeeding  epoch. 

Thus  the  period  of  these  rocks  came  to  a  close  somewhat  similar  to 


422 


MESOZOIC   TIME. 


that  of  the  Carboniferous  age.  The  Carboniferous  age  ended  in  a 
period  of  disturbance,  escape  of  heat,  as  shown  in  consolidations  and 
metamorphism,  and  a  general  destruction  of  life  along  the  Continental 
border  ;  and  so  the  period  of  these  sandstones  was  closed  in  uplifts, 
fractures,  emissions  of  heat,  consolidations,  and  destructions  of  life. 
But,  in  the  former  case,  the  catastrophe  resulted  in  mountain-making 
through  foldings  ;  in  the  latter,  the  action,  though  ranging  along  the 
same  line  of  coast,  from  South  Carolina  to  Newfoundland,  was  more 
limited  ;  the  surface  rocks  were  only  tilted  and  broken,  and  heat  ex 
hibited  its  effects  chiefly  in  eruptions  of  melted  rock. 

Geography.  —  The  position  of  the  beds  on  the  Atlantic  border  shows 
that  this  part  of  the  continent  stood  nearly  at  its  present  level.     The 

Fig.  735. 


Map  of  the  submerged  border  of  the  continent,  off  New  Jersey  and  Long  Island,  with  lines  of  equal 
soundings  in  fathoms.  N.  Y.,  City  of  New  York  ;  N.  J.,  State  of  New  Jersey  ;  N.  H.,  New  Ha- 
Ten  ;  B.,  Brooklyn  ;  St.,  Staten  Island  ;  S.,  Sandy  Hook  ;  M.,  Montauk  Point ;  Bl.  Block  Island. 

strange  absence  of  marine  deposits,  along  the  Atlantic  Border,  may  be 


TRIASSIC   PERIOD.  423 

accounted  for  by  supposing  that  the  dry  land  stretched  farther  to  the 
eastward  than  now,  and  that  seashore  deposits  were  formed  which  arc 
submerged.  A  change  of  level  of  five  hundred  feet  would  take  a 
breadth  of  eighty  miles  from  the  ocean,  and  add  it  to  the  continent. 

This  important  fact  —  which  has  been  before  referred  to,  more  than 
once,  on  account  of  its  bearing  on  the  history  of  the  continent  —  is 
presented  to  the  eye  in  the  accompanying  map,  prepared  from  one  of 
the  charts  of  the  Coast  Survey.  The  dotted  lines  (lines  of  equal 
soundings)  run  back  in  a  long  loop  northwestward,  toward  New  York 
harbor,  showing  deeper  water  along  this  line,  and  evidently  proving 
that  once  the  land  was  above  water,  with  the  Hudson  River  occupying 
this  channel  on  its  way  to  the  ocean.  At  two  or  three  places  along 
this  channel,  there  are  "  deep  holes,"  as  they  are  called  (one  of  them 
at  32,'  where  the  depth  is  thirty-two  fathoms),  which  may  have  been 
former  sites  of  New  York  harbor  ;  for  the  waters  of  the  harbor  are 
now  about  six  fathoms  deeper  than  those  about  its  entrance.  An 
under-water  channel  of  the  Connecticut  also  is  indicated  at  c,  c',  c". 

This  border,  now  submerged,  has,  therefore,  in  former  time,  been 
dry  land  ;  it  may  have  been  partly  so  in  the  Triassic  period,  and  thus 
have  caused  the  imperfect  connection  of  the  Triassic  areas  of  the 
Atlantic  Border  with  the  ocean. 

The  Triassic  continent  spread  westward  to  Kansas,  and  southward 
to  Alabama ;  for,  through  this  great  area,  there  are  no  rocks  more 
recent  than  the  Paleozoic. 

While,  on  the  east,  the  continent  probably  stood  above  its  present 
level,  through  the  Triassic  period,  and  while,  over  much  of  the  Rocky 
Mountain  region,  the  land  was  barely  emerging  from  the  waters,  or 
was  covered  by  interior  salt  seas,  —  farther  west,  over  a  large  part  of 
the  Great  Plateau,  and  the  rest  of  the  Pacific  slope,  the  surface  was 
washed  by  the  waves  of  the  Pacific,  and  peopled  with  its  life.  The 
Sierra  Nevada  was  then  no  barrier  to  the  ocean  ;  for  the  sands,  mud, 
and  limestone  accumulated  in  those  waters  constitute  some  of  its 
rocks.  The  stratified  beds  of  the  mountains  were  then  in  progress  of 
formation,  through  the  action  of  the  Pacific  tides,  currents,  and  waves, 
and  the  growth  of  marine  life.  The  making  of  the  Sierra  was  de 
layed  till  the  rocks  of  still  another  geological  period  had  been  deposited 
upon  the  Triassic. 

2.  FOREIGN  TRIASSIC. 

The  region  over  which  Triassic  rocks  outcrop,  in  England  (see  map 
on  p.  344),  stretches  across  the  island,  from  a  point  in  its  southwestern 
part  on  the  British  Channel,  north-northeastward ;  and  also,  from  the 
centre  of  this  band,  along  a  northwestward  course,  to  Liverpool,  and 


424  MESOZOIC   TIME. 

thence  north,  up  the  wcsfc  coast.  It  is  probable  that  all  of  England, 
east  of  the  Triassic,  was  submerged.  The  rest  of  it  was  divided  into 
three  or  more  parts,  —  a  southwestern  (the  peninsula  of  Cornwall  and 
Devon),  a  western  (Wales),  and  a  northern, — indicating  the  exist 
ence  of  an  archipelago  of  British  Isles  in  the  Triassic  period.  The 
rocks  show  that  the  waters  between  the  islands  were  shallow  and 
partly  brackish. 

In  Europe,  the  Trias  is  found  largely  developed  in  regions  east  and 
west  of  the  Rhine,  from  northern  Switzerland  northward  ;  on  the 
east  side,  through  Wurtemberg,  Odenwald,  Thuringerwald,  and  by 
Giessen  ;  and  on  the  west  side,  along  the  Vosges,  by  Strasbourg  and 
Metz,  to  Aix;  and,  in  each  of  these  regions,  they  indicate  brackish  or 
shallow  waters,  instead  of  deep  seas.  The  beds  occur  also  in  other 
parts  of  central  Europe,  in  the  eastern  Alps,  Poland,  Russia,  Spain, 
etc.,  and  in  the  far  north,  on  Spitzbergen. 

I.  Rocks:  kinds  and  distribution. 

The  subdivisions  of  the  Trias  are,  —  (1)  the  Variegated  Sandstone  ; 
(2)  the  Shell  Limestone  ;  (3)  the  Red  Marls,  or  the  Keuper ;  (4)  the 
Rhaetlc  beds,  between  the  Trias  and  Lias.  The  rocks  are  mainly  red 
sandstones  and  marlytes,  with  an  impure  limestone  as  the  middle 
member,  in  Germany.  There  is  a  "  bone-bed  "  near  the  top  of  the 
series,  both  in  England  and  Germany. 

The  subdivisions  recognized  in  France  and  Germany  are  three  in  number;  whence 
the  name,  from  the  Latin  tria,  three.  The  beds  are  denominated,  in  these  countries 
and  England,  beginning  with  the  lowest:  — 


I.  England. 

Salif erous  beds,  or  New 
Red  Sandstone,  1,200 
to  2,500  feet. 


II.  France. 

1.  Gres  bigarre. 

2.  Calcaire  coquillier. 

3.  Marnes  irise"es. 


III.    Germany. 

1.  Bunter  Sandstein,  1,200  to  1,600  ft. 

2.  Muschelkalk,  1,000  to  1,200  feet. 

3.  Keuper. 


In  English  works,  the  names  of  the  European  beds,  translated,  are,  —  1.  Variegated 
sandstone;  2.  Shell  limestone;  3.  Red  marlytes, or  Keuper;  yet  they  are  often  written 
without  translation.  The  names  indicate  the  kinds  of  rocks.  In  England,  they  are 
sandstone  and  mottled  clays  (marlytes),  mostly  red.  In  Europe,  near  the  Rhine,  a  thick 
fossiliferous  impure  limestone  lies  between  a  sandstone  below  and  marlytes  above. 
The  formation  is  sometimes  called  the  Pcec'ditic  (or,  badly,  Poikilitic),  from  the  Greek 
for  varieyated. 

This  formation  contains  the  principal  salt-beds  of  Europe;  and  hence  it  is  often 
called  the  Saliferous  system.  The  salt  in  Germany  is  connected  with  the  middle  group, 
as  in  Wurtemberg,  where  there  are  noted  salt  works.  In  Vic  and  Dieuze,  France,  they 
are  in  the  upper;  and  a  thickness  of  180  feet  of  rock-salt  occurs  in  the  course  of  650 
feet  of  rock.  The  salt  layers  alternate  with  clay  and  gypsum  or  anhvdrite.  In  Eng 
land,  the  upper  part  affords  the  salt;  and  at  Northwich,  in  Cheshire,  two  beds  of  salt, 
nearly  pure,  are  90  to  100  feet  thick. 

St.  Cassian  series.  —  The  beds  of  the  St.  Cassian  series  include,  beginning  below,  — 


TRIASSIC   PERIOD. 


425 


(1.  Werfen  beds,  shale,  sandstone,  gypsum,  salt. 
2.   Guttenstein  beds,  shale  and  limestone 150  feet. 
3.  St.  Cassian  beds,  red,  pink,  and  white  limestone,  at  St.  Cas-  )    gQQ  ^     , 
sian  and  Ilallstatt •  ' 

f  4.  Dachstein  beds,  white  and  grayish  limestone 2,000  feet. 

B  !  5.  Kiissen  beds  (Rhcetic  of  Giimbel,  Upper  St.  Cassian  of  Escher 

and  Merian),  gray  and  black  limestone  and  marls' ...        50  feet. 

The  Werfen  beds  are  regarded  as  corresponding  to  the  Bunter-sandstein ;  the  Gut- 
tenstein,  to  the  Muschelkalk  and  Lower  Kcuper;  the  St.  Cassian,  to  the  Middle 
Keuper;  the  Dachstein  and  Kossen,  to  the  Upper  Keuper.  The  Kcissen  beds  are  the 
Kinetic  beds  of  Giimbel,  and  are  by  some  referred  to  the  Lower  Lias.  The  St.  Cas 
sian  beds  of  St.  Cassian  and  Halstatt  (between  the  head  waters  of  the  Inn  and  Drave, 
the  former  on  the  south,  and  the  latter  on  the  north  side  of  the  Austrian  Alps),  are 
remarkable  for  containing,  among  the  600  species  of  invertebrate  fossils,  many  of 
Paleozoic  genera,  some  of  them  not  found  elsewhere  above  the  Permian.  The  Rhaetic 
group  in  England  (called  the  Penarth  in  the  Government  survey)  includes  beds  of 
"the  Avicula  contorta  zone",  between  the  Trias  and  Lias.  They  occur  in  Dorset, 
Somerset,  and  Warwick  to  Lincolnshire.  They  include  the  "White  Lias"  of  Wm. 
Smith,  and  the  "  landscape  marble  "  of  Gotham,  near  Bristol;  and,  next  below  these, 
black  paper  shales,  with  many  fossils  and  a  bone-bed,  and  then  marlytes.  mostly 
without  fossils.  The  St.  Cassian  Series  is  sometimes  called  the  "  Alpine  Trias." 


II.    Life. 

The  European  Triassic  beds  have  afforded  teeth  of  one  species  of 
mammal,  but  fail  of  relics  of  birds. 

1.  Plants. 

Equiseta,  Ferns,  Cypress  evergreens,  arid  Cycads  (Fig.  739)   are 
Figs.  737-739. 


Fig.  737,  Voltzia  heterophylla ;  738,  one  of  its  fruit-bearing  branches  ;  739,  Pterophyllum  Jfegeri. 

the  prevailing    forms.     No   true  Grass,  Moss,  Palm,  or  Angiosperm 
has  yet  been  found  in  beds  of  this  period. 

Characteristic  Species. 
Figs.  737,  738,  parts  of  branches  of  the  Voltzia  heterojihylla  Bnigt,  of  the  Cypress 


426 


MESOZOIC    TIME. 


group.  Fig.  739,  the  Cycad  Pterojrfiylhtm  J(vc/eri  Brngt.,  from  Stuttgart.  There  are 
also  species  of  JEquisetum,  Calamites,  etc.  Some  names  of  European  plants  are  given 
on  p.  409.  JEthojihylluin  spedosum  Schp.  &  Mg.,^.  stijmlare  Schp.,  Ecliinostacliys 
oblonya  Brngt.,  and  E.  cylindrica  Schp.  &  Mg.,  are  names  of  species  of  grass-like  plants, 
referred  to  the  Typhaceae  or  "Cat-tail  "  family. 

2.  Animals. 

Kadiates,  though  not  abundant,  are   represented  by  Crinoids  (Fig. 
740,  the  "Lily  Encrinite  "),  Star-fishes,  and  a  few  Corals. 

Figs.  740-743. 


-Fig.  740,   Encrinus  liliiformis.    LAMELLIBRAJTCHS.  —  Fig.  741,    Oervillia   socialis ;    742, 
Myophoria  lineata.     OSTRACOID.  —  Fig.  743,  Estneria  miuuta. 

tf^: 


CEPHALOPOUS.  —  Fig.  741,  Ceratite-s   uudosus ;  745,  dorsal  view  of  portion   of  same,  showing  the 
dorsal  lobes  of  the  septj. ;  718,  Ammonites  tornatus ;  747,  side-view  of  same  ( x  }£)• 

Mollusks  were  numerous,  and  among  them  species  of  the  Ammonite 
group  (Figs.  744,  740). 

The  Articulates  included  Insects,  Crustaceans  arid  Worms. 


TRIASSIC    PERIOD. 


427 


Among  Vertebrates,  the  Fishes  were  all  Ganoids  or  Selachians. 
The  Amphibians  comprised  the  gigantic  Lakyrinthodon,  a  scale-covered 
animal,  of  a  Batrachian  form,  the  skull  of  which  (Fig.  748)  was  three 

Figs.  748-752. 


Fig.  753. 


AMPHIBIANS.  — Figs.  748,  Mastodonsaurus  giganteus  (x  J^) ;  749,  tooth  of  same  ;  750,  Cheirothe- 
riurn  ( x  fa) :  751,  track  of  turtle  ?    TRUE  REPTILES.  —  Fig.  752,  Telerpeton  Elginense. 

or  four  feet  long,  and  the  teeth  (Fig.  749)  three  inches,  —  magnitude 
enough  for  the  Otozoum  of  the  Connecticut  valley.  The  tracks  (Fig. 
750)  referred  to  a  genus  named  Cheirotherium  (because  of  a  resem 
blance  in  form  to  the  human  hand)  are  supposed  to  be 
those  of  a  Labyrinthodon. 

True  Reptiles  were  represented  by  Swimming  Saurian s 
(Enaliosaurs)  ;  Rhynchosaurs,  or  Saurians  with  a  beaked 
turtle-like  mouth  ;  Belodonts,  between  Lacertians  and 
Crocodiles  ;  and  true  Lacertians. 

The    species    of  Mammal,    Microlestes    antiquus    Plien., 
a  tooth  of  which  is  represented  in  Fig.  753,  was  a  marsupial,  and 
was  closely  related  to  that  of  North  Carolina   (p.  415). 


428 


MESOZOIC    TIME. 


Characteristic  Species. 

1.  Radiates.  —  Fig.  740,  Enciinus  liliiformis  Schlot.,  from  the  European  "  Mus- 
chelkalk."     The  limestone,   in  some  places,  is  largely  made  up  of  Crinoidal  remains. 
Aspidtira,  loricata  Ag.,  is  a  Star  fish  related  to  the  Ophiurce. 

2.  Mollusks.  — (a.)  Brachiopods. —  Terebratula  vulyaris  Schlot.,  Spinfer  Miin- 
Mcii  Dav.,  etc.     (b.)   Conchiftrs. —  Fig.  741,  Gervillia  socialis  Schlot.     Fig.  742,   M;i<>- 
phoria  lineata  Mii.r  of  the  Trigonia  family;  also  Limn  striata  Desh.,  species  of  Ari<;d-i, 
Pecten,  etc.    (c.)  Cephaiopods.     Fig.  744,  Ceratites  nodosus  Schlot.,  related  to  the  Am 
monites  (p.  400);  745,  view  of  hack  of  shell,   showing  shape  of   pockets:   Fig.   74(5, 
Ammonites  tornatus  Braun,  from  the  St.  Cassian  beds;  747,  side  view  of  same.     Species 
of  Orthoceras  have  been  described  from  the  same  beds. 

3.  Articulates.  —  (<t.)    Crustaceans.  — Ostracoids:   Fig.   743, 
Esthena    (Posidonomya)  minuta,  Morris.  —  Macrourans :    Fig.    754, 
Pemphix  Sueurii  Mey.,  a  species   near  the   Crawfish  (genus  Asta- 
CMiS.). — (6.)  fnsects. — Species  of  Curculionites,  Glaphyropterci,  etc. 

4.  Vertebrates.  —  (a.)  Fishes.  —  Among  Hybodont  Selachians, 
Fig.  509,  Hybodus  plicatilis  Ag.;    Fig.  508,   B.  minor  Ag.     Among 
Cestracionts,  species  of  Acrodus,  Ceratodus,  etc.    Ganoids,  especially 
of  the  genera  Saurichthys,  Gyrolepis,  Amblypterus,  and  Pakeoni-gcug, 
the  last  of  the  heterocercal  species ;  and,  of  the  Pycnodont  division, 
Pijcnodus  yiya-t  Ag.,  etc. 

(b.)  Amphibians  of  the  Labyrinthodont  tribe:  Fig.  748,  Mastodon- 
saurus  yiya.nteus  Jag. ,  reduced  to  one  twelf th  the  natural  size ;  Fig. 
749,  one  of  the  teeth,  reduced  one  half;  they  have  the  Labyrinthine 
structure,  explained  on  p.  264;  Fig.  750,  prints  of  the  fore  and  hind 
feet  of  a  Cheirotherium,  one  twelfth  natural  size,  from  Hildburg- 
hausen,  Saxony,  supposed  to  be  those  of  a  Mattodotuawrvt. 

The  larger  track  in  one  was  eight  inches  long,  with  a  stride  of  four 
inches;  in  another,  twelve  inches  long.     Similar  tracks  have  been 
found  at  Storton,  England.     C'ipitosaurus,  Trematosaurus  are  names 
Pemphix  Sueurii.      of  Qther  great  Labyrinthodonts  of  Europe. 

(c.)  Tnie  Reptiles.  —  Enaliosaurs  (or  Sea-Saurians),  of  the  genera  Simosaur,  Xotho- 
saur,  Pistosaur,  and  Conchwsaur,  occur,  mostly  in  the  Muschelkalk  of  Europe,  and 
especially  at  Luneville,  Bayreuth,  and  in  Upper  Silesia.  They  differ  from  the  Jurassic 
Enaliosaurs  in  the  extraordinarily  large  temporal,  orbital,  and  nasal  openings  through  the 
cranium,  which  leave  little  bone.  The  Xothosaurus  mirabil/s  Mii.  was  about  seven  feet 
long.  In  the  bone  bed  at  the  top  of  the  Trias,  in  England,  occur  remains  of  two  or 
three  Plesiosaurs  of  the  Lias,  as  P.  HawkinsiiOw.  and  P.  costatus  Ow.,  and  of  Ichthyo- 
saurs,  Sea-saurians  of  higher  grade. 

Lacertinns  and  other  Saurians.  — Most  of  the  species  of  the  Trias  have  biconcave 
vertebrae,  like  the  Thecodonts  and  Enaliosaurs  (in  this  approximating  to  Fishes).  A 
species  of  the  Permian  genus  Thecodontosaurus  is  found  in  the  Trias  at  Leamington, 
England.  The  turtle-headed  Rlnjnchosaurs  were  among  the  most  remarkable  of  Triassic 
Saurians. 

Fig.  751,  Telerpeton  Elf/inenxe  Mantell,  a  species  found  on  the  south  side  of  the 
Moray  Frith,  in  a  whitish  sandstone  supposed  to  be  Devonian,  but  now  thought  by  most 
geologists  to  be  Triassic.  The  animal  is  a  L;icertian  of  modern  type  in  most  points, 
according  to  Huxley  (Q.  Jour.  G.  Soc.,  xxiii);  this  snpc'riority  to  known  Permian  and 
Carboniferous  Reptiles  is  partly  the  reason  for  making  the  beds  Triassic.  In  the  same 
rock,  there  were  thirty-four  consecutive  footprints  of  an  Amphibian.  The  genus  Belodon, 
of  Meyer,  included  carnivorous  crocodile-like  species. 

Turtles.  —  Tracks  like  Fig.  751,  observed  in  Germany,  have  been  referred  to  a  Turtle, 
the  earliest  representative  of  the  tribe.  The  tracks  form  two  distant  parallel  lines,  as 
they  should  for  an  animal  having  a  broad  shwll-coveix-d  body  and  short  legs. 


TRIASSIC   PERIOD.  429 

Coprolites  of  Reptiles  are  also  common. 

('/.)  Mammals.  —  Fig.  753  represents  the  side-view  of  a  tooth  of  Microlestes  antiquus 
Plien.,  from  the  bone-breccia  of  Wurtemberg.  A  tooth  of  the  same  species  Avas  found 
at  Frome,  England.  Owen  regards  the  species  as  probably  near  the  modern  Myrme- 
cobius,  and  closely  related  to  another  extinct  Marsupial,  Playiauhtx,  of  the  English  Up 
per  Oolyte.  Fig.  753  a  shows  the  crown  of  the  tooth. 

Fossils  characteristic  of  the  subdivisions  of  the  Trias.  —  The  following  are  character 
istic  fossils  of  the  three  subdivisions  of  the  Trias:  — 

1.  Lower  group.  —  Voltzia   heteropJiylla,    Calamitts   Mouyeoti  L.  &  H.    Neuropteris 
eleyans  Brngt. ;  Placodus  impressus  Ag. ;  Nothosaurus  S chimp eri  Mey. ;   Trematosaurus; 
footprints  of  Labyrinthodonts. 

2.  Middle   group.  —  Encrinus   liliiformis,   Gervillia  socialis   Qu.   (common  to  all    the 
groups),  Myophoria  (Triyonia)    vulyaris  Br.,  M.   lineata   Mii.,    Terebratula  vulyaris, 
Ceratites  nodosus,  Nautilus  bidors:itus  Br.,  Pemphix  Sueurii ;  Hybodus  Mougeoti  Ag.,    H. 
major  Ag.,  Phcodus  (several  species);  Nothosaurus  (species  differing  from  those  of  the 
lower  group),  Simosaurus,  Pistosaurus. 

3.  Upper  group,    or   Keuper.  —  Eyuiseta,    Calamites  arenaceus  Jag.,    Pteropliyllum 
Jceyem  Brngt.,  Pt.  lonyifolium  Brngt.,  Pt.  (Pterozamites)  Miinsteri  Gopp.,   Mastodon- 
saurus  yiyanteus,  Belodon,  Termatosaurus ;  Microlestes  antiquus. 

The  Estheria  minuta  ranges  through  all  the  divisions. 

The  St.  Cassian  beds  contain  species  of  the  Paleozoic  genera  Orthoceras  (seven  or  eight 
species), Cyrtoceras,  Goniatites,  Loxmema,  Holopella,  Murcl/isonia,  Euomphalus,  Porcellia 
(BeUerqphon),  Meyalodon,  Cyrtia,  which  are  not  known  afterward,  along  with  others 
peculiarly  Triassic.  such  as  Monotis  sattnaria  Br.,  Hdlobia  Lommeli  Wiss.,  Myophorice, 
Ammonites.  The  Dachstein  beds  contain,  among  their  fossils,  Meyalodon  triqueter^Wuli., 
Avicula  intermedia  Emmr.,  Spinfer  Miinsteri  Dav.,  Sp.  rostratus  Schloth.,  Terebratula 
cornuta  Sow.,  T.  pyriformis  Suess,  T.  yreyari'i  Suess,  Rhynchonellft  corniyera  Schafh., 
The  Kbsxen  beds  have  afforded  an  OrtJioceras,  aBelemnite,  Ammonites  trisulcatus  Brngt , 
Pleurotomaria  expansn  Goldf.,  ^feyalodon  triqueter  Wulf.,  Gervillia  inflata  Schafh., 
Avicula  contorta  Portl.,  A.  incequwakw  SOAV.,  Limn  yiyantea  Sow.,  Pinna  folium  Phil., 
Ccirdium  Rhceticum  Mcrian,  Hemicardium  WulJ'eni,  Pecten  Hasinas  Nyst.,  Pecten  Valo- 
niensis  Defr.,  Litltostrotion,  etc. 

The  Rhretic  beds  in  England  contain  Aricula  contorta,  Pecten  Valoniensis  Defr. 
(these  two  species  characteristic  and  abundant),  A.  incerjuivakis,  Cardium  Rhceticum, 
Pullastra  arenicola  Strickl.,  Monotis  decussata  Mii.,  Modiola  minima  Sow.,  Ostrea  lias- 
sica  Strickl.;  Spirifer  Miinsteri,  Estheria  minuta ;  Acrodus  minimus  Ag.,  Hybodus  pli- 
Cdtilis,  Saurichthys  apicalis  Ag.,  Gyrolepis  tenuistriatus  Ag.,  vertebra?  of  Ichthysosaurs 
and  Plesiosaurs,  tracks  of  Cheirotherium;  teeth  of  Microlestes  (at  Fromc).  Many  of  the 
species  occur  also  in  the  Lias. 

The  Triassic  rocks  of  Spitsbergen,  partly  bituminous  shales,  have  afforded  species  of 
Nautilus,  Ammonites,  Ceratites,  Halobia,  etc.,  closely  like,  if  not  identical  with,  species 
of  the  St.  Cassian  beds  (Laube). 


3.  GENERAL  OBSERVATIONS  ON  THE  TRIAS. 

Life  of  the  Period.  —  The  steps  of  progress  in  the  life  of  the 
globe,  as  the  Mesozoic  era  opened  in  the  Triassic  period,  were  espe 
cially  important.  The  storing  away  of  the  excess  of  atmospheric 
carbon,  as  coal,  had  purified  the  atmosphere ;  and,  soon  after  the  close 
of  Paleozoic  time  —  whose  great  feature  was  that  its  animal  life  had 
made  rocks,  and  its  plants,  coal  —  there  were  higher  races  breathing 
the  better  air.  Saurians  became  numerous ;  and  the  vertebrate  type 
expanded  by  the  appearance  of  species  of  the  new  class  of  Mammals 


430  MESOZOIC   TIME. 

and  probably  also  of  that  of  Birds.  Among  these  types,  the  Saurian 
continued  rapidly  to  rise  in  perfection,  with  the  following  periods  of 
the  age  ;  while  Birds  and  Mammals  remained  of  inferior  types,  the 
forerunners  of  an  age  of  higher  progress. 

While  Birds  were  just  beginning.,  in  long-tailed  or  Reptilian  species, 
and  Mammals  in  the  semioviparous  Marsupials,  the  corresponding 
inferior  division  of  Reptiles,  the  Amphibians,  here  passed  their  culmi 
nation,  the  Labyrinthodonts  ending  and  the  Amphibians  being  after 
ward  fewer  and  smaller. 

Remarkable  harmony  of  form  characterized  the  higher  terrestrial  life. 
The  group  that  gathered  over  the  mud-flats  of  the  Connecticut  com 
prised  the  biped,  scale-covered,  crocodile-toothed  Amphibians,  from 
two  or  three  inches  to  twelve  or  fifteen  feet  in  height ;  Dinosaurs  that 
could  raise  themselves  erect,  and  march  off  like  birds  ;  Birds  measur 
ing  height  with  the  Amphibians,  and  outreaching  them  by  their  longer 
necks  ;  and  Marsupial  Mammals  with  their  hind-legs  probably  the 
longer,  kangaroo-like.  There  was  throughout  a  great  development  of 
the  posterior  extremities.  All  were  oviparous  vertebrates,  except  the 
semi-oviparous  Marsupials. 

The  rocks,  both  in  Europe  and  North  America,  were,  to  a  large  ex 
tent,  of  marsh,  shallow- water,  or  estuary  origin.  But,  on  the  borders 
of  southwestern  Austria,  there  was  an  open  sea,  with  clear  waters ; 
and  extensive  limestone  formations  were  in  progress,  thus  anticipating 
the  conditions  that  characterized  much  of  Britain  and  Europe  in  the 
era  of  the  Lias. 

Climate.  —  The  occurrence  of  the  Trias  in  Spitsbergen,  with  some 
of  its  characteristic  fossils,  is  evidence  of  a  moderate  climate  in  the 
Arctic.  At  the  same  time,  the  fact  (learned  from  the  St.  Cassian 
beds)  that  many  Paleozoic  genera  continued  far  into  the  Triassic  era, 
and  perhaps  nearly  to  its  close,  south  of  the  latitude  of  Vienna,  while 
absent  from  northern  Europe,  appears  to  be  evidence  of  unlike  zones 
of  temperature  over  that  continent  —  a  warmer  southern  half,  and  a 
colder  northern.  It  is  not  improbable  that  the  warm  seas  of  the  In 
dian  Ocean  then  swept  over  southern  Europe.  It  may  be  that  the 
extermination  of  life  terminating  Paleozoic  time  —  one  of  the  most 
universal  in  geological  history  —  was  due  to  the  intervening  of  an  era 
of  cold  climate  after,  or  cotemporaneously  with,  the  mountain-making 
epoch  which  gave  the  Alleghanies  birth ;  that  the  cold  climatal  condi 
tions  were  brought  on  by  Arctic  elevations,  as  well  as  by  upward 
movements  of  land  in  the  higher  temperate  latitudes ;  and  that  the 
cold  Arctic  oceanic  currents  thus  produced,  to  which  the  destructions 
of  oceanic  life  were  owing,  did  not  affect  so  seriously  parts  of  southern 
Europe,  owing  either  to  the  lay  of  the  emerged  laud,  or  to  the  Indian 


JURASSIC   PERIOD.  431 

Ocean  current  alluded  to,  or  to  both  circumstances  combined.  The 
indications  of  floating  ice,  which  Ramsay  has  found  in  the  British 
Lower  Permian,  may  have  been  a  mark  of  the  slow  approach  of  such 
an  era  of  cold. 

2.   JURASSIC   PERIOD  (17). 

The  Jurassic  period  derives  its  name  from  the  Jura  Mountains,  on 
the  western  borders  of  Switzerland,  one  of  the  regions  characterized 
by  the  formation. 

1.  AMERICAN. 

I.  Rocks  :  kinds  and  distribution. 

On  the  Atlantic  Border,  the  upper  portion  of  the  formation  described 
in  the  preceding  pages,  on  the  Triassic,  may  belong,  as  has  been  ob 
served,  to  the  Jurassic  period.  The  absence  of  marine  fossils  leaves 
the  question  in  doubt. 

On  the  Gulf  Border,  there  are  no  rocks  of  this  period  anywhere  ex 
posed  to  view. 

In  the  Western  Interior  region,  the  Jurassic  period  may  claim  a  part 
—  perhaps  a  large  part  —  of  the  gypsiferous  beds  referred  to  the  Tri 
assic  ;  but  fossils  are  here  also  wanting. 

Apart  from  these  doubtful  beds,  there  are  true  Jurassic  strata,  full 
of  marine  fossils,  overlying  in  many  places  the  gypsiferous  marlytes  and 
sandstone.  They  have  been  observed  about  the  Black  Hills,  the  Lara- 
mie  range,  and  other  eastern  ridges  of  the  Rocky  Mountains  ;  also 
over  the  Pacific  slope,  in  the  Uintah,  Wahsatch,  and  Humboldt  moun 
tains,  and  in  the  Sierra  Nevada.  Whitney  has  found  that  Jurassic 
fossils  occur  in  auriferous  slates  of  the  Sierra. 

In  the  Arctic  region,  also,  there  are  a  number  of  localities  of  fossil- 
iferous  Jurassic  strata. 

The  discovery  and  identification  of  the  Jurassic  of  the  Black  Hills  of  Dakota  were 
made  by  Hayden  &  Meek.  The  rocks  occur  also  at  Red  Buttes  on  the  North  Platte, 
west  of  the  Black  Hills;  also  along  the  southwest  side  of  the  Big  Horn  Mountains  (43^° 
N.,  108°  W.),  and  the  northeast  side  of  the  Wind  River  Mountains;  also  beyond  the 
Wind  River  .Mountains,  on  the  west;  also  about  the  head-waters  of  the  Missouri  —  at 
all  of  which  places  fossils  occur.  (Hayden.)  Other  localities  are  near  the  valley  of 
Green  River,  east  of  the  Great  Salt  Lake,  as  announced  by  Meek  &  Engelmann ;  and 
near  Fort  Hall,  in  Idaho.  The  rocks  observed  are  in  general  a  gray  or  whitish  marly 
or  arenaceous  limestone,  with  occasional  purer  compact  limestone  beds,  intercalated 
with  laminated  marls.  The  thickness  at  the  Black  Hills  is  about  200  feet;  on  the  north 
east  side  of  the  Wind  River  Mountains,  800  to  1,000  feet;  about  Long's  Peak,  where 
the  marlytes  are  absent,  50  to  100  feet.  Another  region  of  Jurassic  rocks,  on  the 
north  slope  of  the  Uintah  Mountains,  has  been  described  by  Marsh.  The  rock  is  lime 
stone  (containing  species  of  Trif/onia,  Camptonectes,  Chemnitzia,  etc.),  overlaid  by  red 
gypsiferous  beds,  sandstone,  and  red  and  gray  shales  (containing  Btlemnitts  densus),  in 


432 


MESOZOIC    TIME. 


all  300  feet  in  thickness.  In  the  Wahsatch,  Jurassic  beds  occur  on  the  eastern  side, 
beneath  the  Cretaceous. 

In  the  auriferous  slates  of  the  Sierra  Nevada,  on  the  Mariposa  estate,  there  occur 
Aucella  Errinytoni  Gabb,  Pholndomyn  (?)  orllculata  Gabb,  Helemnites  Pacificus  Gabb; 
and  other  species  in  Genesee  Valley,  and  probably  at  Spanish  Flat,  El  Dorado  County. 

The  Arctic  localities  are  —  the  eastern  shores  of  Prince  Patrick's  Land,  in  76°  20/  N., 
117°  20'  W.;  the  islands  Exinouth  and  Talbe,  north  of  Grinnell  Land,  77°  10'  N.,  95° 
W.;  and  Katmai  Bay,  or  Cook's  Inlet,  in  Northwest  America,  60°  N.,  151°  W. 


II.  Life. 


Several  of  the  genera  of  Radiates  and  Mollusks  which  mark  the  Ju 
rassic  beds  of  Europe  have  been  found  in  the  American  Jurassic,  the 
most  prominent  of  which  are  Pentacrinus,  Trigonia,  Ammonites,  and  Be- 

Figs.  755-700. 


Fig.  755,  a  segment  of  the  column  of  Pentacrinus  asteriscus  ;  756,  Monotis  curta ;  757,  Trigonia 
Conradi ;  758,  Tancredia  Warreniana  ;  759,  Ammonites  cordiformis  ;  759  a,  Side-view  of  same,  a 
little  reduced  ;  760,  Belemnites  densus. 

lemnites.  The  characteristics  of  Ammonites  are  briefly  mentioned  on  p. 
124,  and  again  on  p.  409.  The  fossil  Belemnite  (Fig.  760)  is  the  in 
ternal  bone,  or  osselet,  of  a  Cephalopod,  answering  to  the  pen  of  the 
squid  (Fig.  159,  p.  119).  They  are  much  heavier  than  the  same  part 
in  any  modern  species.  The  fossil  represented  in  Fig.  760  is  really 
only  the  lower  and  stouter  part  of  the  osselet:  its  structure  is  radiately 
fibrous.  It  has  a  conical  cavity  (or  alveolus)  within,  opening  upward, 
and  at  the  bottom  of  this  cavity  there  is,  when  it  is  perfect,  a  small 
chambered  cone  called  the  pkragmocone,  which  has  a  siphuncle.  The 
osselet,  when  unbroken,  has  a  thin  edge,  and  is  further  prolonged  on 
one  side  into  a  delicate  concave  blade,  a  variety  of  which  is  shown  in 
Fig.  792,  on  p.  440.  The  animal  was  much  like  that  of  a  Sepia  (see 
Fig.  159,  p.  119)  ;  and  its  ink-bag  was  contained  within  the  cavity  of 
the  osselet.  The  first  species  of  the  genus  known  was  found  in  the 


JURASSIC   PERIOD.  433 

Rhastic  beds,  of  the  Upper  Triassic,  which  directly  underlie  the  lowest 
Jurassic.  Like  Ammonites,  they  are  exceedingly  common  fossils  in 
the  Mesozoic  age,  and  are  unknown  afterward. 

An  Ammonite  of  the  American  Jurassic  is  represented  in  Figs.  759, 
759  a,  the  latter  a  side  view.  One  of  the  five-sided  disks  of  the  stem 
of  a  Pentacrinus,  a  genus  of  Crinoids  characteristic  of  the  Mesozoic, 
is  shown  in  Fig.  755.  The  triangular  shell,  represented  in  Fig.  757, 
belongs  to  the  genus  Trigonia,  which  is  characteristic  of  the  early 
and  middle  Mesozoic.  Here  also  begin  the  genus  of  the  Oyster 
family,  called  Gryphcea,  in  which  the  beaks  are  incurved,  and  the 
large  pearly  Inoceramus,  both  peculiarly  Mesozoic  types. 

Characteristic  Species. 

PLANTS.  —  No  plants  have  been  described,  except  a  few  by  Newberry,  from  a  coal 
seam  in  the  gypsiferous  sandstone  of  the  Upper  Colorado,  in  the  Moqui  country  (near 
the  meridian  of  111°),  the  age  of  which  is  doubtful.  The  observed  genera  are  Cyclop- 
teris,  Pecopteris,  Neuropteris,  SpJienopteris,  and  Clatliropteris. 

The  Glatkropteris  from  near  the  middle  of  the  Connecticut  River  sandstone  (Fig.  707, 
p.  407),  as  suggested  by  Hitchcock,  is  some  evidence  —  though  far  from  decisive  —  for 
referring  the  upper  half  of  that  formation  to  the  Jurassic.  The  European  species  of 
this  genus  occur  in  the  Lias  and  Trias. 

ANIMALS. — 1.  Radiates.  —  Fig.  755,  a  joint  of  the  stem  of  Pentacrinus  asteris- 
cus  M.  &  II.,  a  Crinoid  with  a  pentagonal  column. 

2.  Mollusks.  —  («•)  LameUibrcmchs.  —  Fig.  756,  Monotis  curta,  from  the  Black 
Hills;  Fig.  757,  Trigonia  Conradi  M.  &  H.,  ibid.;  758,  Tancredia,  Warreniana  M.  & 
H.,  ibid,  (b.)  Ccplialopods. — Fig.  759,  young  specimen  of  Ammonites  cordiformis  M. 
&  II.,  ibid.;  Fig.  759  a,  side-view  of  the  same;  Fig.  760,  Belemnites  densus  M.  &  H., 
the  upper  part  broken  away,  ibid. 

The  Jurassic  beds  of  Genesce  valley,  Plumas  County,  California,  contain  a  Belemnite, 
Triyonia  pandicosta  M.,  a  Gryphcea  near  G.  vesicularisTlr.,  fnoceramus  (?)  obliquus  M., 
/.  (?)  rectanyulus  M.,  Rhyncltonella,  (jnatliopliora  M.,  and  others  of  the  genera  Limn, 
Pecten,  Mytilus,  Astarte,  Unicardium,  Myacites,  and  Terebratula.  In  the  beds  of  the 
Uintah  Mountains,  Marsh  found  specimens  of  Pentacrinus  asteriscus,  Belemnites  densus, 
a  Trigonta,&ad.  other  Mollusks,  and  also  the  right  humerus  of  a  small  Crocodilian. 

Among  the  Arctic  fossils  of  this  period,  there  are,  at  Prince  Patrick's  Land,  Am 
monites  M'Clintocki,  a  species  near  A.  concavus  Sow.,  of  the  Lower  Oolite;  and  at 
Cook's  Inlet,  Ammonites  WosnessensJd,  A.  biplex  Sow.  (?),  Belemnites  paxillosus  (B. 
ntyer  List  ?),  and  Pleuromya  unioides  Br.  (  Unio  liassinus  Schubler).  A.  biplex  also 
is  reported  to  occur  in  the  Chilian  Andes,  in  latitude  34°  S.,  and  probably  also  in  Peru 
near  the  equator,  as  well  as  in  Britain  and  Europe. 

2.  FOREIGN. 
I.  Rocks:  kinds  and  distribution. 

The  strata  of  the  Jurassic  period  in  England  (see  map,  page  344,  on 
which  the  areas  numbered  7,  8  are  Jurassic)  appear  at  the  surface 
over  a  narrow  range  of  country  (averaging  thirty  miles  in  width),  com 
mencing  at  Lyme-Regis  and  Portland  on  the  British  Channel,  and 
extending  across  England,  north  of  northeast,  to  the  river  Humber, 
and  still  farther  north,  on  the  eastern  coast  of  Yorkshire,  almost  to 

28 


434  MESOZOIC   TIME. 

the  mouth  of  the  Tees.  The  Jurassic  seas  appear  to  have  covered 
the  eastern  part  of  England  ;  while  the  western  part,  from  the  north 
to  Cornwall,  was  apparently  an  elevated  barrier  against  the  ocean. 
Jurassic  beds  also  occur  on  the  northeast  coast  of  Ireland,  as  at  the 
Giants'  Causeway  and  on  the  Western  Isles. 

Following  the  line  of  the  British  Jurassic  belt  from  Lyme-Regis 
and  Portland  across  the  English  Channel,  we  come  upon  an  apparent 
continuation  of  the  belt  in  France.  It  sweeps  south,  by  the  borders 
of  Brittany,  to  the  central  plateau  of  France,  and  then  east  and  north, 
by  the  eastern  boundary  of  the  empire,  thus  surrounding  a  large  area 
of  which  Paris  is  the  centre. 

The  line  of  barrier-islands  of  western  England  is  continued  in  Brittany,  in  western 
France;  the  line  of  the  outcropping  Jurassic,  in  similar  outcropping  Jurassic  in  France; 
and  the  area  of  the  shallow  Jurassic  sea  over  eastern  England,  in  the  extensive  Parisian 
basin,  —  a  sea  which  was  then  the  western  and  southern  border  of  the  German  Ocean, 
and  covered  Avhat  are  now  the  sites  of  London  and  Paris. 

The  central  plateau  of  France  — a  region  of  crystalline  rocks —  is  nearly  encircled  by 
Jurassic  strata;  and  the  rocks  are  continued  eastward  over  the  Jura  Mountains  (by 
Xeufchatel),  and  along  their  continuation  through  Wurt  em  berg  and  Bavaria  in  south 
ern  Germany.  They  appear  also  in  northern  Germany  (Westphalia)  and  the  Alps 
(Savoy,  etc.). 

Jurassic  beds  occur  also  along  the  Andes  in  many  regions,  from  their  northern  limit 
to  Tierra  del  Fuego.  They  are  found  in  many  parts  of  Asia,  and  have  been  recognized 
by  W.  B.  Clarke  in  Australia. 

The  Jurassic  period,  in  England  and  Europe,  is  divided  into  three 
epochs:  (1)  the  epoch  of  the  Lias,  or  the  Liassic,  so  designated  from 
a  provincial  name  of  the  rocks  in  England  (No.  7  a  on  the  map  re 
ferred  to)  ;  (2)  the  epoch  of  the  Oolyte,  or  the  Oolytic  (No.  7  b),  so 
called  because  a  prominent  rock  of  the  series  in  England  is  oolyte 
(see  p.  86)  ;  and  (3)  the  epoch  of  the  Wealden  (No.  8  on  map),  named 
from  a  region  called  The  Weald,  in  Kent,  Surrey,  and  Sussex,  where 
the  beds  were  first  studied.  The  Wealden  are  transition  beds  between 
the  Jurassic  and  Cretaceous,  and  are  often  referred  to  the  latter,  al 
though  more  closely  related  physically  to  the  upper  part  of  the  former 
period. 

The  Liassic  beds  consist  mainly  of  grayish  limestones,  containing 
marine  fossils. 

The  Oolytic  include  limestones,  part  of  which  are  oolitic  in  texture, 
and  others  arenaceous  and  clayey.  One  of  the  limestones  is  a  coral- 
reef  rock.  All  of  the  beds  are  of  marine  or  sea-shore  origin,  as  the 
fossils  show,  excepting  strata  in  the  local  Purbeck  beds  near  the  top 
of  the  series,  one  of  which,  on  the  island  of  Portland,  is  called  the 
Portland  dirt-bed. 

The  Wealden  is  wholly  of  estuary  or  fresh-water  origin  ;  the  beds 
consist  of  clays,  sands,  and,  to  a  small  extent,  fresh-water  limestone. 


JURASSIC   PERIOD.  435 

The  promiment  subdivisions  of  the  Jurassic  formation  observed  in  England  (though 
not  present  alike  in  all  its  Jurassic  regions)  are  the  following,  beginning  below:  — 
I.  LIAS. 

1.  Lower  Lias :  consisting  of  grayish  laminated  limestone,  with  shale  above. 

2.  Middle  Lias :  a  coarse  shelly  limestone,  called  marlstone. 

3.  Upper  Lias:  beds  of  clay  or  shale,  with  some  thin  limestone  layers. 

II.    OOLYTE. 

1.  Lower  or  Bath  Oolyte,  consisting  of  — 

(1.)  Inferior  Oolyte }  a  limestone  with  fossils  and  layers  of  sand. 

(2. )  Fuller' s-earth  group,  or  clayey  layers. 

(3.)   Great  Oolyte,  limestone,  mostly  oclitic. 

(4.)  Forest-marble  group,  sandy  and  clayey  layers,  with  some  oolite. 

(5.)  Cornbrash,  a  coarse  shelly  limestone. 

The  Stonesfield  slates,  noted  for  their  remains  of  Saurians,  as  well  as  of  the  earliest 
British  Mammals,  and  also  of  Insects  and  other  species,  occur  near  Oxford  in  England, 
and  belong  to  the  Lower  Ocilyte,  below  the  Great  Oolyte. 

At  Brora,  in  Sutherlandshire,  there  is  a  bed  of  Oolytic  coal  of  good  quality,  three  and 
a  half  feet  thick,  which  has  been  long  worked:  it  is  covered  by  several  feet  more  of 
impure  coal,  containing  pyrite.  It  is  supposed  to  belong  with  the  Great  Oolyte. 

2.  Middle  or  Oxford  Oolyte:  consisting  of  — 

(1.)  Kelloway  Rock,  a  calcareous  grit,  overlying  blue  clay,  and  overlaid 

by  (2. )  the  Oxford  clay. 
(3.)  Calcareous  grit  and  o<  litic  coral  limestone,  called  the  Coral  Ray. 

3.  Upper  or  Portland  Oolyte :  consisting  of  — 

(1.)  Kimmeridye  Clay. 

(2. )  Shotover  Sand,  a  calcareous  rock  with  concretions. 

(3.)  Portland  Oolyte. 

4.  Purbeck  beds:  consisting  of  (1)  the  Lower  Purbeck,  fresh-water  marls,  with 
the  "Portland  dirt-bed,"  and  resting  on  the  upper  layers  of  the  "Portland 
stone;"  (2)  the  Middle  Purbeck,  mostly  a   bed  of  marine  limestone,  30  feet 
thick;  (3)  the  Upper  Purbeck,  50  feet  of  fresh-water  deposits.     The  dirt-bed 
of  the  Purbeck  is  the  second  deposit  affording  remains  of  British  Mammals. 
It  contains  also  numerous  remains  of  Cycads,  etc. 

III.  WEALDEN. 

1.  Hastings  Sands:  sandstone,  with  some  clayey  and  limestone  layers,  containing 
Saurian  remains,  fluviatile  shells,  etc. 

2.  Weald  Clay  :  clayey  lavers,  with  some  calcareous  beds  containing  fresh-water 
shells. 

The  British  subdivisions  are  for  the  most  part  recognized  in  France,  and  have  re 
ceived  special  names  from  D'Orbigny.  They  are  (I.)  in  the  LIAS,  —  1,  the  Sinemurian 
(Lower  Lias,  named  from  the  locality  at  Semur);  2,  Liasian  (Middle  Lias);  3,  Toarcian 
(from  the  locality  at  Thours);  (II.)  in  the  OOLYTE,  — 1,  Bajocian  (the  inferior  part  of 
the  Lower  Oolyte,  named  from  the  locality  at  Bayeux);  2,  Batlwnian  (the  Great  Oolyte, 
Bath  Oolyte):  3,  Callovian  (Kelloway  Rock);  4,  Oxfordlan  (Oxford  Clay);  5,  Corallian 
(Coral  Rag);  6,  Kimmvridyian  (Kimmeridge  Clay);  7,  Portlandian  (Portland Oolyte). 
In  the  French  Juras,  the  Lias  limestone  is  called  also  Gryphite  limestone,  from  the 
abundance  of  the  fossil  Gryj)hcea  incurva. 

For  the  "Inferior  Oolyte"  Marcou  has  used  the  name  Lcedonian ;  for  the  Fuller's 
earth,  Vesulian.  Thurman  and  Etallon  have  restricted  Corallian  to  the  lower  part  of 
the  Corallian  of  D'Orbigny  (the  part  called  Rauracinn  by  Creppin),  and  named  the 
upper  part,  commencing  with  the  beds  containing  Astarte  minima  and  including  the 
lower  part  of  the  Kimmeridge  clay,  the  Astartian  (the  same  is  the  Sequanian  of  M. 
Jourdy);  the  Kimmeridyian,  comprising  the  middle  part  of  the  Kimmeridge  Clay,  is 
the  Strombian  of  Thurmann.  The  Portland  Oolyte  is  the  Portlandian  of  Marcou  (or 
Viryulian  of  Thurmann) ;  and,  lastly,  the  Purbeckian  is  the  DuUisian  of  Desor  and 
Tithonic  of  Oppel.  The  Wealden  is  Lower  Neocomian  of  D'Orbigny. 


436 


MESOZOIC   TIME. 


The  famous  beds  of  Lithographic  slate  at  Solenhofen,  a  very  fine-grained  calcareous 
rock,  affording  remains  of  many  Insects,  several  species  of  Saurians,  Pterodactyls,  etc., 
are  situated  in  the  district  of  Pappenheim  in  Bavaria,  and  are  of  the  age  of  the  Middle 
Oolyte,  or  that  of  the  Coral  Limestone. 

II.  Life. 
1.  Plants. 

The  land-plants  of  the  Jurassic  period  were  mainly  Ferns,  Conifers, 
and  Cycads,  as  in  the  Triassic.  Leaves  and  stems  are  found  in  many 

Figs.  761,  762. 


Fig.  761,  Section  from  near  Lullworth  Cove,  showing  stumps  of  trees  (a)  in  the  Portland  "  dirt 
bed  ;  ••  762,  stump  of  the  Cyca,d,  Mantellia  (Cycadeoidea)  megalophylla  (Xy^ )' 

of  the  strata,  and  remains  of  a  forest  in  what  is  called  the  Portland 
dirt-bed  (Fig.  761),  the  trees  of  which  were  Conifers  and  Cycads. 
Figure  762  represents,  much  reduced,  one  of  the  Cycad  stumps. 
Near  Whitby,  on  the  sea-coast  of  Yorkshire,  and  in  the  Stonesfield 
slate,  fossil  ferns  are  common. 

No  Jurassic  Angiosperms  are  known. 

2.  Animals. 

Sponges  were  not  uncommon  ;  one  kind  is  shown  in  Fig.  768.     The 
Figs.  768-770. 


SPONGE,  of  the  Oolyte.  — Fig.  768,  Scyphia  reticulata.     POLYP-CORALS,  of  the  Oolyte.  — Fig. 
Montlivaltia  caryophyllata  ;  770,  Prionastraea  oblonga. 


JURASSIC    PERIOD. 


437 


earliest  known  of  the  coin-shaped  Rhizopods,  called  Nummulites  and 
Orbitolites,  occur  in  Jurassic  beds  of  Franconia,  Germany.  (A  Ter 
tiary  species  is  figured  on  p.  499.)  Corals  are  of  various  kinds  (Figs. 
769,  770),  and  many  have  a  modern  look.  Among  Echinoderms, 
there  were  Crinoids,  mostly  of  the  genera  Pentacrinus  and  Apiocrimis, 
a  species  of  the  latter  of  which  (minus  a  part  of  its  long  stem)  is 
represented,  reduced,  in  Fig.  771  ;  also  free  Crinoids  of  the  Comatula 
type  (Fig.  772),  as  well  as  many  Star-fishes;  also  Echinoids  (Figs. 
773,  774),  many  with  very  stout  spines,  as  in  Fig.  774  a. 

Figs.  771-774. 


EcmxonERMS.  —  Fig.  771,  Apiocrinus  Roissyanus  ( x%],  the  middle  part  of  the  stem  omitted; 
772,  Saccocoma  pectinata:  773,  Diademopsis  seriate;  774,Cidaris  Blumenbachii ;  774  a,  spiue  of  the 
last.  All  Oolytic,  excepting  the  last,  which  is  Liassic. 

Among  Mbllusks,  there  was  a  great  variety  of  new  forms,  many 
peculiar  to  the  Mesozoic  era.  The  last  of  the  Brachiopods  of  the 
Spirifer  and  Leptcena  families  appeared  in  the  Lias  (Figs.  775-777). 
These  Leptcena  were  minute  species  (Fig.  776  «),  contrasting  won 
derfully  with  the  abundant  and  large  Leptcence  of  the  Silurian,  when 
the  family  was  at  its  maximum.  The  prevailing  Brachiopods  were  of 
the  modern  genera  Terebratula  and  Rhynchonella. 


438 


MESOZOIC    TIME. 
Figs.  775-779. 


BRACHIOPODS  and  LAMELLIBRAXCHS,  of  the  Lias  — Figs.  775,  776,  Leptasna  Moorei  (X7);  776  a, 
same,  natural  size:  777.  Spirifer  Walcotti ;  778,  Lima  (Plagiostoma)  gigantea  (X%)\  779, 
Gryphaea  incurva  (X%). 

Lamellibranchs  comprised  several  new  genera.  Gryplicea  (Figs. 
779,  782),  of  the  Oyster  family,  having  an  incurved  beak,  commenced 
in  the  Lias,  and  was  a  characteristic  kind. 

Figs.  780-785. 


LAMELLIBRAXCHS,  of  Oolyte.  —  Fig.  780,  Ostrea  Marshii  :  781,  Exogyra  virgula  ;  782,  Gryphaea  dila 
tata  ;  783,  Trigonia  clavellata  ;  784,  Astarte  minima ;  785,  Diceras  arietina. 


JURASSIC   PERIOD. 


439 


The  Gasteropoda  were  represented  by  several  new  modern  genera, 
besides  others  that  are  now  extinct.     One  of  the  more  peculiar  forms 


Fig.  786. 


Figs.  787,  788. 


GASTEROPOD.  —  Fig.  786,  Nerinaea  Goodhallii.     CEPHALOPODS.  —  Fig.    787,  Ammonites    spinatus  ; 

788,  A.  BucklandL 

was  that  of  the  genus  Ncrincea  (Fig.  786),  in  which   the  spiral  cavity 
has  one  or  more  ridges,  as  shown  in  Fig.  b. 

But  the  type  of  Cephalopoda  especially  underwent  great  expansion. 

Figs.  789,  790. 


CEPHALOPODS.  — Fig.  789,  Ammonites  Ilumphreysianus  ;  790,  A.  Jason. 

The  group  of  Ammonites  abounded  in  species.  Figs.  787,  788,  are 
Liassic  species ;  and  Figs.  789,  790,  others  from  the  Oolyte.  The  last 
two  figures  have  the  aperture  unbroken  ;  and  in  790  it  is  much  pro 
longed  on  either  side. 

In  addition  to  these  Cephalopoda  with  external  chambered  shells 
(Tetrabranchs  or  Tentaculifers),  there  were  also  those  having  an  in 
ternal  shell  or  bone  (Dibranchs  or  Acetabulifers),  a  group  which 


440 


MESOZ01C    TIME. 


includes  very  nearly  all  known  existing  species.     The  most  abundant 
of  these  were  the  Belemnites,  already  described  on  page  432.     Figs. 


Figs.  792-796. 


CEPHALOPODS.  —  Fig.  792,  Complete  osselet  of  a  Belemnite,  side-view,   reduced;   793,   dorsal  riew 
of  same;  794,  a,  B.paxillosus  ;  795,  B.  clavatus  ;  796,  Ink-bag. 

794,  795  represent  the  bones  or  osselets  of  two  species,  in  their  ordi 
nary  broken  state  ;  and  Figs.  792,  793  an  unbroken  one,  in  two  dif 
ferent  positions. 

Fig.  797. 


Acauthoteutliis  uutiquus  (X}£),  of  the  Oolyte. 


JURASSIC   PERIOD. 


441 


Fig.  797  represents  the  animal  of  an  allied  genus,  called  Acantho- 
teuthis.  There  were  also  species  of  the  Sepia  or  Cuttle-fish  family, 
and  Calamaries  or  Squids  ;  and  the  ink-bags  of  these  species  are  some 
times  found  fossil  (Fig.  796),  and  also  the  smaller  ones  of  Belemnites. 
Buckland  states  that  he  had  drawings  of  the  remains  of  extinct  spe 
cies  of  Sepia  made  with  their  own  ink. 

The  sub-kingdom  of  Articulates  was  represented  by  various  Worms, 
Crustaceans,  Spiders,  and  Insects  ;  and,  of  the  last,  all  the  principal 
tribes  appear  to  have  been  represented,  even  to  the  highest,  the  Hy- 
menopters.  Figs.  799,  800  are  Crustaceans  of  the  Oolyte,  from  So- 
lenhofen  ;  798,  801,  remains  of  Insects  ;  798,  a  Dragon-fly,  or  Libel- 


Fiffs.  798-802. 


ARTICULATES.  —  Fig.  798,  Libollula;    799,    Eryon  arctifermis ;    SCO,  Arohawmeus  Brodiei ;  801, 
elytron  or  wing-case  of  Buprestis  ;  802,  Palpipes  priscus. 

lula  (Neuropter)  ;  801,  the  wing-case  of  a  Beetle  (Coleopter),  from 
Stonesfield.  Fig.  802  is  one  of  the  Spiders.  The  oldest  known  (in 
1873)  British  Crab,  a  long-legged  Triangular  Crab  (Palceinachus  lon- 
gipes  Woodward),  comes  from  the  Lower  Oolyte. 

The  sub-kingdom  of  Vertebrates  included  species  of  Birds,  as  well 
as  Fishes,  Reptiles,  and  Mammals. 

FISHES.  —  The  Fishes  were  almost  solely  Ganoids  and  Selachians ; 
but  none  of  the  former  have  vertebrated  tails,  this  Paleozoic  feature 
having  disappeared. 


442 


MESOZOIC   TIME. 


The  Teliosts  or  Osseous  fishes  are  supposed  also  to  have  had  here 
their  first  species ;  but  they  were  little  numerous,  compared  with  the 
other  kinds,  or  with  their  abundance  in  the  next,  or  Cretaceous,  period. 

Figs.  803,  80-i. 


GANOIDS.  —  Fig.  803,  JEchmodus  (Tetragouolepis)  (X)^),  from  the  Lias;    a,  Scales  of  same  :  804; 
Aspidorhyncus  (X/sf),  from  the  Oolyte. 

Figs.  805-810. 


REPTILES. —Fig.  805,  Ichthyosaurus  communis  (X^-Q  )  >  806>  Head  of  same  (X¥V)'  80"  a'  b> 
view  and  section  of  vertebra  of  same  (XX) !  808,  Tooth  of  same,  natural  size  ;  809,  Ple>iosaurus 
dolichodoirus  (X-i-) ;  810  «,  810  6,  view  and  section  of  vertebra  of  same. 

REPTILES.  —  During  this    era,  the   Reptilian   type  underwent   an 


JURASSIC   PERIOD. 


443 


expansion  more  remarkable  than  that  of  Cephalopods.  The  true 
Reptiles  were  represented  by  numerous  Enaliosaurs  (sea-saurians,  p. 
339),  of  higher  grade  than  the  Simosaurs  of  the  Triassic,  as  is  shown 
in  their  solid  bony  skulls ;  by  Lacertians  and  Crocodilians,  many  of 
which  were  15  to  50  feet  in  length  ;  by  great  Dinosaurs,  the  highest 
of  Reptiles  ;  by  Flying  Saurians  (Pterosaurs),  having  wings,  much 
like  Bats  ;  by  Turtles  of  several  genera. 

(1.)  Enaliosaurs  or  Swimming  Saurians.  —  The  more  common 
genera  of  Enaliosaurs  are  the  IdithyosauruSi  Plesiosaurus  and  Plio- 
saurus.  The  Ichthyosaurs  (the  name,  from  the  Greek,  signifiying  fisk- 
2izard)werQ  gigantic  animals,  10  to  40  feet  long,  having  paddles  some- 

Fi<r.  811. 


REPTILE  —  Plesiosaurus  macrocephalus 


what  like  the  Whale  (Fig.  805),  long  head  and  jaws,  numerous  (in 
some  species  200)  stout,  conical,  striated  teeth  (Fig.  808),  an  eye  of 
enormous  dimensions  (as  shown  in  Fig.  806),  thin,  disk-shaped,  bicon 
cave  vertebrae  (Figs.  807  a,  807  b).  The  L  communis,  found  in  the 
Lias  of  Lyme-Regis  and  elsewhere,  was  28  or  30  feet  long. 

The  Plesiosaur  (the  name  meaning  allied  to  a  Saurian),  (Figs.  809, 


444  MESOZOIC    TIME. 

811)  had  a  long,  snake-like  neck,  consisting  of  twenty  to  forty  verte 
brae,  a  small  head,  short  body,  paddles,  and  biconcave  vertebrae  dif 
fering  little  in  length  and  breadth.  P.  dolichodeirus  (Fig.  809)  was 
25  to  30  feet  long.  P.  macrocephalus  is  represented  in  Fig.  811,  just 
as  it  lay  in  the  rocks.  The  British  rocks  of  the  Jurassic  and  Creta 
ceous  periods  have  afforded  sixteen  species  of  Plesiosaurs ;  and 
twenty-one,  in  all,  are  known,  of  which  twelve  were  found  in  the  Lias, 
and  seven  in  the  Oolyte.  The  Pliosaurs  were  other  swimming  Sau- 
rians,  near  the  Plesiosaur :  some  individuals  were  thirty  to  forty  feet 
long.  Remains  of  more  than  fifty  species  of  Enaliosaurs  have  been 
found  in  the  Jurassic  rocks. 

(2.)   Crocodilians.  —  Many  of  the  Crocodilians  were  of  the  Teleo- 
saur  type,  having  slender  jaws  like   the  Gavial,  but  biconcave  verte- 

Fig.  812. 


Mystriosaurus  Tiedmanni. 

bra?9  _  the  latter  a  mark  of  both  antiquity  and  inferiority.  Fig.  812 
represents  the  skull  of  one  of  these  species,  the  Mystrioscuir. 

Another  and  larger  Crocodilian  was  the  Cetiosaur,  from  the  Oolyte, 
an  animal  at  least  fifty  feet  in  length,  u  not  less  than  ten  feet  in  height 
when  standing,  and  of  a  bulk  in  proportion,"  and  "  unmatched  in 
magnitude  and  physical  strength  by  any  of  the  largest  inhabitants  of 
the  Mesozoic  land  or  sea."  (J.  Phillips.)  One  of  the  fossil  femurs 
(thigh-bones)  is  64  inches  long,  nearly  a  foot  in  diameter  at  middle, 
and  20f  inches  at  the  upper  extremity.  The  food  was  probably 
vegetable.  The  caudal  vertebrae  were  biconcave,  while  the  dorsal 
were  convexo-concave.  Cetiosaurian  remains  occur  in  the  Oolyte, 
from  the  Lower  beds  to  the  Wealden. 

(3.)  Dinosaurs.  —  Still  other  famous  Crocodile-like  animals  were 
the  Megalosaurs,  carnivorous  Reptiles,  whose  remains  occur  in  the 
Lias,  Oolyte,  and  AVealden.  M.  BucMandi  is  the  species  best  known. 
It  was  twenty-five  or  thirty  feet  long,  with  the  hind  limbs  twice  the 
longer  and  stouter.  It  waded  in  the  waters,  or  prowled  over  the  land, 
moving  about  — "•  not  as  a  ground-crawler,  like  the  Alligator,  but 
with  free  steps,  and  chiefly,  if  not  solely,  on  the  hind  limbs,  claiming 
thus  a  curious  analogy,  if  not  some  degree  -of  affinity,  with  the 
Ostrich."  (J.  Phillips.)  It  had  a  few  large  teeth,  with  sharp  crenu- 
lated  edges.  The  limb  bones  seem  to  have  been  hollow,  —  one  of  its 
bird-like  characteristics,  —  while  the  hind  feet  were  probably  three- 


JURASSIC    PERIOD. 


445 


toed,  like  those  of  other   Dinosaurs,   with  strong   compressed   claw- 
bones.      The  sacrum  corresponded,    as    in  Mammals,    to  five  united 


Fiir.  813. 


Megalosaurus  Bucklandi  (X-^-)  as  restored  by  Phillips. 

vertebra?.  This  Reptilian  Carnivore  was  of  very  high  grade  in  its 
class,  higher  than  the  huger  Cetiosaur ;  it  compared  in  size  with  the 
Cetiosaur,  nearly  as  the  highest  Mammalian 
Carnivores  with  the  Elephantine  Herbivores. 

The  Iguanodon  of  Man  tell  was  an  herbivor 
ous  Dinosaur  of  the  "Wealden.  It  was  thirty 
feet  long,  and  of  great  bulk,  and  had  the  habit 
of  a  Hippopotamus.  The  femur,  or  thigh 
bone,  in  a  large  individual,  was  about  thirty- 
three  inches  long,  and  the  humerus,  nineteen 
inches.  The  teeth  (Fig.  814)  were  flat,  and 
had  a  serrated  cutting  edge  like  the  teeth  of 
the  Iguana  ;  and  hence  the  name,  signifying 
Iguana-like  teeth :  many  of  them,  from  old 
animals,  are  worn  off  short.  This  species 
occurs  also  in  the  Cretaceous. 

The  Hijlceosaur,  another  Tilgate  Forest  Di 
nosaur,  had  its  skin   covered  with  circular  or 
elliptical  plates,  and  was  twenty  to  twenty-two      Tooth  of  IKuanodon  Mantc»»- 
feet  long. 

The  Coprolites  (fossil  excrements)  of  the  Saurians  are  not  uncom 
mon  ;  one  is  represented  in  Fig.  816.  They  are  sometimes  silicified, 
and,  notwithstanding  their  origin,  are  beautiful  objects,  when  sliced 
and  polished. 


446  '  MESOZOIC    TIME. 

(4.)  Pterosaurs  or  Flying  lizards.  —  The  flying  lizards  were  -of  sev 
eral  genera,  the  first  known  of  which  is  Pterodactylus  —  so  named  from 
the  Greek  for  wing  and  finger,  the  outer  finger  of  the  hand  being 
greatly  prolonged,  to  serve  as  a  support  for  the  expanded  membrane 
of  the  side  of  the  body  and  limb,  arid  the  whole  thus  making  a  wing 
or  flying  organ,  analogous  to  that  of  a  Bat. 

Fig.  815  represents  the  skeleton  (reduced  in  size)  of  P.  crassirostris> 

Figs.  815,  816. 


PTEROSAUR.  —  Fig-  815.  Pterodactylus  crasrfrostris  ( X  X)  ]  816,  Coprolite. 

The  species  was  a  foot  in  length  ;  and  the  spread  of  the  wings  was 
about  three  feet.  As  in  Birds,  the  bones  of  Pterodactyls  are  hollow, 
to  fit  them  for  flying ;  but,  unlike  Birds,  they  have  the  skin,  claws 
and  teeth  of  Reptiles.  Their  habits  were  those  of  bats  rather  than 
birds.  They  range  from  the  Lias  into  the  Chalk. 

BIRDS.  —  Birds  occur  fossil  at  Solenhofen,  both  their  bones  and 
impressions  of  their  feathers.  A  specimen  there  found  is  represented 
in  Fig.  817,  reduced  to  one  fourth  its  natural  size.  The  Bird,  named 
by  Owen  Archceopteryx  macrura  (meaning  long  tailed  ancient-bird)  t 
had  a  tail  of  20  vertebra,  11  inches  long  and  3£  inches  broad,  with  a 
row  of  feathers  along  either  side,  a  pair  to  each  caudal  vertebra.  The 
wing  appears  to  have  had  a  two-jointed  finger. 

MAMMALS.— The  Mammals  of  the  Jurassic  have  been  found  in 
the  Lower  Oolyte  at  Stonesfield,  and  in  the  Middle  Purbeck  beds  of 
the  Upper  Oolyte. 

The  relics  from  the  Stonesfield  slate  (a  bed  of  shelly  limestone  only 
six  feet  thick)  are  referred  to  Marsupials,  Fig.  818  represents  the 
jawbone  of  the  Amphitherium  (Thylacotherium)  Broderipii,  and  Fig. 


JURASSIC   PERIOD. 

Fig.  817. 


447 


Archaeopteryx  macrura. 

819  the  same  of  the  Phascolotherium  Bucklandi,  — each  twice  the  size 
of  nature.  The  former  species,  according  to  Owen,  is  most  nearly 
related  to  the  Marsupial  Insectivores.  The  lower  jaw  of  another 
genus,  called  Stereognathus,  has  been  found  in  the  same  bed. 


448 


MESOZOIC    TIME. 


The  Middle  Purbeck  has  afforded  relics  of  about  fourteen  species 
of  Mammals,  along  with  fresh-water  shells  and  Insects.     The  species 

Figs.  818,  819. 


MAMMALS.  —  Fig.  818,   Amphitherium  (Thylacotherium)  Broderipii  (X  2):  819,  Phas^olotherium 

Bucklandi  (X  2). 

have  been  referred  mostly  to  the  Insectivorous  Marsupials  ;  but  two 
species,  of  the  genus  Plagimdax,  have  the  teeth  of  Rodents,  and  were 
related  to  the  Kangaroo-rat ;  while  another,  of  the  genus  Galastes,  as 
large  as  a  polecat,  was  a  Predaceous  Marsupial.  The  remains  of  the 
Purbeck  were  all  "  obtained  from  an  area  less  than  500  square  yards 
in  extent,  and  from  a  single  stratum  but  a  few  inches  thick." 


Characteristic  Species. 
1.  Liassic  Epoch.     (L.  stands  for  Lower  Lias,  M.  for  Middle,  and  U.  for  Upper.) 

1.  Radiates.  —  POLYP  CORALS.  —  Isastrcea  Stncklandi  Duncan,  L. ;  Montllcaltia 
Gitettardi  Dfr.,  L. ;  M.  mucronata  Dune.,  L. ;  M.  cuneata  Dune.,  M. ;  Thecocyathus  rugo- 
sus  Dune.,  L. ;  Thecosmilia  Tarquemi  Dune.,  L.  (genera  of  corals  widely  different  from 
the  Paleozoic);  CRINOIDS,  Pentacnnus  Briareus  Mill.,  L. ;  P.  basalt  if ormis  Mill.,  L. ; 
ECHINOIDS,  Fig.   773,  Diachma  seriale  Ag.,L. ;   Cidaris  Edwardsii  Wright,  L.     British 
Liassic  species  of  Holothuria  have  been  made  out, from  the  occurrence  of  minute  wheel- 
shaped  calcareous  pieces,  such  as  are  found  in  some  sections  of  the  tribe. 

2.  Mollusks.  —  BRACHIOPODS,   Fig.  777,   Spi/ifer  Walcotti  Sow.,   L.,  and  M. ; 
Terebratula  numisnutlis  Lam.,  L.,  and  M. ;   T.  rimosa  Buck,  M. :  Rh yncliondla  acuta 
Sow.,  L. ;  Figs.  775,  776,  Leptsena  Moorei  Dav.,  U. ;  776  a,  natural  size;   R.  variabilis 
D'Orb.,  L.     Five  species  of  Leptcen-i  and  about  twice  as  many  Spirifers  occur  in  the 
Lias.     While  these  old  Silurian  genera  were  disappearing,  the  new  Brachiopod  genus 
Thecidea  began;  and  with  it  there  were  Lingufa,  Rhynchonelfa,  and  Crania,  and  many 
Ttrebratulve.     The  genera  Rliynchontlla  and  Crania,  it  should  be  remembered,  are  lines 
reaching  from  the   Silurian  to  the  present  time;  and  Ttrebratula  dates  back  to  the 
Devonian. 

LAMELLIBRANCHS. —  Fig.  779,  Gryphcea  incurva  Sow.,  L.  (Gryphite  Limestone);  G. 
yiyantea  Sow.,  M.;  G.  cymblum  Lam.,  M. ;  Gervillla  crnssa  Buckm.,  L.;  Ostrta  liatsica 
Strickl.,  L.;  0.  KnorriiVoltz,  U. ;  Fig.  778,  Lini'i  (Playiostoma)  gigantea  Sow.,  L. ; 
Cardinia  (Pachyodon)  Listen  Stutch.,  L.,  and  M. ;  Pecten  cequivalvis  Sow.,  M. ;  Phola- 
domya  ambigua  Sow.,  U.,  M.,  and  L. :  GASTEROPODS,  Pleurotomaria  Anglica  Dfr.,  L.; 
P.  expansa  Phill.,  L.  and  M. ;  Turbo  helicif ormis  Geol.  Surv.,  L. ;  T.  subduplic/itus 
D'Orb.,  U.:  CEPHALOPODS,  Fig.  788,  788  a,  Ammonites  Bucklandi  Sow.,  Brngt.,  L. ; 


JURASSIC    PERIOD.  449 

A.  planorbis  Sow.,  L. ;  A.  Conybeari  Sow.,  L. ;  Fig'.  787,  A.  spinatus  Brug.,  M, ;  A, 
heterophyllus  Sow.,  M.  and  U. ;  A.  radians  D'Orb.,  U. ;  A.  serpentinus  Schl.,  U.;  Bele-m- 
nites  acutus  Miller,  L. ;  Fig.  795,  B.  clavatus  Schl.,  L.  and  M. ;  B.  irregidaris  Schl.,  U. ; 
GeoteutMs  Bollensis  Mil.,  U.  The  fossil  beak-like  jaws  of  Cephalopods  are  called 
Rhyncholites.  The  last  species  of  Conularia  occurs  in  the  Lias. 

3.  Articulates.  —  CRUSTACEANS,  Eryon  BwrroveriasWGoy,  L. ;  Glyph ea  liassina 
Meyer,  L. ;  INSECTS,  species  of  Buprestids,  Curculionids,  Carabids,  Gryllus,  Ephemera, 
Asilus  (Dipter),  etc. 

4.  Vertebrates.  —  FISHES,  Acrodns  nobilis  Ag.,  L. ;  sEchmodus  angidifer  Eg.,  L. ; 
JE.  Leachii  Eg.,  L. ;  Dapedius  politus  Leach,  L. ;  Hybodus  reticulatusAg.,  L. ;  REPTILES, 
Figs.  805-808,  Ichthyosaurus  communis  Conyb.,  L.;  /.  intermedius  Conyb.,  L. ;  /.  tenuiros- 
^m  Conyb.,  L. ;  Figs.  809,   810,   Plesiosaurus  dolichodeirus  Conyb.,  L. ;  Fig.   811,   P. 
macrocephalus  Owen,  Dimo-rphodon  macronyx,  L. ;  Teleosaurus  Chapmanni  Konig,  L. 

2.   Oolytic  Epoch. 

I.  LOWER  OOLYTP;. —  (1. )  Inferior  Oolyte. —  Anabacia  hemisphcerica  E.  &  H.,  Mont- 
Hvaltia  trochoides  E.  &  H. ;  Fig.  770,  Prionastrcen  oblonya,  Dy  sassier  ringens  Ag.,  Clypeus 
IIuyiAg.;  Rhynchonella  spinosa  Dav.,    Terebratula  Jimbria  Sow.,    T.  perovalis  Sow.; 
Ostrea  Mnrshii  Sow.,   0.  acuminata  Sow.,  Camptonectes  (Pecttn)  lens  Sow.,   Trigonia 
costata  Park.,  Pholadomya  fdicula  Sow.,    Litorina  ornata  Sow.,  Pleurotomaria  granu- 
lataDir.,  P.  elongata  Dfr. ;  Fig.  789,  Ammonites  IlumpJi reysiamis  Sow.,  A.  Parkinsoni 
Sow.,  A.  Braikenridf/ii  Sow.,  Nautilus  lineatus  Sow.,  Bekmnites  giyanteus  Schl. 

(2.)  Great  Oolyte  (Bath  Oolyte,  including  Stonesfield  slate.  Cornbrash  and  Forest 
Marble).  — Pecopteris  diversa  Phill.,  P.  approximate  Phill.,  SphenopterisplumosaPhill., 
Pakeozumiameyapliylla  Phill.,  Thuyites  articulatus  Stcrnb.,  T.  divaricatus  Stern b.  (all 
plants  of  Stonesfield  Slate);  —  Fig.  769,  Montlirnltia  caryophyllnta  Lmx.;  Apiocrinus 
Parkinsoni  Schl.,  A.  eleyans  D'Orb.,  Clypeus  patella  Ag. ;  Terebratula  digona  Sow.; 
Ostrea  acuminata,  Camptonectes  lens,  Pecten  vayans  Sow.,  Pholadomya  yibbosa,  Trigonia 
cosf.ata;  Purpuroidea  nodulatn  Lye.,  Cylindrites  acutus  L.  &  M. ;  Ammonites  discus, 
Sow.,  A.  bullatus,  A.  Caprinus  Schl.,  Bekmnites  giganteus;  Libellula  Westwoodii;  Fig. 
813;  Meyalosaurus  Bucklandi  Mey.,  Teleosaurus,  Cetiosaurus  Oxoniensis,  Pterodactyls, 
Rmnphorhynchus  Bucklandi,  etc.  Fig.  818,  Amphitherium  Broderipii ;  Fig.  819,  Plias- 
colotherium  Bucklandi. 

II.  MIDDLE  or  OXFORD  OOLYTE. —  (1.)  Oxford  Clay  and  Kelloway  Rock. — Fig.  768, 
Scyphia  reticulata  (Sponge);   Anabacia  orbit ulites  Lmx.,    Isastrcea  cxplanata  Goldf . ; 
Disaster  canaliculatusAg.,  D.  ovalis,  Ag.   Fig.  772,  Saccocomapectinata  Ag. ;  Terebratula 
diphya  Bu.,   Fig.  780;   Ostrea   Marshii,    0.   yreaaria   Sow.,    Gryjjhcea  dilatata  Sow.> 
Trif/onia  elongata  Sow.,  Fig.  783,    T.  cltvellata  Park.,  Fig.  790;  Ammonites  Jason  Mil., 
A.  coronatus  Brug.,  A.  Calloviensis  Sow.,  Belemnitcs  hastatus  Blv. 

(2.)  Con d  Limestone  (Coral  Rag). —  Thecosmilia  annularis  M.  Edw.,  Thamnastrcea 
nrachmndes  M.  Edw.,  Isastrwa  explanata  Goldf.,  Stylina  tubulifera  M.  Edw. ;  Fig.  771, 
Apiocrimis  Roissyanus  D'Orb.,  Ilemicidaris  intermedia  Forbes,  Cidaris  coronata  Goldf., 
Fig.  774,  Cidaris  Blumenbachii  Miinst.,  Pygaster  patelliformis  Ag. ;  Ostrea  gregaria, 
Triyonia  Bronnii  Ag.,  T.  costata  Park.,  Fig.  785,  Diceras arietinum Lam.,  Astarte  eleyans 
Sow,,  A.  ovata  Smith,  Fig.  784,  A.  minima,  Phiil. ;  Nerincea  fasciata,  Voltz.,  Fig.  786  a, 
b,  N.  Goodhallii  Sow.;  Ammonites  Altenensis,  A.  plicatilis  Sow.  At  Solenhofen,  Fig. 
799,  Eryon  arctiformis  Br.,  Fig.  798,  L/bellnla-  Fig.  804,  Aspidorhynchus ;  Fig.  817, 
Archceopteryx  macrura  ;  Pterodactylus  craasirostris  Goldf.,  and  other  species. 

III.  UPPER   OOLYTE — (1.)   Kimmeridye  Clay.  — Ostrea  drltoidea   Sow.,   Fig.    781, 
Exogyra  viryutaDefr.,  Trigonia  muricata  Ag.,    T.    clavellat't    Park.;  Nerincea    Gosce 
Ri;m.,  Pterocera  Oceani  Brngt. ;  Ammonites  decipiens  Sow.,  A.  rotundus  Sow.,  A.  biphx 
Sow.;  species  of  Ichthyosaurtis,   Plesiosatmis,  Pliosaurus,   Teleosaurus,  Meyalosaurus, 
Goniopholis,  Steneosaurus,  etc. 

(2.)  Portland   Oolyte. —  Isastrcea   oblonya  E.   &  H. ;  Ostrea  expansa  Sow.,   Triyonia 
yibbosa  Sow  ,  Fig.  783,    T.    clavellata,    Lucina    Portlandica   Sow.,   Cardium  dissimile 
29 


450  MESOZOIC    TIME. 

Sow.,  Mactra  rostrata  ;    Natict  eleyans  Sow.;    Ammonites  yiyanteus  Sow.;    Hybodtts 
strictus  Ag. ;   Cetiosaurus  lonyus  Owen. 

7.  PURBECK  BEDS.  —  Mantellia  meyalophylla  Br.  (Fig.  762);  Heiniddaris  Purbeck- 
ensis  Forbes;  Ostrea  distorta  Sow.;  Paludina  carinifera  Sow.;  Cypris  (various  species); 
Aspidorhynchus  Fishtri  Eg.,  Goniopholis  crassidens  Ow.  (a  Crocodilian);  Fig.  800,  Ar- 
chceoniscus  Brodiei  (an  Isopod  Crustacean).  Mammals,  Playiaulax  Becklesii,  P.  minor, 
Spalacotherium  Brodiei  Owen. 


3.   Wealden  Epoch. 

1.  Plants. —  Conifers  closely  allied  to  Araucaria,  Abies,  Cupressus,  Juniperus; 
Cycads;  trees  allied  to  Dracaena,  Yucca,  and  Bromelia;  Ferns,  the  Sphenopteris  Mantelli 
Brngt.,  Clathraria  Lydlii  Mant.,  etc. ;  the  delicate  Charce  of  rivulets. 


MOLLUSKS.  —  Fig.  820,  Unio  Yaldensis;  821  Viviparus  (Paludina)  fluviorum. 

2.  Mollusks.  —  Fresh-water  species  in  large  numbers,  especially  of  the  genera 
Cyrena,  Planorbis,  Limncea,  Unio,  and.  Paludina.    Fig.  820,  Unio  Valdensislblant.;  821. 
Viviparus  (Paludina)  fluviorum  Sow.,  also  Melania  attenuata  Sow.,  Neritina  Fittoni 
Mant. 

3.  Articulates.  —  Ostrncoids,   related  to    Cypris,    etc.,  very  abundant  in   some 
layers.    Insects  of  thirty  or  forty  families,  including  Coleopters,  Orthopters,  Neuropters, 
Hemipters,  and  Dipteis,  or  Beetles,  Crickets,  Dragon-flies,  Cicada,  May-flies,  etc. 

4.  Vertebrates. — Fishes,  of  the  orders  of  Ganoids  and  Selachians,  in  all  thirty 
or  forty  species,  including  Lepidotus  Fittoni  Ag.,  Pycnodus  Mantelli  Ag.,  Hybodus  sub- 
carinatus  Ag.     Reptiles. — Enaliosaurs,  of  the  genera  Ichthyosaurus  and  Plesiosaurus  ,- 
Dinosaurs, of  the  genera  Iguanodon,  Hylceosaurus,  Meyalosaurus,  Reynosaunis ;  Fig.  81i, 
tooth  of  the  Iguanodon  ;  Crocodilians  with  biconcave  vertebrae,  of  the  genera  Suchosaurus 
Goniopholis,  P&cilopleuron,  etc. ;  with  convexo-concave  vertebrae,  of  the  genus  Cetwsaurus, 
and  also  the  first  of  the  concavo-convex,  or  procoelian,  in  species  of  the  modern  genus 
Crocodilus;    Pterodactyls;    Turtles,  as   the    Tretostemum  punctatum   Owen   (Trionyx 
Bakewelli  Mantell),  etc. 

3.  GENERAL  OBSERVATIONS. 

Geography.  —  From  the  outcropping  of  the  Jurassic  beds  along  the 
Black  Hills  and  the  flanks  of  the  Rocky  Mountains,  Hayden  &  Meek 
have  inferred  with  good  reason  that  these  rocks  probably  underlie  the 
wide-spread  Cretaceous  strata  of  the  eastern  slope  of  the  Rocky 
Mountains  ;  and,  as  the  elevation  of  the  Rocky  chain  above  the  ocean 
was  not  completed  until  long  after  the  close  of  the  Cretaceous  period 


JURASSIC   PERIOD.  451 

(although  begun  long  before,  as  regards  some  of  its  subordinate  ridges), 
we  may  infer  that  the  condition  mentioned  as  characteristic  of  the  Tri- 
assic  period  —  a  shallow  submergence  beneath  an  inland  sea  (p.  423) 
—  was  followed  in  the  Jurassic  period  by  a  somewhat  deeper  submer 
gence,  or  at  least  that  the  waters  communicated  directly  with  the 
ocean,  so  that  marine  life  once  more  covered  the  Rocky  Mountain 
region,  from  Kansas  westward  beyond  the  summit  of  the  chain,  even 
to  the  Pacific,  and  that,  in  these  shallow  seas,  limestones  were  forming 
again,  as  in  the  later  half  of  the  Carboniferous  age. 

The  absence  of  sea-shore  Jurassic  beds  from  the  Atlantic  border 
leads  to  the  same  conclusions  with  regard  to  the  coast,  in  the  Jurassic 
period,  that  were  deduced  for  the  Triassic  (p.  422). 

The  Jurassic  period  commenced  in  England  with  the  marine  de 
posits  of  the  Lias.  Through  the  era  of  the  Oolite,  the  alternations 
were  very  numerous,  indicating  oscillations  between  clear  seas  and 
shallow  water  or  half-emerging  land,  in  the  course  of  which  there  were 
coral  reefs  in  England  and  Europe.  The  evidences  of  shallow  water 
and  emerging  flats  increase  toward  the  close  of  the  period,  dry-land 
intervals  begin  to  predominate  over  the  marine,  and  finally  the  rock- 
formations  are  partly  those  of  lakes  and  estuaries.  The  history  in 
Europe  in  part  runs  parallel  with  this,  although  with  many  local  pecu 
liarities. 

The  position  of  the  Jurassic  beds  across  England,  on  the  east  of  the 
older  parts  of  the  island,  and  their  continuation  over  parts  of  northern 
France,  correspond  with  the  view  that  they  were  formed  on  the  bor 
ders  of  a  German  Ocean  basin.  This  is  well  shown,  as  regards  Eng 
land,  on  the  map  on  p.  344. 

While,  in  both  Europe  and  America,  the  Triassic  period  was,  in  the 
main,  one  of  great  marine  marshes  and  shallow  waters,  the  Jurassic 
was  in  both  as  generally  characterized  by  moderately  deep  waters  and 
open  continental  seas. 

Life.  — It  is  evident  from  the  review  that  Conifers,  Tree  Ferns,  and 
Cycads  gave  character  to  the  forests  of  the  Jurassic  world ;  while  Rep 
tiles  and  Marsupials  were  the  dominant  types  of  the  fauna.  Reptiles 
were  preeminent  in  each  of  the  three  elements,  —  in  place  of  whales 
in  the  water,  of  beasts  of  prey  and  herbivores  on  the  land,  and  of 
birds  in  the  air. 

The  multitudes  of  Reptilian  and  other  remains,  entombed  in  the 
Stonesfield  slate,  the  Wealden,  and  the  beds  at  Solenhofen,  do  not  indi 
cate  an  excess  of  population  about  these  spots.  They  point  out  only 
the  places  where  the  conditions  were  favorable  for  the  preservation  of 
such  relics  ;  they  in  fact  prove  that  the  land  was  everywhere  covered 
with  foliage,  and  swarming  with  life. 


452  MESOZOIC    TIME. 

The  dirt-bed  of  Portland,  abounding  in  Mammalian  remains,  and 
yet  only  five  inches  thick,  shows  strikingly  what  we  ought  to  find  in 
the  Coal  formation,  with  its  many  scores  of  dirt-beds  of  far  greater 
thickness,  if  Mammals  were  then  living. 

Climate. — The  existence  of  Belemnites  paxittosus  and  Ammonites 
biplex  (or  closely-allied  species)  in  the  Arctic,  in  the  Andes  of  South 
America,  and  in  Europe,  indicates  a  remarkable  uniformity  of  climate 
over  the  globe  in  the  Jurassic  period.  This  has  been  made  still  more 
striking,  by  the  discovery,  by  Sir  Edward  Belcher,  of  the  remains  of 
an  Ichthyosaur  011  Exmouth  Island,  in  77°  1C'  N.  and  96°  W.,  570  feet 
above  the  sea  ;  and  also  by  that  of  Captain  Sherard  Osborn,  of  two 
bones  of  a  species  related  to  the  Tehosaurs,  on  Bathurst  Island,  in  76° 
22'  N.  and  104°  W.  No  facts  are  yet  ascertained,  connected  with  the 
geographical  distribution  of  species,  that  sustain  the  idea  of  a  diversity 
of  zones  approaching  in  amount  the  present.  The  climate  of  the 
Arctic  regions  in  the  Jurassic  was  probably  at  least  warm-temperate. 

The  existence  of  coral  reefs  in  England,  in  the  Oolitic  era,  consist 
ing  of  corals  of  the  same  grand  groups  with  those  of  the  existing 
tropics,  shows  that  the  Coral-sea  limit  —  marked  off  by  the  water- 
isothermal  of  68°  F.  as  the  average  of  the  coldest  winter  month  (see 
page  41  and  chart  of  the  world) — extended  north  of  part  of  the 
British  seas,  or  30°  (over  3.000  miles  in  distance)  farther  north  than 
its  present  most  extra-tropical  position  just  outside  of  the  Bermudas. 
The  Gulf  Stream  was  probably  the  cause  of  this  long  northward 
stretch  of  tropical  waters.  The  Oolytic  isocryme  of  68°  F.,  accord 
ingly,  would  have  had  nearly  the  position  of  the  present  line  of  44° 
F.,  but  with  a  little  less  northing  and  more  leaning  to  the  eastward. 
The  whole  ocean  was  enough  warmer  to  allow  this  ocean  current  to 
bear  the  heat  required  for  corals,  as  far  north  as  northern  England. 

4.  DISTURBANCES  CLOSING  THE  JURASSIC  PERIOD. 

The  igneous  eruptions  which  made  the  trap  ridges  and  trap  dikes 
that  intersect  the  Connecticut  River  valley  and  other  Triassic  regions, 
from  Nova  Scotia  to  South  Carolina  (described  on  page  417).  may 
have  taken  place  at  the  close  of  the  Jurassic  period.  All  that  the 
facts  definitely  teach  is  that  the  outbreaks  were  subsequent,  in  part  if 
not  wholly,  to  the  deposition  of  the  accompanying  sandstone  beds,  and 
anterior  to  the  Cretaceous  period. 

On  the  Pacific  border,  the  evidences  of  disturbance,  at  this  epoch, 
are  more  positive  ;  and  the  results  were  of  a  grander  character.  The 
Sierra  Nevada,  according  to  the  facts  brought  out  by  Professor  Whit 
ney,  dates  its  existence  from  this  time.  As  has  been  stated,  Triassic  and 


CRETACEOUS   PERIOD.  453 

Jurassic  rocks  enter  into  its  constitution  (their  fossils  being  found  along 
a  distance  of  2oO  miles,  on  the  western  side),  while  the  Cretaceous 
beds  lie  unconformably  on  the  flanks  of  the  mountains.  The  chain, 
in  the  language  of  Professor  Brewer  (in  a  review  of  Whitney's  Geo 
logical  Report),  "  consists  essentially  of  an  immense  core  of  granite, 
flanked  on  either  side  by  metamorphic  slates ;  "  "  the  culminating 
points  in  the  southern  portion  [Mt.  Whitney,  the  highest  among  them, 
about  15,000  feet  above  the  sea]  are  of  granite;  in  the  central,  of 
slates  ;  and  in  the  northern,  of  volcanic  rocks  "  [of  later  date].  Yo- 
semite  Valley  lies  in  the  broad  central  granite  belt  of  the  southern 
part.  Again  he  says,  "  In  passing  along  the  foot-hills  of  the  chain,  at 
its  western  base,  we  find,  at  numerous  points,  the  marine  Tertiary,  or 
Cretaceous,  or  both,  resting  in  a  horizontal  position  on  the  upturned 
edijes  of  the  metamorphic  rocks  of  the  auriferous  series."  "  These 
horizontal  strata  occur  at  intervals  for  over  400  miles,  along  the  west 
ern  base  of  the  chain ; "  "  to  the  north,  the  Cretaceous  predominating, 
and  to  the  south,  the  Tertiary." 

As  the  quartz  veins  intersect  the  Triassic  and  Jurassic  (now  meta 
morphic)  slates,  they  also  are  part  of  the  results  of  the  great  upturn 
and  uplift.  They  show  where  the  leaves  of  the  slates  were  opened  or 
broken,  and  where  great  fractures  were  made  through  the  deep  forma 
tions,  in  the  course  of  the  upturning ;  and  where  the  heat,  developed 
by  the  up  turning,  turned  all  water  or  moisture  present  into  hot  alka 
line  solutions  of  silica ;  and  these  solutions,  passing  into  the  cavities 
and  all  opened  spaces,  deposited  the  silica  and  so  filled  them  with 
quartz.  Thus  the  auriferous  quartz  "  reefs  "  or  veins  were  made  ;  for 
the  gold  and  all  associated  metallic  ores  were  carried  in  at  the  same 
time,  the  hot  waters  gathering  them  far  and  wide  from  the  slates  ad 
joining.  Some  of  the  auriferous  quartz  veins  thus  made  are  of  extraor 
dinary  size.  "  In  the  Pine  Tree  and  Josephine  mines,  near  the  north 
end  of  the  [Mariposa]  estate,  the  average  breadth  of  the  quartz  is 
fully  twelve  feet ;  and  in  places  it  expands  to  forty  feet." 

While  the  Sierra  Nevada  was  in  process  of  formation  on  the  east 
ern  borders  of  California,  the  Wahsatch,  another  high  range  parallel 
with  it,  and  the  Uintah,  a  transverse  range,  were  in  progress,  accord 
ing  to  the  observations  of  Clarence  King,  over  a  region  east  of  the 
meridian  of  Great  Salt  Lake ;  and  still  others,  called  the  Humboldt 
ranges,  over  the  plateau  between  the  Sierra  and  the  Wahsatch. 

3.  CRETACEOUS  PERIOD  (18). 

The  Cretaceous  period  is  the  closing  era  of  the  Reptilian  Age.  It 
is  remarkable  for  the  number  of  genera  of  Mollusks  and  Reptiles 


454  MESOZOIC    TIME. 

which  end  with  it,  and  also  for  the  appearance,  during  its  progress,  of 
the  modern  types  of  plants. 

The  name  CRETACEOUS  is  from  the  Latin  creta,  chalk.  The  Chalk 
of  England  and  Europe  is  one  of  the  rocks  of  the  period. 

1.  AMERICAN. 

Epochs.  —  1.  EPOCH  of  the  Earlier  Cretaceous  ;  2.  EPOCH  of  the 
Later  Cretaceous. 

I.  Rocks :  kinds  and  distribution. 

The  Cretaceous  beds  occur  (1)  at  intervals  along  the  Atlantic  Border 
south  of  New  York,  from  New  Jersey  to  South  Carolina  ;  (2)  ex 
tensively  over  the  States  along  the  Gulf  Border,  thence  bending  north 
ward  along  the  Mississippi  valley,  nearly  or  quite  to  the  mouth  of  the 
Ohio,  over  what  was  then  a  great  Mississippi  bay  ;  (3)  through  a 
large  part  of  the  Western  Interior  region,  over  the  slopes  of  the  Rocky 
Mountains,  from  Texas  northward  to  the  head-waters  of  the  Missouri, 
and  westward  through  Dakota,  Wyoming,  Utah,  and  Colorado  terri 
tories  ;  along,  farther  west,  some  parts  of  the  valley  of  the  Colorado 
River,  but  not  over  the  plateau  between  the  Sierra  Nevada  and  the 
Wahsatch  Range  ;  (4)  along  the  Pacific  Border,  in  the  Coast  ranges 
west  of  the  Sierra  Nevada ;  (5)  in  British  America,  on  the  Saskatch 
ewan  and  Assiniboine ;  also  (6)  on  the  Arctic  ocean,  near  the  mouth 
of  the  Mackenzie,  and  in  North  Greenland.  On  the  Atlantic  Border, 
they  are  unknown  north  of  Cape  Cod. 

The  formation  has  its  greatest  thickness  —  9,000  feet,  or  more,  — 
in  Wyoming,  Utah,  and  Colorado.  In  these  Rocky  Mountain  terri 
tories,  it  passes  upward  without  interruption  into  a  coal-bearing  for 
mation,  several  thousand  feet  thick,  on  which  the  following  Tertiary 
strata  lie  unconformably.  The  lower  portion  of  the  coal  series,  con 
taining  one  or  more  coal  beds,  may  be  Cretaceous  ;  the  rest  of  it  is 
beyond  referred  to  the  Tertiary. 

On  the  map,  p.  144,  the  Cretaceous  areas  are  indicated  by  broken 
lines  running  obliquely  from  the  right  above  to  the  left  below :  one 
area  crosses  New  Jersey ;  other  outcrops  on  the  Atlantic  Border  are 
indicated  by  the  lettering  O;  an  extensive  area  covers  the  Gulf 
States  ;  and  another,  the  region  west  of  the  Mississippi.  The  region 
along  the  Gulf  Border  as  well  as  the  Atlantic,  lined  closely  from  the 
left  to  the  right,  is  Tertiary ;  and  it  probably  covers  Cretaceous, 
throughout.  The  part  of  the  Rocky  Mountain  region  more  openly 
lined  in  the  same  direction  has  a  surface  of  fresh-water  Tertiary ;  but 
Cretaceous  beds,  in  many  places  at  least,  lie  beneath. 


CRETACEOUS   PERIOD.  455 

The  rocks  comprise  beds  of  sand,  marlyte,  clay,  loosely-aggregated 
shell  limestone,  or  "  rotten  limestone,"  and  compact  limestone.  They 
include  in  North  America  no  chalk,  excepting  in  western  Kansas, 
where,  350  miles  west  of  Kansas  City,  a  large  bed  exists.  The  Cre 
taceous  limestones  in  Texas  are  firm  and  compact ;  and  some  beds 
contain  hornstone  distributed  through  them,  like  the  flint  through 
the  Chalk  of  England. 

The  sandy  layers  predominate.  They  are  of  various  colors,  —  white, 
gray,  reddish,  dark  green  ;  and,  though  sometimes  solid,  they  are  often 
so  loose  that  they  may  be  rubbed  to  pieces  in  the  hand,  or  worked 
out  by  a  pick  and  shovel. 

The  dark-green  sandy  variety  constitutes  extensive  layers,  and  goes 
by  the  name  of  Green-sand  ;  and,  as  it  is  valuable  for  fertilizing  pur 
poses,  and  is  extensively  dug  for  this  object,  it  is  called  marl  in  New 
Jersey  and  elsewhere.  This  Green -sand  owes  its  peculiarities  to  a 
green  silicate  of  iron  arid  potash,  which  forms  the  bulk  of  it,  and 
sometimes  even  90  per  cent.,  the  rest  being  ordinary  sand.  There  is 
a  trace  of  phosphate  of  lime,  evidently  derived  from  animal  remains, — 
as  animal  membranes  and  shells  contain  a  small  percentage  of  phos 
phates.  Its  value  in  agriculture  is  due  to  the  potash  and  phosphates. 

Fossil  shells  are  abundant  in  many  of  the  arenaceous  and  marly 
beds  ;  and  in  some  they  lie  packed  together  in  great  numbers,  as  if 
the  sweepings  of  a  beach,  or  the  accumulations  of  a  growing  bed  in 
shallow  waters,  sometimes  cemented  together,  but  generally  loose,  so 
as  to  be  easily  picked  out  by  the  fingers. 

The  most  northern  outcrop  of  the  Cretaceous  observed  on  the  Atlantic  coast  is  in 
New  Jersey,  just  south  of  Sandy  Hook.  Mather  suggested,  in  his  "New  York  Geological 
Report,"  that  the  formation  underlies  the  sands  of  Long  Island  through  its  whole 
length,  on  the  ground  that  fossil  shells  and  lignite  have  been  found  in  digging  wells, 
and  other  excavations ;  but,  as  he  had  seen  none  of  the  shells,  the  evidence  thus  far 
published  is  as  good  for  the  existence  of  Tertiary  beds  as  for  Cretaceous. 

The  inner  limit  of  the  Cretaceous  formation,  on  the  Atlantic  border  (see  map,  p.  144), 
follows  a  line  across  New  Jersey, from  Staten  Island  to  the  head  of  Delaware  Bay; 
across  Delaware  to  the  Chesapeake;  across  Mary larrd, between  Annapolis  and  Balti 
more,  southwest  into  Virginia.  The  formation  occurs  at  Elizabeth  on  Cape  Fear  River, 
in  North  Carolina,  and  sparingly  in  South  Carolina.  But,  more  to  the  westward,  at 
Macon,  Georgia,  commences  the  large  Southern  Cretaceous  region,  which  is  continued 
into  the  Mississippi  basin,  and  whose  inner  outline  passes  by  Columbus  in  Georgia, 
Montgomery  in  Alabama,  and  then  bends  northward  over  northeastern  Mississippi 
across  Tennessee,  just  west  of  the  Tennessee  River,  toward  the  mouth  of  the  Ohio ;  it 
outcrops  southward  on  the  west  side  of  the  Mississippi  over  eastern  Arkansas,  spread 
ing  at  the  same  time  westward,  south  of  Little  Rock  and  Fort  Washita.  Not  far  from 
the  last  point,  the  Cretaceous  area  expands  southward  over  part  of  Texas ;  also  north 
ward,  covering  part  of  the  western  border  of  Iowa  and  Minnesota,  and  continuing  on 
in  the  same  direction,  beyond  the  northern  boundary  of  the  United  States,  into  British 
America.  It  also  spreads  over  a  large  part  of  the  eastern  slope  and  the  summit  region 
of  the  Rocky  Mountains,  as  already  mentioned.  West  of  the  summit,  it  extends  over 
much  of  the  valley  of  the  Colorado,  to  the  meridian  of  113°  W.  In  California,  the  Cre- 


456  MESOZOTC   TIME. 

taceous  occurs  in  the  Coast  ranges,  and  along  the  foot-hills  of  the  Sierra  Nevada, 
from  Placer  County  to  Shasta;  and  in  Oregon,  east  of  the  Cascade  range  (Marsh). 

As  the  Cretaceous  formation  is  very  fully  represented  in  the  region  of  the  Upper 
Missouri,  a  detailed  section  of  it,  by  Meek  &  Hayden,  is  here  given,  beginning 
below :  — 

1.  EARLIER  CRETACEOUS. 

1.  Dakota  Group.  —  Yellowish,  reddish,  and  whitish  sandstones  aud  clays,  with 

lignite  and  fossil  Angiospermous  leaves:  thickness,  400  feet.  Location, 
near  Dakota,  and  reaching  southward  into  northeastern  Kansas.  This 
division  may  require  to  be  united  with  No.  2  (M.  &  H. ). 

2.  Benton  Group.  —  Gray  laminated  clays,  with  some  limestone:  thickness,  800 

feet.  Location,  near  Fort  Benton,  on  the  Upper  Missouri,  also  below  the 
Great  Bend ;  eastern  slope  of  the  Rocky  Mountains. 

3.  Niobrara  Group.  —  Grayish  calcareous  marl:  thickness,  200  feet.     Location, 

Bluffs  on  the  Missouri,  below  the  Great  Bend,  etc. 

2.  LATER  CRETACEOUS. 

4.  Pierre  Group. — Plastic  clays:  thickness.  700  feet;  —  middle  part  barren  of 

fossils.  Located  on  the  Missouri,  near  Great  Bend,  about  Fort  Pierre  and 
out  to  the  Bad  Lands,  on  Sage  Creek,  Cheyenne  River,  White  River  above 
the  Bad  Lands. 

5.  Fox-Hills  Group.  —  Gray,  ferruginous,  and  yellowish  sandstones  and  arenaceous 

clays:  thickness,  500  feet.  Location,  Fox  Hills,  near  Moreau  River,  above 
Fort  Pierre  near  Long  Lake,  and  along  the  base  of  Big  Horn  Mountains. 

No.  1  occurs  at  different  points  in  New  Mexico  (Newberry).  No.  2,  on  the  north 
branch  of  the  Saskatchewan,  west  of  Fort  a  la  Corne,  lat,  54°  N. ;  in  NCAV  Mexico 
(Meek).  No.  3,  over  the  region  from  Kansas  through  Arkansas  to  Texas:  in  the 
Pyramid  Mountain.  No.  4,  in  British  America,  on  the  Saskatchewan  and  Assiniboine; 
on  Vancouver  Island;  Sucia  Islands,  in  the  Gulf  of  Georgia.  No.  5,  at  Deer  Creek» 
on  the  North  Platte,  and  not  identified  south  of  this.  (Meek  &  Hayden.) 

With  regard  to  the  Cretaceous  strata  of  Utah  and  Wyoming  (8,000  to  10,000  feet 
thick),  Meek  remarks  that  the  lower  beds  represent  in  their  fossils  No.  2  of  the  Upper 
Missouri  section,  and  that  the  later  beds,  Nos.  3,  4,  5,  cannot  be  identified,  although 
probably  present. 

In  Mississippi,  Hilgard  has  made  out  the  following  subdivisions:  — 

1.  (Lowest)  Eutaw  group  (Coffee  group  of  Safford),  consisting  of  clays,  with  usually 
some  sand  beds  above,  and  containing  beds  of  lignite  and  rarely  other  fossils,  the  thick 
ness  300  to  400  feet. 

2.  Rotten-Limestone  group,  not  less  than  1,200  feet  thick,  made  up  of  soft,  chalky, 
white  limestones,  underlying  the  prairies,  and  containing  Phcuna  scabra  Mort.,  Neithea 
Mortoni  Gabb,   Gryphcea  convexa  Mort.,  G.  mutabilis  Mort.,  G.  Pitcheri    Mort.,  Ostrea 
falcata  Mort.,  Rudistes,  Mosasaurus,  and  including  the  "  Tombigbv  Sand,"  in  which 
occur  many  Selachian  relies  and  the  gigantic  Ammonites  M  ississippiensis. 

3.  The  Ripley  group,  hard  white  limestones,  often  glauconitic  and   sandy,  underlaid 
by  black  or  blue  micaceous  marly tes,  300  to  350  feet  thick,  and  containing  Cucullcea 
capax  Con.,    Gervillin   ensiformis   Con.,   Baculites   Spillmani  Con.,   Scaphites    Conradi 
D'Orb.,  Ammonites  placenta  Dekay,  etc.,  forming  the  Pontotoc  ridge  in  Mississippi,  the 
Chunnenugga  ridge  in  southeastern  Alabama,  and  occurring  also  at  Eufaula,  Ala.     1 
is  Hayden's  No.  1;  2,  his  No.  4;  and  3,  his  No.  5  (Hilgard,  Am.  J.  Sci.,  III.  ii.  392). 

In  Tennessee,  there  are  the  Coffee  Sand,  200  feet  thick;  the  Green-sand  or  Shell  bed 
(Rotten  Limestone),  200  to  350  feet;  the  Ripley  group,  400  to  500  feet  thick,  consisting 
mostly  of  stratified  sands. 

In  Alabama,  the  thickness  of  the  Cretaceous  is  2,000  feet,  900  to  1,100  of  it  the  Rotten 
Limestone. 

In  Texas,  the  beds  consist  mainly  of  compact  limestone,  and  the  larger  part  are  of  the 
Later  Cretaceous.  Shumard  gives  the  following  subdivisions:  Marly  clay,  150  feet 


CRETACEOUS    PF.RIOD.  457 

overlaid  by  arenaceous  beds,  80  feet  (Nos.  1  and  2).  (a. )  Caprotina  limestone,  con 
taining  Orbitoli.no,  Texana,  etc.,  55  feet;  (b.)  Blue  marl,  50  feet;  (c.)  Washita  lime 
stone,  100  to  120  feet  (No.  3).  (d.)  Austin  limestone,  100  to  120  feet  (No.  4).  (e.) 
Comanche  Peak  Group,  300  to  400  feet;  (/.)  Caprina  limestone,  60  feet. 

In  the  New  Jersey  Cretaceous,  the  beds  and  their  relations  to  those  of  Nebraska  are 
thus  stated  by  Meek  &  Harden,  from  the  observations  of  G.  H.  Cook:  — 

1.  EARLIEK  CRETACF.OUS  ( ?). — No.  1(?)   Bluish  and  gray  clays,  micaceous  sand, 

with  fossil  wood  and  Angiospermous  leaves :  thickness,  130  feet  or  more. 

2.  LATER  CRETACEOUS.  —  Nos.  4  and  5.     (a.)  Dark  clays  (130  feet),  overlaid  by  (b.) 

ihejirst  bed  of  Green-sand,  50  feet  thick.  —  No.  5.  (a.)  Sand-beds  colored  by  iron, 
60  to  70  feet;  (b.)  second  bed  of  Green-sand,  45  to  50  feet;  (c.)  yellow  lime 
stone.  The  whole  thickness  has  been  stated  at  400  to  500  feet. 

In  California,  the  coast  ranges,  according  to  Whitney,  "  are  to  a  large  extent  made  up 
of  Cretaceous  rocks,  usually  somewhat  metamorphic,  and  often  highly  so."  Many  of 
the  altered  beds  are  jaspery,  and  some  are  serpentine.  They  occur  also  on  the  flanks  of 
the  Sierra  Nevada,  in  Northern  California.  The  beds  referred  to  the  Cretaceous  belong 
as  shown  by  Gabb's  study  of  the  fossils,  to  two  or  three  groups:  (1)  the  Shasta  Group, 
or  older  Cretaceous,  which  includes  beds  occurring  in  mountains  west  and  northwest 
of  Sacramento  valley,  on  Cottonwood  Creek,  etc. :  also  in  Mitchell  Canon,  north  side  of 
Mount  Diablo:  (2)  the  Chico  yroup,  or  Middle  Cretaceous,  the  most  extensive  in  Cali 
fornia,  represented  in  Shasta  and  Butte  counties,  and  in  the  foot  hills  of  the  Sierra 
Nevada  as  far  south  as  Folsom,  and  also  on  the  eastern  face  of  the  coast  ranges  border 
ing  the  Sacramento  valley ;  and  including  at  top  the  Martinez  group  on  the  north  flank 
of  Mount  Diablo;  also  in  Oregon,  at  Jacksonville,  etc.,  and  on  Vancouver's  Island,  the 
coal-bearing  strata  of  that  island  being  referred  to  it.  The  third  group — the  Tejon 
group  —  occurs  about  Fort  Tejon  and  Martinez,  and  from  there  along  the  Coast  ranges 
to  Marsh's,  liftceu  miles  east  of  Mount  Diablo;  also  on  the  eastern  face  of  the  same 
range,  to  New  Idria,  etc.,  and  near  Round  Valley  in  Mendoeino  County,  it  being  the 
only  coal-produciny  formation  in  California. 

The  "reference  to  the  Cretaceous  of  the  whole  of  the  Coal-bearing  or  "Lignitic" 
group,  of  Wyoming,  Utah,  Colorado,  and  the  eastern  slope  of  the  Rocky  Mountains,  is 
sustained  by  the  occurrence  in  them  of  some  Cretaceous  types  of  Mollusks  and  Reptiles, 
as  species  of  Inoceramus,  Anchura,  Gyrodes,  and  Dinosaurs.  In  each  of  the  territories 
just  mentioned,  occur  specimens  of  7.  problematicus,  at  different  levels  in  the  Coal  for 
mation;  near  Bear  River,  Wyoming,  a  bed  is  full  of  good  specimens;  at  Coalville, 
specimens  occur  over  one  of  the  lowest  beds  of  coal,  and  another  species  of  Inoceramus 
in  a  sandstone  thousands  of  feet  higher;  and  none  of  the  specimens,  mostly  casts,  bear 
any  evidence  of  transfer  from  an  older  formation  (Meek).  Again,  Marsh  found,  over 
the  coal  series,  six  miles  from  Green  River,  near  Brush  Creek,  in  Utah,  a  layer  full 
of  Ostrea  conyesta  Con.,  a  typical  Cretaceous  fossil,  and  above  this  a  crinoid  per 
haps  related  to  the  Cretaceous  Marsupites,  and  also  scales  of  a  Beryx.  a  genus  of  Cre 
taceous  fishes;  and  in  shales,  below  the  coal  bed,  remains  of  Turtles  of  Cretaceous  types, 
and  teeth  "  resembling  those  of  a  Meyal-osaurus."  Again,  Meek  found  the  remains  of 
a  Dinosaur,  since  described  by  Cope,  in  the  coal  series  of  Black  Butte  Station,  on  Bitter 
Creek,  Wyoming. 

On  the  other  hand,  the  Mollusks  of  the  Rocky  Mountain  coal  formation,  with  the  ex 
ception  of  the  Inocerami  ami  species  of  Anchura  and  Gyrodes,  are  stated  b}'  Meek  to  be 
decidely  Eocene  Tertiary  in  character;  so  much  so  that,  if  the  Inocerami  were  absent,  the 
Tertiary  character  would  not  be  doubted.  Further,  the  fossil  leaves,  which  are  of  many 
kinds,  are,  according  to  Lesquereux,  distinctively  Eocene,  or  at  least  Tertiary,  types. 

While  much  doubt  exists  with  regard  to  the  larger  part  of  the  coal  series,  it  *eems  to 
be  most  probable  that  the  coal-seam  and  the  associated  beds  of  rock  near  Brush  Creek, 
Utah,  examined  by  Marsh,  are  true  Cretaceous,  the  Ostrea,  Crinoid,  Beryx  scale,  and 
Megalosaurian  remains  being  a  combination  of  Cretaceous  features  difficult,  without 
further  study,  to  set  aside.  The  same  may  be  true  of  a  coal-bed  fifteen  miles  north  of 
Denver,  Colorado,  first  described  by  LeConte,  where  Baculitts,  Scaphites,  and  Ammo- 


458  MESOZOIC    TIME. 

wftes  have  been  reported  to  occur  in  the  overlying  rock.  But  the  larger  part  of  the  Coal 
series  may  be  Eocene  Tertiary,  as  held  by  Hayden  and  Lesquereux ;  and  it  is  described 
beyond  under  that  head.  Still  it  may  turn  out  that  all  will  have  to  go  together  —  either 
all  Cretaceous,  or  all  Eocene. 

It  is  also  probable  that  the  Tejon  group,  the  coal-bearing  group  of  California,  is  an 
equivalent  of  the  Wyoming  coal  series,  and  that  this  also  is  Eocene,  if  true  of  the  other. 
Gabb  states  that  a  species  of  Ammonites  extends  through  the  group  to  the  very  top,  and 
affords  strong  evidence  of  its  Cretaceous  age ;  and  this  is  made  stronger  by  the  occur 
rence  also  of  three  or  four  species  of  the  Chico  group  in  the  Tejon  group,  e.  rj.,  Mactra 
(Cymbophorti}  Ashburnerii  Gabb.,  Xucala  truncata  Gabb.,  Avicula  pellucida  Gabb. 
To  show  the  Tertiary  aspect  of  the  shells,  the  genera  are  enumerated  on  page  508. 
Conrad  referred  the  California  beds  to  the  Eocene. 

The  Vancouver  Island  Cretaceous  has  afforded  Inocerami,  Triyonia  (T.  Evansnna 
M.)  and  other  Cretaceous  fossils. 

Economical  Products. 

Mines  of  Cinnabar,  the  chief  ore  of  quicksilver,  occur  at  various 
points  in  the  metamorphic  Cretaceous  rocks  of  the  Coast  ranges  of 
California.  The  usual  associated  rocks  are  serpentine  and  argillaceous 
and  siliceous  slates.  The  most  productive  region  is  that  of  New 
Almaden,  fifty  miles  south-southwest  of  San  Francisco.  It  is  worked 
also  at  New  Idria,  in  Fresno  County,  at  the  Reddington  mine  in  Lake 
County,  and  at  some  other  points. 

The  Coal-beds,  whether  Cretaceous  or  Tertiary,  are  of  great  value 
to  the  country.  They  are  described  under  the  Tertiary. 

Gold  is  found  sparingly  in  the  metamorphic  Cretaceous  of  California, 
but  has  not  repaid  working.  Copper  also  occurs  in  many  localities, 
but  not  in  workable  veins.  Chromic  iron  is  found  in  the  serpentine 
of  California,  but  not  in  a  condition  to  repay  mining. 

The  Green  S»nd  has  already  been  mentioned  as  a  valuable  fertilizer.  The  green 
grains  (called  also  Glmiconite)  consist  of  about  50  per  cent,  of  silica,  20  to  25  protoxyd 
of  iron,  8  to  12  potash  and  soda  (mostly  potash),  and  7  to  10  water,  with  also  a  trace  of 
phosphate  of  lime.  For  analyses,  see  author's  "Treatise  on  Mineralogy." 


II.  Life. 
1.  Plants. 

With  the  opening  of  the  Cretaceous  period,  we  find  indicated  in  the 
rocks  a  great  change  in  the  vegetation  of  the  continent.  The  Cycads 
of  the  Triassic  and  Jurassic  still  existed,  but  they  were  accompanied 
by  the  first  yet  knoivn  of  the  great  modern  group  of  Angiosperms,  — 
the  class  which  includes  the  Oak,  Maple,  Willow,  and  the  ordinary 
fruit  trees  of  temperate  regions,  —  in  fact,  all  plants  that  have  a  bark, 
excepting  the  Conifers  and  Cycads.  More  than  one  hundred  species 
have  been  collected ;  and  half  of  them  were  allied  to  trees  of  our  own 
forests  —  the  Sassafras  (Fig.  825),  Tulip  Tree  (Fig.  826),  Plane  (or 


CRETACEOUS    PERIOD. 


459 


Sycamore),  ffickory,  Willow  (Fig.  828),  Oak,  Poplar,  Maple,  Beech, 
Fig,  or  the  genera  Sassafras,  Liriodendron,  Plafanus.  Juglans,  Salix, 
Quercus,  Populates,  Acer,  Fagus,  Ficus.  Leaves  of  Sassafras,  Tulip- 
tree,  and  Yfillow  are  common.  There  were  also  species  of  Redwood 
(Sequoia),  the  genus  to  which  the  "  Big  Trees  "  of  California  belong. 
There  were  also  the  first  of  the  Palms.  Fossil  palm-leaves,  of  the 
genus  Sabal,  are  met  with  on  Vancouver's  Island,  in  deposits  which 
have  been  pronounced  Cretaceous. 

Coccoliths,  calcareous  disks  less  than  a  hundredth  of  an  inch  in 
diameter  (p.  135),  which  are  now  common  over  the  bottom  of  the 
deep  oceans,  contributed  to  the  Cretaceous  limestones,  though  not  yet 
recognized  among  the  fossils  of  the  American  beds. 

Fig.  825,  Sassafras  Cretaceum  Ncwb.,  from  the  Dakota  group,  along  with  the  three 
following  (Meek  &  Ilayden);  Fig.  826,  Liriodendron  Meekii  Heer;  Fig.  827,  Leyumi- 

Figs.  825-828. 


ANGIOSPERMS   (or  DICOTYLEDONS). —  Fig.   825,  Sassafras   Cretaceum ;    826,   Liriodendron   Meekii; 
827,  Leguminosites  Marcouanus  ;  828,  Salix  Meekii. 

nosifes  Marcouanus  Heer^  Fig.  828,  Salix  Meelcii  Newb.  Large  stumps  of  Cycads  have 
been  found  in  Maryland,  near  Baltimore ;  one  is  twelve  inches  in  diameter' and  fifteen 
high.  (P.  T.  Tyson). 

The  Cretaceous  species  of  Platanus  are  mostly  analogous  to  P.  aceroides.  Other  spe 
cies  from  Kansas  or  Nebraska,  Actr  oltusilobum  Lsqx.,  Sequoia  Reiclienbachi  Heer,  Se 
quoia  for mosa  Lsqx.,  Litjuidambur  inteyrifolius  Lsqx.,  P^mlitts  fmjifdla  Lsqx.,  Ficus 


460  MESOZOIC    TIME. 


..,  Sassafras  Mudf/ii  Lsqx.,  S.  mirabilis  Lsqx.,  S.  obtttws  Lsqx.,  S.  re- 
curvatus  Lsqx.,  Lauropltyllum  reticuhitum  Lsqx.,  Platanus  Heerii  Lsqx.,  Pterospermitt* 
(  Crednena)  Sternberyii  Lsqx.,  Pt.  Ilaydenii  Lsqx.,  Pi.  rugosus  Lsqx.,  Sulix  proteifolia 
Lsqx.,  Betula  Beatriciana  Lsqx.,  Fayus  polydadus  Lsqx.,  Quercus  primordialis  Lsqx., 
Maynolia  tenuifolia  Lsqx.,  Pterophyllum  Haydenii  Lsqx.  (a  Cycad). 

2.  Animals. 

Among  Protozoans,  the  group  of  Rhizopods  had  a  special  impor 
tance  in  the  Cretaceous  period.  Their  shells,  foraminifers*  are  abun 
dant  in  many  of  the  beds,  in  New  Jersey  and  other  Cretaceous  regions 
of  North  America,  though  less  so  than  in  the  chalk  beds  of  Europe. 

Figs.  829-831. 

829  ^~~ 


RHIZOPOD.  —  Fig.  829,  Orbitolina  Texana.    BRACHIOPODS.  —  Fig.  830,  Terebratulina  plicata  ;  831, 

Terebratuia  Ilarlani. 

In  one  genus,  Orbitolina,  the  species  are  disk-shaped  (Fig.  829),  and 
closely  resemble  in  form  some  of  the  Nummulites.  Sponges  also  are 
common  fossils,  although  little  known  thus  far  in  America. 

Under  the  sub-kingdom  of  Mollusks,  the  most  common  Brachiopods 
are  of  the  Terebratuia  family  (Figs.  830,  831).  The  more  character 
istic  genera  of  Lamellibranchs  were  the  three  of  the  Oyster  family, 
Ostrea  (Fig.  833),  Gryphaa  (Figs.  835,  836),  and  Exoyyra  (Fig.  834) 
(species  of  which  'occurred  in  the  Jurassic  period,  but  were  more  com 
mon  and  larger  in  the  Cretaceous),  and  Inoceramus  (Fig.  837),  a 
genus  related  to  Avicufa.,  some  species  of  which  are  of  great  size,  and 
have  the  surface  in  undulations. 

Another  group  characteristic  of  the  Chalk  period,  and,  moreover, 
not  known  after  it,  is  that  of  the  Rudistes  (Figs.  8G2-866).  It  in 
cludes  the  genera  Hippurites,  Radiolites,  Sphcsrutites,  and  a  few  others. 
Hippurites  has  a  long  tapering  form  (Fig.  862),  somewhat  like  a 
nearly  straight  but  rude  horn,  with  a  lid  on  the  top,  the  lid  being  the 
upper  valve  and  the  conical  portion  the  lower.  Within,  there  is  a 


CRETACEOUS   PERIOD. 


461 


subcylindrical,  tapering  cavity,  having  one   or  more  projecting  ridges 
on   the  sides,  running  the  whole  length.     Some  foreign  Cretaceous 

Figs.  832-837. 


CONCHIFERS.  —  Fig.  832,  Exogyra  arietina  ;  833,  Ostrea  larva  ;  834,  Exogyra  costata  ;  835,  Gryphsea 
vesicularis  ;  836,  G.  Pitcher! ;  837,  luoceramus  problematicus. 

species  are  figured  on  page  462  ;  Fig.  862  a  shows  the  interior  of  one  : 
there  are  two  prominent  ridges,  but  one  is  only  partly  free  in  the  in- 


888 


Figs.  838-843. 
843* 


GASTEROPODS.-Fig.  838,  Pyrifusus  Newberryi;  839,  Fasciolaria  buccinoides  ;  840,  Anchura 
(Drepanocheilus)  Americana  :  841,  Margarita  XebrascenMs  ;  842,  Nerintea  Texaua  ;  843  a,  b,  Bulla 
speciosa. 


462  MESOZOIC   TIME. 

terior  space.  The  other  genera  have  a  similar  anomalous  character, 
but  differ  in  the  interior.  Fig.  863  represents  the  lid  or  upper  valve 
of  a  Radiolites,  showing  the  projections  below  (b,  c),  to  which  the 
muscles  closing  the  lid  are  attached  ;  and  Fig.  864  is  the  same  in 
Sphcerulites.  The  Rudistes  are  supposed  to  be  related  to  Chama 
among  the  Dimyary  Mollusks. 

Some  of  the  Gasteropods  are  represented  in  Figs.  838  to  843.  F'ig. 
842  is  a  Nerincea,  a  shell  having  a  ribbed  interior,  as  shown  on  page 
439.  The  genus  began  in  the  Jurassic,  and  ends  with  the  Cretaceous. 

Of  Cephalopoda,  there  were  numerous  Belemnites  (Fig.  844)  and 
Ammonites  (Fig.  845).  One  of  the  most  common  of  the  New  Jersey 
Belemnites  is  represented  in  Fig.  844.  Some  of  the  Ammonites  from 


CEPHALOPOD.  — Beleninitella  mucronata. 

beyond  the  Mississippi  are  over  three  feet  in  diameter.  There  was 
also  a  multiplication  of  other  genera  of  the  Ammonite  family,  the 
shells  of  which  are  like  Ammonites  more  or  less  uncoiled ;  as  Scaphites 
(Figs.  846,  847),  from  scapha,  a  boat;  Crioceras,  p.  473,  from  Kpi6s,a 
ram's  horn  :  Ancyloceras,  from  dyKv\.rj,  a  hook  or  handle  ;  Hamites,  from 
hamus,  a  hook ;  Toxoceras,  from  TO£OV,  a  bow;  Baculites  (Fig.  848), 
from  baculum,  a  walking-stick.  Turrilites  (Fig.  871).  a  form  unlike  other 
Ammonitids  in  being  a  turreted  spiral ;  another,  opened  spiral,  called 
Helicoceras.  Figures  of  several  of  these  forms  are  given  on  p.  473. 
Among  these  genera,  Ammonites,  Scaphites,  Ancyloceras,  Hamites, 
Ptychoceras,  Baculites,  Turrilites,  and  Helicoceras  have  been  found  in 
American  Cretaceous  rocks.  Baculites  ovatus  (Fig.  848)  attained  a 
length  of  a  foot  or  more,  and  a  diameter  of  two  and  a  half  inches ;  and 
Scaphites  Conradi  (Fig.  846),  a  length  of  six  inches. 

Among  Vertebrates,  there  was  the  first  appearance  of  several  prom 
inent  modern  groups,  marking  grand  steps  of  progress  in  the  life  of 
the  world. 

Among  Fishes,  Sharks  and  Ganoids  continued  to  be  common,  as 
before.  In  addition,  there  were  large  numbers  of  the  Common  or  Os 
seous  fishes,  or  Teliosts,  the  tribe  which  includes  the  larger  part  of 
modern  fishes  and  nearly  all  edible  species.  The  Cestraciont  Sharks 
still  continue  ;  and  the  bony  pavement  pieces  of  the  mouth  are  not 
rare  fossils.  Two  views  of  one  from  New  Jersey  are  given  in  Figs. 
853,  853  a.  The  Sharks  were  largely  of  the  modern  type  of  Squalo- 


CRETACEOUS   PERIOD. 
Fig.  845-850. 


463 


S4oo 


CEPHALOPODS.  — Figs.  845,  845  a,  845  b,  Ammonites  placenta;  846,  Scaphites  Conradi;  847,  S. 
laryaeformis  ;  848,  848  a,  Baculites  ovatus  ;  849,  Section  of  B.  compressus,  reduced;  850,  Nautilus 
Dekayi. 

donts,  which  have  teeth  with  sharp  cutting  edges,  besides  other  pecu 
liarities.     A  tooth  of  one  large  species  is  represented  in  Fig.  852. 
Several  species  of  Teliosts  have  been  described  by  Cope,  from  the 


464  MESOZOIC   TIME. 

Upper  Cretaceous  of  Kansas,  related  to  the  Salmon  and  Saury-pike ; 
and  a  Beryx,  from  the  Green-sand  of  New  Jersey. 

Figs.  852-853. 


SQUALODONT  SELACHIAN.  —  Fig.  852,  Otodus  appendiculatus.     CESTRACIONT  SELACHIAN. —Figs.  853, 
853  a,  Ptychodus  Mortoni. 

Reptiles  were  exceedingly  numerous,  and  many  of  them  of  enor 
mous  size.  There  were  Enaliosaurs,  or  swimming  Reptiles,  related  to 
the  long-necked  Plesiosaur,  fifteen  to  forty  feet  \Q\\g-,  snake-like  Reptiles, 
having  short  paddles,  called  Mosasaurs,  ten  to  seventy  feet  long ;  car 
nivorous  and  herbivorous  Dinosaurs,  some  of  great  size,  that  walked 
as  bipeds,  like  those  of  the  Triassic ;  others  related  to  the  Iguanodon, 
somewhat  like  Megatheria  in  their  habits  ;  Crocodilians,  some  of  old 
Teleosaurian  type,  having  biconcave  vertebras,  and  others  related  to 
the  Gavial  of  the  Ganges  ;  flying  reptiles,  or  Pterosaurs,  of  various 
sizes  —  one,  Pterodactylus  ingens  of  Marsh,  having  a  spread  of  wing  of 
twenty-five  feet ;  besides  Turtles,  large  and  small. 

Among  the  Dinosaurs,  the  Hadrosaur  closely  resembled  the  Iguan 
odon,  and  was  full  twenty-eight  feet  in  length.  The  Lcelaps,  twenty- 
four  feet  long,  was  carnivorous,  and  differed  little,  if  at  all,  from  the 
Megalosaur,  having  longer  limbs  behind  than  before ;  and,  as  Cope 
states,  it  probably  was  able  to  stand  erect  on  its  hind  feet,  carrying  its 
head  at  least  twelve  feet  high.  Another,  the  Ornithotarsus  of  Cope, 
having  the  habit  of  Lcelaps,  is  supposed  to  have  been  thirty-five  feet 
in  length.  North  America  abounded  in  Dinosaurs,  during  the  era  of 
the  Connecticut  River  sandstone  —  the  Triassico-Jurassic  ;  and  it  ap 
pears  also  to  have  vastly  exceeded  Europe  in  the  number  of  its  Creta 
ceous  Dinosaurs. 

Among  Enaliosaurs,  or  Sea-saurians,  one,  called  Discosaur  by 
Leidy  (Elasmosaurus  platyurus  Cope),  was  fifty  feet  long,  and  had  a 
neck  of  over  sixty  vertebra?,  measuring  twenty-two  feet  in  length.  It 


CRETACEOUS   PERIOD. 


465 


was  carnivorous ;  and  the  teeth  and  scales  of  fishes  have  been  found 
with  the  bones,  where  the  stomach  once  lay. 

Mosasaurs,  great  swimming  snake-like  reptiles,  were  literally  the 
sea-serpents  of  the  era.  Remains  of  over  forty  American  Cretaceous 
species  of  this  tribe  have  been  found  —  about  fifteen  in  New  Jersey, 
six  or  more  in  the  Gulf  beds,  and  over  twenty  in  Kansas ;  and  one  of 
them,  at  least,  Mosasaurus  princeps,  was  seventy-five  to  eighty  feet 
long.  The  first  one  known  was  found  in  Europe,  near  the  river 

Fig.  854. 


MOSASAURIDS.  —  Fig.  854  A,  Tooth  of  Mosasaurus  princeps(x  K);  B,  snout  of  Tylosaurus  nricro- 
mus,  showing  bases  of  four  teeth  (X  %)\  C,  right  paddle  of  Lestosaurus  simus  (X-V);D, 
restored  jaw  of  Edestosaurus  dispar  [X  %). 

Meuse,  and  hence  the  name.  The  body  was  covered  with  small  over 
lapping  bony  plates.  The  paddles,  of  which  there  were  four,  had  the 
regular  finger  bones,  as  shown  in  Fig.  854  C,  and  hence  more  resem 
bled  those  of  a  whale  than  those  of  the  Enaliosaurs.  The  position  of 
the  teeth  in  the  jaws  is  shown  in  Fig.  854  D ;  and  one  of  them,  from 
Mosasaurus  princeps  Mh.,  half  the  size  of  some  in  this  species,  is  rep 
resented  in  Fig.  854  A.  Besides  these  teeth,  there  were  two  rows  of 
formidable  teeth  along  the  roof  of  the  mouth,  adapted  (as  in  Snakes) 
for  seizing  their  prey.  Fig.  854  B  represents  the  prolonged  snout  of 
one  of  the  species.  The  most  anomalous  feature  in  their  structure  was 

30 


466  MESOZOIC    TIME. 

an  articulation,  with  regular  articulating  surfaces  for  lateral  motion,  in 
either  ramus  of  the  lower  jaw  (at  a  in  Fig.  854  D),  in  place  of  the 
usual  suture.  Besides  this,  the  extremities  of  the  two  rami  were  free. 
The  joint  consequently  enabled  the  two  jaws  to  serve  like  a  pair  of 
arms,  in  working  down  the  immense  throat  any  large  animal  it  might 
undertake  to  swallow  whole. 

Among  Pterosaurs,  remains  of  two  species  have  been  discovered  in 
Kansas,  that  were  twenty  to  twenty-five  feet  in  expanse  of  wings,  and 
another,  eighteen  feet. 

One  of  the  Kansas  Turtles,  the  Atlaniochelys  gigas,  had,  according 
to  Cope,  a  breadth,  between  the  tips  of  the  extended  flippers,  of  more 
than  fifteen  feet.  The  shell  of  a  Turtle  is  made  by  the  coalescence  of 
the  ribs,  in  connection  with  the  deposit  of  bone  in  the  skin ;  and  in 
the  young  state  the  ribs  are  free.  Cope  observes,  that  this  ancient 
turtle,  although  so  large,  was  like  the  young  of  existing  species,  in  its 
ribs. 

Birds.  —  A  number  of  Birds  have  been  described  by  Marsh,  from 
Xew  Jersey  and  Kansas  ;  of  these,  one,  the  Hesperornis,  was  a  Diver, 
and  five  and  a  half  feet  high ;  four  were  related  to  the  Cormorants 
(sea-shore  web-footed  birds,  good  fishers,  and  now  common  on  guano 
islands)  ;  five  were  species  related  to  the  Waders  (the  order  contain 
ing  Snipes  and  Herons). 

Besides  these  of  modern  type,  Kansas  specimens  have  been  de 
scribed  by  Marsh,  which  have  biconcave  vertebra*,  like  fishes  and  some 
reptiles,  and  also  numerous  pointed  teeth  in  both  jaws,  a  characteristic 
hitherto  unknown  among  birds.  Marsh  suspects  that  it  may  have 
had  a  long  tail,  like  that  of  the  Jurassic  Bird  of  Solenhofen  (p.  446). 

Mammals.  —  Species  must  have  been  numerous,  as  they  existed  in 
the  preceding  age,  but  no  relic  of  them  has  yet  been  found. 

Characteristic  Species. 

1.  Protozoans RMzopods.  —  Textularia  Missouriensis,  T.  ylobulosa,  Ehr.,  Pha- 

nerostoinum  senarium,  Rotalia  lenticulina ,   R.  senaria  Ehr.,   Grammostomum  jihyllodes, 
from  the  Cretaceous  of  the  Upper  Missouri,  identified  by  Ehrenberg;  Cristelluiia  rotu- 
lata  D'Orb.,    Dentalina  pulchra   Gabb,   etc.,   from   New  Jersey;  Fig.  829,  Orbitolina 
Texana  R.,  from  Texas,  a  species  having  the  form  of  a  disk,  slightly  conical. 

2.  Radiates.  —  (a.)  Polyp-Corals.  —  Astrocoenia  Sancti-Sabce  R.,  Texas;  A.  Gua~ 
daloupce   R.,    Texas;    Montlivaltia   Atlnntica   Lonsd.,    New  Jersey,   etc.;   Trochosm'dia 
(jranulifera  Gabb,  Chico  group,    Chico  Creek,  California;   Trochosmilia  conoidea  Gabb 
&  Horn,   New  Jersey;  T.  (?)  Texana  Con.,   Texas;  Platytrochus  spetiosus  G.  &  H., 
Tennessee;  Flabelluni   stri'ttum  G.   &  H.,  Alabama;  Micrabacia  Americana  M.,   Ne 
braska. 

(b.)  Echinoderms.  —  Holaster  simplex  Shum. ;  II.  (Ananchytes)  cinctus  Ag. ;  Toxaster 
elegans  Gabb. ;  also  species  of  Diadema,  Hemiaster,  Holectypus,  Cyphosoma,  etc. 

3.  Mollusks.  —  (a.)  Bnjozoans. — Numerous   species  have   been   described  and 
figured  by  Gabb  £  Horn,  of  the  genera  Meinbranipont,  Flustrella,  Eschdripora,  Bijius- 
tra,  etc. 


CRETACEOUS   PERIOD.  467 

(b.)  Brachiopods.—Yig.  830,  Terebratulina  plicnta ;  Fig.  831,  Terebrahda  Harlani 
Mort.,  from  New  Jersey;  Linyula  nitida  M.  &  H.,  Nebraska;  Rhynchonella  Whitneyi 
Gabb,  Shasta  group,  California. 

(c.)  Lamellibranchs.  —  Fig.  833,  Ostrea  larva  Lam.,  found  also  in  Europe;  (A  cow- 
</esto  Con.,  from  Arkansas  and  Nebraska;  Ostrea  malleiformis  Gabb,  Chico  group, 
California;  Fig.  832,  Exoyyra  arietina  R.,  from  Texas;  Fig.  834,  E.  costata  Say,  from 
the  Cretaceous  of  the  Atlantic  and  Gulf  borders;  E.  parasitica,  Gabb,  Chico  group, 
Texas  Flat,  California;  Fig.  835,  Gryphaa  vesicularis  Lam.,  at  nearly  all  North  Ameri 
can  localities,  including  the  Californian,  and  also  a  European  species;  Fig.  836,  G. 
Pitcher i  Mort.,  from  Cretaceous  region  west  of  the  Mississippi  River  ;  Fig.  837,  Ino- 
ceramus  problematicus  Schloth.,  from  west  of  the  Mississippi,  and  also  European. 
Triyonia  Tryoniana  Gabb,  Chico  group,  California.  Among  Rudistes,  Radiolites 
Austinensis  R,,  a  species  five  to  six  inches  in  diameter,  from  Alabama,  Mississippi,  and 
Texas;  Radiolites  lamettosus  Tuomey,  from  Alabama;  Ilippurites  Texanus  R.,  a  species 
eight  inches  long  and  four  in  diameter,  from  Texas;  Caprotina  Texana  R.,  from 
Texas.  Haploscnpha  yrandis  Con.  is  supposed  to  be  related  to  the  Rudistes;  one 
Kansas  specimen  had  a  diameter  of  twenty-six  inches ;  it  is  from  the  Niobrara  group. 

(d.)  Gasteropods. —  Fig.  838,  Pyiifusus  Xeicberryi  M.  &  H.,  from  Nebraska;  Fig. 
839,  Fasciolaria  bucdtioides  M.  &  H.,  from  Nebraska;  Fig.  840,  Anchura  (Di-ei>ano- 
cheilus)  Americana  M.  (—  Rostellana  Americana  Evans  &  Shumard),  from  Nebraska; 
Fig.  841,  Margarita  Nebrasctnsis  M.  &  H.,  from  Nebraska;  Fig.  842,  Nerincea  Texana 
R.,  from  Texas;  N.  acws  R.,  from  Texas;  Figs.  843 a,  8436,  Bulla  speciosa  M.  &  H., 
from  Nebraska ;  Maryaritella  anyulata  Gabb,  Chico  group,  California. 

(e.)  Cephalopods. — Nautilus  Texanus  Shum.,  Texas  and  California;  Fig.  845,  Am 
monites  placenta  Dekay,  from  Atlantic  Border,  Gulf  Border,  and  Upper  Missouri,  young 
specimen,  natural  size;  Fig.  845  a,  outline  side  view  of  the  same,  reduced;  Fig.  845  b, 
one  of  the  septa  of  the  same,  natural  size ;  Ammonites  Breweril  Gabb  and  A.  Ilaydenii 
Gabb,  and  others,  from  Shasta  group,  Cottonwood  Creek,  California;  Fig,  846,  Sca- 
phites  Conradi  Mort.,  from  the  same  localities  as  preceding;  Fig.  847,  S.  larvceformis 
M.  &  H.,  from  Nebraska;  Hamites  Vancouver  ends  Gabb,  Chico  group,  Vancouver 
Island;  Fig.  848,  Baculites  ovatus  Say,  from  New  Jersey;  Fig.  848  a,  outline  of  section, 
showing  oval  form;  Fig.  849,  outline  of  section  of  B.  compressus  Say,  Upper  Missouri; 
Baculites  Chicoensis  Trask,  California;  B.  inornalm  M.,  Sucia  Island,  Gulf  of  Georgia; 
Fig.  850,  Nautilus  Dekayl  Mort.,  from  the  Atlantic  and  Gulf  borders,  and  west  of  the 
Mississippi  from  Texas  to  Upper  Missouri,  and  also  reported  from  Europe,  Chili,  and 
Pondicherry  in  the  East  Indies.  Fig.  844,  Belemnitella  mucronata  Schloth.,  same  U.  S. 
distribution  as  preceding,  excepting  the  Upper  Missouri  region;  Belemnites  impressus 
Gabb,  Shasta  group,  California;  Ancyloceras  Remondii  Gabb,  Shasta  group,  California; 
Turrilites  Oreyonensis  Gabb,  Chico  group,  Jacksonville,  Oregon. 

4.  Vertebrates.  —  (a.)  Fishes.  —  Fig.  852,  Otodus  appendictdatusAg.,  from  New 
Jersey.  Figs.  853,  853  a,  different  views  of  a  tooth  of  Ptycliodus  Mortoni  (Cestraciont), 
a  species  found  in  New  Jersey.  Pt.  occidental  L.,  from  Kansas.  Dipristis  Meirsii 
Mh.,  Enchodus  semistriatus  Mh.:  also  species  of  Lamna,  Oxyrhina,  etc.;  JBeryx  in- 
sctdpttts  Cope,  Edaphodon  mirificus  L.,  all  from  New  Jersey.  The  Cretaceous  of 
Kansas  has  afforded  Cope  species  of  Portheus  (one,  Portheus  molossus  Cope,  with  a 
head  as  long  as  in  a  full-grown  grizzly  bear,  and  some  of  the  slender  sharp  teeth  project 
ing  three  inches),  Tchthyodectes,  Saurocephalus,  Cimolichthys,  Enchodus.  etc. 

(b.)  Reptiles.  — Among  Dinosaurs,  Hadrosaurus  Foulkii  L.,  from  New  Jersey,  twenty- 
eight  feet  long;  H.  minor  Mh.,  about  half  this  in  length,  ibid.;  H.  ayUis  Mh.,  from 
Kansas.  Among  Crocodilians,  Hyposaurus  Royersi  Owen,  a  Teleosaurian,  it  having 
biconcave  vertebrae;  H.ferox  Mh.,  with  fluted  teeth,  from  New  Jersey;  Thoracosaurus 
NeoccKsanensis  Cope,  New  Jersey,  form  and  size  near  the  same  in  the  Gavial  of  the 
Ganges:  ffolops  obscurus  L.,  New  Jersey;  H.  brevispinis  Cope,  New  Jersey;  Botto- 
saurus  Ifarlani  Ag.,  from  New  Jersey,  related  to  the  American  Alligator.  Among 
Enaliosaurs,  Discosaurus  carinatus  L.,  near  Fort  Wallace,  300  miles  west  of  Leaven- 
worth;  Polycotylus  latipinnis  Cope,  Plesiosaur-like,  eighteen  feet  long.  Among  Mosa- 


468  MESOZOIC    TIME. 

saurs:  Fig.  854  A,  tooth  of  Mosasaurus  princeps  Mh.,  from  N^w  Jersey;  M.  maximum 
Cope,  from  New  Jersey;  M.  minor  Gibbes,  from  Alabama.  Fig.  854  D,  form  of  jaw  of 
Kdettowntrvi  dispar  Mh.,  a  species  from  Kansas,  thirty  feet  long;  Fig.  854  B,  snout  of 
Tylosaurus  micromus  Mb.,  from  Kansas;  T.  proriyer  Mh.  (Leiodon  proriyer  Cope). 
from  Kansas;  T.  dyspelor  Mh.  (Leiodon  dyspelor  Cope),  fifty  to  sixty  feet  long,  from 
Kansas,  etc. ;  Fig.  854  C,  paddle  of  Lestosaurus  simus  Mh.,  from  Kansas,  a  short-nosed 
kind;  Clidastes  iguanavus  Cope,  from  New  Jersey;  C-  intermedium  L.,  from  Alabama; 
C.  pumilus  Mh.,  from  Kansas,  twelve  feet  long;  BaptOXntrtu  platyspondi/lus  Mh.  and 
B.  fraternus  Mb.,  both  from  New  Jersey.  The  Mosasaurs,  according  to  Marsh,  have 
very  short  necks,  like  the  Ichthyosaurs.  The  vertebrae,  in  the  genera  Clidastes  and 
Edestosaurus,  are  united  by  a  zygosphene  articulation,  as  in  snakes  and  the  Iguanas. 

Among  Pterodactyls,  Pterodactylus  ingens  Mh.,  Pt.  occidentalis  Mb.,  Pt.  velox  Mh., 
all  from  Kansas,  severally  about  twenty-five,  twenty,  and  fifteen  feet  in  expanse  of 
wings. 

The  birds,  described  by  Marsh,  comprise  five  Waders,  of  the  genera  Termatornis  and 
PaloBotrvnya}  all  from  New  Jersey;  six  Natatores,  of  the  genera  Graculavus,  Ilesper- 
ornis,  and  Laonu»t  from  New  Jersey  and  Kansas;  and  two  birds  with  teeth  (Odont- 
ornithes),  of  the  genera  Ichthyornis  and  Apatornis,  from  the  Upper  Cretaceous  shale  of 
Kansas. 

See,  on  Cretaceous  Reptiles:  LEIDY,  Smithsonian  Contrib.  No.  192,  1865,  4to,  and 
later  papers  in  the  Proc.  Acad.  Nat.  Sci.  Philad.,  Reports  in  connection  with  Hayden's 
Explorations;  COPE'S  Synopsis,  4to,  1869,  Trans.  Amer.  Phil.  Soc.,  and  later  papers 
in  the  Proc.  Am.  Phil.  Soc.,  and  Acad.  Nat.  Sci.,  and  Hayden's  Rocky  Mountain 
Reports;  MARSH,  Am.  Jour.  Sci.,  vols.  i.  to  v.  of  the  3d  series.  Also,  on  Birds. 
MARSH,  ib.  The  existence  in  Mosasaurs  of  the  articulation  in  the  lower  jaw  was  first 
made  known  by  Cope;  and  that  of  hind  paddles  and  scales,  as  well  as  th«  character 
of  the  paddles,  by  Marsh.  (Am.  Jour.  Sci.,  III.  iii.  448.) 

III.    Fossils    characteristic    of    the    Subdivisions    of    the 
Cretaceous. 

A.  EARLIER  CRETACEOUS.  —  No.  1  (Dakota  group).     Upper  Missouri:  Pharella  (?) 
Dakotensis  M.  &  H.,  Axincea   Siouxensis  Gabb.,   Cardium,   Corbicula,    Yoldia,   Tellina, 
Lcptosolen  Conradi  M.,  Cyrena  ( Cyprina )  arenariaW..  Unio  Nebrascensis  M.,  Leaves 
of  Anyiosperms.     Alabama:   Ceratites  (?)  Americanus  Harper,  Leaves  of  Anyiosperms. 
New  Jersey :  Leaves  of  Anyiosperms. 

No.  2  (Benton  group).  Upper  Missouri:  Inoceramus  problematicus,  /.  umbonatiis 
Ostrea  congestrt,  Pholadomya  (Anatimya)  papyracea  Con. ;  Ammonites  percarinatus  H. 
&  M.,  A.  vespertinusMort.  (=A.  TexanusR,.),  Scaphites  larvxformis  M.  &  H.  Texas: 
Ammonites  percarinatus,  Inoceramus  capulus  Shum.  New  Jersey :  none. 

No.  3  (Niobrara  group).  Upper  Missouri:  Ostrea  conyesta,  Inoceramus problematicus, 
I.  aviculoides  M.  &  H.,  7.  pseudo-mytiloides  Schiel.  Arkansas:  Toxaster  eleyans,  Hoi- 
aster  simplex,  Cardivm  multistriatum  Shum.,  Inoceramus  problematicus,  I.  confertim- 
annuluius  R.,  Gryphcea  Pitcheri.  Texas:  Holaster  simplex,  Epiaster  eleyans,  Cidaris 
hemigranosa,  Gryphcea  Pitcheri,  Ostrea  subovata  Shum.  (0.  Mnrshii  Marcou),  Inocera 
mus  proble mat 'icus,  Turrilites  Brazoensis  R.,  Ammonites  Texanus,  Hamites  Fremonti 
Marcou.  New  Jersey :  none. 

B.  LATER  CRETACEOUS. — No.  4  (Pierre  group).     Upper  Missouri :  Nautilus  Dekayi, 
Ammonites  plucenta,  A    complexes  II.   &  M.,   Baculites  ovatus,  B.  compressun,  Ilelico- 
ceras  Mortoni  M.  &  II.,    fnocer'amus   subleris  H.  &  M.,   Mo.wsaums  Missonriensis  L. 
Alabama:  in  bed  a,  Teredo  tlbinlis  (?)  Mort.;  in  bed  b,  Exoyyra  costata,  Gryphcea  resic- 
ularis,    Inoceramus    Informix,   Pecten   §-cost«tus    Mort.,   Nautilus   Dekayi  Mort.,    Am 
monites  placenta,    A.  Delawarensis  Mort.,   Baculites   ovatus;  in   bed  o,   Ostrea   larva, 
Gryphcea  lateralis  (G.  vomer  Mort.),    Neitliea   Mortoni  Gabb.     New  Jersey:  Bed   a, 
Ammonites  placenta,  Baculites  ovatus ;  bed  b,  Amm.  Delawarensis,  A.  complexus,  Bacu- 


CRETACEOUS   PERIOD.  469 

lites  ovatus,  Nautilus  Dekayi,  Beleinnitella  mucronata ;  bed  c,  Terebratulina  plicata, 
Pholadomya  ocddentalis  Mort.,  Ostrea  larva,  Grypheea  vesicularis,  Exoyyra  costata, 
bones  of  Mosasaurus. 

No.  5  (Fox  Hills  group).  Upper  Missouri:  Nautilus  Dekayi,  Amm.  placenta,  A.  loba- 
tus  Tuomey,  Scaphites  Conradi,  Baculites  ovatus,  Mosasaurus  Missouriensis.  Alabama: 
Exoyyra  costata,  Gryphcea  vesicularis,  Nautilus  Dekayi,  Baculites  ovatus,  Scaphites  Con 
radi.  New  Jersey:  Montlivaltia  Atlantica,  Nucleolites  crucifer,  Anancliytes  cinctus, 
A.  Jimbriatus  Mort.,  Tertbratula  Hatiani,  Grypheea  lateralis,  G.  vesicularis,  Neithea 
Murtoni. 

The  New  Jersey  region  abounds  in  Oysters  and  Exoyyrce,  has  some  Ammonites,  Bacu 
lites,  and  Echinoderms,  but  no  ffippurites  or  Caprince. 

The  Upper  Missouri  has  very  few  Oysters,  no  Exoyyrce,  many  and  large  Ammonites 
and  Baculites,  but  one  rare  Echinoderm  (Hemiaster  Humph  reysiarius  M.  &  II.),  no 
Braohiopods,  except  two  Linyulce,  and  no  Ifippurites  or  Caprince. 

The  Alabama  beds  resemble  the  New  Jersey,  and  the  Arkansas  the  corresponding 
or  middle  beds  of  Nebraska,  and  upper  of  New  Jersey ;  but  both  contain  Hippurites 
and  Echinoderms. 

The  Texas  region  has  but  few  species  in  common  with  the  others,  —  Ammonites 
vcspertinus,  Inoceramus  latus  (?),  and  /.  Bambini,  the  latter  being  still  questioned;  and 
it  is  characterized  by  Ilippurites,  Caprince,  Nerincece,  etc.,  like  the  Upper  Chalk  of 
southern  Europe. 

The  species  common  to  Nebraska  and  New  Jersey,  according  to  Meek  &  Harden, 
are  Nautilus  Dekayi,  Scaphites  Conradi,  Ammonites  placenta,  A.  complexus,  A.  lobatus, 
Baculites  ovatus,  Amauropsis  (?)  paludinieformis  M.  &  II. 

2.  FOREIGN. 
I.    Rocks:  kinds  and  distribution. 

The  Cretaceous  formation  covers  a  large  part  of  southeastern 
England,  eastward  of  the  limit  of  the  Jurassic,  from  Dorset  on  the 
British  Channel  to  Norfolk  on  the  German  Ocean  ;  and  also  a  narrow 
coast-region,  about,  and  south  of,  Flamborough  Head,  as  shown  on  -the 
map,  p.  344.  Like  the  Jurassic,  it  reappears  again  in  northern 
France,  across  the  British  Channel.  It  also  occurs  in  other  parts  of 
France,  in  Sweden,  and  in  southern  and  central  Europe,  covering 
much  of  the  territory  between  Ireland  and  the  Crimea,  1,140  miles  in 
breadth,  and,  between  the  south  of  Sweden  and  south  of  Bordeaux, 
840  miles.  (Lyell.) 

The  rocks  are  (1)  Sandstone,  generally  soft,  and  of  various  colors  ; 
(2)  marlytes  or  clayey  beds  ;  (3)  the  variety  of  limestone  called 
Chalk,  the  common  writing  material,  in  beds  of  great  thickness  ;  (4) 
other  limestones,  either  loose  or  compact.  Among  the  sandy  por 
tions,  the  Green-sand  beds  are  a  marked  feature,  especially  of  the 
lower  part  of  the  formation.  This  is  so  eminently  the  fact  that  the 
Lower  Cretaceous  in  England  is  called  the  Green-sand,  although  only 
a  part  of  the  layers  are  green,  and  in  some  regions  none  at  all. 

The  Chalk  often  contains  flint,  in  nodules,  which  are  distributed  in 
layers  through  it,  like  the  hornstone  in  earlier  limestones.  Though 
generally  more  or  less  rounded,  they  often  assume  fantastic  shapes, 


470  MESOZOIC   TIME. 

• 

and  are  of  concretionary  origin.  The  exterior  is  frequently  white,  and 
penetrated  by  chalk,  proving  that  they  are  not  introduced  bowlders  or 
stones,  but  have  originated  where  they  lie.  Moreover,  many  chalk 
fossils  are  turned  into  flint ;  and  the  flint  nodules  have  often  fossils  as 
nuclei. 

The  Cretaceous  beds  of  Europe  have  been  divided  into:  — 

I.  The  Loirer  Cretaceous,  including  in  England  the  Lower  Green-sand,  800  to  900 
feet  thick,  and  in  other  regions  beds  of  clay,  and  limestone  sometimes  chalky. 

II.  The  Middle  Cretaceous,  including  in  England  (a)  the  clayey  beds  or  marly tes, 
called  Gault,  150  feet  thick,  and  (b)  the  Upper  Green-sand,  100  feet. 

III.  The  Upper  Cretaceous,  including  in  England  the  beds  of  Chalk,  in  all  about 
1,200  feet:  it  consists  of  (a)  the  Lower  or  Gray  Chalk,  or  Chalk  Marl,  without  flint; 
(6)  the  White  Chalk,  containing  flint;  (c)  the  Maestricht  beds,  rough  friable  limestone, 
at  Maestricht  in  Denmark,  100  feet  thick. 

The  subdivisions  of  the  Cretaceous  are  various!}'  named,  in  different  parts  of  Europe. 

Lower  Cretaceous. — Superior  Neocomian  of  D'Orbigny  (the  Wealden  being  the 
Inferior);  the  Hils-conglomerat  of  Germany. 

Middle  Cretaceous.  — 1.  Gault,  lower  part  Aptian,  of  D'Orbigny;  the  upper,  Albian 
of  D'Orbigny;  2.  Upper  Green-sand,  Cenomanian  of  D'Orbigny;  Lower  Quadersand- 
stein  (or  Unterquader)  of  the  Germans;  Lower  Planerkalk  of  Saxony. 

Upper  Cretaceous.  — 1.  Gray  Chalk,  or  Chalk  without  flints,  Turonian  of  D'Orbigny; 
Hippurite  Limestone  of  the  Pyrenees;  Middle  and  Upper  Planerkalk  of  Saxony;  Mit- 
telquader  of  Germany.  2.  White  Chalk  or  Chalk  with  Jlints,  Senonian  of  D'Orbigny; 
Upper  Quadersandstein  (Oberquader)  of  the  Germans;  La  Scaglia  of  the  Italians.  3. 
Maestricht  beds,  of  Limburg;  Danian  of  D'Orbigny;  Faxoe  Kalke  of  Denmark;  Cal- 
caire  pisolitique  near  Paris. 

In  mineral  character,  the  beds  of  each  division  vary  much  over  Europe,  the  Chalk 
of  England  being  synchronous  with  marlytes  and  solid  limestones  in  Europe. 

The  Cretaceous  of  Great  Britain  is  not  found  on  any  part  of  the  Atlantic  coast,  ex 
cepting  a  small  area  in  the  vicinity  of  the  Giants'  Causeway.  The  beds  of  northern 
France  spread  eastward  over  Belgium  and  Westphalia,  but  not  to  the  Atlantic  on  the 
west :  farther  south,  they  occur  at  the  deep  indentation  of  the  Bay  of  Biscay.  They 
cover  part  of  the  Pyrenees,  and  reach  into  Spain, in  what  has  been  called  the  Pyrenean 
basin,  which  in  the  Cretaceous  period  was  a  bay  on  the  Atlantic.  There  is  another 
sea-border  deposit  at  Lisbon,  in  Spain.  In  southern  France,  over  what  is  called  the 
Mediterranean  basin,  the  beds  extend  from  the  Gulf  of  Lyons  along  the  Mediterranean 
coast,  northeast  to  Switzerland,  though  with  interruptions.  The  formation  is  found  in 
the  Juras  and  Alps,  in  Italy,  Savoy,  Saxony,  Westphalia,  Moravia,  Bohemia,  northern 
Germany,  Poland,  middle  and  southern  Russia,  Greece,  and  other  places  in  Europe. 

In  Asia,  it  has  been  observed  about  Mount  Lebanon  and  the  Dead  Sea,  the  Caucasus, 
in  Circassia  and  Georgia,  and  elsewhere ;  in  northern  and  southern  Africa ;  in  South 
America,  along  the  Andes,  and  on  the  Pacific  coast,  occurring  in  Venezuela,  in  Peru, 
at  Concepcion  in  Chili,  in  the  Chilian  Andes  at  the  passes  of  the  Portillo  and  Rio  Vol- 
can,  at  an  elevation  of  9.000  to  14,000  feet,  in  the  Straits  of  Magellan  at  Fort  Famine 
in  Fuegia. 

The  Cretaceous  formation  occurs  also  in  Queensland  (northeast  Australia),  and  in 
Victoria,  west  of  Flinders  river.  It  also  exists  in  North  Greenland,  where  some  of  the 
fossil  leaves  are  identical  in  species  with  European. 

II.  Life. 

The  Life  of  the  Cretaceous  period  in  Europe  resembled  that  of 
America,  but  was  far  more  abundant. 


CRETACEOUS   PERIOD. 


471 


1.  Plants. 

Angiosperms  and  Palms  were  growing  in  Europe ;  and,  among  the 
former,  there  were  the  Magnolia,  Myrtle,  Willow,  Walnut,  Maple,  Fig, 
and  Holly,  besides  a  Redwood  (Sequoia)  and  a  Palmacites.  The 
relics  of  Ferns,  Conifers,  and  Cycads  still  preponderate  ;  for  the  Cre 
taceous  was  properly  the  closing  part  of  the  era  of  Cycads.  Vegetable 
remains  of  all  kinds  are  rare,  as  the  deposits  are  mostly  marine. 

The  microscopic  Pro.tophytes,  called  Diatoms  and  Desmids,  are 
found  in  some  of  the  beds,  especially  in  the  flint  of  the  Chalk.  The 
former  have  siliceous  cases,  as  explained  and  illustrated  on  p.  135, 
and  they  may  have  contributed,  as  has  been  suggested,  to  the  material 
of  the  flint  nodules.  The  Desmids  are  not  siliceous,  but  are  still  very 
common  in  the  flint,  —  far  more  so  than  Diatoms  (which  are  rare)  : 
the  kinds  which  have  been  called  Xanthidia  are  especially  abundant ; 
their  forms  are  very  similar  to  those  from  the  Devonian  hornstone, 
figured  on  p.  257.  The  microscopic  Coccoliths,  alluded  to  on  p.  135, 
have  been  detected  in  Chalk. 

2.  Animals. 

Foraminifers,  or  the  shells  of  Rhizopods,  are  the  principal  material 
of  the  Chalk.     According  to  Ehrenberg,  a  cubic  inch  of  it  often  con- 
Figs.  856-859. 

858,^        859  _ 


RHIZOPODS.  — Fig.  856,  Lituola  nautiloidea;  857,  o,  Flabellina  rugosa  ;  858,  Chrysalidina  gradata  ; 
869,  a,  Cuueolina  pavonia. 

Figs.  860,  861. 


861. 


SPONGE,  Fig.  860,  Siphonia  lobata.     Fig.  861  a-h,  Sponge  Spicules. 

tains  more  than  a  million  of  microscopic  organisms,  among  which  far 
the  most  abundant  are  these  Rhizopods.  Some  of  the  species  are 
represented  in  Figs.  856-859. 


472 


MESOZOIG   TIME. 


Sponges,  also,  were  of  great  importance  in  the  history  of  the 
Cretaceous  rocks.  They  occur  cup  or  saucer-shaped,  tubular,  branched, 
and  of  other  forms.  One  is  figured  in  Fig.  860.  Their  siliceous 
spicula  (Fig.  861  a-g]  are  common  in  the  flint,  and  have  contributed, 
as  well  as  Diatoms,  toward  the  silica  of  which  it  was  made.  The 
recent  discovery  over  the  ocean's  bottom  of  sponges  whose  fibres  are 
wholly  siliceous,  shows  that  these  species  may  have  contributed  much 
to  flint-making.  The  Ventriculites  of  the  chalk  are  supposed  to  have 
been  siliceous  Sponges. 

Among  Radiates,  the  Corals  and  Echinoids  were  mostly  of  modern 
types. 

The  same  genera  of  Mollusks  abounded  that  are  enumerated  on  p. 
460.  The  genera  of  Gasteropods  were  to  a  greater  extent  modern 
genera  than  in  the  preceding  period  ;  and  the  proportion  of  siphonated 


S62a 


Figs.  862-866. 

862 


CONCHIFEBS,  Rutfistes  Family.  — Fig.  862.  Hippurites  Toucasianus ;  862  a,  II.  dilatatus;  863, 
Radiolites  Bournoni ;  864,  Spherulites  Hoeninghausi.  GASTEROPODS.  —  865,  Nerinaea  bisulcata  ; 
866,  Avellana  Cassis. 

species  (those  having  a  beak)  was  nearly  as  great  as  in  existing  seas. 
The  Rudistes  (Figs.  862-866)  were  very  common  in  southern  Europe 
and  Asia  Minor  ;  and  about  eighty  species  have  been  described.  Only 
a  single  species  —  Radiolites  Mortoni  Woodw.  —  has  been  found  in 


CRETACEOUS    PERIOD. 


473 


England.  The  Ammonites  and  the  uncoiled  forms  of  the  same  family 
mentioned  on  p.  462,  several  of  which  are  here  figured  (Figs.  867- 
871)  were  particularly  abundant.  One  English  Ammonite  (the  A. 
Lewesiensis  Mant.),  from  the  Lower  Chalk,  has  a  diameter  of  a  yard. 

Figs.  867-871. 


CEPHALOPODS,  Ammonite  Family.  —  Fig.  867,  Crioceras  Duvalii ;  868,  Ancyloceras  Matheronianuiiu 
869,  Hamites  attenuates;  870,  Toxoceras  bituberculatuni;  871,  Turrilites  catenatus. 

In    the    sub-kingdom    of  Vertebrates,    there    were    Fishes    of  the 
modern  order  of  Teliosts,  or  Osseous  fishes,  and  Sharks  of  the  modern 

Fig.  872. 


TELIOST.  —  Osnieroides  Lewesiensis ,( X  >£  )• 

tribe  of  Squalodonts,  as  stated  with  regard  to  America.     One  of  these 
Osseous  fishes  is  represented  in  Fig.  872.     They  included  representa- 


474 


MESOZOIC  TIME. 


tives  of  the  Salmon  and  Perch  families.     The  teeth  of   Cestraciont 
Sharks  are  common. 

The  class  of  Reptiles,  in  the  earlier  part  of  the  Cretaceous  period, 
included  the  Iguanodon  and  Teleosaur.  Both  then  and  later,  there 
were  Plesiomurs  and  Icthyosaurs ;  other  swimming  Saurians,  called 
Polyptychodon  by  Owen,  nearly  fifty  feet  long ;  over  a  dozen  species 
of  Pterodactyls,  one  of  which  was  twenty-five  feet  in  the  spread  of  its 
wings ;  also,  in  the  later  part,  a  Mosasaur,  probably  forty-five  feet  long 
(Fig.  873)  ;  besides  other  large  species. 

Fig.  873. 


Mosasaurus  Hofmanni  ( X  -A?  )• 

Of  the  class  of  Birds,  two  species  have  been  found  near  Cambridge, 
England,  about  as  large  as  Pigeons,  and  probably  related  to  the  Gulls. 

Characteristic  Species. 

1.  Protozoans. —  (a.)    Sponges.  —  Fig.    860,    Siphonin   lobata,   from  the    Chalk- 
Over  one  hundred  species  related  to  the  Sponges  occur  in  the  Cretaceous  strata  of  Eng 
land.     Scyphia,  Sponyia,  and  Ventriculites  are  the  more  common  genera. 

(ft.)  Rhizopods.  —  Fig.  856,  Lituolu  nnutiloidta  Lam.;  Fig.  857,  Flabettina  ntyosa 
D'Orb. ;  Fig.  857  ci,  profile  of  same;  Fig.  858,  Chrysalidina  yradata  D'Orb. ;  Fig.  859, 
Cuneolinaparonia  D'Orb.;  Fig.  859  a,  profile  of  same;  all  much  magnified.  Other  genera 
are  Rotalia,  Textularia,  Nodosaria,  etc.  The  Chalk  formation  of  England  has  afforded 
over  one  hundred  and  twenty  species,  and  between  twenty  and  thirty  genera,  and  among 
them  two  species  of  the  genus  OrUtolina,  an  American  species  of  which  is  represented 
in  Fig.  829. 

2.  Radiates.  —  („.)  Polyp-Corah.  —  Species  of    Cyathina,    Trochocyathw,    Tro- 
chosmilia,  ParasmiUa,  Micrabacia,  etc. 

(b.)  EcMnorlerms.  —  Species  of  the  genera  Ciflans,  Dindema,  Cyphosoma,  Heminster, 
Cardiaster,  Galerites,  Holaster,  Micraster,  etc.;  also  Crinoids,  of  the  genus  Jfarsupites, 
etc. 

3.  Mollusks.  —   (rt.)     Bryozoans.  —  Genera     Kschara,    Escharina,    Vincularia, 
Fhistra,  Cncoporn,  etc. 

(/>.)  JSracJiiopods. — Numerous  species  of  Ttrebratula,  Terebratetta,  Terebratulina, 
Rhynchonella,  Crania,  Thecidea^  etc. 


CRETACEOUS   PERIOD.  475 

(c.)  Lamellibranchs. — Species  of  Gryphcea,  Exogyra,  Inoceramus,  Gerrillia,  Trigo- 
nia,  —  all  extinct;  also  of  Cardium,  Astarte,  Cardita,  Cvrbula,  Isocardia,  Lima,  Crassa- 
tella,  Cyprina,  Cytherea,  Venus  (?),  Lucina,  Panopcen,  Avicula,  Pecten  (?),  Neithea, 
Pholas,  Spondylus,  Tellina,  PKcatula,  and  many  other  genera  of  existing  seas,  which 
give  a  modern  aspect  to  a  conchological  cabinet  of  the  Cretaceous  period.  Among  the 
species  of  the  extinct  tribe  of  Rudistes,  Fig.  862,  IJippurik-s  Timcasianus  D'Orb.,  from 
the  Upper  Cretaceous,  one  of  the  most  common  species  of  southern  Europe ;  Fig.  862  o, 
H.  dilatatus  Defr.,  vertical  view,  showing  the  interior  of  the  lower  conical  valve,  from 
the  Lower  Cretaceous;  Fig.  803,  Radiolites  Bournoni  D'Orb.,  upper  valve  in  profile, 
from  the  Upper  Chalk;  Fig.  864,  Sphcerulites  Hceninyhausi  Desm.,  upper  valve  in  pro 
file,  from  the  Upper  Chalk;  b,  c,  in  863,  864,  attachments  of  muscles. 

((/.)  Gasteropods.  —  The  extinct  genera  Nerincea,  Actatonina,  Actteonella,  Avellana, 
etc.  The  modern  genera  VOLUTA,  Oliva,  FASCIOLARIA,  Ovur,A,  CYPR.EA,  Trochus, 
Nerita,  Natica,  Mitra,  Conus,  Cerithiitm,  Bulla,  etc.,  showing  a  striking  approxima 
tion  to  the  present  age,  in  the  closing  period  of  the  Mesozoic.  (The  genera  in  small 
capitals  are  some  of  those  which  are  supposed  to  have  made  their  first  appearance  in 
the  Cretaceous  period.)  Fig.  865,  Nerincea  bisulcnta  D'Archiac,  from  the  White  Chalk. 
Fig.  866,  Arellana  Cassis  D'Orb.,  from  the  Upper  Green-sand;  «,  outline  sketch,  show 
ing  the  toothed  aperture. 

(e.)  Cephalopods.  —  Ammonites:  Fig.  867,  Crioceras  Duvalii  Leveille,  from  the  Lower 
Cretaceous;  Fig.  868,  Ancyloceras  Matheronianum  D'Orb.,  Lower  Cretaceous;  Fig. 
869,  Hamites  attenuates  Sow.,  Middle  Cretaceous;  Fig.  870,  Toxoceras  bituberculatum 
D'Orb.;  Fig.  871,  Turrilites  catenatus  D'Orb.,  Gray  Chalk.  Also  Baculites  (as  B.  an- 
ceps  Lam.,  etc.).  —  Also  Belemnitella  mucronata  D'Orb.,  a  common  species  of  the  Upper 
Cretaceous;  also  species  of  Belemnites  and  Conoteuthis. 

4.  Articulates. —  Worms   of    several   genera.     Crustaceans,  of   the  Brachyural 
genera,  Grapsus,   Podophthalmus,   Podopilumnus,  Arcania,  Notopocorystes,  etc. :  and  the 
Mac-rural,    Scyllarus,   Cattianassa,  Palceastacus,  etc.     Of  the  tribe  of  Cirripeds,  Tubici- 
nella,  Pollicipes.     Also  Ostracoids. 

5.  Vertebrates.  —  (a.)  Tdiost  Fishes.  —  Fig.  872,  Osmeroides  Lewesiensis  Ag., 
from  the  Chalk  at  Lewes,  — a  fish  of  the  Salmon  family  (Cycloid)  related  to  the  Smelt 
(genus  Osmerus),  and  about  fourteen  inches  in  length.     Another  species  of  the  genus, 
from  the  same  beds,  0.  Mantelli  Ag.,  is  eight  or  nine  inches  long.     There  were  other 
Cycloids,  of  the  genus  Clupea   (Herring),  etc.     Several   species  of  Beryx,  a  genus  re 
lated  to  the   Perch    (Ctenoid),   occur  in  the   Chalk;  one,   B.  Lewesiensis  Dixon,  is  a 
broad  fish,   six  to  twelve  inches  long;  another,   B.  superbus  Eg.,  sometimes  thirteen 
inches  long.     Ganoids  were  numerous   in  species,  of  the  genera  Bdonostomus,  Caturus^ 
Lepidotus,    etc.,    besides   others   of    the    Pycnodont    family,   Pycnodus,    Gyrodus,    etc. 
Sharks  of  the,  Hybodont  family  were  sparingly  represented:  Cestraciont  remains  were 
very  common,  especially  of  the  genera  Ptychodus  and  Acrodus.     Teeth  of  Squalodonts 
are  occasionally  met  with,  of  the  genera  Carchariat,  Lamna,  Oxyrhina,  Odontaspis,  etc. 

(b.)  Reptiles. — Fig.  873,  Mosasnurus  Hofmanni  Mant.,  head  from  the  Chalk  at 
Maestricht,  one  eighteenth  the  natural  size:  a  species  which  has  been  found  also  at 
Lewes  in  England.  In  the  figure,  the  articulation  in  the  lower  jaw  is  concealed  by  the 
fragment  of  a  jaw  overlying  it;  and  hence  its  existence  was  never  found  out  from  the 
study  of  the  specimen. 

Leiodon,  RapJnasturus,  and  Coniosiurus  are  other  genera  of  the  Upper  Cretaceous. 
The  genera  Ichthyosaurus,  Plesiosturus,  and  Pterodactylus  reach  even  into  the  Upper 
Cretaceous :  Jyuanodon  and  Teleosaurus  occur  in  both  Lower  and  Upper  Green-sand 
in  England. 

The  several  divisions  have  the  following  characteristic  fossils:  — 

I.  LOWER  CRETACEOUS.  —  1.  Lower  Green-sand,  or  Neocomian. — Holocystis  elegans 
E.  &  H.,  Toxaster  complanatus  Ag.,  Rhynchonella  Gibbsiana  Dav.,  R.  depressa  D'Orb., 
Tertbratula  sella  Sow.,  Ostrea  Leymerii  Desh.,  Exnyi/ra  sinuata  Sow.,  E.  Couloni 
D'Orb.,  Gervillia  anceps  Desh.,  Myacites  mandibula  Sow.,  Perna  Mulleti  Desh.,  Tri- 
f/onia  dcedalea  Park.,  T.  caudata  Ag.,  Pleurotomaria  yiymtea  Sow.,  Pterocera  Fittoni 


476  MESOZOIC   TIME. 

Forbes,   Ammonites  Martini  D'Orb.,  Ancyloceras  yiyas  D'Orb.,  BeJemnites  dilatatus 
Blainv.,  Ciioceras  Duvaliij  Igu'inodan,  Pterpttutrt,  etc. 

II.  MIDDLE  CRETACEOUS.  —  1.  Gault  (Albian). —  Cyatlina  BowtrbcatJdi  E.  &  H., 
Trochocyathus  Fittoni,  T.  conulus  E.  &  H.,  Trochosmilia  sulcata  E.  &  H.,  Hemiaster 
Baihji  Forbes,  Pentacrinus  Fittoni  Austin;   Inoceramus  concentricus  Park.,  /.  sulcatns 
Park.,  Rostellaria    carinata  Maut.,  Ammonites   dentatus   Sow.,   A.  splaidens  Sow.,  A. 
varicosus  Sow.,  Belemnites  minimus  Lister,  Ilamites  attenuatus  Sow.,  //.  rotundus  Sow., 
Ancyloceras  spiniyer  D'Orb.     In  the  lower  part  (Aptian  or  Speeton  Clay),  Belemnites 
Brunswickensis,  Ammonites  nisus  D'Orb.,  A  venustusPhi\\.,  Plicatula  pl'icunea,  Lain. 

2.  Upper  Green-sand  (Cenomanian). — Siphoniapyriformis  Goldf.,  VerticilUtes  anas- 
tomosans,  Micrabacia  coronal' i  E.  &  H.,  Ifolnsfer  titbglobosiu  Ag.,  H.  carin'itus,  Dia- 
dema  Bennettice  Forbes,  Echinus  granulosus  Miinst.,  Cidaiis  vesiculosa  Goldf.  ;  RJtyn- 
chonella  latissima  Dav.,  Terebratella  pectita  D'Orb.,  Terebratula  bipltcata  Defr.,  Area, 
carinata  Sow.,  Exogyra  columba  Goldf.,  E.  lateralis  Dubois,  Gryphcua  vesiculosa  Sow., 
Ostrea  frons  Park.,  Pecten  asper  Lam.,  Pecten  quinyuecostatus,  Inoceramus  stnatus 
Mant.,  Trigtmia  dcedalea,  Protocardium  Hittunum,  Caprina  adversa.  Ammonites  auritus, 
A.  rostrtitus  Sow.,  A.  Rhotomayensis  Brngt,  A.  rarians,  Sow.;  lyu-.nutdon,  Ttltosaurus, 
Ichthyosauri,  Pliosnurus,  Pterodactyls ;  birds  mentioned  above. 

III.  UPPER  CRETACEOUS.  —  1.  Lower  part  (Turoiiian).  —  Stephanophyllia  Boicerbankii 
E.  &  H.,  Galerites  conicus  Desor,  Ilolaster  subylobosus  Ag.'Inoceramus  mytiloides  Mant., 
/.  Bronyniarti  Sow.,  Exogyra  columba  Goldf.,  Ostrea  frons,  Lima  Hoperi  Desh.  Plica- 
tula  injiata  Goldf.,  Triyonia  scabra  Lam.,  Ammonites  complanatus,  Brngt.,    A.peramplus 
Mant.,  Baculites  anceps,  Bekmnitella  plena  Sharpe,  Ilamites  simplex  D'Orb.,  Scaphites 
equalis  Sow.,  S.  Gtinitzii  D'Orb..  Turrilites  costatus  Lam.;  Dolichosaurus,  IctJiyosaurus, 
Plesiosanrus,  Polyptychodon,  Pterodactylus  Cucieri  Bowerbank. 

2.  Upper  part  of  Upper  Cretaceous  (Senonian).  —  Siphonia  pyriformis,  Choanites 
Koniyii,  Mant.,  Ventriculites  decurrens  Smith,  V.  radiatus  Mant.,  Cristellaria  rotulita 
D'Orb.,  RotaKnaornataMoms,  Ananchytes  ovatus  Lam. ;  Cardiaster  granulosus  Forbes, 
Galerites  albogalerus  Lam.,  Marsupites  ornatus  Miller,  Micruster  Cor-anauinum  Ag.; 
Terebratula  carnea  Sow.,  Ostrea  resicularis  Lam.,  Exogyra  conica  Sow.,  Inoceramus 
Bronyniarti  Sow.,  /.  Cucieri  Sow.,  Hippurites  oryanisans  Desmoulins,  Baculites  anceps, 
Nautilus  Danicus  Schlot.,  Turrilites  polyplocus  R.,  Bekmnitella  muciwita;  Beryx 
Lewesiensis  Mant.,  Osmeroides  Lewesiensis  Ag.,  Mosasaur,  etc. 

Species  of  Wide  Geographical  Distribution. 

The  following  species  are  reported  from  different  continents  (Bronn):  — 

Ostrea  larva,  North  America;  Europe;  India.  Gryphcea  resicularis,  North  America; 
Europe;  southwest  Asia.  Exogyra  leriyata  Sow.,  Europe;  Columbia,  South  America. 
Exogyra  Boussingaullii  D'Orb.,  Europe;  Columbia,  South  America.  Inoceramus  Crispii 
Mant.,  North  America;  Europe.  Inoceramus  latus  Mant.,  North  America;  Europe. 
Inoceramus  mytiloides  Mant.,  North  America;  Europe.  Neitliea  Mortoni,  North  Amer 
ica;  Europe;  India;  Peru,  South  America.  Pecten  circitliris  Goldf.,  North  America; 
Europe;  India;  Peru,  South  America.  Triyonia  limbata  D'Orb.,  North  America; 
Europe;  India.  Triyonia  aliformis  Sow.,  North  America;  Europe;  southwest  Asia; 
Columbia,  South  America.  Triyonia  longa  Ag.,  Europe;  Columbia,  South  America. 
Hi/jpurites  oryanisans,  Europe;  southwest  Asia;  Peru  and  Chili,  South  America. 
Nerincea  bisulcata  D'Arch.,  North  America  (Texas);  Europe.  Baculites  anceps,  North 
America;  Europe;  Chili,  South  America.  Ammonites  respertinus  Mort.,  North  America; 
Europe. 

The  following  Ammonites,  according  to  D'Orbignv,  are  common  to  Europe  and  South 
America:  A.  Boyotensis  Forbes,  A.  Dumnsimus  D'Orb.,  A.  Didayanus  D'Orb.,  A. 
galeatus  Buch.,  A.  Vandeckii  D'Orb.,  A.  TethyslVOrb.,  A.  prtelonya,  A.  simplus  D'Orb., 
besides  others.  The  Echinoid  Toxaster  complanatus  Ag.  &  D.  is  said  to  have  the  same 
range. 

The  following  table  of  species  in    the  Earlier   and  Later  Cretaceous  of  America, 


CRETACEOUS   PERIOD.  477 

•showing  their  relations  to   species  of  the  corresponding  divisions  in  Europe,  is  from  a 
paper  by  Meek  &  Hayden :  — 

Earlier  Cretaceous  W.  of  Miss.  R.  Lower  or  Gray  Chalk  in  Europe. 

Ammonites  respertinus  Mort.          occurs  in  Austria. 

A.  percarinatus  H.  &  M.  probably  identical  with  A.  Woolyari  Mantell. 

Scaphites  Warreni  M.  &  H.          scarcely  distinct  from  S.  cequalis,  Sowerby. 

S.  Inrvceformis  M.  &  H.  same  type  as  S.  aiyualis. 

Nautilus  eleyans,  var.  scarcely  distinct  from  N.  eleyans  Sowerby. 

Inoceramus  latus  (?)  appears  to  be  the  same  as  /.  latus  Mantell. 

Lproblematicus  cannot  be  distinguished  from  1.  probkmaticus 

Schlot.;  reported  also  from  thy  Upper  Green- 
sand  of  Europe. 

Species  common  to  the  Later  Cretaceous  of  America  and  the  Upper  or  White  Chalk 
of  Europe:  Saurocephalus  lundformis  Harlan,  Lamna  acuminata  Ag.,  Belemnitella 
mucronata,  Neithea  Mortoni,  Ostrea  larra,  Gryphvea,  lateralis,  Gryphcea  vesicularis, 
Nuchjolites  crucifer  Mort.  The  Crryphcea  vesicularis  is  supposed  by  some  to  occur  also 
in  the  Upper  Green  sand  and  the  Lower  or  Gray  Chalk;  but  the  form  found  in  these 
lower  portions  is  regarded  by  other  authorities  as  a  distinct  species. 

Genera  of  the  Later  Cretaceous  of  America  not  yet  found  below  the  White  Chalk 
of  Europe :  Mosasaurus,  Saurocephalus,  Cattia.nassa,  Pleurotoma,  Fasciolaria,  Cyprcea 
Pulvinites,  Cassidulus.  There  are  also  in  the  American  Later  Cretaceous  the  t\vo 
genera  Pseudcbuccinum  and  Xi/lophaya  (?),  which  have  not  yet  been  found  as  low  as 
the  Cretaceous  in  Europe. 

3.  GENERAL  OBSERVATIONS. 

1.  Origin  of  the  Chalk  and  Flint.  —  From  the  absence  of  vegetable 
remains  and  earthy  ingredients,  the  abundance  of  sponges,  and  the 
relations  of  the  fossils  to  species  now  found  in  the  deep  Atlantic,  it  is 
supposed  that  the  Chalk  was  formed  at  a  distance  of  some  miles  from 
shore,  where  the  water  was  at  least  several  hundred  fathoms  deep. 
The  abundance  of  Rhizopod  shells,  as  already  stated,  suggests  that 
these  were  the  main  material  ;  and  the  recent  observation  that  the 
lead  in  deep-sea  soundings  over  the  north  Atlantic  has  often  brought 
up  sand  composed  almost  wholly  of  minute  Rhizopods,  as  first  an 
nounced  by  Bailey,  sustains  the  conclusion.  These  shells  are  like 
grains  of  sand  in  size,  and  are,  therefore,  ready  for  consolidation  into  a 
compact  rock,  needing  no  previous  trituration  by  way  of  preparation  ; 
and  thus  they  are  especially  fitted  for  making  deep-water  limestones. 
In  the  Atlantic,  the  mud  of  the  bottom,  where  not  over  2.500  fathoms 
in  depth,  is  often  eighty-five  per  cent,  the  shells  of  Globigerina,  the 
kind  of  Rhizopod  represented  in  Fig.  171  ;  the  most  common  species 
is  G.  bulloides.  The  softness  or  imperfect  aggregation  of  Chalk  is 
probably  due  to  this  origin,  and  particularly  to  the  fact  that  each  grain 
is  a  cellular  shell,  or  collection  of  air-cells,  instead  of  solid.  The  coral 
reefs  of  the  Pacific  do  not  under  ordinary  circumstances  give  rise  to 
chalk.  The  only  chalk  known  in  coral  regions  is  on  Oahu,  at  the  foot 
of  an  extinct  volcanic  cone ;  and  there  it  is  probable  that  warm  waters 


478  MESOZOIC   TIME. 

had  some  connection  with  its  origin.  Chalk  appears  to  have  been 
forming  over  the  bottom  of  the  ocean,  where  the  depth  does  not  ex 
ceed  15,000  feet,  ever  since  the  Cretaceous  era,  and  probably  from  a 
period  long  anterior  to  this. 

The  Flint,  as  stated  on  page  471,  has  been  attributed  to  the  siliceous 
Infusoria  of  the  same  waters  and  the  spicula  of  Sponges.  In  the 
soundings  of  various  seas,  microscopic  siliceous  shells  of  Infusoria 
(Diatoms  or  Polycystines)  are  as  abundant  as  the  Rhizopods  in  the  At 
lantic,  which  favors  strongly  this  opinion.  There  are  microscopic  float 
ing  sponges,  that  becloud  the  sea-waters  at  times,  as  well  as  the  large 
siliceous  and  more  common  kinds,  all  of  which  may  have  contributed 
to  the  result.  The  minute  portion  of  silica  which  the  alkaline  waters 
of  the  ocean  can  dissolve  —  especially  when  the  silica  is  in  what  is 
called  the  soluble  state  (p.  o3),  as  is  usual  in  these  microscopic  organ 
isms  —  gives  an  opportunity  for  that  slow  process  of  concretion  which 
might  result  in  the  flints  of  the  Chalk.  And  the  tendency  to  aggrega 
tion  around  some  foreign  body  as  a  nucleus,  especially  when  such  a 
body  is  undergoing  chemical  change  or  decomposition,  explains  the 
frequent  occurrence  of  fossils  within  flints,  and  the  silicification  of 
shells. 

2.  American  Geography  —  The  Cretaceous  beds  of  New  Jersey 
and  of  the  rest  of  the  border  region  of  the  continent,  east  and  south, 
show,  in  their  structure  and  position,  and  in  the  character  of  their  fos 
sils,  that  they  were  formed  either  along  a  sea-coast  or  in  off-shore  shal 
low  waters.  The  limestones  of  Texas  indicate  a  clearer  sea ;  while 
the  soft  sandy  and  clayey  formations  to  the  north  and  northwest  are 
evidence  that  the  same  sea  spread  in  that  direction,  but  was  mostly  of 
diminished  depth.  In  the  closing  part  of  the  Cretaceous,  in  the  Rocky 
Mountain  region,  there  was  a  change  permanently  from  a  condition  of 
general  submergence  under  salt  water,  to  one  of  oscillations  between 
emergence  and  submergence ;  and  this  condition  continued  on  through 
a  long  era  in  the  Eocene  Tertiary,  if  the  Coal  series,  excepting  the 
lowest  part,  is  of  that  age. 

The  outline  of  the  Cretaceous  formation  over  the  continent  points 
out  approximately  the  outline  of  the  sea  in  the  Cretaceous  period,  and 
the  general  form  of  the  dry  land.  This  is  presented  to  view  in  the 
accompanying  map,  in  which  the  white  part  is  the  dry  land  of  the  con 
tinent,  and  the  shaded  the  Cretaceous  area,  and  therefore  the  sub 
merged  portion. 

The  line  qf  the  coast  on  the  east  extended  from  a  point  in  New 
Jersey,  to  the  southeast  of  New  York  City,  across  to  the  Delaware 
River,  whose  course  it  followed  :  this  river,  therefore,  emptied  into 
the  Atlantic  at  Trenton  ;  and  the  regions  of  the  Delaware  and  Chesa- 


CRETACEOUS   PERIOD. 


479 


peake  bays  were  out  at  sea.     From  the  Delaware,  it  continued  south- 
westward,  at  a  distance  of  sixty  miles  or  more  from  the  present  coast- 


Fig.  874. 


North  America  iu  the  Cretaceous  period;  MO,  Upper  Missouii  region. 

line  between  New  Jersey  and  South  Carolina.  It  next  turned  west 
ward,  being  about  one  hundred  miles  from  the  Atlantic  in  Georgia, 
nearly  two  hundred  miles  from  the  Gulf  in  Alabama,  and  still  more 
remote  from  the  Western  Gulf  shore  in  Texas.  The  Appalachians 
stood  at  a  less  elevation  than  now,  by  sixty  to  six  hundred  feet. 

The  Gulf  of  Mexico,  as  the  map  illustrates,  was  prolonged  north 
ward,  along  the  valley  of  the  Mississippi,  nearly  to  the  mouth  of  the 
Ohio,  making  here  a  deep  bay.  Into  it  the  two  great  streams  entered, 
with  only  the  mouth  in  common  ;  and  probably  the  Ohio  was  the 
larger,  as  its  whole  \vater-shed  had  nearly  its  present  elevation  and 
extent,  while  the  Mississippi  area  was  very  limited.  More  to  the 
westward,  from  the  region  of  Texas,  the  Gulf  expanded  to  a  far 
greater  breadth  and  length,  stretching  over  much  of  the  Rocky  Moun 
tain  region,  which  was  therefore  so  far  submerged.  It  reached  sit 
least  to  the  head-waters  of  the  Yellowstone  and  Missouri  (which 
rivers  were,  therefore,  not  in  existence)  ;  and,  judging  from  isolated 
observations  in  British  America,  the  waters  may  have  continued  north- 


480  MESOZOIC   TIME. 

westward  to  the  Arctic  seas,  at  the  mouth  of  Mackenzie  River,  where 
beds  of  this  period  occur. 

This  Cretaceous  Mediterranean  Sea  spread  westward  among  several 
of  the  elevations  of  the  Rocky  Mountain  summits ;  and,  in  New 
Mexico,  it  spread  still  farther  westward,  over  the  region  of  the  Upper 
Colorado,  to  or  beyond  the  meridian  of  113°  AV.  In  California,  it 
covered  the  region  west  of  the  base  of  the  Sierra  Nevada. 

By  comparing  the  above  map  with  that  of  the  Archaean  (p.  149),  it 
is  seen  that  the  continent  had  made  great  progress  since  the  opening 
of  the  Silurian  age.  But,  as  all  this  Cretaceous  area  was  under  Cre 
taceous  seas,  much  was  still  to  be  added  to  the  permanent  dry  land 
before  its  completion. 

The  great  Interior  Continental  basin,  which  had  been  a  limestone- 
making  region,  for  the  most  part,  from  the  earliest  period  of  the  Si 
lurian,  was  still,  in  its  southern  part,  —  that  is,  in  Texas,  —  continuing 
the  same  work  ;  for  limestones  eight  hundred  feet  thick  were  there 
formed.  To  the  north  of  Texas,  where  the  waters  were  shallower, 
there  appear  to  have  been  none  of  the  Echinoderms,  Corals,  Orbi- 
tolinag,  etc.,  which  were  common  in  Texas. 

3.  Foreign  Geography.  —  The  distribution  of  the   Cretaceous  beds 
over  other  continents  shows  that  the  lands  were  to  a  great  extent  sub 
merged.     The  sea  covered  a  large  part  of  the  region  of  the  Andes,  as 
well  as  of  the  Rocky  Mountains  ;    and  large  portions  of  both  chains 
were  not  yet  raised   into   mountain-shape :  the  Alps,  Pyrenees,  and 
Himalayas  were  partly  under  water,  or  only  in  their  incipient  stages  of 
elevation.     Europe  was   mostly  a  great  archipelago,  with  its  largest 
area  of  dry  land  to  the  north  ;  it  resembled  North  America  in  the 
latter  point,   while  widely  differing  in  the  former.     The  Urals  and 
Norwegian  mountains   were  the  principal    ranges  of  Europe,  as  the 
Appalachians  and  the  Laurentian  heights  of  Canada  and  beyond  were 
in  America.     Western  Britain  was  the  high  land  of  that  region  ;  and, 
under  its  lee  and  that  of  other  lands  southwestward  across  the  Chan 
nel,  the  new  formations  of  eastern  England  and  northern  France  were 
in  progress  in  deep  waters  bordering  the  German  Ocean. 

4.  Climate.  —  The  geographical  distribution  of  species  indicates  a 
prevalence  of  warm  seas  in  the  northern  hemisphere  to  the  parallel  of 
60°,  and  in  the  southern  to  the  Straits  of  Magellan.     For  the  table  on 
page  476  shows  that  several  species  are  common  to  Britain,  Europe, 
and  either  equatorial  America,  India,  or  the  United  States.    The  survey 
of  the  life  of  the  period,  therefore,  so  far  as   now  known,  affords  no 
evidence  of  the  existence  of  the  present  cool  temperature  in  the  waters 
of  the  temperate  zone. 

The  corals  of  the  Cretaceous  beds  in  England  may  be  those  of  cool 


CRETACEOUS    PERIOD.  481 

seas  ;  but  the  coral  reefs  of  central  and  southern  Europe  show  that  a 
large  part  of  that  continent  was  within  the  Cretaceous  coral  seas,  or 
what  is  called  the  sub-torrid  zone  on  the  map  of  oceanic  temperature. 
The  warming  influence  of  the  Gulf  Stream  was  less  than  in  Jurassic 
times  (p.  452).  The  present  position  of  the  winter  line  of  48°  F.,  if 
drawn  on  the  Physiographic  chart,  would  probably  run  near  that  oc 
cupied  by  the  line  of  68°  F.  in  the  latter  part  of  the  Cretaceous  period, 
except  that  the  submergence  of  much  of  Europe  would  have  given 
a  very  different  sweep  to  the  Gulf  Stream. 

The  occurrence  of  a  group  of  stones  in  the  white  chalk  of  southern 
England,  the  largest  of  syenyte  and  weighing  forty  pounds,  appears  to 
indicate,  as  Mr.  Godwin  Austin  states,  that  there  must  have  been  float 
ing  ice  in  the  sea  at  times. 

There  is  a  difference,  in  the  later  Cretaceous,  between  the  species 
of  northern  and  southern  Europe,  arid  also  between  those  of  the 
northern  and  southern  United  States,  as  explained  on  page  478 ;  and 
this  difference  is  probable  due  to  diversity  of  temperature.  There  is 
a  wide  difference  in  North  America,  in  the  life  of  the  two  regions, 
Texas  and  the  Upper  Missouri ;  but,  as  Meek  has  remarked,  this  may 
be  largely  owing  to  the  difference  in  the  horizon  of  the  beds,  and  also 
to  that  of  the  clearness  or  purity  of  the  waters. 

4.  GENERAL   OBSERVATIONS   ON   THE   MESOZOIC. 
I.  Time-ratios. 

An  estimate  of  the  comparative  lengths  of  the  Paleozoic  ages  is 
given  on  page  381.  According  to  it,  the  lengths  of  the  Silurian, 
Devonian  and  Carboniferous  Ages  are  approximately  as  the  ratio  4 : 
1:1.  The  facts  in  European  geology  lead  to  probably  the  same  re 
sult  ;  the  doubt  arises  from  the  uncertain  thickness  of  the  Primordial 
rocks. 

The  thicknesses  of  the  Mesozoic  formations  lead,  in  a  similar  man 
ner,  to  the  time-ratio  for  the  Paleozoic  and  Mesozoic  nearly  4 :  1,  and 
for  the  Triassic,  Jurassic,  and  Cretaceous  approximately  1  :  1^  :  1. 

II.  Geography. 

Through  the  Mesozoic,  North  America  was  in  general  dry  land ; 
and  on  the  east  it  stood  a  large  part  of  the  time  above  its  present 
level.  Rocks  were  formed  on  its  southeastern  and  southern  border, 
and  over  its  great  Western  Interior  or  Rocky  Mountain  region. 
Europe,  at  the  same  time,  was  an  archipelago,  varying  in  the  extent 
of  its  dry  lands,  with  the  successive  periods  and  epochs.  Rocks  were 


, 


482  MESOZOIC    TIME. 

in  progress  along  its  more  southern  borders,  and  through  its  interior 
seas. 

In  Eastern  America,  and  partly  in  Western,  but  few  marked  subdi 
visions  of  the  formations  can  be  made  out,  the  Triassic  and  Jurassic 
making  seemingly  one  continued  series,  and  the  Cretaceous  another, 
with  three  or  four  subordinate  divisions.  In  Europe,  the  number  of 
epochal  changes,  or  abrupt  transitions  in  the  rocks,  is  large,  —  much 
more  so  than  in  the  Carboniferous  age. 

In  Eastern  America,  there  is  but  little  limestone  and  little  evidence 
of  clear  interior  seas,  except  in  the  closing  epoch  of  the  Cretaceous  in 
Texas,  and  some  thin  interpolations  in  the  earlier  formations  ;  and  in 
Western,  there  is  less  of  limestone  in  the  interior  region  than  of  frag- 
mental  rocks.  In  Europe,  the  Lias  and  a  large  part  of  the  Oolite  and 
Chalk  are  limestone  formations. 

The  facts  indicate  great  simplicity  in  the  oscillations  of  North 
America,  and  remarkable  complexity  and  diversity  of  extent  in  those 
of  Europe. 

III.  Life. 

The  following  are  some  of  the  facts  illustrating  the  general  steps  in 
the  progress  of  life  during  the  Mesozoic  era :  — 

PLANTS.  —  Instead  of  forests  of  Conifers,  Tree-ferns,  and  Lyco- 
pods  (Lepidodendra,  etc.),  as  in  the  Carboniferous,  there  were  forests 
of  Conifers,  Tree-ferns,  and  Cycads  ;  and  finally,  in  the  Cretaceous 
period,  these  forests  included  also  Angiosperms  and  Palms.  The  type 
of  Cycads  culminated  in  the  Mesozoic,  and  afterward  had  relatively 
few  representatives. 

ANIMALS. — 1-  Radiates.  —  Corals  of  the  Paleozoic  type,  having 
the  parts  multiples  of  four  in  number,  the  Cyathophylloids,  were  almost 
wholly  wanting,  while  those  of  the  modern  Astraea  type,  having  the 
rays  a  multiple  of  six,  abounded. 

Among  Echinoderms,  Crinoids,  so  abundant  and  important  as  rock- 
makers  in  the  Paleozoic,  were  comparatively  little  numerous,  while 
Echinoids  and  Starfishes  were  common. 

Mollusks.  —  Brachiopods  were  vastly  inferior  in  number  of  indi 
viduals  to  other  higher  species  ;  and  the  kinds  which  existed,  as  the 
Terebratulce,  etc.,  were  inferior  to  those  of  earlier  time,  the  type  of 
Brachiopods  having  culminated  in  the  Paleozoic  era. 

Gasteropods  were,  to  a  considerable  extent,  of  modern  genera ;  but, 
unlike  the  moderns,  the  higher  siphonated  species  (those  having  the* 
aperture  of  the  shell  beaked),  as  well  as  the  siphonated  Lamellibranchs, 
were  in  the  minority,  these  groups  culminating  in  a  subsequent  era. 

Among  modern  genera,  the  following  occur  in  the.  Jurassic:  Rimula,  Planorbis,  Palti- 


MESOZOIC    TIME.  483 

dinn,  Melanin  (f),  Nerita,  Pterocera,  7V/m'/,  Corbis,  Anomia,  etc.  Tn  the  Cretaceous: 
Xeitliea,  Crass-itella,  Axincea  (Pectunculus),  Petricola,  Venus  (?),  OHvrt,  Ovula,  Cyprcea, 
Voluta,  Turns  (Pleurotoma),  Pseudobuccinum,  etc. 

Cephalopods,  the  highest  of  Mollusks,  culminated  in  the  Mesozoic ; 
and,  in  their  culmination,  the  culmination  of  the  grand  type  of  Mol 
lusks  took  place.  This  fact  is  strikingly  exhibited  in  the  history  of 
the  Ammonite  and  Belemnite  groups.  The  genus  Goniatites,  a  Pal 
eozoic  form  of  the  Ammonite  type,  ended  in  the  Triassic ;  but  before 
this  the  earliest  Ammonites  had  already  appeared  ;  arid  these  continued 
afterward  to  increase  in  variety  and  numbers  through  the  Mesozoic. 
Nearly  1,000  species  of  the  Ammonite  family  have  been  found  fossil 
in  the  Mesozoic  rocks.  Besides  these,  the  Belemnite  family  —  charac 
terized  by  an  internal  shell  —  commenced  in  the  epoch  of  the  Lias  ; 
and  over  1 20  of  its  species  have  been  gathered  from  the  Jurassic  and 
Cretaceous  strata.  There  were  also  many  species  of  Nautilus.  In 
existing  seas,  there  are  only  four  species  of  chambered  external  shells  ; 
and  these  belong  to  this  latter  genus.  The  Ammonite  and  Belemnite 
families  died  out,  or  nearly  so,  with  the  close  of  the  Cretaceous  period, 
It  is  to  be  noted  that  the  above  are  the  numbers  of  species  of  cham 
bered  shells  found  fossil:  it  may  be  but  a  small  part  of  those  which 
were  actually  in  the  waters  of  the  era.  The  age  was  therefore  re 
markable  for  the  great  expansion  of  the  type  of  Cephalopods. 

The  type  began  in  the  straight  Orthoceras,  with  plain  septa,  and 
the  half-coiled  and  equally  simple  Lituites  of  the  Lower  Silurian  ;  it 
reached  its  maximum  in  the  large  and  complex  Ammonite  of  the  Ju 
rassic,  and  the  associated  Belcw.nite  and  Cuttle-fishes  ;  it  declined  in 
the  later  Mesozoic,  through  the  multiplication  of  the  half- coiled  forms 
of  the  Ammonite  family  (p.  462)  and  the  straight  Bacidite  ;  and,  at 
the  close  of  the  period,  there  was  a  sudden  disappearance  of  genera 
and  species.  Whether  any  of  the  modern  Cuttle-fishes  (Dibranchs) 
are  equal,  or  superior,  to  the  highest  Cephalopods  of  the  Jurassic,  it 
is  difficult  to  determine.  The  modern  genus  Nautilus  —  representing 
the  chambered  species  (Tetrabranchs)  —  is  certainly  of  far  lower 
grade  than  the  Jurassic  Ammonite. 

It  is  therefore  one  of  the  great  facts  connected  with  the  Mesozoic 
era  that, in  its  later  half, the  sub-kingdom  of  Mollusks  passed  its  period 
of  culmination.  But,  while  this  is  true  of  the  sub-kingdom  as  a 
whole,  it  is  not  true  of  each  of  its  subdivisions  ;  for  the  inferior  tribes 
of  Lamellibranchs  and  Gasteropoda  continue  on  the  rising  grade 
through  the  Mesozoic,  and  probably  have  their  maximum  display  at 
the  present  time. 

Articulates.  —  The  class  of  Crustaceans  rose  to  Macrurans 
(Shrimps  and  Lobsters)  and  true  Crabs  ;  and  among  the  latter  all  the 
higher  divisions  were  represented.  The  class  of  Insects  was  also  un- 


484  MESOZOIC    TIME. 

folded,  even  to  its  highest  tribe,  that  of  Hymenopters,  species  of  this 
group,  related  to  the  bee,  having  occurred. 

Vertebrates.  —  Fishes. —  Ganoids  and  Selachians  (or  fishes  of  the 
Shark  tribe)  continued  to  be  predominant  kinds  through  the  era ;  but 
the  higher  type  of  Teliosts  (or  common  osseous  fishes)  appeared  in 
the  Jurassic,  and  included  many  species  in  the  Cretaceous. 

The  Ganoids  lost,  in  the  Triassic,  the  Paleozoic  feature  of  verte- 
brated  tails  ;  and  this  is  a  mark  of  progress  ;  for  it  is  an  example  of 
that  abbreviation  of  the  posterior  extremity  which  generally  marks 
elevation  in  grade  as  well  as  progress  in  embryonic  development.  In 
tho  Jurassic  period,  the  number  of  species  of  Ganoids  reached  its 
maximum,  arid  also  the  diversity  of  generic  forms ;  and  this  therefore 
was  their  period  of  culmination.  The  Ganoids  are  at  present  nearly 
an  extinct  tribe. 

The  tribe  of  Sharks  was  numerously  represented  by  large  species 
of  the  Hybodont,  Cestraciont,  and  other  groups ;  and  the  family  of 
Cestracionts,  those  having  a  pavement  of  bony  pieces  in  the  mouth, 
for  mastication,  appears  to  have  passed  its  maximum  in  the  Creta 
ceous  :  it  is  now  nearly  extinct.  But  the  highest  species  of  the  Sela 
chians  existed  later  in  the  Tertiary. 

Reptiles.  —  The  scale-covered  Amphibians,  called  Labyrinthodonts, 
which  first  appeared  in  the  Carboniferous  age,  had  gigantic  species  in 
the  Triassic,  and  none  afterward,  so  far  as  known.  The  type  of 
Amphibians  therefore  culminated  in  the  Triassic,  the  Labyrinthodonts 
being  its  highest  species.  We  have  now  among  Amphibians  only  the 
little,  naked-skinned  Frogs  and  Salamanders. 

Of  true  Reptiles,  all  the  grand  divisions  of  the  class  were  displayed ; 
and  the  type  culminated  in  this  era. 

The  Enaliosaurs  or  Swimming  Saurians  of  the  Triassic —  the 
Nothosaur  type  —  had  the  open  skull  of  a  Batrachian  ;  but,  in  the 
Jurassic,  the  group  rose  to  the  higher  grade  of  the  Ichthyosaurs  and 
Plcsiosaurs ;  and  there  were  several  genera  and  numerous  species  : 
with  the  Cretaceous,  the  species  disappeared. 

The  Lacertians  commenced,  perhaps,  in  the  Carboniferous,  and  the 
Crocodilians  in  the  Permian,  in  species  with  the  ichthyic  characteristic 
of  biconcave  vertebra?,  and  retained  it  through  the  Triassic  and  in  some 
Jurassic  species.  In  the  Jurassic  and  Cretaceous,  the  Crocodilians  came 
forth  in  many  other  species  of  great  size,  without  this  low  feature. 

Snake-like  Reptiles  occurred,  of  enormous  size,  in  the  Mosasaur 
tribe,  and  with  articulated  jaws,  precursors  of  our  modern  smaller 
snakes. 

The  Saurian  type  in  the  Jurassic  rose  to  the  grade  of  Dinosaurs, 
the  highest  in  rank,  and  among  the  largest  of  Reptiles  ;  and  these  all 
disappeared,  by  or  soon  after  the  close  of  the  Cretaceous  period. 


MESOZOIC    TIME.  485 

There  was  also  an  expansion  of  the  type  to  flying  farms,  the  Ptero 
saurs,  in  the  Jurassic  ;  and  this  type  continued  into  the  Cretaceous, 
but  then  ended. 

Thus,  in  all  the  grand  divisions,  there  was  a  culmination  and  de 
cline.  The  Reptilian  type  was  unfolded  in  its  complete  diversity  : 
the  sea,  air,  and  earth  had  each  its  species  ;  and  there  were  both  grazing 
and  carnivorous  kinds,  of  large  and  small  dimensions.  Not  only  every 
species,  but  also  every  Mesozoic  genus,  with  perhaps  one  or  two  ex 
ceptions,  became  extinct  at  or  near  the  close  of  the  era. 

'  The  reality  of  this  Reptilian  feature  of  the  age  will  appear  from  a 
comparison  of  England  as  it  was  in  Reptilian  times  with  England  as 
it  is,  or  with  all  the  world. 

In  a  single  era,  that  of  the  Wealden  and  Lower  Cretaceous,  —  for 
the  two  were  closely  related  in  vertebrate  species,  —  there  were,  in  the 
British  dominions  of  sea  and  land,  four  or  five  species  of  Dinosaurs, 
twenty  to  fifty  feet  long,  ten  or  twelve  Crocodilians,  Lacertians,  and 
Enaliosaurs,  ten  to  fifty  or  sixty  feet  long,  besides  Pterodactyls  and 
Turtles.  As  only  part  of  the  species  in  existence  would  have  left 
their  remains  in  the  rocks,  it  would  be  evidently  no  exaggeration  to 
increase  the  above  numbers  two  or  three  fold.  But,  taking  them  as 
made  out  by  actual  discovery,  the  facts  arc  sufficient  to  establish  the 
contrast  in  view.  For,  since  Man  appeared,  there  is  no  reason  to 
believe  that  there  has  been  a  single  large  Reptile  in  Britain.  In 
India,  or  the  Continent  of  Asia,  there  are  but  two  species  over  fifteen 
feet  long  ;  in  Africa,  but  one ;  in  all  America,  but  three ;  and  not 
more  than  six  in  the  whole  world  ;  and  the  length  of  the  largest  does 
not  exceed  twenty -five  feet.  The  number  of  living  species  exceeding 
ten  feet  in  length,  is  only  sixteen  or  eighteen. 

The  Galapagos  Islands  are  strikingly  Reptilian  at  the  present  time. 
But  they  afford  only  four  Lizards,  as  many  Snakes,  a  Turtle,  and  a 
large  Tortoise.  The  largest  of  the  lizards,  an  aquatic  species,  of  the 
genus  Amblyrhynchus  (having  feet,  however,  instead  of  paddles),  is  but 
three  to  four  feet  long. 

If  so  large  a  number  of  species  as  above  mentioned  existed  in  Brit 
ain  arid  its  vicinity  during  the  age  of  Reptiles,  what  should  be  the 
estimate  for  the  whole  world  at  that  time  ?  The  question  is  a  good 
one  for  consideration,  although  no  definite  reply  can  be  looked  for. 

As  in  the  case  of  Mollusks,  the  culmination  of  the  grand  type  does 
not  imply  a  culmination  of  all  its  subdivisions.  There  is  no  evidence 
that  the  Mesozoic  species  of  Turtles  are  superior  in  grade  to  those  of 
the  Cenozoic  and  the  present  age. 

Birds.  —  Birds  probably  began  in  the  Triassic,  for,  although  the 
evidence  from  tracks  in  the  Connecticut  Valley  Sandstone  is  doubtful, 


486  MESOZOIC   TIME. 

it  is  not  directly  opposed  to  their  existence  ;  and,  further,  it  is  highly 
improbable  that  Mammals,  the  superior  type  of  Vertebrates,  should 
have  existed  before  Birds.  In  the  Jurassic,  the  occurrence  of  species 
is  beyond  question  ;  and  some  of  them,  if  not  all,  had  that  striking 
mark  of  inferiority,  a  long  vertebrated  tail,  along  with  some  other 
peculiarities  that  allied  them  to  Reptiles,  and  especially  to  the  three- 
toed  Dinosaurs.  In  the  Cretaceous  era,  the  species  were  evidently 
numerous  ;  and  the  most  were  of  modern  type.  But  among  them 
were  kinds  with  teeth  and  biconcave  vertebra?,  which  were  probably 
allied  to  the  Jurassic  birds. 

Mammals.  —  The  class  of  Mammals  began  in  the  Triassic,  according 
to  present  knowledge,  with  species  of  the  inferior  tribe  of  Marsupials ; 
arid  the  same  continued  to  be  the  prevailing  kind  through  the  rest  of  the 
Mesozoic.  It  is  questioned  whether  there  may  riot  have  been  among 
them  some  species  of  Insectivores  (the  group  to  which  the  Mole  and 
Shrew  belong) :  but  no  higher  species  of  ordinary  Mammals  than 
these  have  yet  afforded  even  doubtful  evidence  of  their  existence. 
The  Mammals  were  evidently  far  inferior  in  size  and  numbers,  and  in 
grade  of  life,  to  the  Reptiles  of  the  era. 

IV.  Disturbances  during  Mesozoic  Time. 

In  American  history,  the  displacements  of  the  beds  of  the  Triassic 
or  Triassico-Jurassic  areas  on  the  Atlantic  Border,  and  the  multitudes 
of  trap-dikes,  which  intersect  these  areas,  indicate  that  their  deposition 
was  followed  by  an  epoch  of  disturbance.  The  facts,  and  the  con 
clusions  from  them,  are  stated  on  page  417.  The  time  was  either  in 
some  part  of  the  Jurassic  period,  or  at  its  close.  The  beds  next  in  age 
along  the  Atlantic  Border,  the  Cretaceous,  did  not  participate  in  the 
upturning  ;  and  thus  it  is  known  that  the  ejections  of  trap  took  place 
anterior  to  the  era  they  represent.  The  facts  (1)  that  the  trap-dikes 
are  mostly  confined  to  the  sandstone  areas  ;  (2)  that  they  consist  of 
the  same  kind  of  dolerytic  rock  throughout,  and  (3)  that  the  areas 
and  the  fractures  are  parallel  to  the  preexisting  Appalachian  chain, 
have  been  pointed  to  as  evidence  that  all  belong  to  one  continental 
mountain-making  movement. 

West  of  the  Rocky  Mountain  summit,  the  close  of  the  Jurassic 
was  the  epoch  of  some  of  the  grandest  disturbances  in  the  Earth's 
history,  —  those  in  which  the  lofty  Sierra  Nevada,  the  Humboldt 
ranges,  the  Wahsatch  and  the  Uintah  Mountains  were  made  (p.  452). 
No  unconformability  between  the  Triassic  and  Jurassic  strata  has  been 
there  observed. 

The  Cretaceous  strata  of  North  America  are  throughout  conform 
able.  The  positions  of  the  successive  beds  indicate  some  oscillations 


CRETACEOUS    PERIOD.  487 

of  level ;  and  their  thickness,  —  10,000  feet  in  the  Rocky  Mountain 
region,  and  half  that  in  California,  —  is  proof  of  profound  subsidences 
in  progress  ;  but  all  went  on  regularly  and  without  intervening  dis 
turbances. 

In  Europe,  during  the  progress  of  the  Mesozoic,  the  rocks,  Triassic, 
Jurassic,  and  Cretaceous,  appear  to  have  been  laid  down  for  the  most 
part  conformably,  with  few  examples  of  non-concordance,  yet  with 
those  variations  in  their  distribution  that  arise  from  variations  of  the 
ocean's  level,  as  a  consequence  of  gentle  heavings  of  the  earth's  crust. 
There  were  thus  elevations  and  depressions  producing  the  varying 
geography  of  the  age,  and  successive  destructions  of  species  attending 
them,  so  that  only  a  very  small  number  of  Liassic  species  has  been 
found  in  the  Oolyte,  and  less  than  a  dozen  of  the  Jurassic  in  the  Cre 
taceous  ;  while  also  many  subordinate  eras  were  separated  by  epochs 
of  destruction. 

A  disturbance  took  place,  between  the  Triassic  and  Jurassic  periods, 
in  the  region  of  the  Thuringian  Forest  and  the  frontiers  of  Bohemia 
and  Bavaria,  the  Jurassic  beds  overlying  unconformably  the  Triassic. 
This  system  of  uplifts  is  named  by  De  Beaumont  the  System  of  the 
Thuringian  Forest ;  and  the  trend  mentioned  is  N.  50°  W.  Again, 
between  the  Jurassic  and  Cretaceous,  was  formed  De  Beaumont's 
System  of  the  Cote  U Or,  having  the  trend  N.  50°  E. 

The  rocks  of  the  Cretaceous  and  Jurassic  are  very  nearly  hori 
zontal,  in  the  great  Anglo-Parisian  region  —  the  part  of  the  German 
Ocean  basin  now  exposed  to  view. 

5.   DISTURBANCES   CLOSING  MESOZOIC   TIME. 

The  epoch  of  mountain -making  which  took  place  after  the  Mesozoic 
era,  in  North  America,  was  delayed  till  the  middle  of  the  Eocene 
period  in  the  Tertiary  age,  unless  the  coal-bearing  series  of  the  Rocky 
Mountains  and  California  are  true  Cretaceous.  This  question  of  age 
is  still  undecided  ;  but  the  evidence  appears  to  favor  most  strongly  the 
view  of  their  Eocene  age.  This  reference  of  the  epoch  to  the  Middle 
Eocene  puts  the  North  American  movements  of  the  crust  nearly  into 
harmony  with  the  European  and  Asiatic ;  for,  there,  some  of  the 
highest  mountains  date  from  the  close  of  the  Nummulitic  section 
of  the  Eocene. 

But,  if  the  mountain-making  took  place  at  a  later  date,  there  were 
other  changes  of  vast  influence  ;  for  at  the  close  of  the  Cretaceous 
occurred  one  of  the  most  complete  exterminations  of  species  of  which 
there  is  record. 

No  species  of  the  European  Cretaceous  is  known  to  occur  in  the 
Tertiary  formation,  and  none  of  Asia  or  of  Eastern  North  America. 


488  CENOZOIC    TIME. 

In  the  Rocky  Mountain  region,  some  Cretaceous  species  and  genera 
continue  on,  if  the  coal  series  is  Tertiary  ;  and  yet  the  number  now 
known  is  less  than  half  a  dozen.  The  vast  majority  of  the  species, 
and  nearly  all  the  characteristic  genera,  disappear. 

The  facts  do  not  authorize  the  inference  that  extermination  was  so 
complete  as  is  implied  in  the  above  statement,  although  establishing 
that  it  was  remarkable  for  its  universality  and  thoroughness.  It  has 
been  found  that,  in  the  bottom  of  the  Atlantic,  a  living  species  of  Tere- 
bratula  ( T.  caput-serpentis)  is  probably  identical  with  one  of  the  Cre 
taceous  species  (T*  striata),  and  several  genera  of  corals,  known  hith 
erto  only  among  Cretaceous  fossils,  have  their  species  in  the  Atlantic 
depths,  some  of  which  differ  but  little  from  those  of  the  Cretaceous. 
Such  facts  prove  that  the  deep  ocean  was  beyond  the  reach  of  the 
agencies  that  produced  extermination  over  the  Continental  seas. 

Cause  of  the  Destruction  of  Life.  —  The  general  extermination  of 
species  at  the  close  of  the  Cretaceous  period  was  probably  connected 
with  changes  of  level,  which  took  place  at  the  time  over  the  higher 
latitudes  of  America,  Europe,  and  Asia,  bringing  on  an  era  of  un 
usual  cold,  and  sending  cold  Arctic  currents  southward  over  the  Conti- 

S 

nental  seas.  In  North  America,  there  are  no  marine  Tertiary  beds 
known  north  of  southern  New  England,  on  the  east,  and  none  in  the 
Arctic  regions,  —  indicating,  apparently,  that  the  whole  area  was  above 
the  sea  then,  as  now.  This  cause  would  have  been  sufficient  to  pro 
duce  all  the  effects  mentioned  ;  and  it  appears  to  be  the  only  cause  that 
would  be  sufficiently  complete  and  universal  in  its  action.  It  is  there 
fore  most  probable  that  the  destruction  was  due  (1)  to  the  more  or 
less  complete  emergence  of  the  continents,  especially  their  northern 
portions  ;  and  (2)  to  the  change  of  climate  and  oceanic  temperature 
thus  occasioned,  —  both  aerial  and  oceanic  currents  being  rendered 
colder  than  in  the  Mesozoic  era.  This  source  of  destruction  would  not 
have  acted  over  the  bottom  of  the  Atlantic  and  other  deep  oceans ; 
and  hence  species  even  of  the  Cretaceous  era  may  survive  there. 


IV.     CENOZOIC  TIME. 

It  has  been  observed  that,  before  the  close  of  the  Mesozoic,  the 
mediaeval  features  of  the  era  were  already  passing  away.  The  Cycads 
had  begun  to  give  place  to  the  Sassafras,  Tulip  tree,  Willow,  Maple, 
Oak,  and  Palm  ;  the  ancient  type  of  Ganoids,  to  Salmon,  Perch,  and 
Herring  ;  and  the  Corals,  Echini,  and  Mollusks,  were  in  a  great  degree 
allied  to  those  of  existing  seas,  though  of  extinct  species.  But,  not 
withstanding  these  progressing  changes,  the  Mesozoic  aspect  continued 


TERTIARY  AGE.  489 

on  to  the  end,  appearing  prominently  in  the  multitudes  of  Ammonites 
and  Belemnites,  in  the  predominance  of  Cestracionts  and  Ganoids 
among  Fishes,  and  in  the  supremacy  of  the  great  class  of  Reptiles. 
Even  the  little  Mammals,  which  appeared  among  the  Reptiles,  bore 
the  mark  of  the  age  ;  for  the  larger  part,  at  least,  approximated  to 
the  oviparous  Reptiles  and  Birds,  in  being  themselves  of  a  semi- 
oviparous  type,  the  Marsupial. 

But  these  Mammals  were  prophetic  species  :  with  the  opening  of 
a  new  era,  the  Reptiles  dwindled  in  numbers,  variety,  and  size  ;  and 
Mammals  in  their  turn  became  the  dominant  race.  At  the  same  time, 
types  much  like  those  of  the  age  of  Man  were  multiplied  in  all 
departments  of  nature.  As  the  era  advanced,  species  still  living 
appeared, —  a  few  among  multitudes  that  became  extinct,  and  after 
ward  a  larger  proportion  ;  and,  before  its  close,  nearly  all  kinds  of 
life,  excepting  Mammals,  were  identical  with  those  of  the  present  era. 
As  the  Paleozoic  or  ancient  life  was  followed  by  the  Mesozoic  or  Medi- 
ceval,  so  now  there  was  as  marked  a  change  to  the  Cenozoic  or  recent 
life  and  world. 

Cenozoic  time  embraces  two  ages  :  — 

I.  The  TERTIARY,  or  age  of  Mammals. 

II.  The  QUATERNARY  age,  or  age  of  Man. 

I.     THE  TERTIARY,  OR  MAMMALIAN  AGE. 

Of  the  TERTIARY  age,  all  the  Mammalian  species  are  extinct ;  and 
the  proportion  of  living  Invertebrates  —  Radiates,  Mollusks,  Articu 
lates  —  varies  from  very  few  in  the  early  part  of  the  period  to  ninety- 
five  per  cent,  in  the  latter  part ;  while,  in  the  Quaternary,  nearly  all 
the  Mammalian  species  are  extinct,  but  the  Invertebrates  are  nearly 
all  living,  not  over  five  per  cent,  being  extinct. 

The  name  Tertiary  is  a  relic  of  early  geological  science.  When  introduced,  it  was 
preceded  in  the  system  of  history  by  Primary  and  Secondary.  The  first  of  these  terms 
was  thrown  out  when  the  crystalline  rocks  so  called  Avere  proved  to  belong  to  no  par 
ticular  age,  — though  not,  without  an  ineffectual  attempt  to  substitute  it  for  Paleozoic; 
and  the  second,  after  use  for  a  while  under  a  restricted  signification,  has  given  way  to 
Mesozoic.  Tertiary  holds  its  place,  simply  because  of  the  convenience  of  continuing 
an  accepted  name. 

EPOCHS.  —  The  earliest  adopted  subdivisions  of  the  Tertiary  were 
the  Lower,  Middle,  and  Upper.  For  these,  Lyell  substituted  the  fol 
lowing,  based  on  the  proportions  of  the  fossils  that  belonged  to  species 
still  living,  namely,  — 

1.  EOCENE,  from  17^5,  dawn,  and  Ktmos,  recent   (the  latter  a  root 
also  in  the  word  Cenozoic)  ;  the  species  nearly  all  extinct. 

2.  MIOCENE,  from  //aco-,  less,  etc. ;  less  than  half  the  species  living. 


CENOZOIC    TIME. 


490 

3.     PLIOCENE,  from  TrAeiW,  more,  etc. ;  more  than  half  the  species 
living. 

In  the  application  of  these  terms  to  British  and  European  rocks,  they  came  to  repre 
sent  certain  beds  in  the  Tertiary  series,  and  thus  to  have  a  significance  independent  of 
the  precise  number  of  living  species  represented  by  the  fossil  remains.  Some  geolo 
gists  make  a  fourth  division,  called  OKgocene,  by  separating  an  upper  portion  of  the 
Eocene,  and  uniting  with  it  the  lower  section  of  the  Miocene. 

1.  AMERICAN. 

The  periods  in  American  Geological  history,  which  are  marked 
off  by  the  breaks  in  the  Tertiary  series,  are  :  — 

1.  The   LIGXITIC    period,  or   that   of   the   earlier  Eocene,  an   era 
largely  of  fresh-water  formations,  whose  beds  over  the  Rocky  Moun 
tain   region   lie  unconformaUy  beneath   those   of  the   next  period,  a 
mountain-making  epoch  having  intervened. 

2.  The  ALABAMA  period,  or  that  of  the  Later  (Middle  and  Upper) 
Eocene,  an  era  of  marine  formations  on  the  borders  of  the  Atlantic, 
Mexican  Gulf,  and  Pacific,  but  ending  in  a  geographical  change  that 
excluded  later  marine  Tertiary  beds  (or  those  having  marine  fossils) 
from  Southern  Alabama,  Mississippi,  and  Texas,  or  the  borders  of  the 
Mexican  Gulf.     Over   the   Rocky  Mountain  slopes  and  summit,  only 
fresh-water  formations. 

3.  The  YORKTOWN  period,  corresponding  to  the  Miocene,  or  Mio 
cene  and  part  of  the    Pliocene  (so  named  from  a  locality  in  Virginia) 
to  which  a  large  part  of  the  beds  in  view  on  the  Atlantic  Border 
belong.     Over  the   Rocky   Mountain  slopes  and  summit,  only  fresh 
water  formations. 

4.  The  SUMTER  period,  supposed  to  correspond  to   the  Pliocene, 
or  part  of  it;  named  from  a  locality  in  South  Carolina. 

I.  Rocks :  kinds  and  distribution. 

The  deposits  are  either  of  marine  or  of  fresh-water  origin.  The 
marine  indicate  the  presence  of  the  ocean's  waters  in  the  region  where 
they  occur,  and  enable  us  therefore  to  mark  out  approximately  the 
limits  of  the  oceans  over  the  continents,  while  the  fresh-water  beds  are 
mostly  of  lacustrine  origin. 

The  Tertiary  areas  on  the  map,  p.  144,  are  lined  obliquely  from  the  left  above  to  the 
right  below;  and  the  fresh  and  brackish-water  Tertiary  area,  which  occurs  on  the  slopes 
of  the  Rocky  Mountains,  is  distinguished  from  the  marine  by  a  more  open  lining. 

The  general  distribution  of  the  marine  beds  is  similar  to  that  of  the 
Cretaceous.  On  the  Atlantic  Border,  the  most  northerly  point  is 
Martha's  Vineyard.  In  New  Jersey,  and  to  the  south,  through  Mary 
land,  Virginia,  and  the  Carolinas,  they  cover  a  narrow  coast-region  ; 
ar.d,  from  South  Carolina,  they  spread  westward  along  the  Gulf  Pordt r, 


TERTIARY    AGE.  491 

the  inner  limit  of  the  region  being  about  one  hundred  miles  from  the 
Gulf  in  Alabama,  and  one  hundred  and  fifty  to  two  hundred  in  Texas. 
Along  the  Mississippi  River,  the  Gulf-border  region  extends  north 
ward  to  southern  Illinois. 

Marine  Tertiary  beds  occur  also  on  the  Pacific  coast,  in  California 
and  Oregon,  forming,  with  the  Cretaceous,  the  Coast  Range  of  hills. 
Some  of  the  Tertiary  ridges  are  2,000  to  3,000  feet  in  height.  They 
also  cover  the  Cretaceous,  over  the  Rocky  Mountain  slopes  and  sum 
mit,  but  alternate,  in  these  parts,  with  extensive  fresh-water  beds. 

The  beds  of  the  Lignitic  period  or  Lower  Eocene  are  well  displayed 
either  side  of  the  Mississippi,  in  Mississippi,  Tennessee,  and  Arkansas  ; 
over  the  eastern  slopes  of  the  Rocky  Mountains,  on  the  Upper  Missouri 
and  elsewhere  ;  over  the  Rocky  Mountain  region,  in  Wyoming,  Utah, 
Colorado,  etc.,  where  the  thickness  is  several  thousand  feet ;  in  Cali 
fornia,  overlying  the  Cretaceous,  and  in  other  parts  of  the  Pacific- 
border  region.  Lignite,  or  carbonized  wood,  and  beds  of  mineral  coal 
occur  in  the  formation.  Part  of  the  beds  outcrop  near  the  Pacific  Rail 
road  ;  and  the  coal  obtained,  often  called  lignite,  is  used  for  the 
engines  on  the  road,  and  for  metallurgical  and  other  purposes.  The 
coal  of  the  vicinity  of  Mount  Diablo  in  California,  and  other  beds  of 
the  Tejon  series,  appear  to  be  of  cotemporaneous  formation. 

The  Middle  and  Upper  Eocene  marine  beds,  or  those  of  the  Ala 
bama  period,  are  extensively  displayed  in  the  States  of  Mississippi, 
Alabama,  and  Georgia;  they  occur  also  at  some  points  in  South 
Carolina  and  Virginia,  though  generally  concealed  on  the  Atlantic 
border  by  the  Miocene  beds.  They  have  been  divided  into  the  CLAI 
BORNE  group,  or  Middle  Eocene,  well  displayed  at  Claiborne,  Ala 
bama,  and  the  VICKSBURG  group,  or  Upper  Eocene,  so  named  from 
Vicksburg  on  the  Mississippi.  Lyell,  whose  observations  in  America 
as  well  as  Europe  first  brought  out  the  true  character  and  relations  of 
the  Tertiary  formations,  makes  the  Claiborne  beds  to  be  probably  the 
equivalent  of  the  Middle  Eocene  of  Great  Britain,  stating  that  several 
of  the  shells  (among  them,  Venericardia  planicosta  Lam.)  are  identi 
cal  with  those  of  European  species  of  that  age. 

The  marine  Miocene  beds  cover  a  large  part  of  the  Atlantic  Border, 
and  are  well  exhibited  and  full  of  fossils  in  Virginia  and  New  Jersey. 
Over  the  Rocky  Mountain  region  and  part  of  the  Eastern  slopes, 
the  beds  of  the  Alabama  period,  as  well  as  the  later  Tertiary,  are  of 
fresh- water  origin ;  and  they  lie  upon  the  upturned  Lignitic  beds, 
generally  in  a  horizontal  position,  or  nearly  so.  As  first  shown  by 
Hayden,  the  beds  were  formed  in  lakes  that  existed  over  the  Rocky 
Mountain  region,  soon  after  it  first  emerged,  and  while  it  was  yet  a  vast 
extent  of  low  and  nearly  level  land. 

These  fresh-water  or  lake  deposits  are,  as  stated,  of  all  periods  from 


492  CEXOZOIC    TIME. 

the  Middle  Eocene  to  the  Pliocene :  the  Eocene  occurring  about  Fort 
Bridger;  the  Miocene,  in  the  Upper  Missouri  region,  about  White 
River,  in  Colorado,  etc. ;  arid  the  Pliocene,  on  the  Loup  Fork  of  the 
Platte,  the  Niobrara,  etc.  The  Fort  Bridger  region  has  been  described 
as  an  immense  basin,  the  bed  of  an  ancient  lake,  sterile  and  almost 
treeless,  having  the  Uintah  Mountains  on  the  south,  and  the  far  distant 
Wind  River  Mountains  on  the  North.  The  Tertiary  beds,  indurated 
clays  and  sand,  are  8,000  feet  thick  and  nearly  horizontal.  The  strata 
have  been  eroded  by  rills  and  streams  from  the  rains,  and  stand  in 
isolated  earthworks  or  embankments,  pyramids  and  spires,  over  the 
great  plain,  —  looking  like  a  field  of  desolate  ruins.  Such  areas  in 
the  Western  Tertiary  are  called  Mauvaises  Terres,  or  Bad  Lands,  this 
name  having  been  originally  applied  to  one  of  the  kind  in  the  White 
River  region,  where  the  beds  are  Miocene  Tertiary. 

Over  the  Coast  region  of  California,  the  Tertiary  formation  is  of 
marine  origin,  and  has  a  thickness  of  at  least  3,000  or  4,000  feet. 

The  Tertiary  strata  often  vary  greatly  in  character,  from  mile  to 
mile.  Instead  of  great  strata  of  almost  continental  extent  and  uni 
formity,  as  in  the  Silurian,  there  is  the  diversity  which  exists  among 
the  modern  formations  of  a  sea-coast. 

Off  our  present  coasts,  we  find  in  one  spot  mud  beds,  with  oysters  or 
other  Mollusks  ;  in  another  region,  great  estuary  flats  ;  a  little  higher, 
on  the  same  coast  perhaps,  accumulations  of  beach  sands  with  worn 
shells,  changing  in  character  every  few  rods.  The  changes  in  the 
Tertiary  strata  are  often  equally  abrupt.  It  should  be  noted  also  that 
coral  limestones  are  now  in  progress  off  the  Florida  coast ;  and,  on 
other  shores,  coarse  shell-limestones.  Still  further,  to  comprehend  the 
diversity  in  the  deposits,  it  is  necessary  to  remember  that,  by  the 
throwing  up  or  removal  of  embankments  on  coasts,  or  by  change  of 
level,  salt-water  marshes  or  estuaries  become  brackish-water,  or  wholly 
fresh-water,  and  the  reverse, —  each  change  bein£  attended  with  a 

7  O  C3 

change  in  the  living  species  of  the  waters,  encroaching  fresh  waters 
destroying  the  marine  species,  and  so  on.  By  considering  carefully 
all  the  various  conditions  incident  to  a  coast  from  these  sources,  the 
ever  varying  character  of  the  Tertiary  beds  will  be  appreciated. 

The  rocks  are  of  the  following  kinds  :  beds  of  sand  or  clay,  so  soft 
as  to  be  easily  turned  up  by  a  shovel ;  compact  sandstones,  useful  for  a 
building-stone,  though  not  very  hard  ;  shell-beds,  of  loose  shells  and 
earth,  the  shells  sometimes  unbroken,  in  other  cases  water-worn  ;  shell- 
rocks  and  calcareous  sandstones,  consisting  of  pulverized  shells  and 
corals,  firmly  cemented  and  good  for  building-stone,  as  at  St.  Augus 
tine  ;  true  marls,  or  clays  containing  carbonate  of  lime  from  pulverized 
shells,  and  hence  effervescing  with  the  strong  acids  ;  compact  solid 


TERTIARY    AGE.  493 

limestones,  sometimes  oolitic  in  structure  ;  green  sand,  like  that  of  the 
Cretaceous,  and  equally  valued  for  fertilizing  ;  biihrstone,  a  cellular 
siliceous  rock,  valuable  for  millstones,  as  in  South  Carolina. 

Although  the  Tertiary  rocks  are  generally  less  firm  than  those  of 
the  Paleozoic,  there  are  in  some  places  hard  slates  and  sandstones,  not 
distinguishable  from  the  most  ancient.  Such  rocks  occur  in  California, 
in  the  vicinity  of  San  Francisco  ;  and  it  is  supposed  that  some  crystal 
line  rocks  of  the  region  are  altered  Tertiary  strata. 

There  are  also  whitish  beds  of  earthy  or  chalky  aspect,  Avhich  consist 
of  siliceous  Infusoria,  and  others  formed  from  the  shells  of  Rhizopods. 

1.  LIGNITIC  PERIOD  OK  LOWER  EOCENE.  —  In  Mississippi,  as  shown  by  Hilgard, 
the  Lignitic  group  covers  a  large  part  of  the  northern  halt'  of  the  State.  It  consists  in 
some  places  at  base  of  small  estuary  deposits,  with  marine  shells;  above  these,  of  clays 
and  sands,  with  lignite  and  fossil  leaves.  Her  divides  it  into  the  Flatwoods  and  the  La- 
yranye  groups.  The  two  groups  continue  north  through  Tennessee  into  Kentucky,  as 
observed  by  Safford,  who  named  the  former  the  Porter's  Creek  group,  and  the  latter,  the 
"  Orange  Sand  "  group;  the  former  is  mostly  clayey  in  its  beds;  the  latter  sandy.  The 
top  of  the  latter  contains  two  or  three  beds  of  lignite,  and  is  called  by  him  the  "Bluff 
Lignite ;  "  whole  thickness  300  to  400  feet.  [Hilgard's  "  Orange  Sand  "  is  Quaternary.] 

In  the  Upper  Missouri  region,  the  Lignitic  formation  has  a  thickness  of  2,OUO  feet, 
and  lies  unconformably  beneath  the  later  Tertiary  beds.  It  occurs  also  in  the  Big  Horn 
region;  in  the  Chetish  or  Wolf  mountains;  about  Fort  Union.  It  extends  far  north 
into  British  America,  and  south  to  Fort  Clarke,  and  beyond  to  Texas.  In  tire  lower 
part,  on  Judith  River,  there  are  brackish  water  deposits,  containing  shells  of  Oysters, 
Corbiculce,  etc.,  mingled  with  fresh-water  shells  of  the  genera  Vivipnrus,  Mtlaina,  etc. 
(Figs.  008-013,  p.  501).  (Meek.) 

In  the  Rocky  Mountain  region,  the  Lignitic  group  of  the  Green  River  basin,  near 
Fort  Bridger,  and  other  parts,  in  Wyoming,  Utah,  Colorado,  etc.,  consists  of  sandy  beds, 
some  of  them  true  marine,  more  of  them  having  a  commingling  of  fresh-water  shells 
with  the  marine,  which  indicates  very  shallow  brackish  waters,  and  a  still  larger  part 
strictly  fresh-water  in  origin;  and  in  these  occur  various  beds  of  mineral  coal.  They 
occur  always  upturned,  and  generally  at  a  high  angle,  along  the  east  foot  of  the  Wah- 
satch,  and  adjoining  others  of  the  mountain  ranges.  The  coal  beds  are  well  seen  on 
Bitter  Creek  in  Wyoming;  on  Weber  and  Bear  rivers  in  Utah:  in  the  Green  River 
Basin,  north  of  the  Uintah  Mountains;  in  Colorado;  New  Mexico,  etc. 

The  principal  localities  where  the  coal  is  exposed  are  —  In  Utah,  at  Evanston  and 
Coalville  (in  the  valley  of  Weber  River),  etc.;  in  Wyoming,  at  Carbon,  140  miles  from 
Cheyenne;  at  Hallville,  142  miles  farther  west;  at  Black  Butte  Station,  on  Bitter 
Creek;  on  Bear  River,  etc. ;  in  the  Uintah  Basin,  near  Brush  Creek,  6  miles  from  Green 
River;  in  Colorado,  at  Golden  City,  15  miles  west  of  Denver,  on  Ralston  Creek,  Coal 
Creek,  S.  Boulder  Creek  and  elsewhere;  in  New  Mexico,  at  the  Old  Placer  Mines  in  the 
San  Lazaro  Mountains,  etc.  The  coal  is  of  the  bituminous  or  semibituminous  kind. 
That  of  Evanston  (where  the  bed  is  26  feet  thick)  afforded  Prof.  P.  Frazier,  Jr.,  37-38 
per  cent,  of  volatile  substances,  5-0  of  water,  7-8  of  ash,  and  49-50  of  fixed  carbon. 
At  the  Old  Placer  mines,  New  Mexico,  there  is  anthracite,  according  to  Dr.  J.  LeConte, 
affording  88  to  91  per  cent,  of  fixed  carbon ;  specimens  from  there,  analyzed  by  Frazier, 
were  seinibituminous,  affording  68-70  per  cent,  of  fixed  carbon,  20  per  cent,  of  volatile 
substances,  and  about  3  per  cent,  of  water.  The  region  of  the  Old  Placer  Mines  is  one 
of  upturned  and  altered  rocks,  like  the  anthracite  region  of  Pennsylvania. 

The  fact  that  the  Lignitic  beds  of  Mississippi,  the  Upper  Missouri,  and  the  Rocky 
Mountain  region  are  cotemporaneous,  is  shown  by  the  identity  of  several  of  the  species 
of  fossil  plants,  as  made  known  by  Lesquereux.  There  are  also  several  fresh-water 
shells  of  the  Upper  Missouri  region,  identical  with  those  of  the  Green  River  Basin  and 
elsewhere. 


494  CENOZOIC    TIME. 

There  is  a  Lignite  deposit  at  Brandon,  Vermont,  associated  with  a  bed  of  limonite 
iron-ore,  and  abounding  in  fossil  fruits,  first  described  bv  E.  Hitchcock.  The  plants, 
according  to  Lesquereux,  are  of  the  same  period  with  those  of  the  Mississippi,  Tennes 
see  and  Arkansas  Lower  Lignite  beds. 

2.  ALABAMA  PERIOD,  or  MIDDLE  AND  UPPER  EOCENE. — The  Claiborne  beds  at 
Claiborne,  Alabama,  or  those  of  the  Middle  Eocene,  consist,  beginning  below,  of  (1) 
Clay,  25  feet,  overlaid  by  a  bed  of  liynite.,  4  feet;  (2)  Marl  with  Oysters  (0.  sellcefurmis 
Con.);  (3)  Marly  arenaceous  limestone;  (4)  Marl  with  Oysters;  (5)  Sand  with  shells, 
partly  showing  a  beach  origin,  often  called  the  "  Orange-sand "  group  in  the  region. 
Whole  thickness,  about  125  feet. 

In  Mississippi,  there  are  (1)  the  Siliceous  Claiborne  beds,  sandstones  and  clayey 
layers,  near  the  middle  of  the  western  half  of  the  State,  150  feet  thick;  (2)  60  feet  of 
tnarlytes  and  limestone;  (3)  80  feet  of  similar  beds,  best  shown  near  Jackson,  Missis 
sippi,  and  sometimes  separated  as  the  Jackson  group;  (4)  12  feet  of  Red  Bluff  beds, 
black  lignitic  clays.  Then  follow  120  feet  of  beds  of  the  Vicksburg  series,  or  Upper 
Eocene.  (Hilgard.) 

The  Claiborne  beds  are  locally  lignitic,  a  feature  which  increases  westward  in  Arkan 
sas,  but  diminishes  eastward  in  Alabama;  and  Hilgard  considers  it  as  proving  that  the 
conditions  under  which  the  bottom  lignitic  beds  (No.  1)  were  formed,  continued  on,  in- 
termittingly,  into  the  following  part  of  the  Tertiary  era. 

The  beds  at  Jackson  are  (1)  Liynitic  clay;  (2)  White  and  blue  marls,  the  former 
often  indurated,  with  numerous  marine  shells  and  remains  of  the  Zeuylodon.  They 
cross  the  State  as  a  narrow  band,  running  east-southeast  through  Scott  and  Jackson 
counties.  Whole  thickness,  80  feet.  (Hilgard.) 

The  beds  of  the  Vicksbury  epoch,  or  Upper  Eocene,  as  represented  at  Vicksburg, 
Miss.,  aje  (1)  Liynitic  clay,  20  feet;  (2)  Ferruginous  rock  of  Red  Bluff,  with  numerous 
marine^ossils,  12  feet;  (3)  Compact  limestones  and  blue  marls,  with  marine  fossils, 
often  called  the  Orbitoldes  limestone,  SO  feet:  in  all,  112  feet.  A  narrow  band  crosses 
the  State  just  south  of  the  Jackson  beds,  from  Vicksburg  on  the  Mississippi.  These 
are  overlaid  by  150  feet  of  the  "Grand  Gulf"  group  of  cl.-.y,  sandstone,  and  loose  sand, 
with  some  gypsum,  occurring  about  Grand  Gulf,  on  the  Mississippi,  and  elsewhere  south 
of  the  latitude  of  Jackson  and  Vicksburg,  covering  the  larger  part  of  the  southern  por 
tion  of  the  State.  (Hilgard.) 

The  Vicksburg  group  is  met  with  in  Alabama,  in  Monroe,  Clarke,  and  Washington 
counties,  and  constitutes  a  limestone  bluff  at  St.  Stephens  on  the  Tombigbee,  and 
limestone  at  Tampa  Bay,  Florida. 

Near  Charleston,  S.  C.,  the  oldest  Eocene  there  displayed  includes  (1)  Buhrstone 
beds,  400  feet;  (2)  White  limestone  and  marls,  called  the  Santee  beds.  A  buhrstone 
of  the  same  age  occurs  also  in  Georgia  and  Alabama;  and  the  siliceous  beds  at  Clai 
borne  are  of  the  same  horizon.  This  group  is  represented  also  near  Fort  Washington, 
Piscataway,  and  Fort  Marlborough,  in  Maryland,  and  on  the  Pamunkey  at  Marlbourne, 
mostly  by  dark  green  sands;  and  in  New  Jersey,  at  Squankum,  etc.,  in  Monmouth 
County. 

The  Vicksburg  epoch  is  represented  in  South  Carolina  by  gray  marl,  on  the  Ashley 
and  Cooper  rivers,  abounding  in  Rhizopods;  and,  adding  the  Santee  beds,  the  whole 
thickness  is  600  to  700  feet. 

Fresh-water  beds  of  the  Middle  and  Upper  Eocene  —  Alabama  period—  occur  in  the 
Green  River  basin,  about  Fort  Bridger,  lying  nearly  horizontally  over  the  upturned  Lig 
nitic  series.  They  include,  beginning  below,  about  2,000  feet  of"  shaly  beds  (Green  River 
shales),  from  some  of  which  fossil  fish  have  been  obtained,  and  in  which  are  some  thin 
beds  of  coal  (as  near  Elko);  and  above  these  a  great  thickness  of  indurated  clays  and 
sand  beds  (sometimes  distinguished  as  the  Bridger  group),  affording  in  the  lower  part 
Mammalian  remains  of  various  tapir-like  animals,  and  higher  up  other  species,  as  the 
Dinocenu,  Uintatherium,  etc.;  and  still  higher  a  great  thickness  of  sandy  beds,  about 
which  it  is  not  fully  decided  whether  thev  are  Eocene  or  not. 

, YORK-TOWN  PERIOD,  OR  MIOCENE.  —  The  Miocene  beds  cover  a  large  part  of  the 


TERTIARY    AGE.  495 

Atlantic  Tertiary  Border,' occurring  at  Gay  Head,  on  Martha's  Vineyard;  in  New  Jer 
sey,  in  Cumberland  County  and  elsewhere;  and  fossils  may  be  collected  in  the  Marl 
pits  of  Shiloh,  Jericho,  etc.;  in  Maryland,  at  St.  Mary's,  Easton,  etc.;  occurring  on 
both  sides  of  the  Chesapeake  for  a  great  distance;  in  Virginia,  at  Yorktown,  Suffolk, 
Smithfield,  and  through  the  larger  part  of  the  Tertiary  region. 

The  strata  at  Gay  Head,  beginning  below,  are  (1)  Clay  filled  with  Turrit ella  alticos- 
tata  Con.,  Cnllistn  (Cytherea)  Sayana  Con.,  etc.;  (2)  Sand,  with  few  shells,  chiefly 
Yoldia  (Nucula)  limatula;  (3)  a  sandy  bed,  made  up  mostly  of  Crepidula  costata, 
Mort.;  (4)  coarse  ferruginous  sand.  Two  miles  off,  the  layer  of  Turritellce  has  changed 
to  a  layer  of  Crepidulce ;  and  the  continual  ion  of  the  Crepidula  layer  is  filled  with  Pec- 
tens.  Venus  diffbrmis,  Ostrea,  etc. 

At  a  locality  on  James  River,  Va.,  there  are  (1)  a  layer  of  shells  of  Pecten  and 
Ostreri,  5  feet;  (2)  bed  of  Chamce,  3  feet;  (3)  bed  of  Pectens,  with  Ostrece,  1  foot;  (4) 
second  bed  of  Chamce,  with  Striarca  centenaria  Con.,  Panopcea  reflexa  Say,  6  feet;  (5) 
bed  of  large  Pectc-ns,  2  feet;  (6)  closely  compacted  bed  of  Chamce  and  Venus  difformis, 
3  feet;  (7)  sand  and  clay,  separated  from  the  preceding  by  a  thin  layer  of  pebbles. 
But  in  other  localities  of  the  same  region,  the  beds  are  different.  The  first  layer  over 
the  Eocene  often  consists  of  pebbles  or  coarse  sand. 

One  of  the  most  remarkable  deposits  in  the  Virginia  Tertiary  is  a  bed  of  Infusorial 
remains,  occurring  near  Richmond.  It  is  in  some  places  thirty  feet  thick,  and  extends 
from  Herring  Bay  on  the  Chesapeake,  Md.,  to  Petersburg,  Va.,  or  beyond,  and  is  an 
accumulation  of  the  siliceous  remains  of  microscopic  organisms,  mostly  Diatoms.  Some 
of  the  beautiful  forms  are  represented,  much  magnified,  in  Fig.  882,  on  the  next  page. 
These  beds  have  been  referred  both  to  the  Miocene  and  to  the  Eocene;  they  arc  called 
Eocene  by  Professor  Rogers,  after  an  examination  of  the  region. 

A  still  thicker  bed — exceeding  fifty  feet  —  exists  on  the  Pacific,  at  Monterey;  the 
bed  is  white  and  porous,  like  chalk,  and  abounds  in  siliceous  organisms.  (Blake.) 

Fresh-water  beds  of  the  older  Miocene  occur  in  the  Upper  Missouri  region,  along  the 
White  River;  the  region  is  that  called  the  "  Mauvaises  Terres,"  or  Bad  Lands.  They 
constitute  the  White  River  yroup  of  Haydcn,  and  have  a  thickness  of  1,000  feet  or 
more.  The  beds  arc  the  burial  ground  of  the  Titanotherium  and  many  other  extinct 
Miocene  Mammals.  This  group  extends  southward  into  Colorado  (Marsh.) 

There  are  als--o,  in  the  Wind  River  valley,  and  on  the  west  side  of  the  Wind  River 
mountains,  other  fresh-water  deposits,  1,500  to  2,000  feet  thick,  called  the  Wind  River 
group,  which  may  be  of  the  same  age  as  the  AVhite  River  group.  (Meek  and  Hayden.) 

In  California  and  Oregon,  the  beds  referred  to  the  Miocene  consist  of  sandstone  and 
shale,  and  arc  in  some  places  4,000  to  5,000  feet  thick.  They  occur  near  Astoria, 
on  the  Columbia  River  and  the  Willamette;  in  the  Coast  ranges  of  California,  north 
and  south  of  San  Franciso,  and  also  in  the  Contra  Costa  hills,  just  east;  in  the  Santa 
Inez  mountains,  some  points  in  which  are  4,000  feet  in  height;  along  the  flanks  of  the 
Peninsula  range,  in  the  latitude  of  San  Diego,  etc.  Both  north  and  south  of  San  Fran 
cisco,  on  the  coast,  there  are  mctamorphic  slates,  part  of  which  are  referred  by  Whit 
ney  to  the  Tertiary. 

SUMTEU  PERIOD,  OR  PLIOCENE.  —  The  beds  referred  to  the  Pliocene  occur  in  North 
and  South  Carolina,  extending  south  as  far  as  the  Edisto  River.  They  contain  forty 
to  sixty  per  cent,  of  living  species  of  shells.  (Tuomey  &  Holmes.)  The  beds  are  soft, 
either  loam,  clay,  or  sand,  and  lie  in  depressions  of  the  older  Tertiary  and  Cretaceous 
formations.  The  equivalents  of  these  beds  in  Virginia  and  New  Jersey  are  not  clearly 
made  out;  neither  are  they  known  from  the  Gulf  States. 

In  the  Upper  Missouri  region,  the  White  River  group  is  overlaid  by  other  fresh-water 
Tertiary  beds,  300  to  400  feet  thick,  called  by  Meek  &  Hayden  the  Loup  River  group. 
They  contain  in  their  upper  part  the  remains  of  numerous  extinct  Mammals,  including 
Camels,  Rhinoceroses.  Elephants,  Horses,  etc.,  besides  land  and  fresh-water  shells 
which  are  probably  of  recent  species.  These  beds  occur  on  the  Loup  Fork  of  the 
Platte,  and  stretch  north  to  the  Niobrara,  and  south  beyond  the  Platte. 

Phosphatic  Deposition  the  South  Cnrolini  Eoctne  beds.  —  The  Eocene  of  South  Caro 
lina,  about  Charleston,  and  in  other  portions  of  the  coast  region,  is  thickly  covered  with 


496 


CENOZOIC   TIME. 


phosphatic  deposits,  partly  nodular  in  structure,  and  often  containing  Eocene  fossils. 
Their  origin  is  explained,  by  Prof.  C.  U.  Shepard,  by  supposing  that  the  Eocene  beds 
were  covered  by  extensive  guano  deposits,  and  that  the  percolating  waters,  carrying 
down  carbonic  acid  and  soluble  phosphates,  decomposed  and  carried  off  part  of  the 
Eocene,  and  altered  other  portions  to  phosphates,  just  as  has  happened  on  the  Guano 
islands  of  the  Caribbean  sea,  where  underlying  corals  and  shells  are  converted  into 
phosphate  of  lime  by  a  similar  process. 

II.  Life. 

1.  Plants. 

1 .  Protophytes.  —  About  one  hundred  species  of  Diatoms  have  been 
described  by  Ehrenberg  and  Bailey,  from  the  Infusorial  stratum  of 

Fig.  882. 
^  a  Jj?_,  


RICHMOND  INFUSORIAL  EARTH. —  a,  Pinnularia  peregrina ;  b,  c,  Odontidium  pinnulatum ;  d, 
Grammatophora  marina  ;  e,  Spongiolithis  appendieulata  ;  /,  Melosira  sulcata  ;  g,  transverse  view, 
id. ;  /(,  Actinocyclus  Ehrenbergii ;  i,  Coscinodiscus  apiculatus  ;  j,  Triceratium  obtusum  ;  k,  Actin- 
optychusundulatus;  /,  Dictyocha  crux  ;  m,  Dictyocha  ;  n,  fragment  of  a  segment  of  Actinop- 
tychus  senarius  ;  o,  Navicula;  p,  fragment  of  Coscinodiscus  gigas. 

Richmond,  besides   a  few  Polycystines  (siliceous   Foraminifers)  and 
many  sponge-spicules.    Fig.  882  represents  a  portion  of  the  Richmond 
earth,  as  it  appeared  in  tho  field  of  view  of  Ehrenberg's  microscope. 
This  is  an  example  of  one  of  the  many  Infusorial  earths  of  the  era. 
2.  Aii'jiosperms,  Conifers,  Palms.  —  The  Lignitic  and  coal-bearing 


TERTIARY    AGE. 


497 


strata,  at  the  bottom  of  the  Eocene,  have  afforded  large  numbers  of 
leaves  of  plants,  in  Mississippi,  Arkansas,  the  Upper  Missouri,  and  in 
the  coal-bearing  series  of  Wyoming,  Utah,  Colorado,  and  other  parts 
of  the  Rocky  Mountain  region  ;  others  have  been  obtained,  together 
with  a  variety  of  nuts,  from  a  bed  of  Lignite  at  Brandon,  Vt.  Among 
the  plants,  there  are  species  of  Plane-tree,  Oak,  Poplar,  Maple,  Hickory, 
Dog-wood,  Magnolia,  Cinnamon,  Fig,  Conifers,  Palms,  etc.  Palm- 
leaves  have  been  found  as  far  north  as  the  Upper  Missouri  region  ; 
one  of  them,  of  the  Fan-palm  family,  —  a  species  of  Sdbal,  —  when 
entire,  must  have  had  a  spread  of  twelve  feet. 

Figs.  883-887. 
884 


•\r 

Fig.  883,  Quercus  myrtifolia  (?);  884,  Cinnamomum  Mississippiense ;  885,  Calamopsis  DanEe  ;  886, 
Fagus  ferruginea  (?);  887,  Carpolithes  irregularis. 

The  plants  of  the  beds  of  Mississippi,  the  Upper  Missouri  and  other 
localities  mentioned,  are  closely  related  to  those  of  the  present  era. 

Among  the  genera  of  the  older  Lignitic  group,  distinguished  by  Lesquereux  and 
Newberry,  are  (1)  Angiosperms,  —  Quercus,  Caryn,  Populus,  Acer,  Ulmus,  Mortis, 
Carpinus,  Fagus,  Juglans,  Betula,  Alnus,  Corylus,  Ilex,  Negundo,  Platanus,  Sapindm, 
Ficus,  Cinnamomum,  Laurus,  Benzoin,  Persea,  Myrica,  Snfisburia,  Cornus,  Ceanothus, 
Viburnum,  JRhus,  Olea,  Rhamnus,  Magnolia,  Smilax,  McClintochia  (an  Arctic  genus), 
Eucalyptus  (an  Australian  genus);  (2)  Conifers,  —  Thuia,  Thuyites,  Sequoia,  Abies, 
Taxodium,  Glyptostrobus ;  Palms,  —  Sabal,  Calamopsis,  Flabtllaria.  The  genera  are 
mainly  those  characteristic  of  North  America  at  the  present  time. 

Golden,  Colorado,  has  afforded  the  European  Eocene  species  Sphenoptens  Eocenica 
Ettingshausen,  of  Mount  Promina,  Europe,  Quercus  angustiloba  A.  Brngt.,  of  the 


498 


CEXOZOIC    TIME. 


Bornstadt  Eocene;  and  Black  Butte,  Myrica  Torreyi,  closel}' like  one  of  Mount  Promina, 
Flcibelluria  latanla  Hooker,  and  F.  Eocenica  A.  Brngt.  The  same  beds  that  afforded 
the  Dinosaurian  remains,  described  by  Cope,  contain  the  plants  Sabal  Campbelli  Newb. 
and  Plfitanus  Raynoldsii  Newb.,  which  are  found  at  three  or  four  other  localities  of  the 
same  coal  series,  along  with  Ficits  corylifolius  Lsqx.,  Laurus  obovata  Weber,  and 
Viburnum  dichotomum  Lsqx.,  not  yet  observed  elsewhere  (Lesquereux).  The  Missis 
sippi  beds  contain  the  following  Rocky  Mountain  species,  Flabellaria  Zinkeni  Heer, 
Populus  Arctica  Heer  (an  Arctic  species),  Quercus  chlorophylls  Ung.,  Laurus  pedata 
Lsqx.,  Cinnamomum  ajfine  Lsqx.,  C.  Mississippiense  Lsqx.,  Magnolia  H'dyardiana 
Lsqx.,  M,  Lesleyana  Lsqx.,  and  Juglans  appressa  Lsqx.  (Lesquereux)  The  Rocky 
Mountain  region  has  afforded  the  following  Arctic  species,  Sequoia  Lanysdorfii'BiT., 
Phraymites  GEninyensls  A.  Brngt.  (Miocene,  in  Europe),  Populus  decipiens  Lsqx.,  P. 
lancifolia  Heer  (Miocene,  in  Europe),  P.  Zaddachi  Heer,  Salix  Grcenlandica  Heer, 
Alnus  Kefersteinii  Gcipp.  (Miocene,  in  Europe),  Quei'cus  Lyellii  Heer  (Miocene,  in 
Europe),  Q.platania  Heer,  Q.  drymejaUng.  (Miocene,  in  Europe),  Q.  Wyominyiana 
Lsqx.,  Q.  Olafseni  Heer,  Q.  Laharpi  Gopp.,  Corylus  McQuarryi  Heer,  Fayus  Deu- 
calionls  Ung.  (Miocene,  in  Europe),  Ficus  tilt'cefolia  A.  Brngt.  (Miocene,  in  Europe), 
Platanus  Gulielmce,  Gopp.  (Miocene,  in  Europe),  Platanus  aceroides  Gopp.  (Miocene,  in 
Europe).  Cinnamomum  Scheuchzeri  Heer  (Miocene,  in  Europe),  Andromeda  reticulata 
Heer,  A.  vaccinifolia  Ung.,  Viburnum  Whymperi  Heer,  Vitis  Olriki  Heer,  V.  Islandica 
Heer,  Magnolia  Inyhfieldi  Heer,  McClintochia  LyM'd  Heer,  Paliurus  Colombi  Heer, 
Zizyphus  hyperboreus  Heer,  Elms  bella  Heer.  Juylans  acuminata  (?)  Heer  (Miocene,  in 
Europe).  Lesquereux,  from  whom  this  catalogue  is  taken,  thus  shows  a  close  relation 
between  the  floras  of  the  Arctic  and  of  more  temperate  latitudes,  as  well  as  a  relation 
to  the  European  Miocene  flora.  The  latter  fact  seems  to  imply  that  the  migration  was 
from  America  to  Europe,  as  the  European  species  existed  in  Europe  only  after  their  first 
appearance  in  America.  Lesquereux  refers  three  of  the  above  species  exclusively  to  what 
he  regards  as  a  later  division  of  the  Eocene  than  the  others:  all  the  others  are  Ton nd  in 
his  Lower  division.  To  the  later,  he  refers  the  Rocky  Mountain  localities  at  Washakio 
Station,  Carbon  Station,  Evanston,  Sage  Creek,  etc.,  in  Utah:  and  to  the  older,  the 
localities  of  the  Raton  Mountains,  Golden,  Denver,  etc.,  in  Colorado;  Black  Butte,  Wy 
oming;  Fort  Ellis  and  Elk  Creek,  Montana;  Fort  Union,  in  Xew  Mexico;  and  in 
Mississippi. 

Fig.  883.  Qtterctw  myr#/b/ia  Willd.*(  ?)>  from  Somcrville,  Tennessee,  the  Lagrange 
group  of  Safford ;  Fig.  884,  Cinnamomum  Mississippiense 
Lsqx.,  from  Mississippi,  northern  Lignitic  group,  at  Win 
ston;  Fig.  885,  Calamopsis  Dance  Lsqx.  ,from  Mississippi, 
northern  Lignitic  group,  in  Tippah,  Lafayette,  Calhoun: 
Fig.  880.  nut  of  Fayus  ferruyi  nea  Michx.  (?)  from  the 
Lagrange  group  of  Tennessee;  Fig.  887,  Carpollthfs  ir- 
reyid'iris  Lsqx.,  from  the  Brandon  Lignite  bed;  Fig.  888, 
Catyolithes  Brandonensis  Lsqx.,  the  most  abundant  of  the 
Brandon  nuts,  natural  size.  The  kind  of  plant  producing 
these  two  fruits  is  undetermined.  Among  the  other  Bran 
don  fruits,  Lesquereux  has  recognized  the  genera  Carya, 
Fric/iis,  Arifitolochifi,  Snpindus,  Cinnamomum,  Jllicium, 
Car/rinus,  and  Nyssa.  (Amer.  Jour.  Sci.,  IT.  xxxii.  355.) 
The  plants  of  the  Lignite  bed  of  Lauderdale  (which  is 
distinctly  overlaid  by  the  Claiborne  Eocene)  "show  the 
greatest  affinity  with  species  of  our  time,  and  are  appar 
ently  of  as  recent  an  epoch  as  the  fruits  of  Brandon." 
(Lesquereux.) 

In   the  beds  of    the   Middle  or  Upper  Eocene,  in  the 

Green  River  or  Fort  Bridger  basin,  overlying  unconformahly  the  Lignitic  Series  (re 
ferred  by  Lesquereux  to  the  Miocene,  but  by  Marsh  and  Cope  to  the  Eocene),  there 
have  been  found,  according  to  Lesquereux,  species  of  Sabal  (palm),  Taxodium,  Salix, 
Myrica,  Quercus,  Ficus,  Platanus,  Laurus,  Eucalyptus,  Ilex,  Ceanothus,  Juylans,  Carya, 


Carpolithes  Brandonensis. 


TERTIARY    AGE. 


499 


Arundo,  Carex,  Cyperites,  Cyperus,  and  Poacites.  Of  the  species,  Arundo  Gcepperti 
A.  Brngt,  Salix  angusta  A.  Brngt.,  Platanus  Gulielmce  Gopp.,  Juglans  Schimperi  Lsqx., 
/.  denticulata  Heer,  are  reported  as  occurring  also  in  the  Lignitic  series. 

2.  Animals. 

1.  INVERTEBRATES.  —  Among  Protozoans,  Rhizopods  are  very  num 
erous    in    some    of  the    beds,  as  in   the    Ashley   Eocene,  in    South 

Figs.  889-893. 

^  891 


EOCENE,  CLAIBORNE  GROUP.  — Fig.  889,  Ostrea  selU-eformis  ;  890,  Crassatella  alta  ;  891,  Astarte 
Conradi ;  892,  Cardita  planicosta ;  893,  Turritella  carinata. 

Figs.  894-900. 


EOCENE,  VICKSBURG  GROUP.  —  Fig.  894,  Pecten  Poulsoni ;  a,  section  of  same  ;  895,  Mortonia  Rog 
ers! ;  896,  Ostrea  Georgiana  ( X  /€);  897,  Anomalocardia  Mississippiensis  ;  898,  Orbitoides  Man- 
telli ;  899,  Cithara  Mississippiensis  ;  900,  Deutalium  Mississippiense. 


500 


CEXOZOIC   TIME. 


Carolina.  The  coin-shaped  fossils,  Nummulites  and  Orbitoides,  es 
pecially  species  of  the  latter,  abound  in  the  Vicksburg  beds  ;  and  one 
species  is  represented  in  Fig.  898. 

Figs.  901-904. 
901     ^itmatm  903 


MIOCENE,  YORKTOWX  GROUP.— Figs.  901,  902,  Crepidula  costata.      LAMELLIBRANCHS.  —  Fig.  903, 
Yoldia  limatula  ;  904,  Callista  Say  ana 

The  Radiates  comprised  Polyps  and  Echini,  partly  of  modern  genera. 
The   Mollusks    embraced   species  of   Oyster,   Venus    (Clam),  Chama, 

Figs.  905-907. 


PLIOCENE,  SCMTER  GROUP.  —  Fig.  905,  Pecten  (Amusium)  Mortoni ;  906,  Area  (Scapharca)  hians. 
GASTEROPOD.— Fig.  907,  Cypraea  Carolinensis. 

Area,  Voluta,  Cyprcea  and  other  modern  genera,  but  no  Brachiopods 
except  Terebratulids  and  Discina*  and  no  Cephalopods  having  cham 
bered  shells  but  those  of  Nautilus.  There  are  numerous  land  and 
fresh-water  shells  in  the  beds  of  the  Upper  Missouri  region. 

Some  of  the  species  of  the  Middle  Eocene  (Claiborne  group)  are 
represented  in  Figs.  889  to  893 ;  others,  of  the  Upper  Eocene  (Vicks 
burg  group),  in  Figs.  894  to  900. 

Others,  of  the  Miocene  and  Pliocene,  in  Figs.  901  to  907. 

Of  Articulates,  there  were  Crabs  and  Insects,  of  all  the  modern 
tribes. 


TERTIARY    AGE. 


501 


The  above  remarks  on  the  animal  life  relate  only  to  the  Middle 
Eocene  and  later  species.  The  Lignitic  beds,  or  Lower  p]ocene,  of  the 
Rocky  Mountain  region  and  the  Pacific  Border  are  remarkable  for 
combining,  along  with  species  of  a  true  Tertiary  character,  others  that 
are  characteristically  Cretaceous,  owing  to  the  fact  that  the  Cretaceous 
strata  pass  up  without  break  or  marked  transition  into  the  Lignitic 
Tertiary.  These  Cretaceous  and  Cretaceous-like  species  include  Ino- 

908-913. 

908  <••- 

HRs^x  QIO 

f    -.    .       JfUV\k\^HOTD^^A.  /C^^^^^BE         &£§K\       <J-L—  I 


LAMELUBRANCHS.  —Figs.  90S,  908  a,  Corbula,  (Potamomya)  mactriformis  ;  909,  Cyrene  (Corbicula) 
intermedia;  910,  Unio  pviscus.  GASTKROPODS.  —  Fig.  911,  Yiviparus  retusus  ;  912,  Melania  Ne- 
brascensis  ;  913,  Viviparus  Leai. 

ceramus  problematicus  (Fig.  837,  p.  461),  and  other  allied  species,  which 
occur  at  various  levels,  through  thousands  of  feet  of  rock,  and  are 

abundant  in  some  beds.     In  Cali- 

„  .  Figs.  914-916. 

rorma,  an    Ammonite  continues  to 

the  top  of  the  Lignitic  series. 
Another  peculiarity,  already  allu 
ded  to,  is  the  abundance  of  fresh 
water  shells  in  some  beds.  Some 
of  these  fresh-water  species,  from 
the  upper  Missouri  region,  are 
represented  in  Figs.  908  to  913. 

II.  VERTEBRATES.  —  The  Lig 
nitic  or  Lower  Eocene  beds  have 
not  yet  afforded  any  remains  of 
Mammals,  and  no  Vertebrate  re 
mains  excepting  those  of  Fishes 
and  Reptiles.  Two  Saurians  occur 
in  it,  related  to  the  Dinosaurs  ;  and 
this  is  another  example  of  the 
Cretaceous  feature  of  the  beds. 
One  specimen  was  found  by  Meek, 
near  Black  Butte  in  Wyoming,  TEETH  OF  SHARKS  :  Fig  914<  Carcharodon  augusti. 

and  another,  related   to    the    Mega-     dens;  91o,Lamnaelegans;  916,Notidanusprirn- 

losaur,  by  Marsh,  south  of  the  Urn-    igenius' 
tah  Mountains. 


502 


CENOZOIC    TIME. 


The  Middle  and  Upper  Eocene  abound  in  remains  of  Vertebrate 
life,  of  all  grades,  Fishes,  Reptiles,  Birds,  and  Mammals.  The  fishes 
were  of  the  orders  of  Teliosts  (Herring,  etc.),  Ganoids  or  Gars,  and 
Sharks ;  Teliosts  and  Sharks  predominating  greatly  over  the  Ganoids, 
and  the  Sharks  much  exceeding  in  size,  variety,  and  numbers  those 
now  living.  The  teeth  of  the  latter  (Figs.  914  to  916)  are  ex- 
Fig.  917. 


Tooth  of  Zeuglodon  cetoides  ( X  ?s  )• 

ceedingly  abundant,  in  both  the  Eocene  and  the  Miocene ;  and  some  of 
the  triangular  teeth  of  Carcharodon  megalodon  Ag.  are  six  and  a  half 
inches  long,  and  five  broad  at  base.  They  are  found  at  Gay  Head, 
as  well  as  in  the  States  south  and  southwest. 

The  Reptiles  embraced  species  of  Turtles,  several  of  true  Crocodiles, 
arid  Snakes  twenty  feet  long  and  shorter. 

The  Birds  discovered  in  the  Eocene  and  Miocene  beds  include  sev- 


TERTIARY    AGE. 


503 


eral  Wader?  ,  an  Owl,  a  species  apparently  related  to  the  Woodpecker, 
and  two  or  three  web-footed  species,  allied  to  the  Gauiiet,  Guillemot, 
etc.  ;  and  the  Pliocene  has  afforded  remains  of  an  Eagle,  as  large  as 
the  Golden  Eagle,  a  Cormorant,  etc.,  sufficient  to  indicate  that  the 
type  of  Birds  was  well  displayed. 

"  The  Mammals,  in  this  age  of  Mammals,  have  a  special  interest.  No 
remains  have  yet  been  found  in  the  Lignitic  group  of  the  marine  Clai- 
borne  beds;  but,  in  the  overlying  Jackson  beds  there  are  bones  of  one 
or  more  species  of  gigantic  whale-like  animals.  The  most  common, 
called  the  Zeuglodon  cetoides  Owen,  was  probably  about  seventy  feet 
in  length.  The  large  vertebra?,  some  of  them  a  foot  and  a  half  long 
and  a  foot  in  diameter,  were  formerly  so  abundant  over  the  country,  in 
Alabama,  that  they  were  used  for  making  walls,  or  were  burned  to  rid 
the  fields  of  them.  Fig.  917  shows  one  of  the  yo&e-shaped  teeth,  to 
which  the  name  (from  £,evy\rj,  yoke,  and  oSou's,  tooth)  alludes.  The  re 
mains  occur  in  Mississippi,  Alabama,  Georgia,  and  South  Carolina  ; 
and  a  species  of  the  genus  is  found  in  the  Tertiary  of  Europe. 

The  earliest  American  Eocene  terrestrial  quadrupeds  yet  known 
are  from  the  Middle  Eocene  of  the  Rocky  Mountain  region.  The 
species  are  related  to  the  modern  Tapirs.  A  figure  of  the  living 
Malayan  Tapir  is  here  given  for  illustration.  A  prominent  feature  of 


Fig.  018. 


Tapirus  Indicus. 

these  Herbivores  is  the  long  and  useful  nose ;  it  is  the  organ  employed 
for  getting  its  food ;  and  in  some  it  is  long  enough  to  be  flexed 
around  a  small  tree.  The  Tapir,  in  this  respect,  is  between  the 
Elephant  and  the  Hog.  Like  these  animals,  and  also  the  Rhinoceros, 
it  belongs  to  the  section  of  plant-eaters  which  has  been  called 
Sthenorhines  (from  o-^eVo?,  strong,  and  ptV,  nose),  in  allusion  to  the  fact 
that  the  nose  is  the  power-organ.  Like  other  species  of  the  Tapir 


504 


CENOZOTC    TIME. 


tribe,  it  is  a  perissodactyl,  that  is,  it  is  odd-toed,  the  third  toe  of  the 
normal  five  being  longer  than  the  others,  instead  of  being  an  artio- 
dactyl,  or  even-toed,  like  the  Hog,  Hippopotamus,  and  all  Ruminants. 
So  far  as  is  now  known,  the  perissodactyls  existed  before  the  Hogs  ; 
and  the  Tapir-like  kinds  among  them  were  the  earliest.  In  this 
connection,  it  is  of  interest  to  note  that  the  character  of  odd-toed  is  a 
mark  of  higher  grade  than  that  of  even-toed,  as  is  illustrated  by  its 
belonging  to  the  higher  Herbivores  and  to  Man.  In  even-toed  or 
artiodactyl  Herbivores,  the  fourth  linger  is  enlarged  to  an  equality 
with  the  third,  and  the  first  is  wanting ;  and  thus  the  greatest  force 
of  the  toes  or  fingers  is  toward  the  little  toe,  instead  of  toward  the 
first  or  big  toe  ;  and  hence  it  is  that  the  feature  indicates  inferiority. 
The  Hog  type  is  therefore  lower  in  grade  than  that  of  the  Tapir, 
whether  posterior  to  it  or  not,  in  time  of  origin. 

The  genera  Hyracliym  and  others  (near  Lophiodon  of  the  European 
Eocene)  and  Palceosyops  (related  to  Palceotherium)  are  among  the 
Tapir-like  groups  of  the  Wyoming  region  in  the  Middle  Eocene. 

Another  kind  somewhat  allied  to  these,  but  Rhinoceros-like  in 
habit,  and  having  horns  in  pairs,  existed  in  the  Later  Eocene  of  the 
same  region.  Among  them,  there  were  the  Dinoceras  of  Marsh,  and 
the  Uintatherium  of  Leidy — animals  like  an  Elephant  in  size,  but 

Fig.  919. 


Dinoceras  mirabile  (X%)- 


without  his  trunk,  outdoing  the  Rhinoceros  in  horns,  the  number  being 
probably  three  pairs,  and  surpassing  any  known  wild  boar  in  its  huge 


TERTIARY    AGE. 


505 


tusks.  The  figure  (Fig.  919,  from  Marsh)  gives  an  oblique  view  of 
the  skull,  one  eighth  its  natural  size,  and  shows  the  pairs  of  horn-like 
prominences,  two.  of  which,  if  not  all,  were  horn-cores,  bearing  horns, 
and  also  the  tusks  or  canines.  The  name  Uintatherium  alludes  to  the 
Uintah  Mountains,  the  southern  boundary  of  the  Green  River  basin, 
and  Dinoceras  to  the  terrible  array  of  horns. 

There  were  also  the  earliest  known  species  of  the  Horse  tribe  in 
America.  The  modern  Horse  has  one  toe,  the  third  one  out  of  the 
five  in  other  animals,  enormously  enlarged  and  elongated  ;  but  either 
side  of  it,  under  the  skin,  there  are  rudiments  of  the  second  and  fourth 

riff.  920. 


FEET  OF  SPECIES  OF  THE  HORSE  TRIBE. — Fi»-  920  «,  Orohippus,  of  the  Eocene  (x  ?§);  920  b,  An- 
chitherium,  of  the  Miocene  ;  920  c,  Hipparion,  of  the  Pliocene  ;  920 d,  the  modern  Horse. 

toes,  in  the  shape  of  long  pointed  bones,  called  splint-bones  (as  shown 
in  Fig.  920  d ),  while  the  first  and  fifth  toes  are  wholly  absent :  occa 
sionally,  a  very  small  hoof  is  seen  hanging  outside  of  a  horse's  leg, 
from  the  extremity  of  one  of  these  splint-bones.  In  the  most  ancient 
of  the  Horse  tribe,  these  rudimentary  toes  were  real  toes,  of  full  length 
and  development,  though  much  smaller  than  the  large  middle  one  ; 
and  thus  there  is  a  gradation  between  some  of  the  Tapir-like  beasts 
and  the  one-toed  Horse.  In  the  Eocene  Horses  of  Wyoming,  of  the 
genus  Orohippus,  of  Marsh,  not  larger  than  a  fox,  there  were  four 
toes  in  the  fore  foot,  all  of  usable  length,  that  is,  three  besides  the 
large  one,  as  shown  in  Fig.  920«,  from  Marsh.  In  the  Miocene  of  the 
Upper  Missouri  and  Rocky  Mountain  region,  and  also  of  Oregon,  there 
are  the  remains  of  Horses  of  the  genus  Anchitherium,  having  three 
usable  toes  (as  illustrated  in  Fig.  920  b,  also  from  a  paper  by  Marsh)  ; 
this  is  an  intermediate  form  between  the  Orohippus  and  the  modern 
Horse.  It  is  like  the  Pcdceotherium  in  having  three  toes,  but  differs 
in  that  the  middle  toe  is  much  larger  than  the  others.  In  the  Plio 
cene  of  Niobrara  and  Oregon,  occur  Horses  of  still  another  extinct 


506 


CENOZOIC    TIME. 


genus,  Hipparion,  which  had  three  toes  (Fig.  920  c),  but  the  two  outer 
too  small  to  reach  the  ground.  With  these  there  were  also  true 
Horses,  of  the  modern  genus  Equus. 

The  American  Later  Eocene  era  had  also,  in  the  Fort  Bridger 
region,  etc.,  its  Carnivores,  related  in  characters  to  the  Cat.  Wolf,  and 
Fox.  The  still  higher  group  of  Quadrumanes  (Monkeys)  was  repre 
sented,  according  to  Marsh,  by  species  related  to  the  Lemurs  and 
Marmosets.  There  were  also  Bats,  Squirrels,  Moles  (Insect  ivores),  and 
Marsupials. 

MIOCENE  Tertiary  quadrupeds  abound  in  the  Upper  Missouri  region 
about  White  River,  and  in  different  localities  about  the  summit  of  the 

Fig.  923. 


IVofli  of  Titanotherium  Proutii  (X/a)- 

Rocky  Mountains,  and  also  in  the  interior  of  Oregon.  The  White 
River  beds  were  early  explored  by  Evans  and  Hayden.  Leidy  has  de 
scribed  from  this  region,  among  Carnivores,  kinds  related  somewhat 
to  the  Hyena,  Wolf,  Tiger,  and  Panther;  among  Herbivores,  two 
Rhinoceroses,  and  species  approaching  the  Tapir,  Hog  or  Peccary, 
Camel,  Lama,  Horse,  Deer,  and  Musk-ox ;  several  Rodents  related  to 
the  Hare,  Beaver,  Squirrel,  etc.  ;  and  a  number  of  Insectivores. 

Flu-.  924. 


Ttoth  of  Ilyracodon  (Rhinoceros)  Nebrasce 


The  Titanothere  (Titanotherium  Proutii  L.)  is  one  of  the  Herbi 
vores,  having  some  relations  to  the  modern  Tapir  and  ancient  Pale- 
othere,  but,  according  to  Marsh,  nearer  to  the  ancient  Dinocerata,  as  it 
had  at  least  one  pair  of  horns.  One  of  the  teeth  is  represented,  half 
natural  size,  in  Fig.  923.  The  animal  was  twice  as  large  as  a  modern 


TERTIARY    AGE. 


507 


Horse,  and  probably  stood  seven  or  eight  feet  high.  Its  remains 
occur  in  the  lower  of  the  Miocene  beds.  With  it  there  is  a  related 
elephantine  horned  beast,  having  a  pair  of  horns,  which  has  been 
named  Brontotherium  by  Marsh. 

One  of  the  Rhinoceroses  (Aceratherium  occidentale  L.),  was  about 
three-fourths  as  large  as  the  East  India  species,  and  another  (Hyraco- 
don  Nebrascensis  L.j  Fig.  924)  half  as  large.  There  were  also  several 


Oreodon  gracilis. 

species  of  a  genus  called  Oreodon  by  Leidy,  intermediate  between  the 
Deer,  Camel,  and  Hog  (a  skull  of  one  species  of  which  is  represented 
in  Fig.  925);  and  others  of  related  genera. 

Among  the  Horses,  there  were  species  of  the  genus  Anchitherium, 
mentioned  on  page  505  ;  but  no  true  one-toed  Horse  (Equus)  is  known 
from  the  beds. 

The  Mammals  of  the  Miocene  beds  on  the  Atlantic  coast,  so  far  as 
known,  are  mainly  species  of  Whales,  Dolphins,  Seals,  and  Walruses, 
bones  of  which  have  been  found  on  Martha's  Vineyard  and  at  other 
places  on  the  Atlantic  coast.  Besides  these,  remains  of  Rhinoceros, 
Lophiodon,  and  Elotherium  have  been  found  in  New  Jersey,  and  of 
Camelus  in  Virginia. 

The  PLIOCENE  of  South  Carolina  has  afforded  the  remains  of  a 
Mastodon  and  a  Stag  (Cervus}.  In  the  Upper  Missouri  region,  exists 
the  great  cemetery  of  the  Pliocene  ;  and  it  is  nearly  as  wonderful  as 
that  of  the  Miocene  Tertiary.  From  remains  gathered  first  by  Hay- 
den,  on  the  Niobrara,  and  on  the  Loup  Fork  from  North  Branch  to  its 
source,  and  some  other  points,  Leidy  determined  and  named  a  large 


508  CENOZOIC    TIME. 

number  of  Mammals,  all  now  extinct.  They  include  three  species  of 
Camel  (genus  Procamelus)  ;  a  Rhinoceros  (R.  crassus  L.)  as  large  as 
the  Indian  species;  a  Mastodon  (M.  mirificus  L.)  smaller  than  the  M. 
Americanus  L.  of  the  Quaternary  ;  an  Elephant  (Elephas  Ameri- 
canus) ,  occurring  also  in  the  Quaternary  ;  four  or  five  species  of  the 
Horse  family,  one  of  which  was  closely  like  the  modern  Horse ;  a 
species  of  Deer  (Cervus  Warreni  L.)  ;  others  near  the  Musk-deer  of 
Asia ;  species  of  Merychyus,  allied  to  Oreodon ;  a  Wolf,  larger  than 
any  living  species;  a  small  Fox ;  a  Tiger  (Fells  augmtus  L.),  as  large 
as  the  Bengal  Tiger,  besides  other  Carnivores  ;  a  small  Bearer  ;  a 
Porcupine.  The  collection  of  animals  has  a  strikingly  Oriental  char 
acter,  except  in  the  preponderance  of  Herbivores.  Other  kinds  have 
been  since  discovered,  much  extending  the  fauna. 

Characteristic  Species. 
1.  LIGNITIC  PERIOD. 

1.  Radiates.  —  In  the  Lignitic  coal-bearing  bed,  south  of  the  Uintah  Mountains, 
Marsh  found  a  Crinoid  near  the  Marsupites  of  the  Cretaceous,  and  in  the  same  vicinity 
Ostrea,  conaesta,  and  scales  of  a  Beryx,  other  Cretaceous  forms.     It  is  at  present  doubt 
ful  whether  the  beds  are  Cretaceous  or  Tertiary. 

2.  Mollusks.  —  In   the  coal-bearing  or  Lignitic  group    of  the  Rocky  Mountain 
region,  referred  by  some  to  the  Cretaceous  formation,  occur,  at  different  levels  (p.  501), 
Inoceramus  problematic^  and  other  Inocerami,  an  Anchura,  Gyrodesdepressa  M.,  all  Cre 
taceous  forms.    With  these  are  found  Cardium  subcurtum  M. ,  Avicula  gastrodes  M.,  Ostrea 
soleniscus  M.,  Cyrena  Carltoni^L,  Modiola  multilinigera  M.,  Neritina  puum  M.,  Tur- 
ritella  Coalvillensis  M.,  T.  spironema  M.,  Cyprimera(?)isonema  M.,  Eulima  funicula  M., 
E.  chrysalis  M.,  E.(?)inconspicuaU.,  Melamjms  antiquus  M.,  species  of  Unio  ;  Corblcula 
securis  M.,  C.  (equilateralis  M.,  C.  fracta  M.,  Vimparus  trochiformis  M. ;  also,  in  some  beds- 
in  the  series,  species  of  the  fresh-water  genera,  Physa,  Valvata,  Cyrena,  Neritina,  with 
those  of  Melampus,  Eulima,  Tumtella,  etc.;  or  of  Goniobasis,  Vimparus,  Corblcula,  Cor- 
bula,  along  with  Ostrea,  Anomia,  and  Modiola.     In  the  fresh  and  brackish  water  Lignitic 
beds  of  the  Upper  Missouri  region,  Figs.  908,  908  a,  Corbuli  (Potamomya)  mactriformis 
M.  &H.;  Fig.  909,  Corbicula  intermedia  M.  &  H. ;  Fig.  910,   Unio  priscus  M.  &  H. ; 
Fig.  911,  Viviparus  retnsus  M.  &  H. ;   Fig.  912,  Mtlania  Nebrascensis  M.  &  H. ;  Fig. 
913,  Vivlparut  Leai  M.  &  H. 

Meek  states  that  the  species  of  Melampus  differ  little  from  those  of  the  Paris  Tertiary 
Basin;  that  the  species  of  Corbida,  Corbicula,  Physa,  Cyrena,  Neritina,  arejery  similar 
to  species  of  the  Lower  Tertiary  in  the  Upper  Missouri  region;  also  that  Vimparus  tro 
chiformis  M.  is  a  Tertiary  species  of  the  Upper  Missouri ;  while,  on  the  other  hand,  an 
Anomia  is  very  similar  to  a  Texas  Cretaceous  species. 

In  California,  in  the  Tejon  group,  occur,  according  to  Gabb,  species  of  Ammonites 
(one,  A.  jugalis  Gabb),  Fusus,  Surcula,  Typhis,  Tiitonium,  Nassa,  Pseudoliva,  OUvetta, 
Fasciolaria,  Mitra,  Ficus,  Natica,  Lunatia,  Neverita,  Naticina,  Scalaria,  Terebra,  Niso, 
Cerithio2)sis,  Architectonica,  Conus,  Rimella,  Cypraa,  Loxotrema,  Turritella,  Galerus, 
Nerita,  Margaritella,  Gadus,  Bulla;  Solen,  Corfmla,  Neiera,  Tellina,  Donax,  Venus, 
Meretrix,  Dosinia,  Tapes,  Cardium,  Cardita,  Lucina,  Crassatella  (C.  altn  Con.),  Myti- 
lus,  Modiola,  Avicula,  Area,  Axincea,  Ptcten,  Ostrea,  with  the  coral  Trochosmilia  stnata 
Gabb. 

3.  Fishes,  Reptiles In  the  beds  of  the  Upper  Missouri,  occur  scales  of  Lepi- 


TERTIARY    AGE. 


509 


dotus ;  remains  of  Turtles,  of  the  genera  Trionyx,  Emys,  Compsemys;  species  of  Croco 
dilus,  etc. 

Bes'des  these,' near  Black  Butte  Station,  bones  referred  to  a  Dinosaur  by  Cope;  and, 
southeast  of  the  Uintah  Mountains,  remains  of  a  Saurian  related  to  the  Meyalosaurs,  dis 
covered  by  Marsh  ;  both  Cretaceous  forms. 

4.  Mammals —  None  yet  found. 

2.  ALABAMA  PERIOD. 

1.  Protozoans.  —  Rhizopods,  Fig.  898,  OrbitoidesMantelliLye\\,Vicksburg group. 

2.  Radiates. — (a.)  In   the    Jackson    Group:  Corals,   Flabellum    Warledi   Con., 
Endopachys  Maclurii  Lea. ;  Echinoderms,    species  of   Scutella,    Clypeaster.     (b.)  In  the 
Vicksburg  Group :    Corals,  Oculina  Mississippiensis  Con.,   0.  Vicksburyensis  Con.,  Tur- 

'Unolii  caulifera  Con.;  Echinoderms,  Fig.  895,   Clypeaster  (Mortonia)  Royersi  Con. 

3.  Mollusks.  —  (a.)    In   the     Cl'iibome    Group:     Fig.    880,    Ostrea   selfaformis 
Con.;    0.  divaricata  Lea;  0.  romer ;  0.  panda,  Mort. ;  Pecten  Lyelli  Lea;   Fig.    890, 
Crassatella  alt  a  Con.;  Fig.  891,  Astarte  Conradi  D.;  Fig.  892,  Cardita  planicosta  Sow., 
from  Canada  de  las  Uvas  in  California,  as  well  as  east  of  the  Mississippi  and  in  Europe 
(  C.  densata  Con.);   (7.  Blandinyii  ;   C.  rotunda  Con. ;   Cardium  Nicolleti;  Fig.  893,  Tur- 
ritella  carinata  Lea;  Calyptrophorus  (Rostellaria)  velatus  Con.,  Pseudoliva  vetusta  Con.; 
Orbis  rotella  Lea;  Nation  JEtites  Con.  (Californian,  as  well  as  east  of  the  Mississippi); 
Anolax  yiyantea  Lea,  Olivella  Alabamensis  Con.,  Maryinella  larvata  Con.,  Volutilitlies 
( Voluta]  petrosa  Con.,  Corbula  yibbosa   Lea;    Nautilites    Vanuxemi  Con.     (b.)  In  the 
Jackson  Group  (species  common  to  the  Jackson  and  Vicksburg  epochs  arc  marked  with 
a  dagger  [t]):    Venericardla  planicosta   Con.;    V.   rotunda^    Lea;    Cardium  Nicolleti 
Con.;    Corbula   bicarinata  Con.;   Leda  multilineata  Con.;    Callista  sobrina-f   Con.;   C. 
imitobilis  Con. ;    Mactra  funerata]    Con. ;  Psammobia   lintea^   Con. ;   Navicul'i   lima-f 
Con.;    Calyptrophorus   velatus   Con.;    Cyprcea  fenestralis   Con.;    C.    lintea\    Con.;   C. 
spheroides'f  Con.;   Conus  tortilis  Con.;    Gastridium  vetustum   Con.;  Mitra    Millinytoni 
Con.;    M.   dumosaCon.',  Valuta  dumosa  Con.,  Natica  Vicksburyensis-fCon.;  Turbindla 
Wilsoni-f  Con.;  Dentalium  Mississippiense^  Con.     (c.)  In   the   Vicksbury  Group:  Fig. 
894,  Pecten  Poulsoni  Con.;    Fig.  896,   Ostrea,  Georyiana   Con.,  one   fourth   linear   di 
mensions  ;    0.    Vicksburyensis   Con.;    Fig.    897,  Anomalocardia  Mississippiensis   Con.; 
Barbatia  Mississippiensis  Con. ;   B.    Lima   Con. ;   Cardium  diversum   Con. ;    Crassatella 
Mississippiensis  Con. ;  Panopcea  oblonyata  Con. ;  Fig.  899,  Cithara  Mississippiensis  Con. ; 
Fig.  900,  Dentalium  Mississippi ense  Con. ;  also  twelve  species  of  Pleurotomidce,  four  of 
Triton,  five  of  Mitra,  etc. 

One-sixth  of  the  species  occur  in  the  Vicksburg  beds,  and  several  in  the  Claiborne. 
At  Red  Bluff,  there  is  a  stratum  between  the  Jackson  and  Vicksburg  beds,  containing 
many  species  peculiar  to  it;  twenty-eight  per  cent,  only  are  Vicksburg  species,  while  six 
per  cent,  are  Jackson. 

4.  Vertebrates.  _  (a. )  In  the  Claiborne  Group.  —  Fig.  915,  Lnmna  deyans  Ag. ; 
Fig.  916,  Notidanus primiyenius  Ag.,  from  Richmond,  Va. 

(b.)  In  the  Jackson  Group.  —  Teeth  of  Sharks.  Fig.  917,  tooth  of  Zeuylodon  cetoides, 
natural  size. 

(c.)  In  the  Vicksbury  Group.  — Teeth  of  Sharks,  Fig.  914,  Carcharodon  anyustidens 
Ag. ;  C.  meyalodon  Ag  ;  Galeocerdo  latidens  Ag. — Reptile,  Crocodilus  macrorliynchus 
Harlan. 

((/.)  In  the  Eocene  Green-sand  beds  of  Squnnkum,  Monmouth  County,  New  Jersey.  — 
The  sword-fishes,  Histiophorus  yracilis  Mh.,  Embalorltynchus  Kinnei  Mh  ,  'CcelorJiyn- 
chus  ornatus  L. ;  the  Saw-fish,  Pristis  curvidens  L.  The  Snakes,  Dinoplns  Halidanus 
Mh.  (Palceophis  Halidanus  Cope),  twenty  feet  long,  D.  littoralis  Mh.,  Dinophis  yrandis 
Mh.,  probably  over  twenty  feet  long;  the  Crocodile,  Crocodilus  Squankensis  Mh.;  Ga- 
vialis  minor  Mh.,  but  six  feet  long.  In  South  Carolina,  Pristis  ensidens  L.  In  Virginia, 
Pristis  brachiodon  Cope. 

(e.)  In  the  Fresh-water  beds  of  the  Rocky  Mountain  Reyion,  in  Wyominy,  Utah,  and 
Colorado. 


510  CENOZOIC    TIME. 

(1.)  FISHES,  in  the  inferior  shales,  in  the  Green  River  basin  (Middle  Eocene).  The 
Gars,  Lepidosteus  yVtber  Mh.,  L.  Whitneyi  Mh.,  Amia  Newberrianus  Mh.,  A.  depressus 
Mh. ;  the  Teliosts.  Clupea  humilis  L.,  Clupea pusilla  Cope,  etc. 

(2.)  REPTILES. — Species  of  Emys,  Trionyx,  etc.,  among  Testudinates;  of  Alligator, 
Crocodilus,  Diplocynodus,  Limnosaurus,  etc.,  among  Crocodilians;  of  Saniva  (of  Leidy), 
Naoceplinlus  (of  Cope),  Thinosaurus  grandis  Mh.  (seven  feet  long),  Glyptosaurus  prin- 
ccps  Mh.  (six  feet  long),  among  Lacertilians ;  Boavus  occidentalis  Mh.,  probabl}*  eight  or 
ten  feet  long,  B.  agilis  Mh.,  B.  brevis  Mh.,  Lithophis  Saryenti  Mh.,  Limnophis  crassus 
Mh.,  among  Serpents. 

(3.)  BIRDS. — An  Owl,  Bubo  leptosteus  Mh. ;  the  Woodpecker  (?),  Uintomis  lucaris 
Mh  \,  the  Waders,  Aletornis  nob  His  Mh.,  A.  gracilis  Mh.,  etc. 

(4.)  MAMMALS. — The  Tapir-like  Sthenorhines,  Lophiodon  Bnlrdianus  Mh.,  Hyra- 
chyus  eximius  L.,  //.  princeps  Mh.,  //.  implicatus  Cope,  Limnohyus  paludosus  L.,  L. 
diaconus  Cope,  P:dteosyops  levidens  Cope,  P.  major  L.,  P.  laticeps  Mh.,  very  large; 
Ifomacodon  vagans  Mh.  Horned  Sthenorhines  (the  horns  in  pairs),  called  Dinocerata 
by  Marsh,  by  whom  the  first  species  was  described;  Uintatherium  robustumL.  Fig. 
919,  Dinoceras  mirabile  Mh.,  Tinoceras  yrande  Mh.  (Eobasileus  pressicornis  Cope),  and 
others.  They  are  all  referred  to  Uintatherium  by  Leidy.  Colonoceras  agreste  Mh. 
(as  large  as  a  Sheep)  had  but  one  pair  of  horns,  and  that  on  the  nose.  Possibly  re 
lated  to  Hyrax,  Anchippodus  minor  Mh.,  Tillutherium  hyracoides  Mh.  Horse-tribe, 
Orohippus  pumilus  Mh.,  0.  agilis  Mh.  (as  large  as  a  Fox).  Carnivores,  Mesonyx  obtu- 
sidens  Cope  (of  the  size  of  a  large  Wolf  ),  Limnofelis  ferox  Mh.  (nearly  as  large  as  a 
Lion),  Limnocyon  riparius  Mh.  (as  large  as  a  Fox),  Oreocyon  latidens  Mh.  (about  as  large 
as  a  Lion).  Insectivores,  Passalacodon  litoralis  Mh.  (size  of  Hedgehog),  Centetodon 
pulcliar  Mh.  (as  large  as  a  Mole),  Centracodon  delicatiuMh.  (id.).  Bats,  Nyctltherium 
velox  Mh.,  N.  priscum  Mh.  Quadrumana,  Notharctus  of  Leidy;  Limnotherium,  TJtino- 
lestts,  and  T<. Imatolest es  of  Marsh,  regarded  as  related  to  the  Lemurs  and  Marmosets; 
Tomithcrium  of  Cope.  Rodents,  Sciuravus  parvidens  Mh.,  Colonomys  celer  Mh., 
Paramys  leptodus  Cope,  P.  robustus  Mh.,  Pseudotomus  hicins  Cope,  etc.  Marsupials, 
Triacodon  fallax  Mh.,  T.  yrandis  Mh.,  T.  aculeat us  Cope,  Stypoloplius  pungens  Cope. 
Many  other  species  have  been  described  from  the  Rocky  Mountain  region. 

3.  YORKTOWX  PERIOD,  or  MIOCENE. 

1.  Mollusks.  —In  the  marine  beds  of   the  Atlantic  Border.  —  Fig.  901,  Crepidula 
costata  Say;  Fig.  902.  inside  view  of  the   same;  Fig.  903,  Yoldia  limatula  Say,  also 
recent;  Fig.  904,  Callista  Sayana  Con. ;  Pecten  decennarius  Con. ;  P.  Viryinianus  Con. ; 
Cctrdium  Virginianum  Con.;  Venus  tridacnoides  Con. ;    V.  capax  Con. ;   Chama  corticosa 
Con. ;  Axincea  tumulus  Con. ;  Anomia,  Ruffini  Con. ;  also,  among  living  species,  Ostrea 
Viryiniana  Gmelin,  or  common  Oyster;    Venus  mercenaria  Lam.,  or  common  Clam, 
V.  cancellata  Gabb,  Mactra  (Mulinia.)  lateralis  Say;  Pecten  concentricus  Say;  Lunatia 
heros  Stimpson;  Oliva  litterata  Lam.,  Nassa  (Tritia)  trivittata  Say,  etc. 

In  the  marine  beds  of  the  Pacific  Border.  —  Some  of  the  species  of  California,  as 
given  by  Gabb,  are  Nassa  fossata  *  Gould,  Neverita  saxea  Con.,  Cerithidea  Califor- 
nica*  Hald.,  Turritelln  Hoffmanni  Gabb,  T.  rariata  Con.,  Machcem  patula *  Cpr., 
Tellina  conyesta  Con.,  Lutricola  alta*  Cpr.,  Lucina  borealis*  Linn.,  Yoldia  impressa  * 
M.,  Pecten  propatulus  Con.;  with  the  Echinoderms  Clypeaster  Gabbii  Rem.,  Scutella 
Gibbsii  Rem.  The  Miocene  of  Oregon  also  contains  various  species. 

2.  Vertebrates.  —  FISHES.  —  On  the  Atlantic  Border.  —  Carcharodon  meyalodon  ; 
Galeocerdo  latidens  Ag. ;  Hemipristis  serra  Ag. ;  Oxyrhina  hastalis  Ag.     In  the  Miocene 
of  Ocoya   Creek,  California,   teeth  of    Sharks,  of  the  genera  Echinorhinus,    Scymnus^ 
Galeocerdo,  Prionodon,  Hemipristis,  Carcharodon,  Oxyrhina,  and  Lamna,  besides  a  tooth 
of  a  Zygobates.     (Agassiz.) 

REPTILES.  —  In  the  Upper  Missouri  region. —  Testudo  Culbertson'd  L.,  T.  hemi- 
sphcericaL.,  T.  Owcni  L.,  T.  lata  L. 

BIRDS.  —  On  the  Atlantic  Border.  —  PuJ/inus  Conradi  Mh.,  in  Maryland;  Catarractes 


TERTIARY    AGE.  511 

antiques  Mh  ,  in  North  Carolina;  Sula  (?)  loxostyla  Cope,  in  Xorth  Carolina.  In 
Colorado,  Meleayris  antiquus  Mh.,  a  wild  turkey. 

MAMMALS.  —  On  the  Atlantic  Border.  — Balcenn prisca  L. ;  B.  palceatlantica  L. ;  Del- 
phinus  Conradi  L. ;  Phoca  Wymani  L.,  etc.;  Elotherium  Leidyanus  Mh.,  a  gigantic 
species  of  the  Hog  family;  Dicotyles  antiquus  Mh.,  a  Peccary;  Rhinoceros  matutinus 
Mh. ;  Anchippodus  riparius  L. ;  Lophiodon  validus  Mh. 

On  the  Pacific  Border,  remains  of  Cetaceans,  etc. 

In  the  Upper  Missouri  region  (White  River  Group).  —  Fig.  923,  Titanotherium 
Proutii  L.,  one  of  the  teeth,  —  the  last  posterior  inferior  molar,  —  half  natural  size. 
Fig.  924,  Hyracodon  Nebrascensis  L.,  three  posterior  superior  molars,  left  side,  natural 
size.  Fig.  925,  Oreodon  gracilis  L.,  skull,  young  animal,  underside;  Oreodon  Culbert- 
soni  L. ;  also,  according  to  Leidy,  species  of  the  geneva  Drepanodon,  Ilywnodon,  Am- 
phicyon,  Dinictis,  of  Carnivores;  Anchithtrium  (A.  Bairdii),  of  Solidungulates;  Ayrio- 
chcerus  (A.  antiquus,  L.,  A.  major  L.,  etc.),  related  to  Oreodon;  Pabrotherium  (P.  Wil- 
soni  L.),  Lept'iuchenia,  Protomeryx,  Merycodus,  of  Ruminants;  Rhinoceros,  Hyracodon, 
Lophiodon,  Mastodon,  of  Sthenorhines;  Chceropotamus,  Leptochcerus,  Hyopotamus,  Elo 
therium  (K.  Mortoni  L.),  and  others,  of  Suillines;  Chalicoinys,  Ischyrotnys,  Palceolayus, 
Euiiiys,  of  Rodents. 

In  the  Miocene  (White  River  Group)  of  Colorado,  besides  several  of  the  above  species, 
Brontotherium  yiyas  Mh,,  nearly  as  large  as  an  Elephant,  B.  inyens  Mh.,  still  larger, 
and  Elotherium  crassum  Mh.,  two  thirds  as  large  as  a  Rhinoceros. 

In  the  Miocene  of  Oregon  occur  Oreodon  superbus  L.,  0.  occidentalis  Mh.,  Ayriochce- 
rus  antiquus  L.,  Anchitherium  Condom  L.,  Rhinoceros  Pacificus  L.(  R.  annecfans  Mh., 
Dicotylts  pristinus  L.,  etc. 

4.  PLIOCENE. 

1.  Mollusks.  —  Fig.  905,  Pecten  (Amusium)  Mortoni  Ravenel ;  Janirn  hemicyclica 
Ravencl;  Fig.  900,  Area  (Barbatia)  h'ans  Tuomey  &  Holmes;  ^1.  lienosa  Say;  Sconsia 
Hodyii  Con. ;  Fig.  907,  Cyprcea  Carolinensis  Con. ;   C. pedicvlus  Lam. ;   Conus  adversarius 
Con.;  Fasciolaria  rhomboidea  Rogers;  Busycon  indie  Conrad.     These  South  Carolina 
Pliocene  beds  contain,  according  to  Tuomey  &  Holmes,  nine  species  of  Echinoderms, 
while  none  are  found  in  the  Yorktown  beds  in  Virginia.     Corals  are  rare  in  the  beds  of 
both  the  Sumter  and  Yorktown  epochs. 

On  the  Pacific  Border,  there  are  many  species.  They  have  been  described,  mostly  by 
Gabb,  in  a  Report  connected  with  Whitney's  geological  survey  of  California. 

2.  Vertebrates —  FISH.  —  Mylocyprinus  robustus  L. 

BIRDS.  —  The  Loup  Fork  beds  have  afforded  a  fossil  Eagle,  Aqu'da  Dananus  Mh.,  a 
Crane,  Grits  Ilaydeni  Mh. ;  and  those  of  Idaho,  a  Cormorant,  Graculus  Idahensis  Mh. 

MAMMALS.  — The  Loup  Fork  region,  on  the  Niobrara,  has  afforded  species  of  Carni 
vores,  of  the  genera  Felis  (Felis  auyustus  L. ),  Canis,  Lcptarctus  (L.  primus  L.),  etc.; 
Sthenorhines,  of  the  genera  Elephas  (E.  imperator  L. ),  Mastodon  (M.  mirificus  L.),  Rhi 
noceros  (R.  crassus  L.),  Dicotyhs  (among  Suillines);  Ruminants,  of  the  genera  Pro- 
camelus,  Homocamelus,  Meyalomeryx,  Merycodus,  Cervus,  etc.;  Solidungulates,  of  the 
genera  Hipparion  (H.  parvulum  Mh.,  of  the  size  of  a  goat,  II.  occidental  L.),  Proto- 
hippus,  Merychippus,  Equus,  etc.;  Rodents,  of  the  genera  Castor  (C.  tortusL.),  Palceo- 
castor,  Hystrix.  The  Equus  excelsus  L.  was  quite  as  large  as  the  modern  Horse. 

The  Oregon  Pliocene  has  afforded  the  Suillines,  Plttyyonus  Condoni  Mh.,  and  Di- 
cotyles  Hesperius  Mh.,  besides  Rhinoceros  Oreyonensis  Mh. 


2.  FOREIGN  TERTIARY. 
I.  Rocks:    kinds  and  distribution. 

The  rocks  of  the  Tertiary  period  in  Britain  are  nearly  all  Eocene  ; 
and  the  thickness  of  the  beds  of  this  era  is  over  2,500  feet.     Above 


512  CEXOZOIC    TIME. 

the  Eocene,  there  are  thin  leaf-beds  of  Miocene  age,  and  about  100 
feet  of  Pliocene.  They  are  most  largely  developed  over  the  "  London 
basin,"  covering  part  of  southeastern  England.  From  this  region  in 
England,  the  Eocene  spreads  southward  over  the  "Paris  basin,"  a  por 
tion  of  northern  France,  having  Paris  near  its  centre.  The  middle 
Eocene,  of  the  southern  half  of  Europe  and  Asia  and  northern  Africa, 
is  remarkable  for  the  abundance  of  the  coin-shaped  fossil  called  Num- 
mulites  (from  the  Latin  nummus,  a  coin),  a  kind  of  Foraminifer  or 
Khizopod  secretion,  as  explained  on  page  131.  Some  limestones  arc 
almost  entirely  made  of  Nummulites.  The  Nummulitic  rocks  extend 
over  large  parts  of  the  Pyrenean  and  Mediterranean  basins,  covering 
portions  of  the  Pyrenees,  the  Alps  (constituting  the  summits  of  the 
Dent  de  Midi,  10,531  feet,  and  of  Diablerets,  10,670  above  the  sea- 
level),  the  Apennines,  and  the  Carpathians  ;  they  extend  into  Egypt 
(where  the  Pyramids  were  in  part  made  of  Nummulitic  limestone)  ; 
also  through  Algeria  and  Morocco,  parts  of  Asia  Minor,  Persia,  Cau 
casus,  India,  the  mountains  of  Afghanistan,  the  southern  slopes  of  the 
Himalayas,  and  to  a  height  of  1G,500  feet  in  western  Thibet.  They 
occur  also  in  Japan,  on  Luzon  in  the  Philippine  Islands,  and  in 
Java. 

Later  in  the  Tertiary,  the  beds  were  much  less  generally  marine, 
and  more  limited  in  extent,  showing  an  approximation  to  the  existing 
era,  in  the  condition  of  the  continents.  The  Miocene  had  still  a  very 
wide  distribution  over  France,  Switzerland,  Belgium,  etc.,  and  is  partly 
marine.  It  has  in  Switzerland  a  thickness  of  7,000  or  8,000  feet. 
The  Lower  and  Upper  Miocene  are  of  fresh  water,  while  the  Middle 
is  of  marine  origin.  The  beds  underlie  a  large  part  of  the  region  be 
tween  the  Alps  and  the  Juras,  and  constitute  some  high  summits,  as 
the  Rigi,  near  Lake  Lucerne.  The  Upper  division,  at  QEningen, 
afforded  the  famous  Homo  diluvii  testis  of  Scheuchzer  (in  1700)  — 
(shown  by  Cuvier  to  be  an  aquatic  Salamander),  and  is  noted  also  for 
its  fossil  plants  and  insects. 

In  the  Pliocene  era,  there  were  some  marine  deposits  in  Britain. 
The  strata  are  most  largely  developed  in  Sicily,  covering  nearly  half 
the  island,  and  having  in  some  places  an  elevation  of  3,000  feet  above 
the  sea. 

The  principal  subdivisions  of  the  Tertiary,  in  Britain  and  Europe,  are  the  following:  — 

1.  Lower  Eocene.  —  (1.)  Thanet  sands  (fluvio-marine),  of  Britain,  containing 
rolled  flints,   etc.;    the  Lower  Landenian  of  Belgium.      (2.)  Woolwich  and   Reading 
beds,  of  Britain;  Upper  Landenian  of   Brussels,  Argile   Plastique  et    Lignite,  Glau- 
conie  Infe'rieur  of  France.     (3.)  London  Clay;  Lower  Ypresian  of  Belgium. 

2.  Middle   Eocene.  — (1.)  Lower  Bagshot  beds;  Upper  Ypresian  of  Belgium, 
Lits  Coquilliers  and  Glauconie  Moyenne  of  France.     (2.)  Bracklesham  beds  of  Britain; 
Bruxellian  of  Dumont,  Calcaire  Grossier  et  Glauconie  Grossiere  of  France.  (Grobkalk, 


TERTIARY    AGE.  513 

Germ.)     The  Suessoninn  (from  Soissons)  of  D'Orbigny  includes  part  of  the  Lower  Eo 
cene  (the  London  Clay  excluded);  also  a  large  part  of  the  Nummulitie  beds. 

3.  Upper  Eocene.  —  (1.)  Barton  Clay,  of  Great  Britain;  Lower  Laeckenian,  of 
Belgium:    Lower   zone  of  Sables  Moyens,  of   France.      (2.)  Upper  Bagshot  beds,  of 
Britain;    Upper  Lasckenian  (?)  of  Belgium;  Upper  zone  of  Sables  Moyens,  of  France. 
(3.)Osborn  and  Headon  beds,  of  Great  Britain;  part  of  Upper  Laeckenian  (?);  Cal- 
caire  Marin  et  Gres  de  Beauchamp.     (4.)  Bembridge  beds,  of  Great  Britain;  Calcaire 
Siliceux,  Calcaire  Lacustre  JVJoyen,  Gypseous  series  of  Montmartre,  of  France;    Ton- 
grian,  of  Belgium.     The  preceding  1  to  4  correspond  to  the  Upper  Nummulitic  beds, 
and  the  upper  part  of  the  Flysch,  of  Switzerland.     (5.)  Hempstead  beds,  of  Great  Brit 
ain;  Marnes  Marines,  Gres  de  Fontainebleau ;  Rupelian  of  Dumont. 

The  Lower  Fahlunian  of  D'Orbigny  included  the  Gres  de  Fontainebleau,  and  the 
Upper,  the  Miocene.  The  Oliyoctne  of  some  geologists  comprises  the  preceding  sec 
tions,  3  to  5,  of  the  Upper  Eocene,  with  the  following  Lower  Miocene.  The  Flysch,  of 
Switzerland,  is  a  thick  formation  of  dark-colored  shale  and  sandstone,  overlying  Num 
mulitic  beds,  and  abounding  in  Fucoids  ( C/iondrites) ;  it  corresponds  to  the  sections  1, 
2,  3  of  the  Upper  Eocene. 

4.  Lower  Miocene. —  Britain.  —  Marine  and  fresh-water  Lignites,  and  Clay  of 
Bovey  Tracey;  Isle  of  Mull  Leaf -bed  and  Coal.     Europe.  —  Part  of  Terrain  Tertiaire 
Moyen;    Lacustrine   of  Auvergne;  Mayence  basin;  part  of  Tile  clay  near  Berlin ;  Cy- 
rena  shale  of  South  Bavaria,  characterized  by  Cyrena  semistriata  Desh. ;  probably  the 
so-called  Miocene  of  Mayence  and  Castel-Gomberto;  also  the  fresh-water  Molasse  of 
the  cantons  of  Vaud,  Berne,  and  Argovie;  Radaboj  beds  of  Croatia;  Miocene  beds  of 
Greenland. 

5.  Upper  Miocene.  —  Britain. —No  marine  beds.     Europe .  —  Upper  Fahlun 
ian  of   D'Orbigny;  Fahluns  of  Touraine;  beds  of  Gironde  and  Landes;  part  of  Vienna 
basin;  Superga  Hill,  near  Turin;  marine  Molasse,  and  Upper  fresh-water  Molasse,  in 
Switzerland;  Siwalik  Hills,  India. 

6.  Older  Pliocene.  —  Britain.-  Coralline  Crag  and  Red  Crag  of  Suffolk,  about 
100  feet  in  all.    Europe.  — Siibapennine  marls  and  sands;  Upper  massive  beds  of  Mont- 
pellier:  Hills  of  Rome;  Mount  Mario,  etc.;  Antwerp  and  Normandy  Crag;  part  of 
Upper  fresh-water  Molasse ;  Aralo-Caspian  deposits. 

7.  Newer  Pliocene.  — Britain.  —Norwich  Crag,  of  fluvio-mnrine  origin,  con 
taining  mostly  shells  of  species  now  found  in  British  seas,  with  some  Mammalian  re 
mains;  Forest-bed  of  Norfolk  cliffs,  with  Elephas  meridionalis,  etc.     Europe. Sicilian 

Pleistocene  formation,  which  covers  nearly  half  the  island  of  Sicily;  near  the  centre  of 
the  island,  at  Castrogiovanni,  it  has  a  height  above  the  sea  of  3,000  feet;  the  upper 
two  thirds  of  the  whole  are  limestone,  and  the  rest  mainlv  sandstone  and  conglomerate, 
underlaid  by  marl  or  clay. 

The  diversity  of  the  beds  in  the  Tertiary  period  is  well  shown  in  the  Paris  basin  for 
mation.  There  is,  first,  a  bed  of  plastic  clay  with  lignite,  containing  in  some  places 
Oysters  (0.  bellovacina)  and  a  few  other  marine  species,  and  in  other  layers  lacustrine 
shells,  along  with  bones  of  the  earliest  quadrupeds  of  the  age ;  second,  a  series  of  beds 
of  coarse  limestone  (Calcaire  Grossier),  with  green  marls,  abounding  in  some  parts  in 
Nummulites  and  other  Rhizopods;  containing  marine  shells  (over  500  species  in  all)  in 
certain  beds,  a  mingling  of  species  of  Cerithium  with  fresh-water  shells  in  others,  and 
also  bones  of  Mammals;  third,  over  this  limestone,  a  siliceous  limestone, containing  a 
few  fresh  water  shells;  fourth,  Gypseous  marls,  well  displayed  in  the  hill  of  Mont 
martre,  the  great  repository  of  the  bones  of  Eocene  Mammals,  explored  by  Cuvier,  and 
containing  also  remains  of  Birds,  Reptiles,  and  Fishes,  with  a  few  fresh-water  shells : 
fifth,  sandstone,  Gres  de  Fontainebleau,  marine  in  origin,  and  regarded  as  of  the  same 
age  with  the  lower  part  of  the  Molasse  of  Switzerland;  sixth,  Upper  Lacustrine,  or 
fresh-water  beds. 

In  the  European  Eocene,  the  fossils  are  all,  or  very  nearly  all,  of 


514  CENOZOIC   TIME. 

extinct  species ;  in  the  Lower  Miocene,  nearly  all  the  shells  are  ex 
tinct  ;  in  the  Upper  Miocene,  the  majority  are  extinct ;  in  the  Older 
Pliocene,  the  majority  of  the  shells  are  of  living  species  ;  in  the 
Newer  Pliocene,  Norwich  Crag,  nearly  all  the  shells  are  living. 

II.  Life. 

1.  Plants. 

Protophytes  were  abundant,  as  in  America  ;  the  well  known  Infu 
sorial  beds  of  Bilin,  in  Bohemia,  have  a  thickness  of  fourteen  feet, 
and  are  fresh-water  Tertiary.  Planitz,  in  Saxony,  is  another  similar 
locality. 

The  higher  plants  are  mainly  Angiosperms,  Conifers,  and  Palms. 

The  Isle  of  Sheppey  is  famous  for  its  fossil  fruits  ;  and  from  them 
Bowerbank  has  distinguished  those  of  thirteen  species  of  Palms,  re 
lated  to  the  Nipce  of  the  Moluccas  and  Philippine  Islands,  showing  that 
England  in  the  Eocene  was  a  land  of  Palms.  In  the  Middle  Eocene, 
in  England,  there  were  species  of  Fig,  Cinnamon,  various  Proteacece, 
etc.,  showing  that  the  vegetation  was  much  like  that  of  India  and  Aus 
tralia.  In  the  Tyrol,  there  are  other  Eocene  beds  containing  Palms ; 
moreover,  out  of  180  species  of  plants,  55  were  Australian  in  character, 
and  23  allied  to  plants  of  tropical  America.  In  the  Miocene,  Palms 
appear  riot  to  have  reached  so  far  north  as  Eiigland  ;  and  the  forests 
of  Europe  were  less  tropical  in  character.  What  is  remarkable,  a 
much  larger  proportion  of  species  than  now  were  of  North  American 
type,  showing  that,  while  the  Eocene  vegetation  of  Europe  was  largely 
Australian,  the  second  or  Miocene  phase  (including  in  part  at  least 
the  Upper  Eocene  of  Lyell)  was  more  like  that  of  North  America 
than  now.  In  the  Pliocene,  the  Flora  embraces  the  modern  genera 
of  Rose,  Plum,  Almond,  Myrtle,  Acacia,  Whortleberry,  besides  Maples, 
Oaks,  etc. 

The  Miocene  of  Greenland,  lat.  70°,  afforded  Heer  1G2  species  of 
plants,  very  few  of  which  now  live  in  the  region.  The  number  of 
Arctic  species  now  known  is  194,  of  which  46  arc  identical  with  Mio 
cene  plants  of  Europe.  They  include  many  kinds  of  trees —  none  of 
which  now  exist  in  Greenland  or  within  10°  of  it  —  among  them,  the 
yew,  Taxodium  dubium  Sternb.,  the  Redwood,  Sequoia  Langsdvrfii, 
Brngt.,  and  several  other  species  of  this  California  genus  ;  also  Alnus 
Kefersteinii  Gopp.,  Fagus  Deucalionis  Ung.,  Platanus  aceroides  Gopp., 
Salix  macrophylla,  species  of  the  Japan  genera  Thuiopsis  and  Salis- 
buria,  besides  Oaks,  Poplars,  Walnuts.  There  were  also  a  Magnolia 
and  a  Zamia.  Spitsbergen,  in  lat.  78°  56',  has  yielded  ninety-five 
species,  including  two  species  of  Taxodium,  and  species  of  Hazel, Pop- 


TERTIARY    AGE.  515 

lar.  Alder,  Beech,  Plane-tree,  and  Lime.  As  Lyell  observes,  "  such  a 
vigorous  growth  of  trees  within  12°  of  the  pole,  where  now  a  dwarf 
Willow  and  a  few  herbaceous  plants  form  the  only  vegetation,  and 
where  the  ground  is  covered  with  almost  perpetual  snow  and  ice,  is 
truly  remarkable." 

Eocene  plant-beds  occur  also  at  Sotzka  in  Upper  Styria,  Sagor  in  Illyria,  Monte  Cro- 
mina  in  Dalmatia,  etc. ;  others  referred  to  the  Miocene  epoch  exist  at  Bilin  in  Bohemia; 
St.  Gallen  in  Switzerland;  (Eningen  in  Germany;  at  Parschlug,  Fohnsdorf,  Leoben, 
Koflach.  etc.,  in  Styria;  at  Swoszowice  in  Galicia,  etc. 

Out  of  180  species  from  the  Eocene  beds  of  Haring,  55,  according  to  Ettingshausen, 
are  Australian  in  type,  28  East  Indian,  23  tropical  American,  14  South  African,  8  Pa 
cific,  7  North  American  and  Mexican,  6  West  Indian,  5  South  European.  The  resem 
blance  to  Australia  consists  not  merely  in  the  number  of  related  species,  but  in  their 
character,  — the  small,  oblong,  leathery-leaved  Proteacece  and  Hfyrtacece,  the  delicately- 
branching  Casucirince,  the  Cypress-like  species  of  Frenela  and  Callitris,  etc.  Only  eleven 
species  have  their  representatives  in  warm -temperate  climates. 

In  the  Miocene  of  Vienna,  nearly  a  third  are  North  American  in  type;  but  with  these 
there  are  some  South  American,  East  Indian,  Australian,  central  Asiatic,  and  not  a 
sixth  European.  The  species  particularly  related  to  those  of  North  America  (its  warmer 
portion)  belong  to  the  genera  Fayus,  Quercus,  Liquidambar,  Laurus,  Bumclia,  D'tcs- 
pyros,  and  Andromedites. 

The  Pliocene  Flora  of  Europe  was  strikingly  North  American  in  type,  as  Brongniart 
has  shown.  He  mentions  as  examples  the  following  genera  of  temperate  North  America, 
which  do  not  now  occur  in  Europe:  Taxodium,  Comptonia,  Liquidambar,  A'yss-j,  Rolinia, 
Gleditschia,  Cassia,  Acacia,  Rkus,  Juylans,  Ccanothus,  Celastrus,  Liriodendron,  Symplo- 
cos.  Moreover,  certain  genera,  as  that  of  the  Oak  (  Quercus),  which  have  numerous 
species  in  America,  had  many  in  Pliocene  Europe,  but  have  few  now. 

In  the  Alpine  Eocene  of  Bavaria,  Gumbel  has  found  cla}r-beds  full  of  Coccoliths,  Avith 
Foraminifers. 

2.  Animals. 

The  shells  of  Rhizopods,  foraminifers,  were  as  important  and  abun 
dant  in  the  Eocene  Tertiary  as  in  the  Cretaceous  period. 
Among  them,  the  coin-shaped  Nummulites  contributed 
very  largely  to  the  constitution  of  some  of  the  Middle 
Eocene  strata,  as  already  stated  (p.  512).  A  common 
species  is  here  represented,  with  the  exterior  of  half  of 
it  removed,  so  as  to  show  the  spiral  ranges  of  cells  that 
-  were  formed  by  successive  budding  of  Rhizopods. 

Mollusks  were  far  more  numerous  in  species  and  in 
dividuals  in  Europe  than  in  North  America.  The  shells  of  some 
localities  —  as,  for  example,  the  Paris  basin  —  often  have  nearly  the 
freshness  of  living  species,  excepting  a  prevalence  of  a  white  color, 
the  original  tints  being  mostly  lost.  There  are  few  Brachiopods 
(about  a  fifth  as  many  as  in  the  Cretaceous)  ;  and  these  are  almost  all 
of  the  groups  of  Terebratulids  and  Rhynchonellids. 

The   Vertebrates  are  the  species  of  highest  interest.     The  order  of 


516  CENOZOIC    TIME. 

Teliosts,  or  common  fishes,  which  began  in  the  Cretaceous,  was  pro 
fusely  represented  ;  their  numbers  exceeding  much  those  of  Ganoids. 
Teeth  of  Sharks  are  also  common,  and  are  like  those  of  America  in 
genera  and  partly  in  species. 

Among  Reptiles,  there  were  many  true  Crocodiles,  —  eighteen  or 
twenty  species  having  been  described.  Over  sixty  species  of  Turtles 
are  known  ;  arid  the  shell  of  one  Indian  species,  of  the  Miocene  — 
ColossocJielys  Atlas  Falconer  &  Cautley  —  had  a  length  of  twelve  feet, 
and  the  animal  a  total  of  nearly  twenty  feet.  The  feet  must  have  been 
larger  than  those  of  a  Rhinoceros. 

A  species  of  Snake,  twenty  feet  long1,  Palteopkit  typhceus  Owen,  was 
discovered  in  the  Bracklesham  beds  of  the  Middle  Eocene,  and  another 
species,  thirteen  feet  long,  in  the  Lower  Eocene  of  Sheppey.  Several 
species  related  to  the  common  Black  Snake  ( Colubridce)  occur  in  the 
Miocene. 

Remains  of  a  large  number  of  Tertiary  Birds  have  been  found  and 
described.  According  to  A.  Milne  Edwards,  the  Miocene  beds  of  the 
Department  of  Allier,  in  central  France  (between  46°  and  47°  in  lati 
tude),  has  alone  afforded  seventy  species  ;  and  many  of  these  Miocene 
birds  are  of  tropical  character.  He  says,  respecting  them — Parrots 
and  Trogons  inhabited  the  woods.  Swallows  built,  in  the  fissures  of 
the  rock,  nests  in  all  probability  like  those  now  found  in  certain  parts 
of  Asia  and  the  Indian  Archipelago.  A  Secretary  Bird,  nearly  allied  to 
that  of  the  Cape  of  Good  Hope,  sought  in  the  plains  the  serpents  and 
reptiles  which  at  that  time,  as  now,  must  have  furnished  its  nourish 
ment.  Large  Adjutants,  Cranes,  and  Flamingoes,  the  Palcelodi  (birds 
of  curious  forms,  partaking  of  the  characters  both  of  the  Flamingoes 
and  of  ordinary  Gralla3)  and  Ibises  frequented  the  banks  of  the  water 
courses,  where  the  larvaB  of  insects  and  mollusks  abounded  ;  Pelicans 
floated  in  the  midst  of  the  lakes  ;  and,  lastly.  Sand-grouse  and  numer 
ous  gallinaceous  birds  assisted  in  giving  to  this  ornithological  popula 
tion  a  strange  physiognomy,  which  recalls  to  mind  the  descriptions  that 
Livingstone  has  given  us  of  certain  lakes  of  southern  Africa. 

The  London  Clay  (Eocene)  has  afforded  Owen  a  bird  with  teeth, 
named  by  him  Odontopteryx,  but  having  the  teeth  simply  dentations 
of  the  bony  edge  of  the  bill. 

Among  the  Mammals,  the  earliest,  or  those  of  the  lower  Eocene  in 
England,  are  Pachyderms,  related  to  the  Tapir,  of  the  genera  LopJtio- 
don,  Coryphodon,  and  Hyracothere,  and  a  dog-like  Carnivore,  the  Pa- 
Iteocyon  of  Owen.  They  were  found  in  the  London  Clay.  In  France, 
beds  supposed  to  be  still  lower,  or  equivalent  of  the  bottom  beds  of 
the  Eocene,  have  afforded,  at  La  Vere,  in  the  department  of  Aisne,  a 


TERTIARY    AGE. 


517 


bear-like  Carnivore,  the  Arctocyon  primcevus  Blv. ;  and  this  is,  as  yet, 
the  earliest  of  known  Tertiary  Mammals.  But  the  greater  part  of 
Eocene  Mammalian  remains  belong  to  the  Tapir  group. 

The  earliest  discoveries  were  made  by  Cuvier.  The  bones  were 
gathered  in  the  vicinity  of  Paris,  from  the  Middle  arid  Upper  Eocene  ; 
and  a  large  number  of  extinct  quadrupeds  came  to  a  new  existence 
through  his  researches.  Among  those  of  the  Middle  Eocene,  the 
Paleothere  (named  from  rroAcuos,  ancient,  and  dijptor,  wild  beast},  related 
to  the  Tapir  in  its  elongated  nose  and  other  respects,  is  one  of  the  most 
characteristic.  The  largest  species  of  the  genus,  Palceotherium  mag 
num  Cuv.,  was  of  the  size  of  a  horse,  and  a  smaller,  P.  curium,  Cuv., 
not  larger  than  a  sheep.  The  P.  magnum,  as  restored  by  Cuvier,  had 
the  stout  form  of  the  Tapir ;  but  a  skeleton,  discovered  in  1874,  re 
ferred  to  this  species,  has  the  long  neck,  and  nearly  the  figure,  of  a 
Lama. 

With  the  Paleothere,  there  existed  other  tapir-like  beasts,  of  the 
genus  Lophiodon,  and  others. 

In  the  Upper  Eocene  of  Paris,  occur  the  remains  of  AnoplotJteres 
and  Xlphodons,  a  group  related  to  the  Ruminants  in  their  two  toes,  but 

Fig.  927. 


Xiphodon  (Anoplotherium)  gracile,  as  restored  by  Cuvier. 

at  the  same  time  having  some  characters  of  the  Hogs ;  the  Xiphodons 
were  of  slender  form  (Fig.  927).  The  species  were  remarkable  for 
having  the  set  of  teeth  as  even  in  outline  as  in  Man,  the  eye-tooth 
having  nothing  of  the  elongation  common  in  brutes  and  a  striking 
part  of  the  armature  of  Hogs  and  Carnivores,  arid  hence  its  name, 
from  aj/o7rA.o?,  unarmed,  and  Orjptov.  The  number  of  teeth  is  forty-four, 
the  complete  series,  it  including,  in  either  half  of  either  jaw,  three  in 
cisors,  four  prsemolars,  or  milk  teeth,  and  four  molars.  With  the 
Anoplothere,  a  related  but  still  more  hog-like  kind  was  the  Chceropota- 
mus.  There  were  also  Paleotheres  and  others  of  the  Tapir  tribe ;  and, 


518  CENOZOIC   TIME. 

with  these,  various  Carnivores,  Rodents,  Bats,  and  an  Opossum,  one 
of  the  Marsupials.  The  Carnivores  included  a  Wolf,  Canis  Parisien- 
sis,  the  weasel-like  Cynodon  Parisiensis,  the  dog-like  Hycenodon  dasyu- 
roides,  etc.  Remains  of  about  fifty  species  of  quadrupeds  have  been 
found  in  the  Paris  Eocene. 

In   the  Miocene,  there   were  Mastodons,  Elephants,  and    the    still 

stranger  Elephantine  animal,  the  Dinothere.  besides  Paleotheres  and 

other  Tapir-like  beasts,  new  Carnivores,  Monkeys,  Deer,  and   the  first 

Edentates,  but,  as  far  as  yet  found,  none  of  the  Bovine  or  Ox  kind. 

Fig.  928  represents  the  skull  of  the  Dinothere  (Dinotherium  gigan- 

teum  Kaup),  much  reduced.     The  head 
Fig.  928.^  carried  a  trunk,  like  an  Elephant,  and 

two  tusks  ;  but  the  tusks  were  turned 
downward.  The  length  of  the  skull  is 
three  feet  eight  inches.  The  jaws  have 
on  each  side  five  molar  teeth,  the  first  two 
answering  to  the  posterior  prremolars. 
There  is  a  mixture  of  the  characteristics 
of  the  Elephant,  Hippopotamus,  Tapir, 
and  the  marine  Manatus  (Dugong),  in 
its  skull.  One  fine  skull  was  dug  up 
at  Epplesheim  in  Germany  ;  and  the 
remains  have  also  been  found  in  France, 

Dinotherium  giganteum  (Xj^jr)- 

Switzerland,  and  a  few  other  regions. 

As  the  Sloth  tribe  is  now  confined  to  other  continents,  it  is  an  in 
teresting  fact  that,  in  the  course  of  the  Miocene,  Europe  had  its 
species,  the  Macrothere,  which  was  related  to  the  African  Pangolin 
(the  Ant-eater),  but  was  six  or  eight  times  its  size. 

All  the  Fishes,  Reptiles,  Birds,  and  Mammals  of  the  Tertiary  are 
extinct  species. 

Characteristic  Species. 

LOWER  EOCENE  OF  ENGLAND.  —  Thanet  sands. — Plwladomya  cuneatn  Sow.,  Cy- 
prina  Morrisii  Sow.,  Corbula-  lonyirostris  Desh.,  Scalana  BowerbankiiMorr. 

Woolwich  and  Heading  beds.  —  Cyrena  cuneiformis  Fer.,  C.  tellintlla  Fer.,  Melania 
inguinatn  Dfr.,  Ostrea  bellovacina  Lain. 

London  Clay  (Island  of  Sheppey,  etc).  —  Nautilus  centralis  Sow.,  N.  imperialls  Sow., 
Aturia  zicz'ic  Bronn,  Belosepia  sepioidea  Blv.,  Valuta  WetJiet'cllit  Sow.,  V.  nndosct  Sow., 
Aporrhais  Sowerbii  Mant.,  Cyrena  cuneiformis,  Cryptodon  (Axinus)  (tnyulatum  Sow., 
Leda  aini/adaloides  Sow.,  Pinna  affinis  Sow.  VERTEBRATES:  Tetrcipterus  priscus  Ag., 
Pristis  bisulcatm  Ag  ,  Lamna  eleyans  Ag.,  Palaopkit  toliapicus  Owen,  Crocodilus  tolia- 
2)icus  Cuv.  &  Owen.  Tapir-like  Mammals,  Lophiodon  minimus  Owen,  Ifyracotherium 
leporinum  Owen,  Corypliodon  Eocaenus  Owen;  the  Carnivore,  Palceocyon. 

MIDDLE  EOCENE  OF  ENGLAND.  —  NummuUtes  levigatus  Lam.,  Ctrdita  planicosta 
Lam.,  Pleurotoma  attenuata  Sow.,  TumttUn  multisulcata  Lam.,  Conus  dcpcrditus  Brngt., 
Ludna  strrala  Sow.;  Myliobates  Edwardsi  Dixon,  Carcharodon  anyustidens  Ag.,  Otodus 


TERTIARY    AGE.  519 

obllquus  Ag.,  Galeocerdo  latidens  Ag.,  Lnmna  eleyans  Ag.  (126  out  of  the  193  species 
occur  also  in  the  Calcaire  Grossier  in  France.)  Reptiles,  Palceophis  typhceus  Owen, 
Gavialis  Dixoni  Owen,  Crocodilus  Hastinysice  Owen;  Mammals,  Dichodon  cuspidatus 
Owen,  Lophiodon  minimus  Cuv.,  Microchcerus  erinaceus  Wood,  Palojdotherium  an- 
nectens  Owen. 

UPPER  EOCENE  OF  ENGLAND.  —  (1.)  Barton  Series.  —  Mitra  scabra  Sow.,  Valuta  am- 
biyua  Lam.,  Ty phis  puny  ens  Morr.,  Voluta  athleta  Sow.,  Terebellum  fusiforme  Lam., 
T.  sopita  Morr.,  Cardita  sulcata Morr.,  Crassatella  sidcata  Sow.,  Nummulites  variolarius 
Morr.  (variety  of  N.  radlatus  Sow.),  Chama  squamosa  Brand. 

(2.)  Headon  Series.  —  Planorbis  euumphalus  Sow.,  Helix  labyrinthica  Say,  Neritina 
concava  Sow  ,  Limncea  caudata  Edw.,  Cerithium  concavumDesh. ;  Lepidosteus ;  Reptiles, 
Emys,  Trionyx;  Mammals,  Pidceotherium  minus  Cuv.,  Anoplotherium,  Anthracothe- 
rium,  Dichodon,  Dichobune,  Spalacodon,  Hycenodon  (a  dog-like  Carnivore). 

(3.)  Bembridge  Series  (120  feet  thick).  —  Cyrena  semistriata  Desh.,  Paludina  lenta 
Desh.,  P  orbicularis  Voltz.,  Melani'i  turritissima  Forbes,  Cerithium  mutabile  Lam., 
Cyrena  pulchra  Morr.,  Bulimus  elli/jticus  Sow.,  Helix  occlusa  Edw.,  Planorbis  discus 
Edw  ;  Trionyx;  Palceotherium  maynum  Cuv.,  P.  medium  Cuv.,  P.  minus  Cuv.,  P. 
minimum  Cuv.,  P.  curium  Cuv.,  P.  crassum  Cuv.,  Anoplotherium  commune  Cuv.,  A. 
secundarium  Cuv.,  Dichobune  cervinum  Owen,  Chctropotamus  Cuvieri  Owen. 

LOWER  MIOCENE  OF  ENGLAND.  —  Hempstead  beds.  —  Corbula  pisum  Sow.,  Cyrena 
semistriata.  Desh.,  Cerithium  pi  catum  Lam.,  C.  eleyans  Desh.,  Rissoa  Chastelii  Nyst, 
Paludina  lenta,  Melania  fasciata  Sow.,  M.  costata  Sow. ;  the  Mammal,  Hyopotamus 
bovinus  Owen. 

PLIOCENE  OF  ENGLAND.  —In  the  Coralline  Crag,  Terebratula  fjrandis  Blumb.,  Lin- 
yula  Dumortieri  Nyst,  Astarte  Omalii  Lajonkair,  Cardita  senllis  Gein  ,  Cyprina  rustica 
Flem.,  Ostrea  princeps  Wood,  Pecten  Gerardi  Nyst,  Pyrula  reticulata  Lam.,  Bullcea 
bicatenata,  Voluta  Lamberti  Sow.,  Echinus  Woodwardii  Desor,  Temnechinus  excavatus 
Forbes.  In  the  Red  Crag,  Terebratula  arandis,  Astarte  obliquata  Sow.,  A.  Omalii,  Car- 
dium  anyustatum  Sow.,  Ostrea  princeps,  Pectunculus  variabilis  Sow.,  Nucida  Cobboldice 
Sow.,  Columbella  sulcata  Wood,  Cancellnria  costellifera  Wood,  Cyprma  Europma,  Mg., 
Fusus  antiquus  Lam.  (Trophon  antiquum  Wood),  Nassa  reticosa  Wood,  Purpura  tetra- 
f/ona  Sow.,  Scalaria  Groenlandica  Beck.,  Voluta  Lamberti  Sow.,  Felis  pardoides  Owen, 
Mastodon  Arvernensis  Croizet  &  Jobert  (anyustidens  Owen),  Rhinoceros  Schleiermacheri 
Kaup  (incisivus  Cuv.),  Tapirus priscus  Kaup  (Arvernensis  Croizet  &  Jobert),  Cervus  ano- 
ceros  Kaup.  In  the  Norwich  Crag,  Rhynchonella  psittacea  Turton,  Nucula  Cobboldice, 
PanopoeaNorveyica  Sow.,  TelUna  obliqua  Sow.,  Astarte  borealis  Nilss.,  Cardium  edule 
Linn.,  Cyprina  Tslandica,  Pholas  crispata  Linn,  (lata  Lister),  Fusus  antiquus,  Litorina 
litorea  Linn.,  Natica  helicoiJes  Johnston,  Turritella  communis  Risso,  Scalaria  Groen 
landica,  Mastodon  Arvernensis,  Elephas  meridionalis  Nesti,  Cervus. 

LOWER  EOCENE  OF  FRANCE.  —  Aryile  plastique,  many  species  identical  with  those 
of  the  London  Clay.  The  Bird,  Gastornis Parisiensis.  The  "Sables  de  Bracheux,"  sup 
posed  to  be  of  the  age  of  the  Thanet  Sands,  have  afforded  the  Carnivore  Arctocyon 
primcRVus  Mey.  (between  Cercoleptes  and  the  Bear). 

The  Upper  Eocene  of  France  has  afforded  nearly  sixty  species  of  Mammals,  of  the 
genera  Pakeotherium,  Anoplotherium,  Xiphodon  (X.  yracilis) ;  the  Carnivores,  Hycenodon 
(//.  leptorliynchusftlv.),  Canis  Parisiensis  Cuv.,  Cynodon  Parisiensis  Pomel,  besides  Bats 
and  an  Opossum. 

The  Auvergne  beds,  between  the  Eocene  and  Miocene  in  age,  contain  more  Carni 
vores  in  proportion,  besides  more  modern  genera.  Among  them,  there  are  Machcerodus, 
Hycenodon,  Cynodon,  Canis,  Amphicyon,  Viverra,  of  the  Carnivores;  Pakeotherium, 
Tapirus,  Anthracolherium,  Hyopotamus,  Rhinoceros,  of  Pachyderms ;  Erinaceus,  of  In- 
sectivores;  Archaomys,  Mus,  Castor,  Steneofber,  Lcpus,  of  Rodents,  etc. 

Some  of  the  Miocene  genera  are  Pliopithecus,  Dryopithecus,  of  Quadrumanes; 
Machcerodns,  Felis,  Hycenarctos,  Hycena,  Canis,  Virerra,  Mustela,  of  Carnivores;  Mas 
todon  (M.  lonyirostris,  M.  tapiroides  Cuv.,  etc.),  Elephas,  Rhinoceros,  Listriodon,  Sn.t, 
Anchitherium,  Ifipparion,  Equus,  Hippopotamus,  of  Pachyderms;  Camdopardalis,  Anti- 


520  CENOZ01C    TIME. 

lope,  Cervus,  of  Ruminants;  Dinotherium  ;  Erinaceus,  Talpn,  of  Insectivores;  Halithe- 
rium,  Squahdon,  Physeter,  Delphimis,  of  Mutilates. 

A  few  of  the  Pliocene  genera,  in  addition  to  the  modern  ones  already  enumerated, 
are  Pithecus,  Semnopitkecus,  of  Quadrumanes;  Machcerodus,  Ursus,  Phoca,  of  Carni 
vores;  Lepus,  Putorius,  Arctcmys,  Lagomys,  Arvicola,  Castor,  of  Rodents;  Balc&na, 
Bakenodon,  of  Mutilates. 

The  Tertiary  Mammals  of  the  Sivalik  Hills,  India,  from  beds  supposed  to  be  Upper 
Miocene,  include,  besides  Quadrumana,  species  of  HycBnarctos,  Hycend,  M<icha>rodus, 
Falls ;  £lepkas,  Mastodon,  Rhinoceros,  Ifexaprotodon,  flippotherium,  Equus,  Hippopo 
tamus,  Sus,  Anoplotherium,  Chalicotherium,  Merycopotamus,  Cfimelus,  Camelopardalis ; 
Sivatlterium,  Antilope.  Mosckus,  Ools,  Bos;  Dinotherium;  Hystrix ;  Enliydriodon.  The 
Sivatherium  was  an  elephantine  Stag,  having  four  horns,  allied  to  the  Deer,  but  larger, 
being  in  some  points  between  the  Stags  and  Pachyderms.  It  is  supposed  to  have  had 
the  bulk  of  an  elephant,  and  greater  height.  Bos  and  the  related  genera  probably 
occur  nowhere  earlier  than  the  Pliocene.  There  were  Crocodiles  of  large  size,  and  the 
great  turtle  Colossochdys  Atlas. 

Noted  localities  of  fossil  fishes  are  Monte  Bolca,  near  Verona,  in  northern  Italy,  of  the 
age  of  the  Nummulitic  beds  or  Middle  Eocene;  Canton  of  Claris,  in  Switzerland,  in 
hard  black  slate,  probably  of  the.  same  era;  Aix  in  Provence,  and  also  in  Auvergne,  of 
the  Upper  Eocene  or  Lower  Miocene;  at  Turin,  Tourame,  Vienna.  Germany,  etc.,  of 
the  Miocene;  (Eningen,  of  the  Pliocene;  also  at  Mount  Lebanon  in  Asia  Minor,  of  the 
early  Tertiary. 


3.  GENERAL  OBSERVATIONS. 

1.  American  Geography.  —  From  the  region  of  the  Mississippi  west 
ward  to  the  Pacific,  the  great  continental  seas,  in  which  the  Cretaceous 
formation  was  in  progress,  were  for  the  most  part  shallow  oceanic 
areas  ;  and  they  covered  nearly  this  whole  range  of  country,  except 
ing  the  sites  of  the  Archaean  mountains,  that  of  the  great  plateau  be- 
tween  the  meridians  of  the  Wahsatch  and  Sierra  Nevada,  and  some 
other  areas  of  Jurassic,  Triassic,  or  older  rocks.  In  the  Rocky  Moun 
tain  region,  and  also  in  California,  the  country  from  north  to  south 
was  undergoing  during  the  Cretaceous  period  a  gradual  subsidence, 
as  already  explained  (p.  487)  ;  and  thus  the  thousands  of  feet  of  rock 
were  slowly  accumulated  in  waters  that  were  never  deep.  As  the  era 
drew  toward  its  close,  the  subsidence  appears  to  have  intermitted  for 
long  intervals,  with  perhaps  some  upward  movements,  so  that  the  land 
became  slightly  emerged.  Later,  the  eras  of  intermitted  subsidence 
became  greatlv  prolonged,  so  that  immense  peat  beds  were  formed 
from  the  vegetation  growing  over  the  quiet  marshes  ;  but,  between, 
in  the  intervening  eras,  during  which  the  sinking  was  renewed, 
thick  sand-beds  and  clay-beds  were  made,  containing  marine  or  fresh 
water  shells,  or  both  commingled,  —  these  intervening  between  the 
coal  beds,  and  the  whole  making  up  the  Tertiary  deposits  of  the 
Lignitic  era. 

Thus  gradually,  so  far  as  rock-making  was  concerned,  the  Creta 
ceous  era  ended,  and  the  Tertiary  age  began. 


TERTIARY    AGE. 


521 


The  same  kind  of  change,  from  constant  submergence  to  an  era  of 
occasional  emergences,  occurred  over  the  eastern  Rocky  Mountain 
slopes,  even  into  the  Mississippi  valley  ;  and  also  in  California  on  the 
west ;  for  the  Lignitic  beds  of  Mississippi  arid  Tennessee,  and  those 
of  California,  show  that  the  marine  era  of  the  Cretaceous  was  there 
followed  by  one  of  fresh-water  or  terrestrial  depositions,  in  which  leaf- 
bearing  and  lignite-bearing  beds  were  formed.  Further,  the  rocks 
which  next  follow  the  Lignitic  beds  —  those  of  the  Claiborne  and 
Vicksburg  series  —  give  evidence  that,  after  the  Lignitic  era,  the  subsi 
dence  was  again  renewed  ;  for  the  deposits  are  again  marine  in  the 
Mississippi  valley  and  about  the  Mexican  gulf;  and,  although  fresh 
water  over  the  Rocky  Mountains,  they  have  there  a  thickness  of  sev 
eral  thousands  of  feet,  as  evidence  of  the  subsidence  in  progress. 

Fiy.  023. 


North  America  in  tho  Period  of  the  Middle  Tertiary. 

The  epoch  of  cold,  which  terminated  the  life  of  the  Cretaceous  Con 
tinental  seas,  would  not  necessarily  have  been  attended  by  breaks  in 
the  series  of  rocks  ;  and  no  such  breaks  are  found  in  the  Rocky  Moun 
tain  region.  The  cold  winds  and  oceanic  currents  appear  to  have  done 
thoroughly  the  work  of  extermination  over  Europe  and  eastern  North 
America,  but  less  completely  in  the  seas  bordering  the  Pacific;  and 


522  CENOZOIC   TIME. 

hence  it  is  that  traces  of  the  Cretaceous  fauna  are  found  in  the  Terti 
ary  beds,  even  through  the  whole  of  the  Lignitic  Eocene. 

With  the  opening  of  the  second  period  of  the  North  American  Ter 
tiary,  the  Alabama  period,  the  continent  had  nearly  the  form  repre 
sented  on  the  accompanying  map,  as  shown  by  the  distribution  of  the 
areas  covered  by  marine  beds.  The  Atlantic  Border  was  submerged, 
nearly  as  in  the  Cretaceous  period  :  there  was  no  Delaware  or  Chesa 
peake  Bay,  and  no  Peninsula  of  Florida.  The  Mexican  Gulf  spread 
far  beyond  its  present  limits  north  and  west,  but  riot,  as  in  the  pre 
ceding  era,  over  the  Rocky  Mountain  slopes.  The  Ohio  and  Missis 
sippi  were  barely  united  at  their  mouths,  if  not  wholly  disjoined. 
Owing  to  the  elevation  of  the  land  westward,  the  Missouri  and  other 
streams  rising  in  the  mountains  had  begun  to  exist.  Yet  this  eleva 
tion  was  small;  and,  as  Hayden  has  rightly  inferred  from  the  great 
fresh-water  Tertiary  deposits,  the  country  was  mostly  covered  by  vast 
fresh-water  lakes. 

After  the  close  of  the  Vicksburg  epoch,  referred  to  the  Upper  Eo-- 
cene,  there  appears  to  have  been  a  further  reduction  of  the  Mexican 
Gulf ;  for  no  later  marine  Tertiary  beds  are  recognized  on  its  borders. 
The  "  Grand  Gulf  beds,"  described  by  Hilgard  as  covering  a  coast  re 
gion,  south  of  Vicksburg,  appear,  as  he  observes,  to  indicate  that,  for  a 
period  after  the  Eocene  and  before  the  Quaternary,  the  coast  line 
was  along  their  northern  border ;  but  no  marine  fossils  occur  in  them, 
and  the  particular  period  to  which  the  beds  belong  is  uncertain. 

The  Atlantic  Tertiary  region  must  have  remained  submerged  until 
after  the  Miocene  era.  The  absence,  from  most  parts  of  the  coast,  of 
deposits  that  can  properly  be  identified  as  Pliocene  is  a  remarkable 
fact,  and  seems  to  show  that  the  continent,  during  the  Pliocene  era,  had 
at  least  its  present  breadth  along  the  larger  part  of  the  Atlantic  coast, 
if  not  a  still  greater  eastward  extension. 

The  change  of  water-level,  which  caused  this  enlargement  of  the 
area  of  dry  land,  was  probably  not  confined  to  the  border  of  the  con 
tinent,  but  was  part  of  a  general  change,  in  which  a  large  part  of  the 
continent  partook,  especially  the  Rocky  Mountain  region. 

2.  European  Geography.  —  In  the  earliest  epoch  of  the  Tertiary, 
in  Europe,  there  appears  to  have  been,  as  has  been  observed  by  others, 
first,  an  emergence  of  the  land  from  the  Cretaceous  seas,  when  the 
Chalk  formation  was  eroded  at  surface,  and  a  flint  conglomerate  in 
some  places  formed ;  and  when,  moreover,  in  some  parts,  Lignitic  beds 
were  made,  as  in  America.  The  return  of  the  land  to  the  sea-level, 
and  in  some  places  to  beneath  it,  commenced  the  formations  of  the  ma 
rine  and  estuary  Tertiary  of  the  succeeding  epoch ;  and  a  still  more 
general  submergence  brought  about  the  state  when  the  great  'Nummu- 


TERTIARY   AGE.  523 

litic  beds  of  the  Middle  Eocene  were  forming  over  so  large  a  part  of 
Europe,  Africa,  and  Asia,  even  over  regions  which  are  now  occupied 
by  the  lofty  mountains  of  these  continents.  At  this  epoch,  Europe 
was  again  an  archipelago,  as  in  the  Cretaceous  period.  The  Paris 
basin  was  one  of  its  great  estuaries,  varying  between  fresh  and  marine 
waters,  with  changes  of  level  and  changing  barriers. 

After  the  Eocene,  in  Europe  (as  well  as  in  America),  the  marine 
deposits  had  much  smaller  extent ;  and  the  continent  was  mostly  dry 
land.  But  the  ocean-border,  instead  of  having  the  American  sim 
plicity,  had  numerous  deep  indentations  and  winding  estuaries. 

But  the  geographical  conditions  here  described  were  brought  about, 
in  connection  with  mountain-making  on  a  vast  scale,  at  different  epochs 
in  the  course  of  the  Tertiary. 

3.  Disturbances  during  the  progress  of  the  Tertiary  Age.  —  In 
the  Tertiary  age,  nearly  all  the  great  mountain  chains  of  the  world 
either  were  made  or  received  additions  of  many  thousands  of  feet 
to  their  heights,  and  hundreds  of  thousands  of  square  miles  to  their 
areas  ;  and,  besides,  far  the  larger  part  of  igneous  eruptions  then  took 
place. 

(1  )  The  first  epoch  of  disturbance  in  North  America  was  one  clos 
ing  the  Lignitic  era.  As  has  been  stated,  the  Lignitic  group  in  the 
Rocky  Mountain  region  is  upturned  at  all  angles,  to  verticality,  be 
neath  the  fresh-water  Tertiary  of  the  Middle  and  Later  Eocene.  Its 
deposition  followed  on  after  that  of  the  10,000  feet  of  Cretaceous 
strata  without  interruption,  and  added  several  thousands  of  feet  to  the 
conformable  beds,  the  whole  indicating  the  progress  of  a  geosynclinal 
of  remarkable  depth.  So,  again,  in  California,  some  hundreds  of  feet 
were  added,  above  the  Cretaceous  series.  Apparently  simultaneously, 
in  these  two  regions,  500  miles  apart,  one  west  of  the  Sierra  Nevada, 
and  the  other  east  of  the  Wahsatch,  an  upturning  began  which  made 
mountains  now  3,000  to  4,000  feet  high  in  California,  consisting  mainly 
of  Cretaceous  rocks,  and  also  elevations  of  considerable  extent  in  the 
Rocky  Mountain  region. 

(2.)  The  second  epoch  of  disturbance  was  that  closing  the  Alabama 
period,  or  the  Eocene  era.  At  this  time,  the  borders  of  the  Mexican 
Gulf,  which  had  been  under  the  sea,  emerged,  so  that  the  later  Ter 
tiary  beds  —  the  Miocene  —  are  confined  to  the  Atlantic  Border.  The 
Rocky  Mountain  region,  in  Wyoming,  Utah,  and  Colorado,  may  have 
also  been  lifted  to  some  small  extent. 

(3.)  The  third  epoch  of  disturbance  closed  the  Miocene  era.  At 
this  time,  the  Tertiary  of  California,  which  had  accumulated  to  a  thick 
ness  of  4,000  or  5,000  feet,  over  the  tilted  Lignitic  beds  and  Creta 
ceous  strata,  and  in  a  more  westerly  trough  or  geosynclinal  than  the 


524  CENOZOIC    TIME. 

geosynclinal  of  the  Cretaceous,  was  upturned  and  made  into  mountain 
ridges  along  the  Coast  region,  parallel  with  the  Cretaceous  ridges  and 
Sierra  Nevada.  Again,  over  the  eastern  slope  of  the  Rocky  Moun 
tains,  there  was,  at  the  close  of  the  Miocene,  a  great  contraction  of 
the  lake  region ;  for  the  Pliocene  lacustrine  beds  have,  according  to 
Hayden,  a  much  more  limited  distribution.  This  is  evidence  that  the 
elevation  of  the  Rocky  Mountains  had  gone  forward  during  the 
period.  There  is  proof  that  mountain-making  pressure,  from  the  Pa 
cific  direction,  had  acted  with  energy  against  the  continental  crust,  in  the 
occurrence  of  extensive  areas  of  igneous  rocks  over  the  Pacific  slope 
and  part  of  the  summit  region.  The  vast  areas  of  trachyte  and  doler- 
yte  show  that  immense  regions  were  flooded  by  outpourings  from  frac 
tures,  at  successive  times.  These  eruptions  continued  to  take  place 
over  those  regions,  at  intervals,  from  the  close  of  the  Miocene  even  into 
the  Quaternary  age;  and  they  have  not  even  now  altogether  ceased;  so 
that  it  is  not  easy  to  decide  the  particular  date  of  the  successive  out 
flows.  The  beds  form  ramparts  of  basaltic  columns,  in  several  ranges, 
along  the  Snake  River,  or  upper  Columbia,  and  have  a  thickness  there 
of  700  to  1,000  feet  (King)  ;  in  the  cut  through  the  Cascade  range 
the  thickness  is  over  4,000  feet  (LeConte).  As  these  eruptions  far 
exceed  all  those  of  earlier  time,  they  may  be  looked  upon  as  the  results 
of  mountain-making  pressure,  after  the  crust  had  become  so  stiff,  from 
its  successive  thickenings  and  the  consolidations  of  the  superficial  de 
posits,  that  it  could  not  bend,  and  hence  broke.  The  rocks  of  the 
eruptions  after  the  close  of  the  Miocene,  included  both  trachytic  arid 
dolerytic  kinds. 

On  the  Atlantic  Border,  the  elevation  of  the  coast,  which  placed  the 
Miocene  beds  above  the  sea-level,  may  have  taken  place  at  this  time, 
as  above  remarked.  There  is  probable  proof  of  elevation  contem 
poraneously  with  the  Rocky  Mountain  movements  of  this  era,  in  the 
present  height  of  the  Tertiary  in  parts  of  Georgia  and  Alabama ;  for, 
while  in  general  the  beds  on  the  Gulf  Border  are  but  one  hundred  to 
two  hundred  feet  above  the  sea,  near  Milledgeville,  Georgia,  they  are 
now  six  hundred  feet,  and  near  Montgomery  about  eight  hundred  feet. 
The  position  of  the  region,  in  a  line  with  the  general  trend  of  Florida, 
suggests  that  its  elevation  may  have  been  connected  with  that  of  the 
Peninsula  of  Florida  itself.  Moreover,  the  northwestward  trend  cor 
responds  with  that  of  the  Rocky  Mountain  region,  and  not  with  that 
of  the  Alleghany  range,  which  was  raised  soon  after  the  Paleozoic. 
In  San  Domingo,  according  to  Gabb,  the  Miocene  has  an  elevation  of 
two  hundred  to  two  thousand  feet. 

The  elevation  of  the  Rocky  Mountains,  which  took  place  in  the 
course  of  the  Tertiary,  and  which  had  reached  fully  its  present  limit 
by  the  close  of  the  age,  amounted  to  not  less  than  eleven  thousand 


TERTIARY    AGE.  525 

feet:  for  marine  deposits  of  the  Cretaceous  era  exist  in  the  mountains 
at  this  elevation. 

Thus  the  North  American  Continent,  which,  since  early  time,  had 
been  gradually  expanding  in  each  direction  from  the  northern  Azoic, 
eastward,  westward,  and  southward,  and  which,  after  the  Paleozoic, 
was  finished  in  its  rocky  foundation,  excepting  on  the  borders  of  the 
Atlantic  and  Pacific  and  the  area  of  the  Rocky  Mountains,  had 
reached  its  full  expansion  at  the  close  of  the  Tertiary  period  ;  and 
even  these  border  regions  received  afterward  but  small  additions.  The 
progress  from  the  first  was  uniform  and  systematic :  the  land  was  at 
all  times  simple  in  outline ;  and  its  enlargement  took  place  with  almost 
the  regularity  of  an  exogenous  plant. 

In  Europe,  the  elevation  of  the  Pyrenees  took  place  after  the  Middle 
Eocene,  or  at  the  close  of  the  formation  of  the  Nummulitic  beds ;  and 
the  same  was  true  of  the  Julian  Alps,  and  of  the  Apennines,  Carpa 
thians,  and  also  other  heights  in  eastern  Europe.  The  Nummulitic 
strata  have  now  a  height  of  ten  thousand  feet  in  the  Alps,  and  nine 
thousand  in  the  Pyrenees.  The  elevation  of  the  chain  of  Corsica,  and 
some  minor  disturbances,  in  Italy  and  other  parts  of  Europe,  are  re 
ferred  to  the  close  of  the  Eocene.  The  western  Alps,  ranging  N.  26° 
E.,  which  include  Mount  Blanc,  Mount  Rosa,  etc.,  were  raised,  accord 
ing  to  Elie  do  Beaumont,  after  the  deposition  of  part  or  all  of  the 
Miocene  ;  for  the  Molasse  of  this  region  was  raised  or  disturbed  by 
the  uplift,  and  not  the  Pliocene.  In  Britain,  there  were  great  erup 
tions  of  igneous  rocks  during  or  at  the  close  of  the  Miocene,  according 
to  Geikie,  the  dolerytic  rocks,  from  the  south  of  Antrim  through  the 
chain  of  the  Inner  Hebrides  to  the  Faroe  Islands,  being  part  of  the 
results.  The  igneous  beds  of  the  Hebrides  are  three  thousand  to 
four  thousand  feet  in  thickness,  and  overlie  beds  containing  leaves  of 
Miocene  plants.  The  Antrim  deposits  cover  eight  hundred  to  twelve 
hundred  square  miles,  and  have  an  average  thickness  of  five  hundred 
and  forty-five  feet.  The  earlier  volcanic  eruptions  of  Auvergne  and 
Velay  are  referred  to  the  same  era.  The  larger  part  of  the  dolerytic 
and  trachytic  eruptions  of  Europe  are  of  Tertiary  origin. 

The  elevation  of  the  eastern  Alps,  from  Valais  to  St.  Gothard,  along 
the  Bernese  Alps,  and  eastward  to  Austria,  ranging  N.  74°  E.,  is 
attributed  by  the  same  geologist  to  the  close  of  the  Pliocene,  as  it 
lifted  the  Pliocene,  but  did  not  disturb  the  Quaternary.  Even  in  the 
later  part  of  the  Pliocene  era,  there  was  an  elevation  of  three  thousand 
feet,  in  apart  of  the  island  of  Sicily  (p.  512).  Thus,  throughout  the 
Tertiary  period,  the  continents  of  Europe  and  Asia,  as  well  as  Amer 
ica,  were  making  progress  in  their  bolder  surface  features,  as  well  as  in 
the  extent  of  dry  land  ;  and  the  evidence  is  sufficient  to  show  that, 


526  CENOZOIC    TIME. 

when  the  period  ended,  the  continents  had  their  mountains  raised  in 
general  to  their  full  height. 

4.  Climate.  —  The  climate  of  the  United  States,  even  the  Northern, 
during  the  Early  Tertiary,  was  at  least  warm-temperate,  as  indicated 
by  the  fossil  plants. 

There  is  evidence,  as  Dr.  Gray  has  remarked,1  from  the  distribution 
of  Tertiary  plants  in  the  Arctic,  made  known  by  Heer  and  others,  and 
their  relation  to  similar  kinds  in  the  Eastern  United  States  and  in 
Asia,  that  the  northern  parts  of  the  Continents  of  America,  Asia,  and 
Europe  were,  during  that  age,  under  a  nearly  common  forest  vegeta 
tion,  with  a  comparatively  moderate  climate.  The  genus  Sequoia,  of 
California,  has  its  species  (as  Heer  has  shown)  in  the  Miocene  of 
Greenland,  Arctic  America,  Iceland,  Spitzbergen,  Northern  Europe  ; 
and  one  Greenland  species  is  very  near  the  great  Californian  £  gigan- 
tea\  and  these  were  successors  to  Arctic  Cretaceous  species.  There 
were  two  species  of  Libocedrus  in  the  Spitzbergen  Miocene  (Heer)  ; 
and  one  (L.  decurrens  Heer)  now  lives  with  the  Redwoods  of  Califor 
nia,  while  the  other  occurs  in  the  Andes  of  Chili.  Gray  adds  that 
the  common  Taxodium,  or  Cypress,  of  the  Southern  States,  occurs  fos 
sil  in  the  Miocene  of  Spitzbergen,  Greenland,  and  Alaska,  as  well  as 
Europe,  and  also,  according  to  Lesquereux,  in  the  Rocky  Mountain 
Miocene.  These  are  only  a  few  of  the  facts.  From  the  Miocene 
plants  of  Greenland  (p. 514),  Heer  concludes  that  the  mean  annual 
temperature  of  the  Arctic  regions,  in  the  Middle  Tertiary,  was  as  high 
as  48°  F. 

Europe  evidently  passed  through  a  series  of  changes  in  its  climate, 
from  tropical  to  temperate.  According  to  Von  Ettingshausen,  the 
Eocene  flora  of  the  Tyrol  indicates  a  temperature  between  74°  and 
81°  F.  ;  and  the  species  are  largely  Australian  in  character.  The 
numerous  palms  in  England,  at  the  same  period,  indicate  a  climate  but 
little  cooler. 

The  Miocene  flora  of  the  vicinity  of  Vienna,  the  same  author  pro 
nounces  to  be  subtropical  or  to  correspond  to  a  temperature  between 
68°  and  79°  F. :  it  most  resembles  that  of  subtropical  America.  Far 
ther  north  in  Europe,  the  flora  indicates  the  warm-temperate  climate 
characterizing  the  North  American  Tertiary  ;  and  it  is  also  promi 
nently  North  American  in  its  types.  In  the  Pliocene,  the  climate 
was  cooler  still,  and  approximated  to  that  of  the  existing  world. 

The  North  American  feature  of  the  Miocene  forests  of  Europe  was 
probably  owing  to  migration  from  America  through  the  Arctic  regions, 
and  not  from  Europe;  for  a  number  of  the  European  species,  as  shown 
by  Lesquereux  (p.  498),  existed  already  in  the  American  Eocene.  The 

1  Mem.  Am.  Acad..  \\.  1859,  and  Am.  Jour.  Set.,  III.  iv.  292. 


QUATERNARY    AGE.  —  GLACIAL   PERIOD.  527 

Australian  feature  also  may  have  been  a  result  of  migration,  but  from 
the  opposite  direction.  The  Indian  Ocean  currents  favor  migration 
northward,  along  the  borders  of  Asia,  and  not  that  in  the  opposite 
direction. 


II.  THE  QUATERNARY  AGE?  AND  ERA  OF  MAN. 

Hitherto,  through  the  ages,  to  the  close  of  the  Tertiary  period,  tho 
continent  of  North  America  had  been  receiving  a  gradual  extension 
to  the  southward,  spreading  itself  southeastward  on  the  Atlantic  side, 
and  southwestward  on  the  Pacific.  The  scene  of  prominent  action 
here  changes;  and,  in  the  Quaternary,  the  great  phenomena  are  mainly 
northern.  The  same  general  fact  is  true  for  all  the  continents,  north 
and  south  :  the  changes  affect  most  decidedly  the  higher  latitudes  of 
the  globe.  The  Quaternary  in  America  includes  three  periods  :  — 

1.  The  GLACIAL,  or  that  of  the  Drift;  2,  the  CHAMPLAIN,  and  3, 
the  RECENT  or  TEKRACE. 

1.  GLACIAL  PERIOD. 

1.  AMERICAN. 
I.  Material,  Phenomena,  and  Distribution  of  the  Drift. 

1.  Drift.  —  The  term  Drift,  as  it  is  commonly  employed  in  Ge 
ology,  includes  the  gravel,  sand,  clay,  and  bowlders,  occurring  over 
some  parts  of  the  continents,  which  are  without  stratification  or  order 
of  arrangement,  and  have  been  transported  from  places  in  higher  lati 
tudes,  by  some  agency  which  (1)  could  carry  masses  of  rock  hundreds 
of  tons  in  weight,  and  which  (2)  was  not  always  dependent  for  mo 
tion  on  the  slopes  of  the  surface. 

Other  portions  of  the  same  transported  material  are  stratified  sands, 
clays,  pebble  beds,  and  cobble-stone  beds ;  so  that  there  is  both  un 
stratified  and  stratified  Drift. 

The  lower  part  of  the  unstratified  Drift  is  generally  a  bed  of  un- 
stratified  clay.  This  clay  usually  contains  stones,  or  bowlders,  and  is 
called  the  bowlder  clay. 

The  unstratified  and  also  the  stratified  Drift,  over  the  interior  of  the 
continent,  contain  no  marine  fossils ;  while  drifted  logs  and  their  accu 
mulations  of  vegetable  material  and,  in  the  stratified,  fresh- water  or 
land  shells  are  not  uncommon.  Toward  or  along  the  seashores,  the 
stratified  beds  often  contain  marine  shells. 

Nearly  all  the  stratified  Drift,  and  a  large  part  of  the  unstratified, 
were  deposited  during  the  Champlain  period ;  and  hence  the 
tion  of  the  former  is  given  with  the  account  of  that  period. 


528  CENOZOIC   TIME. 

2.  General  Geographical  Distribution  of  the  Drift.  — The  unstratified 
Drift  in  North  America  occurs  over  the  British  Provinces,  from  Nova 
Scotia  arid  Labrador  westward  ;  over  all  New  England  and  Long  Isl 
and;  New  York,  New  Jersey,  and  part  of  Pennsylvania,  and  the  States 
west,  to  the  western  limits  of  Iowa  and  Minnesota.  Beyond  the  me 
ridian  of  98°  W.,  in  the  United  States,  it  is  not  known. 

It  has  its  southern  limit  near  the  parallel  of  39°,  in  southern  Penn 
sylvania,  Ohio,  Indiana,  Illinois,  and  Iowa,  while  its  northern  is  unde 
termined.  South  of  the  Ohio  River,  it  is  hardly  traceable  ;  yet  it  is 
stated  to  occur  near  Ashland,  in  Boyd  County,  Kentucky.  Few  bowl 
ders  are  found  about  Baltimore  and  Philadelphia,  and  these  not  on 
the  higher  lands.  It  is  thus  northern  in  its  distribution.  Still,  local 
Drift  deposits  have  been  recognized,descending  from  the  Unaka  Moun 
tains  (the  range  between  Tennessee  and  North  Carolina),  along  tribu 
taries  of  the  Tennessee  River,  and  in  the  Alleghany  Mountains,  West 
Virginia ;  and  of  far  greater  extent  about  the  crest  ranges  of  the  Rocky 
Mountains,  the  Sierra  Nevada,  down  to  latitude  35°  N.,  the  peaks  of 
the  Cascade  Mountains,  and  other  high  ranges  on  the  Paciiic  Border. 

In  East  Tennessee,  the  stones  of  the  Drift  are  of  all  sizes,  to  a  diameter  of  eight  or  ten 
inches,  and  the  trains  have  a  height  of  300  to  400  feet  above  the  streams,  in  their  upper 
portions,  according  to  Safford,  and  of  170  feet  at  Knoxville,  according  to  F.  H.  Bradley. 
R.  P.  Stevens  has  announced  the  occurrence  of  similar  "bowlder  Drift,"  in  Greenbricr 
valley,  West  Virginia,  on  the  west  slope  of  the  Allcghanies,  and  also  near  Covington, 
Va.,  along  the  head  waters  of  the  James,  on  the  opposite  or  east  side.  The  trains  are 
valley  trains,  not  continental  and  northern,  like  the  true  Drift.  In  the  Rocky  Moun 
tains,  and  in  Nevada,  California,  and  Oregon,  there  is  no  northern  Drift,  according  to 
Whitney;  but  there  are  unstratified  and  stratified  Drift  deposits  of  great  thickness, 
following  the  course  of  the  valleys  from  the  higher  mountains.  Belt  states  that  there 
are  bowlder-clays  in  Nicaragua,  2,000  to  3,000  feet  above  the  sea. 

The  closing  Tertiary  age  must  have  left  the  continent  covered  with 
alluvial  and  lacustrine  deposits,  and  among  them  beds  of  peat,  and 
shell-beds  of  fresh-water  origin.  The  preceding  pages  contain  an 
account  of  such  deposits  over  the  Rocky  Mountain  slopes.  But  littlo 
is  known  of  any  such  beds,  north  of  the  Drift  limit,  east  of  the  Mis 
sissippi  :  they  appear  to  have  been  mostly  rearranged,  in  the  making 
of  the  Drift.  The  whole  country  must  have  been  a  vast  forest  region. 
The  forests  were  all  swept  off;  for  existing  forests  over  the  hills  are 
planted  in  general  upon  the  Drift  deposits,  or  on  material  of  later  for 
mation. 

Distribution  in  Elevation.  —  The  unstratified  Drift  extends  not  only 
over  the  lower  country,  but  also  high  up  the  mountains  ;  to  a  level  of 
5,800  feet  on  the  north  side  of  Mt.  Washington,  and  4,400  feet  on  Mt. 
Mansfield,  the  highest  peak  of  the  Green  Mountains.  Bowlders,  often 
of  large  size,  occur  on  most  of  the  New  England  summits,  under 
4,000  "feet  in  height. 


QUATERNARY    AGE.  —  GLACIAL   PERIOD.  529 

3.  Material  of  the  Drift.  —  The  un stratified  Drift  consists  of  (1)  un- 
stratified  clay-beds,  often  with  intermingled  stones;   (2)  the  bowlder- 
clay,  already  mentioned  ;   (3)   sand,  or   (4)  gravel,  in   great   deposits ; 
(5)  bowlders,  small  or  large,  distributed  in  or  over  the  other  deposits, 
—  these  bowlders  sometimes  twenty  to  thirty  feet  across,  and  weighing 
500  to  1,200  tons. 

The  material,  though  varying  much  in  different  regions,  is  in  gen 
eral  coarsest  to  the  north,  and  becomes  gravel  and  sand,  without  stones, 
or  only  small  ones,  toward  the  southern  limit  of  the  Drift  region. 
Nearing  this  limit,  it  stretches  farther  south  in  the  north-and-south 
valleys  than  on  the  hills. 

The  stones  or  bowlders  sometimes  lie  in  long  trains,  as  in  Richmond, 
Berkshire  County,  Mass.,  and  Huntington,  Vt,  crossing  hills  and  val 
leys,  without  following  the  line  of  slope  ;  or  going  obliquely  across  a 
valley  ;  or  the  stones  of  one  ridge  are  found  on  another  ridge  sepa 
rated  from  it  by  a  deep  valley. 

One  bowlder  in  Bradford,  Mass.,  is  30  feet  each  way  (Hitchcock),  and  weighs  not  less 
than  1,250  tons.  Another,  in  Whitingham,  Vt.,  in  the  Green  Mountains,  is  43  feet 
long  and  32  in  average  width,  and  full  40,000  cubic  feet  in  bulk.  It  lies  on  the  top  of  a 
naked  ledge.  Many  on  Cape  Cod  are  20  feet  in  diameter,  and  one  at  Winchester,  N. 
II.,  is  2D  feet  across. 

4.  Source  of  the  Material,  and  Course  of  Travel.  —  By  comparing  the 
stones  of  the  Drift  with  the  rocks  of  the  surrounding  region,  it  has 
been  found  that  the  material  has  come,  for  the  most  part,  from  the 
north,  —  either  the  northeast,  or  the  north,  or  the  northwest,  —  and  in 
most  parts  of  the  country  from  the  northwest ;  and  it  has  been  trans 
ported  to  a  distance  usually  between  a  mile,  or  less,  and  fifty  miles,  but 
sometimes  one  or  more  hundred  miles. 

From  southwestern  Vermont,  the  granyte  of  a  high  hill,  between  Stamford  and  Pow- 
nal,  which  is  almost  as  high  as  the  Green  and  Hoosac  Mountains  lying  to  the  east  and 
southeast,  has  been  carried  southeastwardly  across  the  western  sides  of  these  moun 
tains,  nearly  across  the  State  of  Massachusetts. 

Large  bowlders  strew  thickly  the  north  shores  of  eastern  Long  Island,  which  are  the 
crystalline  rocks,  trap,  and  sandstone  of  New  England;  and  others,  on  western  Long 
Island,  are  from  the  Palisades  and  heights  along  the  Hudson  River.  South  of  Lake 
Superior,  there  are  bowlders  which  have  come  from  the  north  shore  of  the  lake. 

The  iron-ore  bed  of  Cumberland,  Rhode  Island,  furnished  bowlders  for  the  country 
south  of  Providence,  thirty-five  miles  distant,  while  none  are  found  to  the  northward. 

South  of  the  Lake  Superior  region  (where  native  copper  occurs)  masses  of  this  metal 
are  found  in  the  Drift,  over  Michigan,  Ohio,  Indiana,  Illinois,  Wisconsin,  and  Iowa: 
and  bowlders  full  of  fossils,  derived  from  various  Paleozoic  rocks  of  the  upper  Missis 
sippi,  in  the  Drift  of  the  States  to  the  south,  even  down  to  Mississippi.  The  stones  of 
the  Mississippi  Drift  have  been  traced  in  part  to  Tennessee.  Masses  of  native  copper 
occur  also  in  the  Drift  of  Connecticut  and  New  Jersey,  that  were  taken  from  veins 
nearly  north  of  the  places  where  they  occur.  Native  gold,  from  the  rocks  north  of 
Lake  Superior,  occurs  in  the  Drift  of  Ohio,  Indiana,  and  the  States  west. 

The  Transportation  was  sometimes  across,  and  sometimes  in  accord 
ance  with,  the  slopes  of  the  surface.  — The  facts  stated  above,  respect- 

34 


530 


CENOZOIC    TIME. 


ing  lines  of  stones  crossing  valleys  and  hills  without  deviation  from  a 
right  line,  are  examples  of  a  very  general  fact  with  regard  to  the  Drift. 
At  the  same  time,  the  trains  often  follow  the  directions  of  the  grander 
slopes  of  the  surface,  and  especially  the  courses  of  the  larger  valleys. 

A  range  of  country  on  the  west  side  of  the  Connecticut  Valley,  near  the  borders  of 
the  Triassic,  has  in  Connecticut  great  numbers  of  trap  bowlders  —  some  500  to  1,000 
tons  weight  —  which  have  been  transported  from  the  trap  hills  of  the  valley,  in  a  direc 
tion  5°  to  20°  west  of  south,  this  being,  in  Connecticut,  the  direction  of  the  Connecticut 
Valley  (though  not  of  the  river,  see  p.  404).  The  same  general  fact  is  illustrated  in  all 
glacial  regions. 

On  the  other  hand,  bowlders  were  sometimes  carried  up  slopes,  to  a 
height  of  a  thousand  feet  or  more.  Thus,  limestone  bowlders  from 
Canaan,  Conn.,  were  carried  southeastward,  up  to  Goshen,  1,000  feet: 
and  fossiliferous  bowlders  from  the  region  north  of  Mt.  Katahdin  were 
left  on  that  mountain,  at  a  height  of  4,385  feet  above  the  sea,  or  more 
than  3,000  feet  above  the  low  country  to  the  north. 

II.  Attendant  Phenomena  —  Groovings  or  Scratches. 

1.  Evidences  of  Abrasion. —  Besides  the  transportation  of  stones 
and  earth,  there  was  the  abrasion  of  rocks,  which  left  nearly  the 
whole  rocky  surface  of  the  country,  within  Drift  regions,  scratched  or 
grooved  and  polished.  The  following  figure  (Fig.  940)  represents  a 
slab  of  limestone,  from  western  New  York,  thus  scratched  and  planed 

off. 

Fig.  940. 


Drift  groovings,  or  scratches. 

In  addition,  the  stones  and  large  bowlders  of  the  Drift  are  often 
scored,  like  the  rocks  over  which  they  travelled. 

The  bare  ledges  have  not  often  retained  the  scratches,  unless  they  consisted  of  slate 
or  limestone,  or  some  hard  varieties  of  gneiss.  But  these,  and  even  the  softer  rocks, 
are  generally  found  to  be  grooved  or  polished,  wherever  the  soil  has  been  recently 
removed. 


QUATERNARY   AGE.  —  GLACIAL   PERIOD.  531 

The  groovings  are  long,  straight,  parallel  lines,  often  like  the  lines  of  a  music-score, 
or  broad  planings,  ploughing*,  and  gougings  of  the  surface.  The  scratches  generally 
vary  from  fine  lines  to  furrows  three  or  four  inches  deep ;  but  they  are  occasionally  a 
foot  deep  and  several  feet  wide ;  or  even  two  feet  deep,  as  on  the  top  of  Monadnock 
(Hitchcock);  and  even  eight  to  ten  feet  deep,  making  great  mouldings  of  the  surface, 
as  in  the  Connecticut  River  sandstone,  in  North  Haven  (near  New  Haven,  Ct.);  and 
four  to  six  feet  in  compact  limestone,  near  Ithaca,  N.  Y.  At  the  same  time,  the  varia 
tions,  from  broad  smooth  planings  and  ploughings  to  deep  groovings  and  fine  scratches, 
show  variations  in  the  moving  mass.  The  channels  are  sometimes  made  of  broken 
lines,  or  successions  of  slight  curves,  as  if  from  hitches  in  the  progress  of  the  gouging 
agent;  and  the  edge  of  a  layer,  where  there  was  a  sudden  descent,  is  occasionally 
chipped  off,  as  if*  the  heavy  body  had  gone  down  with  a  jump. 

Rocky  ledges  have  been  left  with  polished  and  rounded  surfaces, 
like  those  called,  from  their  shape,  in  the  glacier  regions  of  the  Alps, 
roc/ies  moutonnees  (or  sheep-bach)  (p.  685). 

Again,  the  scratches  exist  over  the  higher  summits  of  the  country, 
as  well  as  over  the  lower,  —  occurring  on  Mount  Mansfield,  in  the 
Green  Mountains  of  Vermont,  4,400  feet  above  the  sea  level,  and  on 
the  White  Mountains  to  a  height  of  5,500  feet.  Moreover,  the  north 
side  of  a  rid^e  or  summit  lias  often  been  smoothed  off  and  made 

O 

steep,  when  the  southern  has  been   left  with   a  gradual   slope.     The 
north  side,  in  such  cases,  is  called  in  Sweden  the  stoss  or  struck  side. 

2.  Direction  of  the  Scratches.  —  The  direction  of  the  scratches  corre 
sponds  with  that  of  the  movement  of  the  Drift,  being  in  general  south 
ward,  between  S.  and  S.  40°  E.  to  S.  50°  E.,  but  varying  to  south 
west  in  some  regions  ;  and  occasionally  to  east  and  west. 

On  the  higher  summits  of  northern  New  England,  the  average  course  is  approxi 
mately  S.  40°  E. ;  to  the  eastward,  in  Maine  and  adjoining  parts  of  Canada,  S.  50°  to 
S.  06°  E.,  increasing  in  easting  to  the  eastward;  in  western  Connecticut  and  New  York 
adjoining,  about  S.  25°  E. ;  in  western  New  York  and  on  the  eastern  side  of  Lake 
Huron,  S.  35°  W. ;  on  the  northeast  side  of  Lake  Huron,  S.  37°-45°  W. 

Over  the  lower  lands  of  a  country,  there  is  commonly  some  conformity  to  the  general 
slopes  of  the  surface,  or  to  those  of  the  principal  river  valleys,  as  stated  with  regard 
to  the  Drift  itself.  While  the  scratches  follow  the  course  of  the  Connecticut  valley,  in 
the  valley  itself  (averaging  S.  to  S.  15°  E.,  for  100  miles  north  of  Massachusetts;  S., 
in  Massachusetts;  S.  100-25°"W.,  in  Connecticut),  to  the  east,  as  well  as  west,  of  the 
valley,  over  the  higher  land,  the  same  southeasterly  course  prevails  that  is  usual  over 
the  more  elevated  parts  of  New  England.  (Am.  Jour.  Sci.,  III.  ii.  233.)  Along  the 
valleys  of  the  Lamoille,  the  Winooski,  and  Otter  Creek,  in  Vermont,  of  the  Merrimack 
in  Massachusetts,  and  in  the  lower  part  of  the  Lake  Champlain  valley,  the  scratches  have 
the  directions  nearly  of  the  valleys.  In  western  New  York  and  western  Canada,  and 
about  the  eastern  borders  of  Lake  Huron,  the  prevailing  course  of  the  scratches  is 
southwest;  but,  at  many  points  south  of  the  eastern  arm  of  Lake  Huron,  called 
Georgian  Bay,  as  recorded  by  Logan,  it  is  southeast;  and  this  is  so,  apparently,  be 
cause  this  is  the  course  of  the  Georgian  Bay  depression. 

There  are  sometimes  two  or  more  sets  of  groovings,  differing  in 
direction.  For  example,  in  western  New  York,  there  is,  in  addition 
to  the  southwest  system,  a  subordinate  south  system  (Hall)  ;  and,  on 
Isle  La  Motte,  in  Lake  Champlain,  there  are  eight  sets  (Adams), 
although  usually  not  over  two  or  three  in  Vermont. 


532  CENOZOIC   TIME. 

Western  and  Southern  North  America.  —  In  the  Rocky  Mountains, 
the  Sierra  Nevada,  and  other  western  ranges,  there  are  scratches, 
polished  rocks,  and  roches  moutonnees  of  vast  extent,  as  well  as  the 
local  Drift  alluded  to  on  page  528 ;  and,  like  the  Drift,  they  have,  in 
general,  the  courses  of  the  valleys  or  slopes.  On  Vancouver's  Island, 
near  Victoria,  however,  the  scratches  have  a  south-southwest  course 
(magnetic),  and  others  a  south-southeast ;  and  these  may  be  connected 
with  a  true  northern  Drift. 

Scratches  and  polishing  of  rocks,  of  limited  extent,  have  been  observed  by  R.  P. 
Stevens,  either  side  of  the  Alleghanies,  in  West  Virginia,  accompanying  the  Drift  de 
scribed  as  occurring  there,  on  page  528. 

The  scratched  and  polished  rocks  of  the  Sierra  Nevada  are  of  great  extent  and  per 
fection,  about  Mount  Lycll  and  several  other  higher  summits  of  the  Sierra  Nevada,  as 
described  by  Whitney,  King,  and  Le  Conte.  They  are  very  remarkable  also  about  the 
Crest  range  of  the  Rocky  Mountains,  in  Colorado,  as  observed  by  Hayden  &  Gardner. 
A  portion  of  one  of  the  valleys  leading  away  from  the  Mountain  of  the  Holy  Cross 
(covered  with  "  sheep- backs  ")  is  represented  in  Fig.  1106,  on  page  685,  from  a  sketch 
from  Hayden 's  Report. 

3.  Forced  Migration  of  Plants.  —  On  the  summits  of  the  White 
Mountains,  the  Adirondacks,  and  some  peaks  of  the  Green  Mountains, 
and  other  places,  less  elevated,  there  are  species  of  snbalpine  plants, 
which  are  believed  to  have  migrated  southward  in  Glacial  times. 

Thirty-seven  kinds,  according  to  Dr.  Asa  Gray,1  occur  on  the  White  Mountains 
alone,  and  part  of  them  on  the  Adirondacks  and  Green  Mountains.  Besides  these, 
Sedum  Rhodiola  D.  C.,  a  subalpine  species,  occurs  on  cliffs  of  the  Delaware,  below  Eas- 
ton,  Pa.;  Saxifraya  oppositifolia  Linn.,  on  Mount  Willoughby,  in  Vermont;  Arennria 
Gronlandica  Sprengel,  a  Greenland  species,  is  found  on  the  top  of  the  White  Mountains, 
the  Catskills,  Shawangunk  Mountain,  and,  in  the  form  of  A.  ylabra  Michx.,  on  the  Al 
leghanies  of  Carolina;  Sclrpus  ccespitosus  Linn.,  alpine  and  subalpine,  has  a  patch  re 
maining  on  Roan  Mountain,  North  Carolina:  Nepliroma  Arcticum  Fries,  and  other 
northern  Lichens, with Lycopodium  selayo  Linn.,  still  live  on  the  highest  Alleghanies. 


2.  DRIFT  IN  FOREIGN  COUNTRIES. 

The  Drift  material  presents  the  same  characteristics  on  the  other 
continents  as  in  North  America.  It  is  confined  to  the  northern  half 
of  Europe  ;  that  is,  Britain,  Denmark,  Scandinavia,  Russia,  Poland, 
and  northern  Germany,  down,  in  some  portions,  to  the  parallel  of 

51°^ a  line  which  has  nearly  the  same  mean  temperature  now  as  the 

southern  limit,  39°,  in  the  eastern  United  States.  In  South  America, 
it  is  met  with,  from  Tierra  del  Fuego,  as  far  toward  the  equator  as 
37°  S.,  and  especially,  as  Agassiz  has  shown,  in  the  great  valley  be 
tween  the  main  chain  of  the  Andes  and  the  Coast  Mountains,  where 
it  was  observed  by  him,  to  the  latitude  of  Concepcion.  It  occurs  like 
wise  on  the  east  side  of  the  Andes  ;  also  over  parts  of  New  Zealand. 

1  American  Journal  of  Science,  II.  xxiii.,  62,  1857. 


QUATERNARY    AGE.  —  GLACIAL   PERIOD.  533 

The  course  of  the  stones,  gravel,  aiid  sand,  and  also  that  of  the 
scratches,  is,  in  the  main,  toward  the  equator. 

In  Europe,  the  Drift  crossed  the  Baltic  from  Scandinavia  to  Den 
mark,  Germany,  and  Poland  ;  and  many  stones  are  of  great  size. 
Scandinavian  rocks  were  also  carried  to  the  coast  of  Norfolk,  in  Eng 
land.  The  distance  of  travel  varied  from  five  miles,  or  less,  to  five 
or  six  hundred.  There  is  evidence  also  of  transportation  toward  the 
Polar  regions. 

In  Great  Britain,  the  movements  were  mainly  in  the  direction  of 
the  slopes  of  the  mountains  and  their  valleys,  the  Drift  radiating  from 
different  centres,  as  the  Highlands  and  Southern  Uplands  of  Scotland, 
the  mountains  of  the  Lake  country  in  northern  England,  and  the 
Snowdonian  heights  in  North  Wales.  There  were  local  movements 
of  Drift  also  about  the  Pyrenees,  and  from  Auvergne  down  the  Dor- 
dogne. 

The  Drift  phenomena  are  exhibited  on  a  grand  scale  about  the  Alps,  especially  along 
the  valleys  of  the  Rhone  and  Rhine.  Lines  of  stones  and  gravel,  and  even  great 
bowlders,  have  been  traced  (first  by  Professor  Guyot)  from  the  Alpine  summits  about 
Mount  Blanc,  by  the  valleys  of  the  Trient  and  Rhone,  to  the  plains  of  Switzerland, 
and  thence  over  the  sites  of  Geneva  and  Neufchatel  to  the  Jura  Mountains  on  the 
borders  of  France;  and  the  declivity  of  this  range,  facing  the  Alps,  is  covered  with 
the  bowlders;  one  of  them,  the  Pierre-a-bot,  —  a  mass  of  granyte  (or  more  properly pro- 
toyine),  —  is  62  feet  long  by  48  broad,  and  contains  about  40.000  cubic  feet,  equivalent 
to  a  weight  of  3,000  tons. 

Moreover,  the  valleys  of  the  Alps  have  their  sides  nearly  horizontally  grooved  or 
planed,  to  a  height  of  10,000  feet  above  the  sea,  or  more  than  two  thousand  feet  above 
the  present  upper  limit  of  the  glaciers,  or  the  level  of  any  existing  adequate  abrading 
agency.  The  bowlders  and  scratches  have  been  traced  beyond  Geneva,  even  to  Lyons, 
and  to  Vienne,  in  Dauphiny. 

About  Mount  Antilihanus,  in  Syria,  in  latitude  34°  N".,  glacial  phenomena  have  been 
observed:  and  also  on  the  southern  side  of  the  Himalayas,  to  within  4,000  feet  of  the 
sea  level,  if  not  quite  down  to  the  plains  of  India. 

Forced  Migrations.  —  Numerous  examples  have  been  observed,  in 
Europe,  of  species  of  both  plants  and  animals  driven  south  by  the 
conditions  of  the  Glacial  period.  Subarctic  shells  are  found  in  Qua 
ternary  deposits,  on  the  borders  of  the  Mediterranean ;  and  one  of  the 
Glacial  colonists,  Fusus  contrarius  Kiener,  still  lives  in  Vigo  Bay  on 
the  coast  of  Spain,  with  other  Celtic  species. 

3.  FIORD  VALLEYS. 

Another  great  fact  that  belongs  to  the  Drift  latitudes  on  all  the 
continents,  and  may  be  connected  in  origin  with  the  phenomena  of  the 
Glacial  era,  is  the  occurrence,  on  the  coasts,  of  fiord  valleys,  —  deep, 
narrow  channels  occupied  by  the  sea,  and  extending  inland,  often  for 
50  or  100  miles.  This  geographical  connection  with  the  Drift  is  a 
striking  one,  Fiords  occur  on  the  northwest  coast  of  Europe,  from 


534  CENOZOIC    TIME. 

the  British  Channel  north,  and  abound  on  the  coast  of  Norway.  They 
are  remarkably  displayed  on  the  coasts  of  Greenland,  Labrador,  Nova 
Scotia,  and  Maine.  On  the  northwest  coast  of  America,  from  the 
Straits  of  De  Fuca  north,  they  are  as  wonderful  as  along  Norway.  On 
the  coast  of  South  America,  they  occur  in  Drift  latitudes,  from  41°  S. 
Drift  latitude?  are  therefore  nearly  identical  with  fiord  latitudes. 

III.  Origin  of  the  Phenomena  of  the  Glacial  Period. 

The  Drift  period  is  usually  called  the  Glacial  period,  under  the 
idea  that  ice,  in  the  form  of  either  icebergs  or  glaciers,  was  concerned 
in  the  transportation  of  the  bowlders,  pebbles,  and  earth.  Ice  may 
float  masses  of  many  thousand  tons'  weight,  when  in  the  condition  of 
an  iceberg ;  and  so  glaciers,  as  in  the  Alps,  may  bear  along  great 
masses  of  rock  or  earth.  But  simple  running  or  moving  water  is  in 
capable  of  such  work.  There  are,  then,  two  theories,  the  Iceberg 
and  the  Glacier.  The  former  supposes  large  parts  of  the  continents 
under  the  sea  ;  the  latter  places  the  same  regions  above  the  sea,  and 
perhaps  at  a  higher  elevation  than  now.  They  thus  diverge  at  the 
outset. 

1.  Iceberg  Theory.  —  (1.)  The  Iceberg  theory  supposes  New  Eng 
land  to  have  been  submerged  5,000  feet  or  more  below  its  present 
level.  It  requires,  in  fact,  that  the  submerged  area  should  have  ex 
tended  wherever  the  Drift  occurs :  and  therefore  this  must  have 
reached  to  the  Ohio  on  the  south,  and  beyond,  according  to  some  ad 
vocates  of  it,  along  the  Mississippi  valley  to  the  Gulf  of  Mexico  ;  and 
far  to  the  north,  over  the  British  possessions,  to  a  limit  yet  undeter 
mined.  But,  in  opposition  to  this  hypothesis,  there  are,  south  of  the 
latitude  of  Hudson's  Bay,  no  shell-bearing  sea-beaches,  as  evidence  of 
such  a  submergence,  beyond  a  height,  at  the  most,  of  500  feet. 

It  appeals,  also,  to  the  facts  that  — 

(2. )  The  icebergs  of  the  Atlantic  are  floated  southward  from  the  Arctic  regions,  and 
come  freighted  with  a  vast  amount  of  stones  and  earth ;  and  that  many  of  them  at  the 
present  day  descend  along  the  coast  of  Labrador  and  Newfoundland,  and  over  the  New 
foundland  Banks,  and,  as  they  melt,  cover  the  coast  with  blocks  that  are  as  large  as  any 
of  the  Drift  epoch,  and  also  strew  the  sea-bottom  with  both  stones  and  earth. 

(3.)  The  Labrador  current  (p.  40)  has  the  direction  of  the  Drift  stones  and  scratches, 
and  must  always  have  had  this  course. 

(4.)  The  material  deposited  by  melting  bergs  would  contain  few,  if  any,  sea  relics. 

(5.)  Stones  in  the  foot  or  under  surface  of  a  grounded  berg  would  scratch  the  surface 
over  which  it  should  move. 

(6.)  The  courses  of  the  scratches  in  the  St.  Lawrence  valley,  not  far  from  the  river, 
and  the  Drift  transportation  were  up  stream,  as  if  from  the  flow  of  the  Labrador  current, 
carrying  ice,  while  the  continent  was  submerged. 

In  the  Iceberg  theory,  there  are  the  following  difficulties:  — 

(1.)  There  are  no  marine  deposits  or  fossils  of  the  era  over  the  interior  of  the  conti 
nent.  The  shore  of  the  sea  of  the  Drift  period  has  not  been  traced  bv  either  beaches  or 


QUATERNARY    AGE. —  GLACIAL   PERIOD.  535 

shells.  The  greatest  height  of  shore  shell-beds  in  or  near  the  United  States  is  470  feet; 
and  this  occurs  on  the  St.  LaAvrence  (p.  550);  nothing  of  the  kind  occurs  over  the  Ohio 
region,  north  or  south  of  the  river. 

(2.)  The  icebergs  of  the  Atlantic  bring  their  burdens  from  the  Arctic  mountains,  hav 
ing  gathered  them  while  glaciers — for  all  icebergs  are  fragments  broken  from  the  lower 
ends  of  glaciers ;  while  the  stones  and  earth  of  the  Drift  were  often  carried  less  than 
fifty  miles.  Consequently,  if  icebergs  were  the  means  of  transport  in  New  England, 
those  icebergs  must  have  commenced  as  glaciers  about  New  England  mountains, — an 
idea  which  has  its  difficulty  in  the  alleged  fact  (inferred  from  the  scratches  and  stones) 
that  even  Mount  Washington  was  all  submerged  but  five  hundred  feet,  and  Mount 
Mansfield  to  its  very  top. 

(3.)  Scratches  made  by  stones  in  the  bottom  of  bergs  that  chanced  to  be  grounded 
could  not  score  so  uniformly,  and  so  completely,  the  whole  surface  of  a  country.  They 
would  make  only  distant  deep  channelings,  unless  the  ice  lay  regularly  over  the  whole 
bottom,  —  a  condition  which  may  be  that  of  the  foot  or  under  surface  of  a  glacier,  but 
not  that  of  an  iceberg. 

(4.)  Bowlders  hundreds  of  tons  in  weight  were  taken  up  from  the  low  hills  in  the 
Connecticut  valley,  and  carried  fifty  miles,  or  less,  to  the  south ;  and,  if  carried  by  ice 
bergs,  the  berg  must  have  picked  up  the  great  mass  by  its  foot,  which  is  not  possible. 

(5.)  If  the  Continent  were  so  submerged  that  the  Mississippi  valley  and  the  St.  Law 
rence  were  one  continuous  oceanic  channel,  the  current  in  the  Mississippi  part  would 
be  one  from  the  south,  as  a  continuation  of  the  Gulf  Stream,  rather  than  one  from  the 
north ;  and  this  would  be  in  direct  disaccord  with  the  facts  with  regard  to  the  course  of 
Drift  transportation  over  the  region. 

(6.)  The  fact  that  there  is  commonly  a  conformity  between  the  directions  of  scratches 
in  the  larger  valleys  and  the  courses  of  these  valleys,  is  incompatible  with  the  idea 
that  icebergs  did  the  work  of  abrasion;  for,  in  a  deep  sea,  they  could  not  have  found  the 
currents  needed  to  carry  them  along  so  many  and  various  courses. 

(7.)  The  submergence  of  the  northern  part  of  America,  as  far  as  the  southern  limits 
of  the  Drift,  would  have  made  a  warm  climate  for  the  continent,  and  not  a  glacial  (p. 
44);  and,  hence,  there  is  great  difficulty  in  accounting  for  either  icebergs  or  glaciers, 
upon  this  view. 

2.    Glacier  Theory.  —  This  theory  is  sustained  on  the  ground  that  — 

(1.)  Glaciers  are  known  to  transport  bowlders,  gravel,  and  earth; 
and  they  may  carry  the  material  short  distances  as  well  as  long. 

(2.)  Glaciers  make  scratches  in  the  rocks  beneath  them,  by  means 
of  the  stories  they  carry  at  bottom,  precisely  like  those  of  the  Drift 
regions,  as  to  regularity,  kind,  number,  and  all  other  peculiarities ;  and 
polished  and  rounded  surfaces  are  other  common  effects  from  moving 
glaciers.  Moreover,  the  stones  themselves  are  scratched  or  polished. 

(3.)  Glaciers  may  make  the  scratches  in  large  valleys  in  the  direc 
tion  of  the  valleys,  when  the  main  mass  is  moving  in  another  direction. 
For,  while  they  take  their  general  course  from  the  grander  slopes  of 
the  upper  surface  of  the  ice-mass,  the  movement  at  the  bottom  will 
accord,  more  or  less  perfectly,  with  the  slopes  of  the  land-surface  ; 
just  as  thick  pitch,  descending  a  sloping  plane  having  oblique  furrows 
in  its  surface,  would  follow  the  general  slope  of  the  plane,  but  have 
an  under  part  diverted  by  the  furrows. 

(4.)  The  presence  of  a  considerable  number  of  alpine  or  subalpine 
plants,  within  the  limits  of  the  eastern  United  States  (p.  532),  can  be 


536  CENOZOIC   TIME. 

accounted  for  on  the  view  of  an  era  of  glaciers,  and  not  on  that  of 
icebergs. 

(5.)  The  objection  urged  against  the  glacier  theory,  that  the  north 
ern  part  of  the  continents  does  not  afford  a  slope  southward,  to  favor 
the  movement,  is  of  no  weight,  since  no  such  slope  was  required.  All 
that  was  needed  was  a  general  southward  slope  in  the  upper  surface 
of  the  glacier ;  or  simply  a  greater  accumulation  of  ice  to  the  north 
than  to  the  south.  The  case  is  just  like  that  of  heaped-up  pitch.  If 
stiff  pitch  be  gradually  dropped  over  a  horizontal  surface  it  will 
spread,  and  continue  so  to  do  so  long  as  the  supply  is  kept  up  ;  and, 
if  that  surface  rises  at  an  angle  in  one  direction,  and  there  is  no  escape 
in  any  other,  it  will  first  fill  the  space  to  the  level  of  the  edge,  and 
then  drop  over  and  continue  onward  its  now.  So  Glaciers,  if  the 
accumulation  is  adequate,  may  go  across  valleys  and  over  elevated 
ridges.  At  the  same  time,  as  above  stated,  the  under  layers  of  the 
ice  will  follow,  to  some  extent,  the  general  slopes  of  the  country  passed 
over. 

A  glacier  filling  the  St.  Lawrence  valley  could  not  move  down  the  valley  (northeast 
ward)  if  the  ice  were  highest  about  its  mouth;  but  it  might,  in  such  a  case,  move  up 
the  valley,  or  across  New  England ;  and,  if  the  latter,  the  portion  in  the  bottom  of  the 
valley  would  be  likely  to  move  up  stream,  because  the  valley,  a  groove  in  the  land, 
might  give  direction  to  the  bottom  layer.  Dr.  Dawson  has  observed  evidence  that,  in 
some  parts  of  the  St.  Lawrence  valley,  the  ice  of  the  Glacial  period  did  actually  move 
up  stream. 

8.  The  glacial  phenomena  of  the  higher  Rocky  Mountain  ranges, 
the  Sierra  Nevada,  and  other  heights  on  the  Pacific  Border,  and  of  the 
mountains  of  Virginia  and  North  Carolina  on  the  Atlantic,  are  all  in 
harmony  with  the  Glacier  theory.  The  several  regions,  as  recognized 
by  all  observers,  are  simply  examples  of  glacier  centres,  like  that  of 
the  Alps,  where  the  mountains  were  lofty  enough  to  determine  the 
surface  slope  of  the  ice,  in  which  case  the  glaciers  of  the  region  would 
necessarily  have  been  local  glaciers.  They  point  to  the  Glacial  period 
of  the  Continent  as  the  time  of  their  origin.  A  few  traces  of  the  old 
glaciers  still  linger,  about  Mount  Shasta,  Mount  Hood,  and  some  other 
of  the  loftier  summits ;  and  two  branches  of  the  Saskatchewan  head 
in  glaciers,  one  of  which  is  nine  miles  long  and  three  wide. 

Similarly,  the  glacial  phenomena  of  Great  Britain,  the  Alps,  the 
Pyrenees,  Mount  Lebanon,  and  the  Himalayas,  are  those  of  Alpine 
glacier  centres,  and  cannot  be  explained  without  reference  to  the  exist 
ence  and  action  of  glaciers.  Geikie  has  shown  that  the  great  glacier 
from  the  Highlands  of  Scotland  extended  northwestward  over  the  Heb 
rides,  and  southward  and  south  westward  through  the  Irish  Channel 
and  over  Ireland  ;  and  it  probably  reached  northeastward  to  the  Ork 
neys  and  Shetlands.  The  occurrence,  in  southern  South  America,  of 


QUATERNARY    AGE.  —  GLACIAL   PERIOD.  537 

bowlders  from  the  Cordilleras,  scores  of  miles  to  the  east  of  the  moun 
tains,  as  well  as  to  the  west  on  Chiloe,  observed  by  Darwin,  re 
quires  the  same  explanation. 

The  absence  of  glacier  action,  over  a  large  part  of  the  region  from 
Virginia  to  Georgia  and  Alabama,  is  shown  by  the  great  depth 
of  decomposed  rock,  covering  in  situ  the  crystalline  rocks  in  many 
places  ;  at  the  north,  all  such  soft  superficial  material  was  scraped  off 
and  carried  away  by  the  glacier. 

It  hence  appears  that  the  glacier  theory  is  alone  capable,  as  first 
shown  by  Agassiz,  of  explaining  all  the  facts. 

The  surface  of  the  glacier  in  North  America  must  have  been  of 
unblemished  whiteness ;  for,  from  New  England  to  the  Rocky  Moun 
tains,  there  was  not  a  peak  above  its  surface,  excepting  the  White 
Mountains,  and  these  probably  had  their  cap  of  snow.  Hence  there 
were,  among  the  depositions,  no  true  lateral  moraines,  although  every 
where  under-glacier  moraines,  or  linear  ranges  of  stones  and  gravel. 

3.  Probable  head  and  lower  limit  of  the  Glacier  of  Eastern  North 
America :  Terminal  Moraines.  —  The  direction  of  the  scratches,  and 
the  extent  of  the  country  they  cover,  appear  to  show  that  the  head  or 
upper  part  of  the  ice-mass,  over  New  England,  New  York,  and  the 
Canadian  region  from  Labrador  to  and  beyond  Lake  Huron,  was  on 
the  water-shed  between  the  St.  Lawrence  River  and  Hudson  Bay. 
The  lower  limit  of  the  New  England  portion  probably  coincided  with 
the  outline  of  the  deep-water  slope,  about  eighty  miles  south  of  Long 
Island,  and  St.  George's  Shoal,  between  Cape  Cod  and  its  continuation 
northeastward  in  Sable  Island  Shoal,  just  outside  of  Nova  Scotia.  In 
this  part,  therefore,  the  depositions  from  the  melting  extremity,  the 
terminal  moraines,  would  have  been  made  in  the  shallow  waters  of  the 
ocean's  border,  and  have  increased  its  shallowness.  St.  George's  Bank 
and  Sable  Island  Shoal  may  be  mainly  terminal  moraines.  Over  the 
continent,  to  the  west,  there  must  have  been  true  terminal  moraines 
formed.  But  they  were  mostly  obliterated  by  the  floods  of  the  suc 
ceeding  period. 

The  highest  ice-surface  must  have  been  somewhere  in  British  America,  in  order  that 
the  ice  might  have  moved  across  the  St.  Lawrence  valley,  climbed  and  passed  the 
mountains  near  the  northern  New  England  boundary,  and  then,  without  any  essential 
change  of  course,  have  traversed  all  New  England  to  the  ocean  on  the  southeast.  The 
direction  of  the  scratches,  in  Maine,  New  Hampshire,  and  Vermont,  and  in  Canada  on 
the  north,  in  eastern  New  York,  western  New  York,  and  the  country  about  Lake 
Huron,  varies  from  west-northwest  on  the  east  to  northeast  on  the  west;  and  the 
scratches,  thus  converging,  point  to  the  watershed  between  the  St.  Lawrence  and  Hud 
son  Bay,  as  the  place  of  origin.  The  southwestward  course  of  the  scratches,  about  the 
Avestern  limit  of  this  great  region,  is  continued,  still  farther  west,  over  the  Maumee  Val 
ley,  through  northwestern  Ohio. 

The  height  of  the  upper  surface  of  the  glacier,  at  the  White  Mountains,  as  the  facts 
show,  was  at  least  0,000  feet  above  the  sea.  According  to  calculations,  the  details  of 


538  CENOZOIC    TIME. 

which  are  given  in  the  American  Journal  of  Science,  volume  v.,  1873,  the  height  on  the 
northern  border  of  New  England,  north  and  northwest  of  the  White  Mountains,  was,  on 
this  basis,  8,000  feet ;  and,  if  ten  feet  a  mile  is  sufficient  to  give  motion,  the  height  over  the 
Canada  watershed  (570  miles  from  Mount  Washington),  was  at  least  13,000  feet.  As  this 
watershed  has  an  average  height  of  1,500  feet,  the  thickness  of  the  ice,  to  make  the 
height,  would  have  been  11,500  feet,  unless  the  watershed  were  above  its  present  level; 
and,  in  view  of  the  enormous  thickness  thus  required,  we  may  reasonably  infer  that  it 
was  more  elevated  than  now,  at  least  some  hundreds  of  feet.  The  movement  of  the 
glacier,  across  the  St.  Lawrence  valley  over  New  England,  proves  that,  about  the  mouth 
of  the  St.  Lawrence,  the  ice  stood  higher  than  over  the  watershed;  and  this  was  owing 
to  two  causes:  (1)  the  greater  amount  of  precipitation  (as  now  true),  near  the  seashore, 
and  (2)  the  higher  latitude,  and  hence  the  greater  cold.  At  the  same  time,  the  course 
of  the  glacier  over  New  England  was  determined  largely  by  the  fact  that  to  the  south 
east  lay  the  ocean,  affording  a  place  of  discharge  for  the  ice-stream. 

The  absence  of  glacial  phenomena  from  the  slopes  of  the  Rocky  Mountains,  within 
the  United  States,  between  the  meridians  of  98°  and  108°,  is  probably  a  consequence  of 
the  small  amount  of  precipitated  moisture  over  that  region  (now  only  20  inches  a  year), 
and  also  of  the  high  summer  temperature. 

4.  Abrasion:  Erosion:  Gathering  of  Material  for  Transportation. — 
The  glacier,  with  a  thickness  of  several  thousand  feet,  must  have  had 
great  abrading  power,  owing  to  (1)  its  weight,  (2)  its  motion,  and  (3) 
the  stones  in  its  under  surface. 

The  weight  of  the  glacier,  equivalent  to  2,000  pounds  to  the  square 
inch  where  4,500  feet  thick,  would  have  pressed  the  bottom  ice,  where- 
ever  the  weight  was  felt,  into  all  depressions  and  crevices  in  and  among 
the  rocky  hills,  and  even  into  the  earthy  material  that  decomposition  had 
made  over  the  hillsides.  It  would  have  filled,  to  its  bottom,  Lake  Erie, 
now  but  80  feet  deep  ;  and  so  also  Long  Island  Sound,  now  150  to 
180  feet  deep  ;  and  it  is  probable  that,  if  the  ice  were  but  a  thousand 
feet  thick,  it  would  have  gone  to  the  bottoms  of  Lakes  Huron  and 
Michigan,  supposing  them  to  have  had  their  present  depth. 

As  the  glacier  slowly  moved,  it  would  have  torn  off  the  tops  and  sides 
of  ledges,  and  have  taken  the  stones  into  its  mass,  for  transportation 
southward.  Thus  it  was  ever  abrading,  and  ever  gathering  material 
for  distribution.  The  stories  and  earth  were  taken  up  by  the  lower 
part  of  the  glacier,  where  in  contact  with  the  hill-tops  and  ledges,  and 
hence  they  occupied,  for  the  most  part,  the  lower  500  or  1,000  feet. 
In  connection  with  the  onward  movement,  and  in  consequence  of  it, 
there  was  intestine  motion  throughout  the  whole  ice-mass,  and  espe 
cially  in  this  lower  portion ;  and  this  would  have  ground  the  stones 
against  one  another,  rounded  their  edges,  caused  scratches  in  their 
surfaces,  and  made,  through  the  mutual  grinding,  the  earth  of  the 
bowlder  clay,  as  well  as  sand  and  pebbles  for  sand  and  pebble  beds. 
The  glaciers  of  Greenland,  which  are  parts  of  the  old  Continental, 
afford  examples  of  all  these  operations. 

Moreover,  since  the  snows  of  the  commencing  Glacial  period  fell  over 
a  continent  of  great  forests,  the  forests  were  in  the  bottom  of  the  first 


QUATERNARY   AGE.  —  GLACIAL   PERIOD.  539 

formed  ice.  As  the  ice  moved,  the  trees  would  have  been  rooted  up 
or  broken  off  and  mixed  up,  and  partly  ground  up,  with  other  debris, 
and,  afterward,  if  not  wasted  by  decomposition,  deposited  with  the 
Drift,  —  some  portions,  perhaps,  in  beds  of  vegetable  material,  and 
others  as  scattered  logs,  stems,  and  roots.  Land  and  fresh-water  shells 
also  would  have  been  gathered  up  for  transport  and  distribution. 

The  excavation  of  valleys  was  part  of  the  work  of  the  ice-period. 
The  valleys  of  the  continent  owe  their  depth  to  erosion  by  the  streams 
flowing  in  them.  Now  this  excavation  has  been  carried  much  deeper 
in  very  many  cases  than  could  have  been  done  with  the  continent  at  its 
present  level.  Dr.  Newberry  states  that  all  the  river  valleys  of  Ohio 
are  examples  of  this ;  that  the  valley  of  Beaver  River  is  excavated  to 
a  depth  of  150  feet  below  the  present  river  level ;  that  of  Tuscarawas 
River,  at  Dover,  175  feet;  that  of  the  Ohio  River,  much  deeper,  100 
feet  of  boring  near  Cincinnati  not  reaching  the  bottom  of  the  alluvium. 
Such  facts  are  evidence  of  erosion  at  some  period  when  the  continent 
was  more  elevated  than  now,  and  are  attributed  by  many  to  the  agen 
cies  of  the  Glacial  era.  The  remarks  on  fiords  on  page  533  are  in 
further  illustration  of  this  subject. 

The  excavation  of  lake  basins  also  has  been  attributed  to  glacial 
action.  In  the  case  of  many  lakes  in  Alpine  regions,  the  origin  is  due 
to  the  filling  of  the  narrow  outlet  of  a  deeply  excavated  valley,  by 
Drift.  But,  in  some  cases,  especially  when  the  rocks  underneath  the 
glacier  were  soft  and  easily  abraded,  the  ice  may  have  gouged  deeply 
into  the  underlying  deposits,  and  then  have  had  this  excavating  action 
stopped  by  a  barrier  of  harder  rock  in  front ;  and  thus  a  lake-basin 
may  have  resulted. 

IV.  .Icebergs. 

While  the  glacier  theory  affords  the  best  and  fullest  explanation  of 
the  phenomena,  over  the  general  surface  of  the  continents,  and  en 
counters  the  fewest  difficulties,  icebergs  have  aided  beyond  doubt  in 
producing  the  results  along  the  borders  of  the1  continents,  across  ocean- 
channels  like  the  German  Ocean  and  the  Baltic,  and,  before  the  final 
disappearance  (as  explained  in  the  account  of  the  Champlain  period), 
over  the  region  of  the  Great  Lakes  of  North  America.  Their  effects 
are  well  exhibited  along  the  coast  of  Labrador. 

V.  General  Observations. 

1.  Geography.  —  The  Glacial  period  a  period  of  high-latitude  eleva 
tion,  and  hence  of  deep  valley-excavation.  —  Elevations  of  land  do  not 
leave  accessible  records  like  subsidences.  Still,  there  is  evidence  on 
this  point  deserving  consideration. 

(1.)  The  existence  of  an  epoch  of  unusual  cold  in  the  early  Qua- 


540  CEXOZOIC   TIME. 

ternary,  when  glaciers  and  icebergs  prevailed  vastly  beyond  their  ex 
isting  limits,  in  itself  suggests  that  the  epoch  was  one  of  some  eleva 
tion  beyond  the  present,  over  the  Drift  or  cold  latitudes. 

(2.)  The  occurrence  of  fiords  only  in  Glacial  latitudes  is  further 
reason  in  favor  of  the  supposed  elevation ;  and  of  Europe  as  well  as 
America.  They  are  positive  evidence  that,  in  the  era  when  they  were 
made,  the  land  stood  above  its  present  level,  and  high  enough  above  to 
allow  of  their  having  been  excavated,  to  their  bottoms,  by  the  flow 
along  them  of  fresh  water  or  fresh  water  and  ice  —  for  they  are  val 
leys  of  erosion.  They  may  have  been  begun  in  earlier  periods, 
and  have  been  partly  finished  in  the  Cretaceous  and  Tertiary  ;  but  the 
almost  precise  identity  of  Glacial  and  fiord  latitudes  over  the  globe 
make  it  a  reasonable  supposition  that  the  Glacial  era  did  the  finishing 
work,  through  the  increased  elevation  of  northern  lands. 

(o.)  This  argument  from  fiords  is  corroborated  by  the  facts  con 
nected  with  the  depth  of  river  valleys,  mentioned  on  the  preceding 
page ;  and  similar  facts  might  be  gathered  from  Europe. 

Further,  there  is  evidence,  as  shown  by  F.  H.  Bradley,  that  waters 
from  Lake  Michigan,  in  some  era,  cut  a  channel  from  the  south  end 
of  the  lake  southwestward  to  the  Mississippi,  following  a  course  south 
to  the  north  line  of  Iroquois  County,  Illinois,  and  thence  southwest 
through  Champaign  and  McLean  counties,  —  the  western  margin  of 
the  trough  being  well  marked  by  buried  escarpments,  in  some  places 
two  hundred  feet  or  more  in  height.  Lake  Erie,  in  like  manner,  has 
been  found,  by  G.  K.  Gilbert,  to  have  discharged  southwestward  along 
the  course  of  the  Maumee,  and  not  by  overflow  merely,  but  by  a  strong 
current  which  cut  its  trough.  The  under-sea  course  of  the  Hudson 
River  channel  has  been  pointed  out  on  page  423 ;  and  there  is  a  simi 
lar  one,  though  less  perfect,  for  the  Connecticut  outside  of  Long  Island 
Sound.  Such  facts  are  explained  only  on  the  ground  of  a  former  ele 
vation  of  the  continent  to  the  north  ;  and  the  Glacial  era  is  the  most 
probable  time  of  its  occurrence.  With  an  elevation  of  but  two  hun 
dred  feet  along  Southern  New  England,  Long  Island  Sound  would 
have  been  for  the  most  part  a  fresh-water  channel,  tributary  to  the 
prolonged  Connecticut. 

(4.)  The  Atlantic  coast  of  North  America,  to  the  north  of  Cape 
Cod,  was  higher  than  now  during  the  Cretaceous  and  Tertiary  eras,  as 
is  shown  by  the  absence  of  seashore  deposits  of  these  eras.  The 
Tertiary  was  an  era  of  extensive  mountain  elevation,  and  of  the  cool 
ing  of  climate,  both  increasing  to  the  end ;  and  it  is  probable  that  the 
elevation  to  the  north  reached  its  extreme  just  after  the  Tertiary,  in  the 
Glacial  era,  when  the  cooling  of  the  climate  also  reached  its  maximum. 

(5.)  The  height  required  for  the  ice-surface,  over  the  Canada  water- 


QUATERNARY   AGE.  —  GLACIAL    PERIOD.  541 

shed,  in  order  that  it  may  have  sent  a  glacier  over  New  England, 
renders  it  probable,  as  stated  on  page  538,  that  part  of  this  height  was 
acquired  through  an  elevation  of  the  land.  It  may  be  that  the  Great 
Lakes  were  largely  drained,  in  consequence  of  the  lifting  at  the  north.1 

The  view  that  the  land  of  Great  Britain  was  above  its  present  level, 
when  the  glacier  was  formed,  is  urged  by  Lyell,  Dawkins,  Geikie,  and 
other  British  geologists.  Erdmann,  in  his  elaborate  memoir  on  the 
Quaternary  of  Sweden,  observes  that  the  fact  of  elevation  is  established 
by  the  extent  to  which  rocks  were  polished  beneath  the  sea  level,  and 
that  the  country  was  probably  so  much  raised  that  a  large  part  of 
the  Baltic  was  dry  land.  Great  Britain  was  probably  at  the  same 
time  joined  to  Europe  (p.  572),  and  to  the  islands  on  the  north.  Scot 
land,  as  its  fiords  and  the  channels  between  the  Hebrides  show,  must 
have  been  at  least  1,000  feet  above  its  present  level. 

2.  Source  of  the  Cold.  —  The  occurrence  of  an  ice-period  was 
probably  dependent  mainly,  as  suggested  by  Lyell,  on  the  extension 
and  elevation  of  the  land  over  the  higher  latitudes.  The  movement 
may  have  resulted  in  the  closing  of  Behring  Straits,  —  only  180  feet 
deep, —  and  the  connection  of  America  and  Europe  across  the  Polar 
Sea.  In  such  a  case,  the  tropical  currents  of  both  the  Pacific  and  At 
lantic  would  have  been  confined  to  these  oceans,  instead  of  flowing  into 
the  Arctic  seas;  and  hence  their  ameliorating  influence  on  the  climate 
of  Northern  Europe  and  America  would  have  been  lost,  enhancing  the 
refrigerating  effect  of  the  high-latitude  movement.  Variations  in  the 
degrees  of  cold,  and  in  the  amount  of  precipitated  moisture,  would 
naturally  have  occurred  at  intervals  in  the  course  of  the  era  of  cold, 
and  have  led  to  retreats  and  extensions  of  the  glacier  ice,  and  varia 
tions  in  the  condition  of  some  parts  of  the  country  invaded. 

Other  sources  of  a  cold  climate  have  been  appealed  to. 

(1.)  The  diversion  of  the  Gulf  Stream  over  the  submerged  Isthmus  of  Panama  into 
the  Pacific ;  or  else  cutting  off  the  South  Atlantic  supply,  by  a  barrier  made  by  the 
elevation  of  the  under-oceanic  ridge  between  the  east  cape  of  South  America  and 
Africa;  — either  is  a  hypothesis  without  facts  or  probabilities  in  its  favor.  It  is  certain 
that,  when  the  Champlain  period  opened,  the  Gulf  Stream,  as  Verrill  has  remarked,  had 
its  usual  course ;  for,  while  the  elevated  sea-border  Champlain  formations  north  of  Cape 
Cod  contain  cold-water  fossils,  those  of  Nantucket,  and  other  localities  south  of  the 
Cape,  contain  warm-water  species,  —  and  the  same  that  now  live  on  these  coasts. 
Hence,  the  currents  flowed  then  as  they  do  now. 

(2.)  The  passing  of  the  earth  through  one  of  its  eras  of  maximum  eccentricity  of 
orbit  (see  page  697):  a  cause  that  puts  the  Glacial  periods  of  the  Northern  and  South 
ern  hemispheres  not  far  from  a  hundred  thousand  years  apart :  at  the  time  that  it  gave 
increased  cold  and  length  to  the  Northern  winters,  it  would  give  an  equable  climate 
to  the  Southern  hemisphere.  The  cause  alone  appears  to  be  wholly  inadequate ;  but 

1  The  author's  views  on  fiords  and  the  subdivisions  of  the  Quaternary  (Post-ter 
tiary)  were  first  published  in  the  Amer.  Jour.  Sci.,  II.  vii.  379,  1849,  and  xxii.  325,  346, 
1856.  The  subject  is  further  reviewed  and  extended  in  III.  i.  1,  ii.  233,  1871,  and  v. 
198,  1873. 


542  CEXOZOIC    TIME. 

the  cooling  effects  from  it  may  have  been  added  to  those  from  the  increase  of  northern 
lands. 

(3.)  An  increase  of  moisture  in  the  air,  and  therefore  of  precipitation,  this  being  suf 
ficient  without  a  northern  elevation,  and  without  an  increase  of  cold  beyond  the  present 
—  a  view  that  is  at  variance  with  the  fact  that  the  average  amount  of  precipitation 
over  different  regions  is  one  of  the  constants  in  nature,  not  alterable  except  by  a  change 
either  in  the  level  of  the  land,  or  in  the  courses  of  the  oceanic  currents;  and  that  any 
change  in  the  currents  except  that  from  elevating  northern  lands  would  tend  to  diminish 
rather  than  increase  evaporation.  A  northern  submergence,  while  it  might  increase  the 
amount  of  precipitation,  would  raise  also  the  mean  temperature,  by  opening  the  Arctic 
more  broadly  than  now  to  the  tropical  Oceanic  currents,  and  so  prevent  a  southward  ex 
tension  of  an  ice-mantle;  and  just  this  took  place  in  the  Champlain  period  or  era  of 
submergence. 

(6.)  Diminished  heat  in  the  Sun,  on  the  hypothesis  that  the  Sun  has  its  long-period 
cycles  of  maximum  and  minimum  heat.  The  action  of  this  cause  would  make  cool 
tropics,  along  with  the  cold  Arctic  regions. 

3.  Exterminations  and  migrations  cqnsequent  on  the  approach  of 
the  cold  period.  —  The  approach  of  the  cold  Glacial  era  probably  pro 
duced  that  extermination  of  species  which  closed  the  Tertiary  age,  be 
sides  causing  the  migration  to  more  southern  latitudes  of  species  not 
exterminated.  Some  facts  illustrating  the  latter  point  are  mentioned 
on  pages  532,  533.  The  former  hardly  needs  illustration.  The  cold 
must  have  come  on  with  extremely  slow  progress.  The  extermina 
tion  of  the  terrestial  Tertiary  mammals,  or  such  as  did  not  find  shelter 
to  the  South,  may  have  been  an  early  effect  of  the  progressing  refrig 
eration  ;  and,  long  before  the  cold  had  covered  the  continent  with  its 
ice-cap,  species  adapted  to  a  more  rigorous  climate,  that  is,  those  of 
Quaternary  times,  may  have  begun  to  occupy  the  country. 

The  Glacial  period,  which  is  here  shown  to  have  been,  in  all  prob 
ability,  an  era  of  high  latitude  elevation,  was  followed  by  one  of  un 
questioned  depression  —  the  Champlain  period. 

2.  CHAMPLAIN   PERIOD. 
1.  AMERICAN. 

The  CHAMPLAIN  period  is  so  named  from  the  occurrence  of  beds 
of  the  period  on  the  borders  of  Lake  Champlain. 

The  term  Champlain  is  applied  to  marine  deposits  of  the  period  by  C.  H.  Hitchcock, 
in  the  Report  on  the  Geology  of  Vermont 

I.  General  Course  of  Events. 

The  earlier  part  of  the  CHAMPLAIN  period  was  the  era  of  the 
melting  of  the  great  glacier,  and  of  most  local  glaciers  ;  and  therefore 
the  era  of  immense  fiords  along  the  valleys  ;  of  many  and  great  lakes  ; 
and  of  the  deposition  of  the  sand  and  gravel  of  the  glacier,  except 
the  relatively  small  part  which  had  been  earlier  dropped.  While  the 


QUATERNARY    AGE.  —  CHAMPLAIN    PERIOD.  543 

Glacial  period  was  eminently  a  period  of  abrasion  and  of  valley- 
erosion,  and  of  the  gathering  and  transportation  of  earth  and  stones, 
and  also  of  some  deposition  along  the  course  of  the  glacier,  and  much 
at  its  terminus,  the  CHAMPLAIN  was  the  era  of  the  general  depo 
sition  of  this  earth  and  stones,  and  the  further  distribution  of  it  by 
inland  waters  in  the  excavated  valleys  and  lake-basins,  and  along  sea- 
borders. 

Facts  demonstrate,  moreover,  that  the  period  was  not  only  one  of 
lower  level  than  the  present,  but,  further,  that  the  amount  of  depres 
sion  increased  northward,  so  that  the  beds  of  rivers  flowing  south 
ward  often  had  diminished  slope  in  Champlain  time,  and  the  waters  a 
slackened  flow,  with,  consequently,  many  expansions  into  lakes  along 
their  course  ;  and  that  their  exit  to  the  sea  was  often  by  long  and 
wide  estuaries. 

The  Champlain  period,  or  era  of  depression,  includes  two  sub 
divisions  :  — 

1st.  The  Diluvian  epoch,  or  that  of  the  depositions  from  the  melting 
glaciers,  which  depositions  began  when  the  melting  had  far  advanced 
(the  earth  and  stones  having  been  in  the  lower  portion  of  the  glacier, 
and  the  melting  having  been  general  over  its  surface),  and  which 
continued  —  probably  with  some  interruptions — until  the  melting 
had  ended.  Direct  evidence  of  the  final  flood  is  contained  in  the 
deposits  (p.  546). 

2d.  The  Alluvian  epoch,  or  the  part  of  the  era  of  depression  after 
the  melting  had  ended,  characterized  by  depositions  of  a  more  quiet 
character. 

II.  Rocks  :    kinds  and  distribution. 

1.  Kinds  of  deposits.  —  The  deposits  of  the  Diluvian  division  of 
the  Champlain  period  are  of  the  following  kinds  :  ( 1 )  those  that  were 
dropped  by  the  glacier,  after  the  period  of  melting  set  in,  over  the 
hills  where  there  were  no  waters  to  receive  them,  and  which  are, 
therefore,  unstratified ;  and  (2)  those  which  fell  into  waters,  or  where 
the  waters  could  gather  them  up  for  transportation,  and  which  there 
fore  became  more  or  less  stratified.  In  other  words,  the  unstratified 
and  stratified  Drift,  as  stated  on  page  527,  were  deposited  mainly  in 
the  Diluvian  era  of  the  Champlain  period. 

To  the  Alluvian  era  belong  the  subsequent  deposits  of  the  period. 

In  both  eras,  there  were,  outside  of  Glacial  latitudes,  and  partly 
within,  other  formations  of  various  kinds  in  progress,  like  those  of 
the  present  day. 

A.  Unstratified  Drift.  —  The  unstratified  Drift  consists  of  sand, 
gravel,  stones,  lying  pell-mell  together,  as  they  were  thrown  down 


544 


CENOZOIC    TIME. 


from  the  melting  glacier.  The  bed  of  bowlder-clay -,  in  progress  of  dep 
osition  during  the  whole  progress  of  the  glacier  (p.  5*27),  would  have 
continued  to  increase  through  the  first  part  of  the  melting,  and  after 
ward  become  covered  with  coarser  material.  Wherever,  in  the  prog 
ress  of  the  deposition  over  the  hills,  a  temporary  run  of  water  was 
made,  some  stratification  would  have  ensued;  and,  if  the  run  was 
afterward  obliterated,  the  deposition  would  have  been  again  unstratified. 

The  vegetable  material  in  the  ice  would  have  been  dropped  when 
ever  the  ice  relaxed  its  grasp  ;  and,  being  in  the  lower  part  of  the 
glacier,  and  often  in  large  amount  at  a  common  level,  it  would  natu 
rally  have  often  found  lodgment  in  the  lower  half  of  the  Drift  deposits, 
either  as  isolated  logs,  or  as  thin  beds  of  vegetable  debris. 

B.  Stratified  Drift  and  Alluvial  Beds.  —  The  material  of  the  strati 
fied  Drift  was  derived  by  the  waters  either  (a)  direct  from  the  melting 
glacier ;  or  (6)  from  the  loose  material  that  remained  over  the  hills 
after  the  ice  had  disappeared ;  or  (c),  for  the  later  Champlain  depo 
sitions,  in  part  from  subsequent  wear  and  decomposition.  The  beds 
were  deposited  either  (d)  along  the  valleys  and  flooded  streams ;  or 
(<?)  in  and  about  flooded  lakes  ;  or  (/)  in  estuaries,  and  along  sea- 
borders. 

Fig.  941. 


Terraces  on  the  Connecticut  River,  south  of  llauover,  N.  II. 

2.  River-border  and  Lake-border  Formations.  —  The  formations  of 
river-borders  and  lake-borders  are  essentially  alike,  except  that  the 
latter  are,  to  a  greater  extent,  of  a  clayey  nature.  The  rivers  were 
often  lakes  at  intervals. 

1.   Topographical  features.  —  The  fluvial  and  lacustrine  formations 


QUATERNARY  AGE.  —  CHAMPLAIN   PERIOD.  545 

have  generally  a  flat  summit,  because  levelled  off  by  the  waters.  They 
stand  at  various  heights,  the  top  often  one  or  more  hundred  feet 
above  the  level  of  the  river  or  the  lake  adjoining.  Very  often,  there 
are  plains  at  one  or  more  levels  besides  the  upper,  owing  to  sub 
sequent  wear  of  the  Champlain  deposits  by  river  action  ;  and,  in  that 
case,  the  valley  is  bordered  by  a  series  of  terraces.  Such  terraces 
around  lake  basins  have  been  significantly  called  benches.  The  accom 
panying  sketch  (Fig.  941),  from  the  Connecticut  River  valley,  some 
miles  south  of  Hanover,  N.  H.,  represents  the  general  appearance  of 
the  formation,  with  its  terraced  surface.  Up  and  down  the  stream, 
horizontal  lines  may  often  be  traced  for  miles,  marking  the  limit  of 
one  or  more  of  the  several  terraces  bordering  it.  Many  villages  in 
the  vicinity  of  rivers  owe  a  large  part  of  the  beauty  of  their  sites  to 
these  natural  terraces. 

2.  Distribution.  —  The  fluvial  and  lacustrine  formations  appear  to 
characterize  all  the  river-valleys  and  lake-basins  of  the  continent,  over 
the  Drift  latitudes,  and  also,  to  a  less  extent,  those  still  farther  south, 
so  that  they  may  be  said  to  have  a  continental   distribution.     The 
fluvial  deposit  generally  accompanies  the   whole    course  of  a  stream 
and  its  tributaries,  to  the  sources   in  the  mountains,  and   fails  only 
where  the  stream  is  a  steep  mountain-torrent,  or  is  bounded   by  lofty 
walls  of  rock.     A  map  showing  the  distribution  of  the  formation  over 
the  continent,  in  Drift  latitudes,  would  hence  be  much  like  a  map  of  the 
rivers,  the  courses  being  the  same  for  each ;  the  only  exceptions  being 
that  the  minor  bends  of  the  rivers  would  be  absent,  and  that  the  breadths 
would   be   very    much   greater.      The    flood-grounds   of  some    largo 
streams  are  now  miles   in  width  ;  but,   in  the  Champlain  period,  the 
waters  often  spread  to  three  or  four  times  the  distance  of  any  modern 
flood,  besides   rising  to  the  high  level   marked  off  by  the  upper  plain 
or  terrace. 

3.  Diluvian  Deposits.  —  The   earlier    stratified  deposits  were  very 
largely  clayey,  the  counterpart  of  the  bed  of  bowlder-clay  among  un- 
stratified  deposits,  but  differing  in  its  distinct  lamination.     Clay-beds 
were  the  prevailing  kind  about  great  lakes,  and  also  along  portions  of 
river  valleys,  where  the  waters  were  slow  in  movement ;  and,  in  view 
of  their  extent  over  the  region  on  .the  north  of  Lake  Erie,  these  lower 
clay -beds  have  been  designated  by  Logan  the  Erie  clays.    But,  where 
the  waters  were  rapid,  even  the  lower  beds  were  sand  or  gravel ;  and, 
in  a  river  valley,  a  deep  deposit  of  laminated  clay  sometimes  changes 
laterally  to  sand,  in  the  course  of  a  few  rods,  showing  that  the  river 
had  its  eddies  where  clays  were  deposited,  while  making  sand  beds  where 
moving  rapidly.     These  lower  beds,  in  the  region  of  the  Great  Lakes, 
have  sometimes,  at  or  toward  the  top,  local  beds  or  patches  of  vegeta- 

35 


546  CENOZOIC    TIME, 

ble  material,  made  of  roots,  logs,  stems,  mosses,  etc.,  blackened  but 
riot  carbonized  ;  as,  for  example,  near  Cleveland,  Ohio,  as  noticed  by 
Newberry,  and  near  the  Grand  Sable  and  Goulais  Rivers,  as  earlier 
mentioned  by  Logan.  Where  clays  form  the  lower  deposits,  they  are 
generally  overlaid  by  a  considerable  thickness  of  beds  of  sand  or  sand 
and  pebbles. 

The  stratification  which  the  deposits  present  varies  from  the  most 
regular,  or  that  of  gently-moving  waters,  to  that  which  could  form 
only  under  a  vast  simultaneous  supply  of  gravel  or  sand  and  water  ;  the 
common  form  of  this  Diluvian  or  Jloiv-and-plunge  style  of  deposition  is 
illustrated  in  the  following  figure  (942),  in  which  the  layers  are  made 

up  of  wave-like  parts,  corresponding  to 
Fig.  942.  .  -A  • 

successive  plunges  in  the  rapidly  flowing 


waters.  Beds  of  this  kind  occur  with 
others  of  horizontal  bedding ;  or  some 
times  locally  in  the  midst  of  coarse  gravel  deposits,  such  stony  gravel 
not  participating  in  it  because  of  its  coarseness. 

In  many  valleys,  the  formation  is  the  fine-grained  nori-bedded  till,  a 
deposit  sometimes  of  great  thickness ;  it  indicates,  by  the  absence  of 
bedding,  that  it  was  made  in  a  prolonged  flood,  not  in  violent  flow  ; 
for  the  floods  of  successive  years  would  have  left  marks  of  the  succes 
sion  in  the  bedding ;  and  violent  movement  would  have  made  oblique 
lamination. 

The  stratified  beds  often  have  unstratified  Drift  at  bottom  ;  the  latter, 
in  that  case,  may  be  a  portion  of  the  Drift  deposited  in  the  course  of 
the  Glacial  era,  or  it  may  be  merely  the  coarse  bowlder  part  of  co- 
temporaneous  depositions,  which,  because  of  the  size  of  the  stones, 
sunk  at  once  in  the  waters  to  the  bottom.  It  is  to  be  remembered 
that  the  larger  part  of  the  unstratified  beds,  with  much  of  the  strati 
fied,  were  deposited  at  the  same  time,  the  character  of  the  surface 
beneath,  land,  or  water,  determining  the  difference. 

The  most  remarkable  of  these  river-valley  formations  is  that  of  the 
great  valley  of  the  continent,  the  Mississippi.  As  shown  by  Hilgard, 
the  beds  —  called  by  him  Orange-sand  beds  —  extend  down  both  sides 
of  the  valley,  from  Kentucky  and  Missouri  to  the  Gulf ;  and,  below 
Natchez,  the  formation  stretches  eastward  into  Alabama,  and  west 
ward  into  Texas.  They  consist  mainly  of  sand,  but  include  some 
pebbly  beds,  the  principal  one  in  the  lower  part  of  the  valley  being  at 
the  bottom ;  and  occasionally  they  contain,  even  in  Mississippi,  stones 
of  ten  to  one  hundred  pounds  in  weight,  and  rarely  one  hundred  and 
fifty  pounds.  There  are  also  some  local  clayey  beds.  The  stones 
show  that  the  material  came  from  the  northward  ;  many  have  in  them 
Paleozoic  fossils.  The  beds  have  generally  the  flow-and-plunge  struc- 


QUATERNARY    AGE.  —  CHAMPLAIN    PERIOD.  547 

ture,  illustrated  in  Fig.  942.  The  facts  prove  that  there  was  a  vast 
and  violent  flow  of  waters  down  the  Mississippi  valley,  bearing  an 
immense  amount  of  coarse  detritus ;  a  result  commensurate  with  the 
width  of  the  glacier  that  lay  over  the  upper  part  of  the  great  valley 
west  of  the  Appalachians,  and  the  extent  of  local  glacier  centres  in 
the  Rocky  Mountains.  Part  of  the  transportation  must  have  been  due 
to  floating  ice  from  the  dissolving  glacier. 

The  "Orange  sand"  is  40  to  100  feet  thick,  and  in  some  places  over  200.  Toward 
the  Gulf,  it  lies  at  considerable  depth  below  the  water  level.  In  an  Artesian  well,  near 
the  Calcasieu  River  (two  hundred  miles  west  of  New  Orleans),  the  Orange  sand  was  173 
feet  thick,  beneath  160  of  clay  (Port  Hudson  group);  and  at  another,  seven  hundred 
yards  to  the  west,  96  feet  thick,  beneath  354  feet  of  clay.  These  and  the  other  facts 
respecting  the  Orange  sand  are  cited  mainly  from  Hilgard's  papers.  In  Tennessee,  the 
beds  arc  called  by  Safford  the  "  Bluff  gravel;  "  they  overlie,  in  part,  Eocene  or  Creta 
ceous  beds,  as  they  do  also  farther  south. 

4.  Alluvian  Deposits.  —  The  Diluvian  beds  along  rivers  and  about 
lakes  aro  often  overlaid  by  others,  whose  texture  indicates  more  quiet 
deposition.  The  land  lay  at  the  same  depressed  level ;  and  hence  the 
lakes  were  still  many  and  large,  and  the  rivers  of  great  breadth, 
though  after  a  while  somewhat  diminished,  from  the  lessened  supply 
of  water.  Floating  ice  from  the  north  may  long  have  aided  in  trans 
portation  of  earth  and  bowlders.  Wherever  the  Diluvian  formation 
was  not  built  up  to  the  level  of  the  flood-waters,  new  beds  were  depos 
ited  ;  mostly  of  earth  or  loam,  making  the  alluvial  beds  or  loess  of  the 
river  borders,  but,  in  other  places,  of  sand  and  coarse  material,  accord 
ing  to  the  rate  of  flow  of  the  waters. 

Sand  and  fresh- water  shells,  teeth  and  bones  of  Quaternary  Mam 
mals,  leaves  and  other  relics  would  naturally  exist  in  deposits  then 
made ;  and  peat-beds  may  have  been  formed  in  marshes,  and  after 
ward  become  buried  under  new  deposits  in  progress. 

Frequently,  the  Diluvian  depositions  filled  the  depression  to  the  water  level  (ilony  the 
sides  of  the  valley  (or  lake  basin),  but  left  a  wide  area  either  side  of  the  river  bed  at  a 
lower  level;  and  over  this  part  the  Alluvian  depositions  were  made,  and  the  whole 
finally  brought  up  to  one  plain.  These  are  points  to  be  considered  in  judging  of  the 
relative  ages  of  the  different  parts  of  any  Champlain  deposit,  whether  fluvial,  lacus 
trine,  or  marine.  The  loess  is  best  developed  on  large  streams. 

In  the  Mississippi  valley,  it  covers  the  "Orange  sand,"  forming  Avith  it  the  "Bluff 
formation  "  —  so  called  because  standing  in  bluffs  in  Missouri  and  also  on  the  east  of 
the  Mississippi  flats.  In  Tiptou  County,  Tennessee,  there  are  (over  about  ninety  feet  of 
Lignitic  Tertiary)  24  to  40  feet  of  Orange  sand  or  "Bluff  gravel,"  and  45  to  68  of  Bluff 
loam,  or  loess.  (Safford.)  The  formation  in  Mississippi  and  Louisiana  has  been  called 
by  Hilgard  the  "Port  Hudson  Group."  It  contains,  like  the  loess  of  the  Rhine,  some 
carbonate  of  lime,  partly  in  concretions,  due  to  fresh-water  shells  mixed  in  powder  with 
the  earth.  At  intervals,  it  has  layers  of  marsh  material,  including  Cypress  stumps  im 
bedded  in  laminated  clays;  and  south  of  New  Orleans  tiiere  are  marine  shells.  As  the 
Orange-sand  deposits  lie  at  considerable  depth  toward  the  Gulf,  the  Port  Hudson  de 
posit  has  a  thickness  in  some  places  of  several  hundred  feet;  and,  where  this  is  the  case, 


548  CENOZOIC    TIME. 

the  lower  part  may  be  the  equivalent  of  a  portion  of  the  Orange  sand.  Above  the  Port 
Hudson  group,  and  a  deposit  overlying  it,  thirty  to  seventy  feet  thick,  without  bedding, 
distinguished  as  "  loess  "  by  Hilgard,  there  is  generallv  a  thin  deposit  of  yellow  loam. 

A  peat  bed  of  the  Alluvian  era,  a  mile  east  of  Germantown,  Montgomery  County, 
Ohio,  has  been  described  by  Prof.  Edward  Orton. 

The  loess  of  the  Mississippi  contains  numerous  fresh-water  shells,  among  them  Pala- 
dinn  ponderosa  Say,  Melania  canaliculata  Say,  Cyclas  livularis  Say,  Cyclostoma  lapi- 
daria  Say,  Physa  heterostroplia  Say,  Limncea  elonyata  Say,  Planarbis  bicarinata  Say, 
Valvata  tricarinata  Sav,  Unios,  etc. 

Level  of  the  Formations.  — The  height  of  the  river-border  formations, 
as  well  as  those  about  lakes,  above  the  level  of  the  adjoining  river  or 
lake,  (1)  increases  on  going  north,  over  most  parts  of  tho  continent, 
in  Drift  latitudes  ;  being,  along  the  larger  streams,  in  Southern  New 
England,  45  to  60  feet;  in  Massachusetts,  on  the  Connecticut,  136  to 
200  feet ;  north  of  Massachusetts,  along  the  same  river,  from  Vernon 
to  Hanover,  200  to  240  feet ;  on  Lake  Ontario  and  the  Great  Lakes, 
300  to  500  feet. 

But  (2),  where  a  river  becomes  much  diminished  in  size  toward 
its  source,  the  height  of  the  upper  plain  diminishes,  notwithstanding 
the  increased  northing,  on  the  general  principle  that  all  small  streams 
have  small  alluvial  formations,  whether  modern  or  ancient. 

Also  (3),  if  a  stream  has  falls  or  rapids,  or  a  rocky  bottom,  the  ter 
races  are  lower  on  this  account. 

Heiyhts  of  Upper  Terraces,  east  of  Rocky  Mountains,  above  the  level  of  rivers  or  lakes. 
—  On  the  coast,  along  the  southern  borders  of  New  England,  as  at  the  mouth  of  the 
Connecticut,  or  at  New  Haven,  the  height  of  the  upper  plain  above  the  river  is  about 
45  feet:  at  East  Hartford,  Ct.,  36  miles  north,  GO  feet;  at  East  Windsor,  Ct.,  48  miles, 
71  feet:  at  Long  Meadow  and  Springfield,  Mass.,  62  miles,  136  feet;  at  Willimansett, 
Mass.,  68  miles,  194  feet;  below  Bellows  Falls,  Vt.,  near  Walpole,  226  to  243  feet;  at 
Brattleboro,  Vt.,  200  to  221  feet;  at  Windsor,  Vt.,  207  feet;  at  White  River  Junction, 
Vt.,  209  feet.  (Hitchcock.)  Measuring  from  the  existing  flood  ground,  the  height  at 
New  Haven,  Ct.,  is  40  to  45  feet ;  at  Hartford,  about  the  same ;  at  Springfield,  112  feet ;  at 
Willimanselt,  170  feet;  at  Walpole,  N.  H.,  190  to  208  feet;  at  Hanover,  N.  H.,  182  feet. 

The  sandy  terrace  between  Schenectady  and  Albany,  N.  Y.,  and  opposite  the  latter 
place,  east  of  the  Hudson,  is  330  to  335  feet  above  the  river,  but  whether  true  stratified 
Drift  at  top  is  not  certain.  On  the  Genesee,  east  of  Portage,  the  upper  level  is  235 
feet  above  the  river. 

The  ridge  road  or  terrace,  south  of  Lake  Ontario,  190  feet  above  the  lake,  the  greatest 
height  (Hall);  terrace  south  and  southwest  of  Lake  Erie,  220  feet;  north  of  Lake 
Ontario,  at  Toronto  and  other  points,  30  to  over  500  feet;  the  Davenport  ridge,  west  of 
Toronto,  250  to  300  feet;  west  of  Dundas,  west  end  of  Lake  Ontario,  318  feet  (under  the 
escarpment  of  the  Niagara  formation,  which  is  100  feet  higher);  near  Fredericton,  New 
Brunswick,  on  the  St.  Johns,  345  feet  above  the  river;  at  other  points  below,  on  the 
same  river,  350  to  400  feet.  On  the  north  side  of  Lake  Superior,  the  maximum  re 
ported,  331  feet  above  the  lake;  near  Lake  Huron,  clayey  deposits,  at  different  levels 
up  to  about  500  feet.  On  the  Lower  Ohio,  50  to  160  feet;  near  Louisville,  52  and  128 
feet  above  low  water,  or  10  and  86  feet  above  high  water:  near  Cincinnati,  100  to  120 
feet  above  low  water.  On  the  Mississippi,  in  Tennessee,  50  to  180  feet;  at  Fort  Adams, 
Loftus  Heights,  163  feet  (made  up  of  90  feet  of  Orange  Sand  and  73  of  loess);  at  New 
Orleans,  about  60  feet.  On  the  Missouri,  in  Platte  County  (N.  W.  Missouri),  335  to 
150  feet.  Atchison  County,  250  to  150  feet.  On  the  Red  River,  in  Texas,  50  to  100  feet. 


QUATERNARY    AGE.  —  CHAMPLAIN   PERIOD.  549 

About  Lake  Winnipeg,  one  of  75  to  100  feet  above  the  lake;  a  second  of  300  to  350 
feet  (at  Peinbina  mountain,  west  of  Red  River)  (Hector). 

In  the  Rocky  Mountains  (where part  of  the  terraces  are  true  moraines)  and  to  the  west 
of  summit.  —  On  the  Athabasca  and  Saskatchewan,  300  to  370  feet;  and  on  Bow  River, 
300  feet  (Hector).  At  an  elevation  of  about  6,000  feet  above  sea  level,  along  the  valley 
of  the  Madison  River,  Montana,  243  feet  (Hayden).  At  nearly  7,000  feet,  south  of 
Jackson  Lake,  head-waters  of  Snake  River,  about  400  feet  (F.  H.  Bradley).  About 
Great  Salt  Lake,  Utah,  900  feet;  on  Marsh  Creek,  Idaho  (one  of  the  old  outlets  of  Great 
Salt  Lake),  1,000  feet  (F.  H.  Bradley);  La  Plata  Creek,  branch  of  Arkansas  (moraine), 
800  feet  (Hayden);  on  Clear  Creek,  another  branch  (moraine),  600  to  800  feet  (Hay- 
den);  Roche  Moutonne'e  Creek,  branch  of  Eagle  River  (Fig.  1106),  on  both  sides  of  valley 
(moraine),  937  feet  (Hayden). 

In  and  west  of  the  Sierra  Nevada,  and  its  continuation  north. —  Mono  Lake  (salt-water), 
385  and  680  feet  above  the  lake;  King's  River  (moraine),  1,500  feet  (Whitney);  Bloody 
Canon,  near  the  Yosemite  (moraine),  500  feet;  Hope  Valley,  ibid.,  600  feet;  Lake  Ta- 
hoe  (moraine),  1,600  (?)  feet  (Leconte);  Island  of  St.  Nicholas,  northeastern  side,  30, 
80,  and  300  feet;  Santa  Monica  Canon,  where  it  reaches  the  coast,  15  miles  from  Los 
Angeles,  148  and  175  feet;  north  side  of  Pajaro  valley,  on  seashore,  south  of  Monterey, 
263  feet;  on  the  Nascimiento  River,  20,  80,  and  187  feet;  on  the  Salinas  River,  for  80 
miles  from  its  mouth,  from  125  to  150  feet;  on  the  Arroyo  Joaquin  Soto,  a  branch  of 
the  San  Benito,  in  the  Mt.  Diablo  range,  225  feet;  on  the  Sacramento  River,  near  Red 
Bluff,  80  to  100  feet  (Whitney);  on  the  Willamette,  Oregon,  50  to  85  feet;  on  Frazer's 
River,  British  Columbia,  near  Lillooett  (122°  W.),  500  or  600  feet  (Begbie);  on  the  Koo- 
tanie  and  Upper  Columbia,  600  feet  (Hector);  on  Canoe  River,  a  northern  branch  of  the 
Columbia,  400  feet  (Selwyn). 

The  moraines,  in  the  Rocky  Mountain  region,  are  evidence  of  the  level  of  the  end  of 
the  glacier,  and  not  of  that  of  a  river  terrace.  A  moraine  on  Texas  Creek,  Colorado, 
600  feet  high,  fades  out  in  eight  miles.  Those  on  Clear  Creek,  Colorado,  600  to  800 
feet  above  the  present  stream,  fall  to  100  feet  in  six  miles.  (Hayden  and  Gardner.) 

Relation  to  the  Level  of  the  Ocean. — In  the  position  of  the  upper 
limit  of  the  river-border  formations,  there  is  no  direct  relation  to  the 
level  of  the  ocean.  They  were  made  by  flooded  rivers  or  lakes ;  and 
the  height  of  the  flood-waters  determined  their  level.  The  streams 
of  plateaus  or  slopes,  2,000  feet  above  the  ocean,  would  have  made 
deposits  at  that  height,  plus  the  height  of  the  flood  above  it. 

3.  Sea-border  Formations. — On  sea-borders,  the  formations  are,  in 
general,  similar  to  those  of  lake-basins  and  valleys,  except  that  they 
often  contain  marine  fossils.  The  seashore  terrace  or  "  bench  "  is 
often  the  termination  of  a  river-border  terrace,  one  graduating  into 
the  other,  the  river  level  and  sea  level  being  the  same  at  the  mouth  of 
a  stream.  They  are  commonly  called  elevated  beaches,  though  not 
always  of  beach  origin.  Like  lake-border  formations,  they  are,  in 
many  cases,  combinations  of  Diluvian  and  Alluvian  depositions  ;  but, 
besides  beds  made-  in  shallow  waters,  containing  shallow- water  fossils, 
there  are  often  others  of  deeper-water  formation,  different  in  most  of 
their  marine  fossils.  They  vary  also  according  as  they  were  made  on 
an  open  coast  or  in  an  estuary. 

About  New  Haven,  Connecticut,  there  is  a  good  exhibition  of  the  deposits  that  were 
made  in  an  estuary  or  bay,  under  the  action  of  tidal  currents,  that  is,  the  incoming  tidal 
flow.  The  beds  are.  for  the  most  part,  obliquely  laminated ;  and  the  laminae  rise  to  the 


550  CENOZOIC    TIME. 

north,  that  is,  in  the  direction  of  the  flow.  Further,  the  effect  of  waves  is  apparent  in 
the  flow-aml-plunge  structure  of  the  obliquely-laminated  beds.  (Fig.  942.)  Such  beds 
are  usually  as  much  as  six  inches  thick,  but  occasionally  six  to  eiyht  feet.  A  thick 
ness  even  of  six  inches  is  proof  that  vast  amounts  of  sand  and  gravel  were  at  the  dis 
posal  of  the  currents  and  waves,  and  that  the  deposition  went  forward  with  great  ra 
pidity. 

The  height  of  the  sea-border  formations  increases  in  going  north,  like 
that  of  the  river-border  and  lake-border  formations.  On  the  southern 
shores  of  New  England,  the  height  above  the  sea  is  40  to  50  feet ;  on 
Nan  tucket,  85  feet ;  at  Point  Shirley,  near  Boston,  75  to  100  feet ;  on 
the  coast  of  Maine,  in  some  places,  217  feet;  on  the  s'hores  of  Lake 
Champlain,  at  different  heights,  up  to  393  feet  above  tide-level,  and 
containing  marine  shells  to  a  height  of  325  feet ;  on  the  borders  of  the 
St.  Lawrence,  with  abundant  marine  fossils,  near  Montreal,  to  a  height 
of  470  feet.  From  this  point,  the  same  formations  continue  on,  and 
border  Lake  Ontario  ;  but  they  are  destitute  of  marine  remains,  —  the 
flow  of  fresh  waters  in  the  river  St.  Lawrence  beyond  having  appar 
ently  prevented  the  farther  ingress  of  the  ocean  and  of  marine  life. 
On  the  coast  of  Labrador,  the  beds  are  400  to  500  feet  above  the  sea. 
They  occur  also  in  the  Arctic  regions  in  many  places,  as  on  Cornwallis 
and  Beechy  Islands  in  Barrow  Straits,  where  they  are  at  different 
heights  to  1,000  feet. 

The  seashore  deposits  on  Nantucket  occur  at  Sancati  Head.  In  Maine,  the  beds  occur 
at  many  places  near  the  coast,  as  Portland,  Cumberland,  Brunswick,  Thomaston,  Cher- 
ryncld,  Lubec,  Perry,  etc.,  at  different  elevations,  not  exceeding  217  feet,  so  far  as  yet 
reported;  also  distant  from  the  coast,  at  Gardiner,  Hallowell,  Lewiston,  Skowhegan, 
Clinton  Falls,  and  Bangor.  At  Lewiston,  a  starfish  and  various  shells  were  found  in  a 
bed  200  feet  above  the  ocean  and  100  above  the  Androscoggin  River;  at  Skowhegan, 
the  beds  are  150  feet  above  the  ocean,  and  100  feet  at  Bangor;  near  Mt.  Desert  (a  sea- 
bottom  deposit,  on  North  Haven  Island),  217  feet. 

There  are  shell-beds  at  several  levels  and  many  localities,  along  the  St.  Lawrence, 
observed  by  Logan;  and  part,  as  Dawson  has  shown,  are  sea-beaches,  and  others  off 
shore  deposits.  At  Montreal,  at  heights  of  470,  420,  366,  200,  100,  above  the  river,  or 
20  feet  more  for  each  above  Lake  St.  Peter;  west  of  Montreal,  near  Kemptville,  at  a 
height  of  250  feet;  on  the  Upper  Ottawa,  65  miles  northwest  of  Ogdensburg,  360  feet; 
in  Winchester,  300;  in  Kenyon,  270;  in  Lochiel.  264  and  290;  at  Hobbes  Falls  in  Fitz- 
roy,  350;  at  Dulham  Mills,  289;  in  the  counties  of  Renfrew,  Lanark,  Carlton,  and 
Leeds,  425;  east  of  Montreal,  near  Upton  Station,  257;  farther  east,  on  the  river  Gouf- 
fre,  near  Murray  Bay,  130  and  360  feet.  At  the  Straits  of  Belle  Isle,  Labrador,  the 
terraces,  on  either  side,  are  about  400  feet  above  the  sea;  at  Chateau  Bay,  500  feet,  prob 
ably  800  feet  in  some  parts  (Packard). 

The  100-foot  level  near  Montreal  was  apparently  beneath  the  sea  at  the  time,  as  the 
shells  in  which  it  abounds  are  not  littoral  species,  neither  are  the  specimens  water-worn. 
At  Beauport,  near  Quebec,  there  are  thick  beds  of  this  kind,  mostly  made  of  shell*, 
partly  littoral,  and  situated  at  heights  of  200  to  400  feet  above  the  sea.  The  depth  of 
water  inferred  for  these  deep-sea  beds  by  Dawson,  from  the  species  of  shells,  is  100  to 
300  feet.  Dawson  makes  the  marine  formation  in  Canada  to  consist  (1)  of  unstratified 
bowlder-clay;  (2)  deep-water  clays  just  mentioned,  called  Leda  clays,  from  one  of  the 
fossils;  (3)  the  overlying  shallow-water  sands  and  gravels,  called  also  the  Saxicava 
sands. 

The  more  common  shells  of  the  Montreal  beds  are  the  following  (Dawson):   Saxicava 


QUATERNARY    AGE.  —  CHAMPLAIN   PERIOD.  551 

Arctica  Desh.,  Myi  truncata  Linn.,  M.  arenaria  Linn.,  Macom't  fragilis  Adams,  M. 
S'dnilos'i  Miirch,  Astarte  Laurentiana  Daws.,  Myt'dus  edulis  Linn.,  Natica  clausa  Brod., 
Yuldl'i  Glacialis  Gray,  Trophon  clathratum  Miirch,  Buccinum  Greenland  icum  Hancock. 

Among  the  Beauport  species,  there  are  the  following:  Lunatia  Greenland  ten  Adams, 
L.  heros  Adams,  Turritella  erosa  Couth.,  Scalaria  Grc&nlandica  Perry,  Litorina  palliata 
Verr.,  Serripes  Groenlandicus  Beck,  Co.rdi.um  Islandicum  Chemn  ,  Pecten  Islandicus 
Chemn.,  Rhynchonella  psiftacea  Gm..  and  manv  others.  All  are  cold-water  species,  so 
that  the  fauna  is  more  Arctic  in  character  than  that  of  Montreal,  corresponding  with  the 
fact  that  Montreal  is  150  miles  northwest  of  Beauport  (Dawson). 

The  coast  of  Maine  has  afforded  (Packard):  Pholas  crispata  Linn.,  Saxicava  Arctica, 
Mya  truncata,  M  arenaria,  Thracia  Conradi  Couth.,  Macoma  fr« gills,  M.  sabulosn, 
Mactra  oralis  Gould,  Astarte  Bunksii  Leach,  A.  ell/ptica  Brown,  A.  Arctica.  Moller, 
Cardium  Islandicum,  Serripes  Grc&nlandicm,  Leda  pernula  Miill.,  L.  minuta  Fabr.,  Yol- 
dia  gladaMt,  Pecten  Grcenl/tndicus  Sow.,  P.  Islandicus,  Natica  clausa,  Lunatia  heros,  L. 
Grcenlandica,  etc. 

The  species  thus  far  discovered,  with  perhaps  one  or  two  exceptions,  are  identical  with 
those  now  inhabiting  the  Labrador  seas.  They  number  over  two  hundred. 

The  Capelin  (Mallotus  villosus  Cuv.,  a  common  fish  on  the  Labrador  coast)  has  been 
found  fossil  on  the  Chaudiere  Lake  in  Canada,  183  feet  above  Lake  St.  Peter;  on  the 
Madawaska,  206  feet;  at  Fort  Colonge  Lake,  3(55  feet. 

On  the  Bay  of  Fundy,  at  Goose  Creek,  there  are  several  levels  of  beaches,  up  to  a 
height  of  490  feet.  (Hind.)  On  the  coast  of  Labrador,  the  elevated  Champlain  beds 
contain  mostlv  the  same  species,  both  those  of  the  Leda  clays  and  the  overlying  beds. 
Among  the  species  less  abundant  farther  south,  or  not  at  all,  are  Cyclocardia  borenlis 
Con.,  Astarte  Banksii,  Margarita  varicosa  Mighels,  Turritella  reticulata  Mighels,  T. 
erosa,  Aporrhais  occidentrdix  Beck,  Admete  viridula  Stp.,  Bela  exnrata  Miill.,  B.  harpu- 
laria  Adams.,  B.  robustaVack.,  B.  turricula  Montf.,  Fusus  tornat'us  Gld.,  F.  Labrador- 
ensis  Pack.,  Buccinum  undatum  Linn.  (Packard.) 

South  of  Cape  Cod,  at  Sancati  Head  on  Xantucket,  and  at  Gardner's  Island,  the 
species  were  the  warm-water  kinds,  now  inhabiting  this  region,  arid  not  the  subarctic 
that  existed  north  of  the  Cape. 

On  the  Pacific  side,  there  are  shell-bearing  sea-border  beds,  at  San  Louis  Obispo  and 
San  Pedro,  80  or  90  feet  above  the  sea,  and  at  higher  levels  (Newberry);  on  north  bank 
of  Lobos  Creek,  and  we.st  of  Black  Point,  near  San  Francisco,  80  to  100  feet.  Terraces 
occur  also  about  Sonora,  Mexico. 

III.  General  Observations. 

1.  American  Geography,  —  The  elevated  sea-border  formations  that 
have  been  described  prove  that,  in  the  Champlain  period,  the  land, 
where  such  formations  occur,  was  at  the  water's  level.  They  show,  for 
example,  that  southern  New  England  was  40  to  50  feet  below  its 
present  level ;  Sancati  Head,  on  Nantucket,  85  feet ;  the  coast  region 
of  Maine,  in  some  parts,  217  feet;  the  borders  of  Lake  Champlain, 
between  350  and  400  feet ;  the  region  of  the  St.  Lawrence,  along  by 
Montreal,  nearly  500  feet ;  about  the  Bay  of  Fundy,  350  to  400  feet ; 
the  Labrador  coast,  400  to  500  feet ;  in  parts  of  the  Arctic  regions, 
1,000  feet.  Again,  the  close  approximation  in  height  between  these 
sea-border  formations  arid  the  river-border  and  lake-border  in  the  same 
latitudes,  over  a  considerable  part  of  the  continent,  and  the  actual  high 
level  over  the  whole,  and  also  the  parallel  increase  in  height  of  the 
whole  on  going  north,  are  strong  evidence  that  the  depression  affected 


552  CKNOZOIC    TIME. 

not  merely  the  sea-borders,  but  nearly  or  quite  the  whole  breadth  of 
the  continent,  arid  that  its  amount  was  greatest  to  the  north. 

We  cannot  suppose  any  damming  of  the  St.  Lawrence  by  ice,  in 
order  to  account  for  the  terraces  of  Lake  Ontario  ;  for  they  are  very 
much  higher  on  the  northern  side  of  the  lake  than  on  the  southern  ; 
and  the  terrace  nearly  500  feet  above  the  St.  Lawrence,  shell-bearing 
near  Montreal,  may  be  traced  along  at  intervals  to  the  northern  bor 
ders  of  the  lake,  proving  unbroken  communication  at  the  time,  and 
a  vast  outflow  of  water.  Admitting  the  submergence,  and  its  increase 
in  amount  northward,  the  inequality  in  the  level  of  the  terraces  on  the 
north  and  south  sides  of  a  lake  gives  no  difficulty. 

We  hence  learn  that,  in  the  Champlain  era,  salt  waters  spread  over 
a  large  coast-region  of  Maine,  and  up  the  St.  Lawrence  nearly  to  Lake 
Ontario,  and  covered  also  Lake  Champlain  and  its  borders.  This 
great  arm  of  the  sea,  full  500  feet  deep  at  Montreal  and  in  Lake 
Champlain,  was  frequented  by  Whales  and  Seals,  their  remains  having 
been  found  near  Montreal,  and  a  large  part  of  the  skeleton  of  a  Whale 
—  Beluga  Verm^ntana  Thompson  (Fis;.  950) — having  been  dug  up 
on  the  borders  of  Lake  Champlain,  sixty  feet  above  its  level,  or  150 
feet  above  that  of  the  ocean.  It  appears,  besides,  that  Nova  Scotia 
was,  at  the  same  time,  an  island,  and  that  the  Labrador  oceanic  cur 
rent  crossed  the  present  isthmus  (now  less  than  twenty  feet  above 
high  tide  at  Cumberland  basin)  with  a  depth  of  water  exceeding  350 
feet,  and  thence  flowed  down  the  Bay  of  Fundy  to  the  coast  of  Maine 
and  eastern  Massachusetts. 

We  learn,  also,  that  the  region  of  the  Great  Lakes  was  probably 
one  immense  lake,  and  that  the  waters  spread  far  south  over  the  States 
of  Ohio,  Indiana,  and  Illinois,  and  discharged  from  Lake  Erie  and 
Lake  Michigan  into  the  Mississippi  valley,  so  that  there  was  abundant 
opportunity  for  transportation,  by  means  of  floating  ice,  from  the 
Glacier  to  the  Gulf.  We  gather  also  that  the  Mississippi  waters  of 
the  Champlain  era,  below  the  mouth  of  the  Ohio,  had  an  average 
breadth  of  fifty  miles,  and,  along  by  Tennessee  and  northern  Missis 
sippi,  of  seventy-fice  miles ;  so  that  it  was  indeed  a  great  stream.  In 
the  Glacial  period,  the  era  of  erosion,  it  was  deepening  its  bed,  through 
the  Paleozoic,  Cretaceous,  and  Tertiary  rocks  ;  but,  in  the  Champlain, 
when  the  land  to  the  north  was  depressed,  the  river  filled  full  the  wide 
valley,  and  made  its  great  breadth  of  Champlain  deposits.  All  the 
other  rivers  of  the  continent,  alike  augmented,  were  at  the  same  work, 
each  according  to  its  capacity.  The  Champlain  period,  in  the  world's 
history,  was  preeminently  the  era  of  fresh-water  formations. 

Other  geographical  changes  of  the  Champlain  period  consisted  in 
the  filling  up  of  old  river-channels,  and  forcing  the  streams  to  open 


QUATERNARY    AGE.  —  CHAMPLAIN   PERIOD.  553 

new  ones.  There  is  an  old  gorge  of  Niagara  River,  commencing  at 
the  Whirlpool,  which  was  thus  filled.  It  is  probable  that,  when  the 
damming  by  Drift  was  accomplished,  the  waters  of  Lakes  Erie  and 
Ontario  were  on  a  common  level,  so  that  there  was  no  river-flow  to 
prevent  the  catastrophe ;  and  that,  when  the  elevation  that  ended  the 
Cham  plain  era  began,  the  river  first  found  out  that  its  old  channel  was 
gone.  The  stream,  then  renewing  its  flow,  began, at  the  Queenstown 
heights,  the  present  cut  through  the  rocks  to  the  Whirlpool  (p.  590). 

Dr.  Newberry  has  stated  that  the  Ohio  River  formerly  had  a  more  southern  channel 
around  the  Falls,  near  Louisville,  and  lost  it,  in  a  similar  way,  in  the  Champlain  period; 
that  formerly  Lake  Huron  discharged  into  Lake  Erie  by  a  more  easterly  channel  than 
the  present  one,  and  was  forced  in  this  era  to  take  the  route  over  the  rocks.  The  chan 
nel  of  discharge,  from  Lake  Michigan  to  the  Mississippi,  which  F.  H.  Bradley  has 
pointed  out  as  having  been  made  or  used  in  the  Glacial  period,  he  shows  was  filled  up 
in  the  Champlain,  and  then  the  more  western  channel,  from  Chicago  along  the  Des 
Plaines  to  the  Illinois,  became  the  outlet,  and  continued  to  be  so  until  the  elevation 
opening  the  Recent  period. 

2.  Circumstances  attending  the  Diluvian  depositions.  The  Final 
Flood  from  the  melting  of  the  Glacier.  —  That  the  melting  of  the 
glacier  should  have  ended  in  a  great  flood  is  evident  from  the  common 
observation  that,  in  cold  latitudes,  floods  terminate  ordinary  snowy 
winters. 

The  subsidence  of  northern  lands  brought  on  the  conditions  of  a 
warmer  climate  ;  and,  as  the  melting  went  slowly  forward,  this  amelio 
ration  must  have  finally  become  very  decided.  Consequently,  there 
was  melting,  not  merely  along  the  southern  edge  of  the  glacier,  but 
over  its  wide  surface;  and,  when  the  thickness  of  the  ice  was  at  last 
reduced  to  a  few  hundreds  of  feet,  and  it  had  become  rotten  through 
out,  the  melting  must  have  gone  forward  with  greatly  augmented 
rapidity;  and  a  flood,  filling  rivers  and  lakes  to  an  unwonted  height, 
must  inevitably  have  followed. 

The  fact  that  such  a  flood,  vast  beyond  conception,  was  the  final 
event  in  the  history  of  the  glacier,  is  manifest  in  the  peculiar  stratifi 
cation  of  the  flood-made  deposits,  and  in  the  spread  of  the  stratified 
Drift  southward  along  the  Mississippi  valley  to  the  Gulf,  as  first  made 
known  by  Ililgard.  Only  under  the  rapid  contribution  of  immense 
amounts  of  sand  and  gravel,  and  of  water  from  so  unlimited  a  source, 
could  such  deposits  have  been  accumulated. 

The  Mississippi  waters,  from  the  mouth  of  the  Ohio  to  the  Gulf  (550  miles),  have  at 
high  water  a  pitch  of  about  six  inches  to  the  mile;  the  level  at  high  water  adds,  at  the 
Ohio,  fifty  feet  to  the  height.  If  the  supply  of  waters  were  sufficient  to  increase  the 
slope  to  eleven  inches  per  mile,  the  height  of  water  would  be  great  enough  to  deposit  all 
the  loess  at  its  pres-ent  level.  But  the  land  was  certainly  depressed,  in  the  latitude  of  the 
Ohio,  at  least  fifty  feet  below  the  present  level;  and,  in  that  case,  with  less  than  nine 
inches  to  the  mile,  the  existing  Champlain  depositions  could  have  been  made.  Much 
greater  changes  of  level  actually  took  place  in  the  vicinity  of  the  Gulf,  according  to 
Hilgard  (Am.  J.  Sci.,  II.  xlviii.  331,  and  III.  ii.  398.) 


554  CENOZOIC   TIME. 

There  is  direct  evidence  that  the  flood  reached  a  maximum  just  be 
fore  the  close  of  the  melting.  In  some  of  the  New  England  estuaries, 
of  the  Champlain  era,  as  that  of  New  Haven  (and  it  may  be  true  of 
all),  the  stratified  deposits  are  mainly  of  sand  and  small  pebbles,  until 
within  fifteen  or  twenty  feet  of  the  top.  But,  above  this  limit,  there 
is  a  sudden  change,  especially  along  the  courses  of  the  streams  enter 
ing  the  estuary,  to  very  coarse  gravel,  the  stones  in  it  often  four  or 
five  inches  through  ;  a  change  which  indicates  that,  when  the  flood 
was  at  its  height,  the  torrent  bore  off  thence  the  sand  and  fine  gravel, 
and  dropped  chiefly  the  stones.  The  finer  material  was  carried  to  the 
west  side  of  the  lower  part  of  the  New  Haven  estuary,  where  the  de 
posits,  through  their  whole  height,  are  of  sand. 

The  sand  deposits  which  succeed  the  "  Erie  clays,"  in  the  region 
of  the  Great  Lakes,  may  be  evidence  of  the  flood  over  those  regions. 
The  logs  and  vegetable  debris,  which  in  some  spots  top  the  clay  beds, 
(p.  546)  may  be  additional  proof  of  the  loosened  grasp  of  the  ice. 
The  depositions  of  Orange  sand  along  the  Mississippi  valley  probably 
took  place  at  this  time  of  maximum  flood. 

There  is  other  evidence  of  this  climax  in  the  flood.  As  stated  on  page  549,  the  lam 
ina}  of  the  obliquely  laminated  layers,  in  the  stratified  deposits  of  the  New  Haven  plain, 
rise  to  the  northward,  as  a  consequence  of  their  deposition  by  the  in-jloitiny  tidal  current. 
The  flooded  rivers  brought  down  the  sand  and  gravel;  and  the  tidal  flow  determined 
the  deposition  of  it.  But,  over  the  regions  whei'e  two  of  the  river  valleys  pass  into  the 
New  Haven  plain,  while  the  northward-rising  or  tide-made  lamination  characterizes 
the  lower  part  of  the  deposit,  the  upper  fifteen  to  twenty  feet  has  the  lamination  reversed, 
the  Iftmince  rising  to  the  south,  showing  that  these  were  deposited  by  the  river  flood. 
The  transition  was  a  sudden  one,  as  the  abrupt  transition  in  the  beds  proves.  It  is 
marked  also  in  a  change  in  the  color  of  the  sands,  from  a  reddish  to  a  biownish  yellow. 
This  change  was  not  owing  to  a  shallowing  of  the  waters;  for  in  most  parts  of  the 
estuary  region,  the  tide-made  oblique  lamination  characterizes  the  beds  to  the  top  of 
the  formation. 

Thus  we  learn  that  the  flood  finally  rose  to  a  height  which  enabled  the  river  flow  to 
overpower  the  tidal  and  put  its  own  impression  on  the  deposits,  besides  making  coarse 
pebble  beds  where  the  torrent  was  most  powerful. 

The  flood  would  have  continued  long  into  the  Alluvian  era,  on  ac 
count  of  the  ice  to  the  north,  yet  with  much  abatement  of  its  violence. 
Even  till  near  its  close,  the  melting  glacier  about  the  northern  margin 
of  the  Great  Lake  region  may  have  sent  off  floating  masses  down  the 
Mississippi  valley,  as  well  as  to  parts  of  the  present  prairie  region  of 
Ohio,  Indiana,  and  Illinois. 

Exterminations  by  the  cold  waters.  — While  the  reinforced  Lab 
rador  current  of  the  Diluvian  era  drove  Arctic  and  Subarctic  marine 
species  southward  along  the  northern  coasts,  the  ice  and  ice-cold 
waters  of  rivers  carried  destruction  to  the  life  of  more  southern  seas. 
Professor  Hilgard  states  that  the  Orange  sand  or  stratified  Drift  of 
the  Mississippi  valley,  where  it  enters  the  Mexican  Gulf,  contains  no 
traces  of  marine  fossils,  and  for  the  reason  that  the  great  ice-cold 


QUATERNARY   AGE.  —  CHAMPLAIN   PERIOD.  555 

stream  was  like  a  Labrador  current  let  loose  in  the  Tropics.  The 
estuary  and  shore  deposits  about  New  Haven,  Connecticut,  are  equally 
destitute  of  marine  shells,  and  for  the  good  reason  that  Long  Island 
Sound  was  actually  occupied  with  ice,  whether  the  land  were  more 
elevated  than  now  or  not. 

B.  CHAMPLAIN  PERIOD  IN  FOREIGN  COUNTRIES. 

The  Glacial  period  of  Britain  and  Europe  was  followed,  as  in 
America,  by  an  era  (the  Champlain)  in  which  the  land  stood  below 
its  present  level,  and  extensive  beds  of  stratified  Drift,  overlaid  and 
somewhat  interstratified  by  others  of  more  quiet  deposition,  were 
made  along  sea-borders,  lake-borders,  and  river  valleys.  The  sea- 
border  formations  of  Sweden  and  Norway  are  closely  like  those  of 
the  coasts  of  Maine  and  the  St.  Lawrence,  even  to  the  "  Leda  clays  " 
and  "  Saxicava  sands"  And  the  valleys  of  Europe,  especiallv  over 
its  northern  half,  have  their  extensive  river-border  formations,  which 
are  equivalents  of  those  along  the  American  river-valleys. 

Lyell  states  that  the  facts  lead  to  the  inference  that,  after  the  period 
of  elevation  with  which  the  Glacial  era  began,  there  "  succeeded  a 
period  of  depression  and  partial  submergence,"  and  of  accumulations 
of  sand  and  bowlder-clay,  with  peaty  clay  in  a  few  places.  This  de 
pression  in  Great  Britain  varied  in  different  parts  from  1,300  to  500 
feet,  except  over  southern  England,  where  it  may  have  been  only  100 
or  200  feet.  The  height  of  the  stratified  Drift  along  the  valley  of 
the  Somme,  above  the  stream,  is  80  to  100  feet,  which  shows  that  the 
depression  was  large  in  Northern  France.  In  Sweden,  the  depression 
varied  from  200  feet  in  the  south  to  400  or  500  in  the  north;  and 
Erdmann  proves  that  the  Baltic  was  connected  with  the  North  Sea, 
over  the  region  of  Jakes  from  Stockholm  westward,  and  with  the 
Arctic  ocean  by  a  great  channel  leading  northeastward  over  Finland 
to  the  White  Sea. 

The  depression  ten  miles  east  of  Glasgow  was  at  least  524  feet,  as  indicated  by  the 
presence  of  marine  shells  in  beds  of  clay,  which  are  overlaid  as  well  as  underlaid  by 
beds  of  till.  The  marine  shells  present  are  those  mainly  of  Arctic  seas,  like  the  St. 
Lawrence  species.  Among  them  are  Saxicava  Arctica,  Pecten  fslandicus,  Natica  clausn, 
Troplwn  clatJiratum,  Yoldia  ylacialis,  Macoma  sabulosa.  In  some  parts  of  Wales, 
Ireland,  and  the  northern  half  of  England,  it  appears  to  have  been  1.000  to  ],400  feet, 
stratified  Drift  Avith  marine  northern  shells  occurring  at  this  height  on  the  south  side 
of  the  Menai  straits;  also  at  a  height  of  1,300  feet,  on  Moel  Tryfaen;  1,200  feet,  at 
Macclestield  in  Central  England;  1.000  to  1,200  feet,  in  Ireland,  County  Wexford, 
south  of  Dublin;  at  a  height  of  568  feet,  near  Blackpool  in  Lancashire,  fifty  miles  from 
the  sea.  In  the  depression  separating  Wales  and  England  —  Murchison's  "Severn 
Straits  "  —  beds  of  marine  shells  are  found  at  a  height  of  100  feet. 

The  lake  and  river  terraces  in  Great  Britain,  and  especially  its  northern  p'U't,  Scot 
land,  are  on  a  scale  as  grand  as  the  sea-shore  deposits.  The  "benches"  of  Glen  Roy 
are  an  example  of  them.  The  upper  terrace  is  1,139  feet  above  tide-level;  the 


556  CENOZOIC   TIME. 

second,  1,059  feet;  the  third,  847  feet.  This  is  one  among  many  cases  that  might  be 
cited.  As  a  general  thing,  the  elevated  sea-border  formations  occur  on  the  coasts  of 
regions  whose  interior  is  diversified  with  high  lake  and  river  terraces. 

A  deposit  generally  regarded  as  among  the  earlier  Quaternary  of  Britain,  or  transi 
tional  between  the  Pliocene  and  Quaternary,  is  called  the  "  Cromer  Forest  Bed  "  :  it  is 
traced  for  over  forty  miles  along  the  Norfolk  Cliffs,  between  Cromer  and  Kessingland, 
beneath  Drift.  It  contains  remains  of  plants,  insects,  and  shells  of  living  species,  along 
with  the  remains  of  some  Pliocene  as  well  as  many  extinct  Quaternary  species,  and 
some  modern  Mammals  (p.  571). 

The  sea-border  shell-bearing  deposits  of  southern  Sweden  have  a  maximum  height 
of  200  feet;  of  western,  200  to  500 'feet,  and  mostly  325  to  400  feet  (Erdmann);  those 
of  the  northwest  coast  of  Norway,  in  Hardanger,  293  to  331  feet  (Sexe). 

The  valley  of  the  Rhine  contains  extensive  deposits  of  this  Cham  plain  era;  part  ap 
parently  due  to  the  earlier  Dilution  epoch,  or  that  of  ice-melting,  but  largely  of  the 
following  Alluvion  part.  The  material  of  the  alluvium  is  mostly  the  Icess,  a  fine  yellow 
ish-gray  loam,  — generally  a  little  calcareous  from  pulverized  shells;  and  in  some  parts 
it  contains  glacially-marked  stones.  Between  Basle  and  Binnen,  this  alluvium  has  a 
thickness  of  several  hundred  feet;  and  throughout  it  there  are  land  and  fresh-water  shells. 
Lyell  speaks  of  its  presenting  a  bluff  front  to  the  river,  and  of  isolated  hills  of  it 
standing  in  the  valley,  and  finds  evidence  in  this  that  it  was  deposited  when  the  land 
stood  at  a  lower  level  It  is  regarded  as  uncertain,  however,  whether  the  loess  may  not 
in  part  be  a  deposition  from  the  floods  consequent  on  a  second  glacial  epoch,  mentioned 
beyond  (p.  561).  Similar  facts  are  reported  from  most  of  the  river  valley's  of  Europe. 

In  Belgium,  according  to  Dupont,  along  the  valley  of  the  Lesse,  and  others,  the  lime 
stone  caverns  situated  at  the  greatest  elevations  —  eighty  to  one  hundred  feet  above  the 
present  river  —  are  those  which  contain  the  older  remains  of  Mammals;  and  those  be 
low  are  successively  more  recent  as  their  height  is  less.  Moreover,  the  river  alluvium 
shows  that,  when  the  upper  caves  were  inhabited,  the  valley  was  filled  with  water  and 
river-border  deposits,  nearly  to  the  level  of  the  cave.  Thus  the  change  of  level,  which 
marked  the  close  of  the  Champlain  period  and  the  introduction  of  the  Recent  period, 
is  very  strikingly  exhibited. 

The  facts  from  Europe  hence  confirm  the  conclusion  from  America, 
that  the  Champlain  period  was  the  era  of  flooded  rivers  and  lakes,  and 
of  the  most  extensive  fresh-water  formations  in  the  world's  history. 
Europe  also  had  rivers  dammed  up  by  gravel  and  sand  from  the 
unlading  glacier.  It  has  been  recently  shown  that  the  Rhine  owes  its 
present  channel  at  the  Falls  at  Schaffhausen  to  its  having  been  forced 
out  of  an  older  one ;  and  it  is  probable  that  the  Champlain  period 
was  the  time  of  the  catastrophe. 

3.    RECENT   PERIOD. 

The  RECENT  Period  is  divided  into  (1)  the  Reindeer,  or  Second 
Glacial  era ;  and  (2)  the  Modern  era.  Evidences  of  a  Second 
Glacial  epoch  have  not  yet  been  clearly  made  out  in  America. 

I.  Rocks:  kinds  and  distribution. 

The  formations  are  such  as  are  found  now  in  progress,  either  over 
the  land,  along  sea-borders,  or  in  seas.  The  following  are  some  of 
the  more  important  kinds  :  — 

OF  MECHANICAL  ORIGIN.  — •  1.  The  Continental.  —  Alluvial  beds 


QUATERNARY    AGE.  —  RECENT   PERIOD.  557 

along  rivers  and  about  lakes  ;  drift  sands  or  dunes  ;  glacial  drift,  like 
that  of  the  Glacial  period,  but  more  local.  2.  Marine.  —  Estuary  and 
delta  formations ;  sea-beach  accumulations  ;  off-shore  deposits  of  de- 
trital  material  carried  into  the  ocean  by  rivers,  or  made  from  the 
battering  of  cliffs  by  the  waves  ;  deep-sea  deposits  of  fine  detritus. 

OF  CHEMICAL  ORIGIN. —  Stalactitic  and  stalagmitic  accumulations 
in  caverns  (p.  75),  the  latter  often  covering  the  floors  of  caverns  to 
a  considerable  depth,  and  enveloping  relics  of  their  former  inhabitants  ; 
travertine  deposits  (concretionary  limestone),  from  streams  holding  bi 
carbonate  of  lime  in  solution,  as  along  Gardiner's  River,  in  the  Yellow 
stone  Park,  and  at  Tivoli,  near  Rome  (p.  75)  ;  siliceous  deposits  of 
hot  springs,  as  those  of  Yellowstone  Park,  and,  with  these,  silicified 
wood,  leaves,  insects,  etc.;  deposits  of  bog-iron  ores  in  marshes,  with 
often  iron-ore  fossils  of  fruits,  stems,  etc. 

OF  ORGANIC  ORIGIN.  —  Peat  beds,  or  swamp  formations  of  vege 
table  character  (p.  G16)  ;  deposits  of  shells  and  shell-limestone  in 
lakes,  or  on  seashores ;  coral-reef  formations  in  the  warmer  oceans, 
often  full  of  fossil  corals  and  shells,  but  of  existing  species  (p.  620)  ; 
chalky  deposits  of  Rhizopod  shells,  over  the  ocean's  bed,  at  various 
depths  down  to  15,000  feet;  siliceous  deposits,  consisting  of  Diatoms, 
or  of  these  and  the  spicules  of  Sponges,  either  in  fresh  water,  or  in 
the  ocean. 

OF  IGNEOUS  ORIGIN.  —  Lavas,  and  other  rocks  of  igneous  ejections, 
either  from  volcanoes  or  through  fissures,  comprising  both  dolerytic 
and  trachytic  kinds.  The  great  beds  of  dolerytic  rocks  which  form 
a  table-like  covering  over  parts  of  the  Drift  of  the  Sierra  Nevada, 
and  other  great  streams  of  doleryte  in  the  Snake  River  region,  are 
among  the  formations  of  the  Recent  period,  besides  the  eruptions  of 
various  volcanoes. 

The  formations  here  enumerated  are  not  always  distinguishable 
from  those  of  the  Ghamplain  period,  even  in  Drift  latitudes,  and  much 
less  easily,  or  not  at  all  so,  from  most  of  those  outside  of  these 
latitudes.  The  shells  and  corals  afford  no  means  of  distinction, 
except  on  certain  coasts,  where  there  has  been  a  change  of  oceanic 
temperature  ;  but  remains  of  Mammals,  and  especially  relics  of  Man, 
when  these  are  present,  sometimes  afford  assistance.  The  seashore 
beds  may  be  at  the  water's  level,  or  they  may  exist  at  different  levels 
above  it ;  yet  it  is  generally,  though  not  always,  easy  to  separate 
the  elevated  Champlain  Drift  deposits  from  the  Recent,  by  the  peculiar 
structure  of  the  sand  accumulations  and  their  geographical  distri 
bution. 

II.  Reindeer  and  Modern  eras  in  North  America. 

The  Recent  period  is  separated  from  the  Champlain,  by  an  elevation 


558  CENOZOIC    TIME. 

of  the  land  over  the  higher  latitudes,  —  that  is,  of  nearly  the  same  area 
that  was  depressed  in  the  Champlain  period.  As  the  Champlain  de 
pression  was  greatest  to  the  north,  so  it  was  with  the  elevation  follow 
ing  it;  for  the  height  at  which  the  Champlain  deposits  now  stand 
over  the  continent,  from  the  southern  Drift  limit  to  the  Arctic,  is  a 
consequence  of  this  elevation.  Terraces  exist  along  all  the  rivers  and 
about  all  the  lakes  of  the  North  American  continent,  excepting  its 
more  southern  portions  ;  and  these  were  a  necessary  consequence  of 
the  changes  of  level,  and  are  testimony  as  to  the  amount  of  this  change, 
and  the  way  in  which  it  went  forward  in  different  regions. 

1.  Terraces.  —  The  connection  of  the  existence  of  terraces  with  an 
elevation  of  the  land  is  illustrated  in  the  following  figures.  Fig.  943 
represents  a  section  of  a  river  valley  filled  up  with  the  stratified  Drift 
of  the  Champlain  period,  and '  having  its  narrow  river-channel  R,  and 

Fig.  943. 


Section  of  a  valley  in  the  Champlain  epoch,  with  dotted  lines  showing  the  terraces  formed  in  con 
sequence  of  an  elevation  of  the  land. 

its  broad  river-flat//',  either  side  of  the  channel.  Rivers  in  an 
open  country  have  always  both  these  two  elements,  a  channel  and  a 
river-flat  or  flood-plain.  The  stream  occupies  the  former  during 
ordinary  low-water,  but  spreads  over  the  latter  during  freshets.  The 
sweeping  violence  of  the  flood  determines  the  limits,  other  tilings 
being  equal,  of  the  flood-plain  or  river-flat. 

If  now  the  interior  of  a  continent  be  raised  a  hundred  feet  higher 
than  along  the  sea-coast,  the  river  will  have  an  increased  angle  of 
slope,  a  quicker  flow,  and  greater  power  of  erosion  ;  and  it  will  grad 
ually  wear  down  its  channel,  if  there  are  no  rocks  to  prevent,  until 
the  old  slope  is  again  attained.  The  flood-plain  will  also  sink  at  the 
same  rate,  although  with  more  or  less  changed  limits,  according  to 
many  causes  of  variation  ;  among  which  causes  a  diminution  in  the 
amount  of  water,  from  any  cause,  would  make  itself  apparent  along 
the  whole  course  of  the  stream.  After  such  an  elevation,  the  level  d  d1 
might  be  the  flood-plain  or  river-flat.  After  another  similar  eleva 
tion,  b  b'  might  be  the  flood-plain  and  channel. 

Similar  effects  would  ultimately  be  produced  from  an  equal  eleva 
tion  of  the  whole  region,  from  the  coast  to  the  head  of  the  stream, 
provided  the  slope  of  the  surface  below  the  coast-line  were  decidedly 
more  rapid  than  the  average  pitch  of  the  river  channel  above  it. 


QUATERNARY    AGE.  —  RECENT    PERIOD. 


559 


In  Fig.  944.  a  section  of  a  valley  filled  with  the  Champlain  deposits, 
and  thus  terraced  in  consequence  of  the  change  of  level,  is  repre 
sented. 

In  the  above  explanation,  the  terraces  are  supposed  to  correspond 
each  to  a  separate  period  of  elevation.  This  may  be  the  case  ;  and, 
when  so,  the  same  terrace  is  traceable  for  great  distances  along  the 
course  of  the  larger  rivers.  But  successive  terraces  may  be  formed 
in  river-valleys,  either  (1)  during  a  single  slowly-progressing  eleva 
tion,  or  (2)  in  the  course  of  the  wear  which  may  be  going  forward  in 
consequence  of  a  single  abrupt  elevation  ;  and  it  is  often  difficult  to 
distinguish  these  accidental  or  intermediate  plains  from  those  that  are 
records  of  distinct  changes  of  level.  One  such  intermediate  terrace 

Fig.  944. 


Section  of  a  valley,  with  its  terraces  completed. 

is  shown  at  r,in  Fig.  944.  Some  of  the  conditions  producing  them 
are  the  following:  (1)  changes  in  the  river-channel  to  one  side  or 
the  other  of  the  river-valley,  altering  thereby  the  action  of  the  flood- 
waters  during  freshets,  and  causing  them  to  commence  wear  according 
to  a  new  outline ;  (2)  resistance  to  wear  in  a  portion  of  the  alluvium, 
owing  to  a  degree  of  consolidation,  or  to  rocks,or  some  other  obstacle  ; 
(3)  a  permanent  diminution  in  the  waters  of  a  stream,  arising  from 
changes  about  its  sources,  or  in  some  other  way. 

Fig.  945. 


Section  of  the   terraced  valley  of  the  Connecticut,  at  Hadley ;    B,   a  brook;    M,  Mill   River; 
II,  Hatfield  ;  C,  Connecticut  River  ;  II,  Hadley. 

Figure  945  represents  terraces  on  the  Connecticut,  as  figured  by 
Hitchcock,  and  illustrates  both  the  regularities  and  irregularities  of 
level  among  them.  It  is  from  the  vicinity  of  Hadley,  Mass. 

It  is  important  to  observe  also  that  the  same  terrace  may  differ  in 
height,  ten  to  fifteen  feet  or  more,  —  because  (1)  the  flood-plains  of 


560  CENOZOIC    TIME. 

rivers  (the  original  condition  of  the  terrace-plains)  often  differ  much 
in  height  in  different  parts  ;  (2)  the  rains  and  streamlets  often  wear 
away  the  soft  material  of  the  terraces,  diminishing  their  height,  and 
sometimes  obliterating  the  plain  altogether,  or  reducing  it  to  a  region 
of  hills,  or  "  horse-backs  ; "  (3)  the  winds  carry  off  the  light  soil  of 
the  surface,  and,  in  the  course  of  centuries,  may  produce  great  results. 

Again,  the  terraces  of  small  tributaries,  at  a  distance  from  the  river 
into  which  they  flow,  are  lower  than  those  of  the  latter,  because  both 
their  floods  and  their  eroding  power  are  less. 

Again,  when  there  are  rocks  in  the  course  of  a  stream,  a  terrace 
above  the  rocky  barrier  may  differ  in  height  from  its  counterpart 
below;  because  the  stream  is  unable  to  wear  down  its  bed,  and  is 
more  or  less  dammed  up  by  the  barrier. 

It  should  be  observed  that  the  deposits  terraced  in  North  America  are  those  of  the 
Champlain  period,  formed  as  explained  on  pages  545,  547  ;  and  consequently  that  the 
beds  of  the  uppermost  terrace,  instead  of  being  the  oldest,  are  usually  newer  than 
those  of  the  lower,  because  they  are  the  upper  part  of  the  Champlain  formation.  The 
formation  in  any  place  is  often  wholly  Diluvian,  and  sometimes  wholly  Alluvian;  and, 
in  either  case,  the  upper  beds  are  the  newer.  Where  the  Alluvian  deposit  along 
the  middle  of  a  valley  has  been  laid  down  over  the  earlier  Diluvian,  in  the  manner 
remarked  upon  on  page  547,  and  then  removed  again  down  to  the  level  of  a  lower 
terrace,  the  deposits  of  the  upper  terrace  would  be  older  than  the  rest.  Again,  if,  as  in 
Europe,  a  second  epoch  of  ice  and  change  of  level  has  following  the  Champlain  period, 
there  may  be  elevated  alluvial  formations  along  the  sides  of  a  stream,  which  are  of 
later  origin  than  those  of  the  Alluvian  era.  Alluvial  beds  of  Modern  time  are  seldom 
present,  unless  locally,  on  any  of  the  terraces  excepting  the  lowest,  or  that  constituting 
the  existing  river-flats. 

Terraces  along  rivers  or  lakes  are  uncertain  evidence  as  to  the  amount  of  the  elevation 
which  occasioned  their  formation.  Only  the  terraces  of  large  open  valleys  give  even  ap 
proximately  the  truth;  and  not  these,  unless  the  bed  of  the  channel  is  alluvial  quite  to 
its  mouth,  so  that  it  is  nearly  certain  that  the  river  has,  since  the  elevation,  excavated 
its  bed  to  the  same  slope  it  had  before  it.  If  there  are  falls  in  the  stream,  or  descents  in 
rapids  over  rocks,  amounting,  say  in  all,  to  seventy-five  feet,  the  excavation  would  in 
most  cases  be  so  much  less  than  the  amount  of  elevation;  and  this  should  be  added,  iit 
order  to  get  an  approximate  conclusion.  There  is  also  an  unknown  amount  to  be  sub 
tracted,  on  account  of  the  greater  slope  of  the  flood-waters  of  the  Diluvian  era  than  that 
of  modern  floods ;  for  the  slope  of  a  flooded  stream  does  not  depend  on  the  slope  of  its 
bed  simply,  but  both  on  that  and  on  the  amount  of  water  supplied  in  the  flood ;  and,  as 
already  stated,  the  slope,  in  such  a  case,  varies  greatly  with  the  character  of  the  valley : 
a  narrow  and  obstructed  gorge  in  the  course  of  the  valley  causing  a  great  rise  of  the 
flood-level  above  it. 

Other  considerations  bearing  on  this  subject,  and  essential  to  right  conclusions,  are 
presented  in  the  chapter  beyond,  on  Rivers. 

2.  Geography The  elevation  which  occurred  at  the  opening  of 

the  Recent  period  made  a  vast  change  in  American  Geography.  The 
New  England  and  Labrador  coasts  gained  much  in  extent ;  and  Nova 
Scotia  was  again  united  to  the  main  land.  The  one  immense  interior 
lake  became  the  five  Great  Lakes  ;  and  hundreds  of  smaller  lakes, 
along  the  rivers  and  elsewhere,  disappeared.  The  Kankakee  Swamp 


QUATERNARY    AGE.  —  RECENT    PERIOD.  561 

country,  twenty-five  miles  wide  and  fifty  long,  in  western  Indiana,  is 
described  by  F.  H.  Bradley  as  one  of  these  obliterated  lakes. 

The  Great  Salt  Lake,  which  is  now  not  over  sixty  feet  deep,  lost 
nine  hundred  feet  in  depth  at  this  time,  and  contracted  proportionally 
in  area ;  and  other  large  lakes,  in  the  Great  Basin  and  at  the  eastern 
foot  of  the  Sierra  Nevada,  lost  equally  in  their  dimensions.  The 
rivers  dwindled  to  one-tenth  their  former  magnitude,  and  became  nar 
row  threads  of  water,  with  contracted  flood-grounds  between  wide  ter 
raced  alluvial  plains,  whose  limits  —  once  their  flood  limits  —  afford  a 
ready  means  to  the  eye  of  marking  off  the  contrast. 

In  Europe,  the  elevation  of  which  the  terraces  are  testimony  appears  to  have  ended 
in  a  second  Glacial  epoch.  Marks  of  this  epoch  may  yet  be  deciphered  in  America. 
Remains  of  the  Reindeer  have  been  met  with  in  New  Jersey  and  New  York;  and  their 
occurrence  so  far  south  may  be  in  consequence  of  such  an  epoch.  The  destruction  of 
the  Elephant  or  Mammoth  of  Champlain  America,  and  of  the  great  Sloth-like  beasts 
and  their  cotemporaries  mentioned  beyond,  may  have  been  a  consequence  of  it.  But 
the  Mastodon  and  some  other  Champlain  species  probably  survived  into  the  later  part 
of  the  Recent  period. 

On  the  coast  of  Maine,  there  are  large  Indian  shell  heaps  of  the  common  Clam  (  Venus 
mercenaria,  the  Quahoy  of  the  Indians)  and,  in  some  places,  of  the  Virginia  Oyster,  spe 
cies  which  are  now  nearly  extinct  on  that  cold-water  coast.  As  made  known  by  Verrill, 
there  is  a  colony  of  living  southern  species  in  Quahog  Bay,  near  Bath  (twenty  miles  east 
of  Portland),  among  which  are  Venus  mercenaiia  Linn.,  Modioltt  plicatula  Lam.,  Ilya- 
nassa  obsoleta  Stimp,  Urosnlpynx  cinerea  Stimp.,  Crepiduln  fornicata  Lam.,  Asterias 
arenicola  Stimp.,  Eupayurus  lonyicarpus  Edw.,  and  others,  reminding  one  strongly,  as 
Verrill  says,  of  the  coast  fauna  of  New  Haven,  on  Long  Island  Sound;  and  the  Venus, 
Ilyanassa,  Modiola,  and  other  species  occur  also  in  Northumberland  Straits,  in  the 
southern  part  of  the  Gulf  of  St.  Lawrence.  At  the  mouth  of  Damariscotta  River,  thirty 
miles  east  of  Portland,  there  is  the  only  locality  of  the  living  oyster  north  of  Massa 
chusetts  Bay.  Shells  of  Oysters,  Clams,  and  Scallops  (the  southern  Pecten  irradians 
Lam.)  are  abundant  in  the  deeper  portions  of  the  mud  of  the  harbor  of  Portland, 
These  species  are  relics  of  a  past  abundant  southern  population ;  none  of  the  shells  are 
found  in  elevated  beaches ;  and  hence  the  migration  from  south  of  Cape  Cod  took  place 
in  the  Recent  period.  Such  a  migration,  extending  to  the  St.  Lawrence  Gulf,  was  not 
possible,  unless  the  Labrador  current  had  first  been  turned  aside;  and  no  change  would 
have  brought  this  about,  short  of  a  closing  of  the  Straits  of  Bellisle,  by  a  union  of  New 
foundland  to  the  continent.  This  implies  an  elevation  of  about  two  hundred  feet;  and 
it  may  be  that  the  one  which  introduced  the  Recent  period  carried  the  continent,  to  the 
north,  to  this  height  above  the  present  level.  Such  an  event  would  have  been  in  har 
mony  with  the  occurrence  of  a  second  Glacial  epoch. 


III.  Recent  Period  in  Europe  and  Great  Britain. 

The  Reindeer  era  or  Second  Glacial  epoch,  which  opens  the  Recent 
period,  was  a  marked  one  in  British  and  European  history.  Evidence 
of  it  is  found  in  the  Glacial  deposits  of  the  Alps  and  of  the  river 
valleys  leading  from  these  mountains ;  in  similar  phenomena,  though 
as  yet  less  well  understood,  in  Great  Britain  ;  in  the  occurrence  in 
southern  France  of  remains  of  Arctic  and  Subarctic  quadrupeds,  among 
which  the  Reindeer  was  prominent ;  in  the  occurrence,  as  explained 
beyond,  of  skeletons  and  tusks  of  the  Elephant  of  the  Champlain  era 

36 


562  CENOZOIC    TIME. 

in  Siberia,  on  the  borders  of  the  Arctic  Sea,  and  of  whole  carcasses, 
the  meat  untainted,  encased  in  Arctic  ice,  proving  that  death  invaded 
the  region  in  consequence  of  a  sudden  refrigeration  of  climate.  It  is 
also  attested  by  facts  connected  with  early  human  history. 

According  to  Von  Morlot,  the  Alps,  after  the  Glacial  period,  that 
is,  at  the  opening  of  the  Champlain,  subsided  one  thousand  feet ;  and 
the  glacier  retreated  from  lower  Switzerland  to  the  Alpine  valleys. 
But  afterward  a  second  extension  of  the  ice  took  place,  covering  again 
all  lower  Switzerland,  but  not  the  Juras,  and  making  new  deposits  of 
loess  along  the  valley  of  the  Rhine. 

Lyell  remarks  on  a  parallel  succession  of  events  in  Britain,  and  on 
the  second  epoch  of  cold  having  been  coincident  with  a  reelevation  of 
the  land.  This  reelevation  probably  went  forward  slowly,  through  the 
closing  part  of  the  Champlain  period ;  and  it  may  have  ended  in  carry 
ing  the  surface  above  the  present  level. 

The  reelevation,  before  it  was  fully  completed,  cut  off  the  Baltic 
again  from  the  ocean  on  the  north  and  west ;  for,  as  Erdmarm  shows, 
while  on  the  upper  terraces  the  shells  of  the  Baltic  coasts  include  the 
outside  kind,  YoldiaArctica,  there  are  lower  terraces  from  which  the 
open  sea  species  are  all  excluded,  excepting  a  few  Baltic  kinds,  of 
which  the  Mytilus  is  the  most  common. 

Terraces  occur  along  the  valleys  of  Great  Britain,  and  of  northern 
and  central  Europe,  like  those  of  North  America.  A  few  of  those  of 
Great  Britain  are  alluded  to  on  page  555.  In  Belgium,  the  gradual 
elevation,  in  which  the  terracing  took  place,  is  recorded  also  in  the 
caverns,  along  the  river  bluffs,  as  stated  on  page  556.  Dupont  states, 
further,  that,  after  the  "  Mammoth  "  (Champlain)  period,  the  riood- 
grounds  of  the  river  Meuse,  of  Belgium,  near  Dinant,  diminished  in 
breadth  from  seven  and  a  half  miles  to  one-fourth  of  a  mile,  —  or  to 
one -thirtieth  the  Champlain  breadth,  —  and  those  of  other  streams 
underwent  a  corresponding  contraction. 

The  deposits  of  the  Recent  period,  after  the  second  Glacial  epoch, 
were  made,  observes  Lyell,  when  the  land  stood  for  the  most  part 
near  its  present  level,  with  the  great  features  of  the  surface  as  they 
are  now.  The  shell  heaps  (Kjokken-modding  or  Kitchen-middens) 
then  made,  on  the  coasts  of  Danish  Islands  in  the  Baltic,  and  at  other 
localities,  contain  no  remains  of  the  Reindeer,  showing  that  the  Arctic 
cold  had  receded  toward  its  present  northern  limits,  while  those  of 
the  Urns,  modern  Stag,  Roedeer,  Wild  Boar,  Dog,  Wolf,  and  other  ex 
isting  species  are  common. 

On  the  southern  side  of  Sardinia,  at  Cagliari,  beds  of  recent  shells,  with  bits  of 
antique  pottery,  are  found  at  heights  of  two  hundred  and  thirty  to  three  hundred  and 
twenty-four  feet  above  the  sea,  as  described  by  Count  Albert  de  la  Marmora,  proving 
that  the  region  has  been  elevated  to  that  extent  in  the  Quaternary  age,  and  possibly  at 
the  opening  of  the  Recent  period. 


MAMMALIAN    LIFE   OF   THE   QUATERNARY. 


563 


4.  LIFE  OF  THE  EARLY  AND  MIDDLE  QUATERNARY. 
It  has  been  already  stated  that  the  Plants  and  Invertebrates  (Mol- 
lusks,  etc.)  of  the  Quaternary  are,  with  a  rare  exception,  living  species, 
while  the  Mammals  are  nearly  all  extinct.  The  latter  are  therefore 
the  species  of  highest  interest.  They  include  not  only  brute  Mam 
mals,  but  also  Man. 

I.  BRUTE  MAMMALS. 
1.  Europe  and  Asia.  —  The   Mammals  or  Quadrupeds  of  Quater 


nary  Europe  are  remarkable  for  their  great  size 
and  Europe  were  the  dens  of  gi 
gantic  Lions  and  Hyenas,  while 
Pachyderms  and  Ruminants,  equal 
ly  gigantic,  compared  with  modern 
species,  roamed  over  the  continent, 
from  the  Mediterranean  and  India 
to  the  Arctic  seas.  The  remains 
are  found  in  the  earthy  or  stalag- 
mitic  floors  of  caverns  ;  mired  in 
ancient  marshes  ;  buried  in  river 
and  lacustrine  alluvium,  or  sea- 
border  deposits ;  or  frozen  and 
cased  in  Arctic  ice.  Stalagmite  (p. 
75)  is  always  forming  in  limestone 
caverns,  and  envelopes  anything 
that  may  lie  on  the  floor. 

In  Great  Britain,  the  Champlain 
Mammals  have  been  found  in  river- 
border  formations,  in  a  large  num 
ber  of  localities ;  and  several  of 
these  have  afforded  also  relics  of 
Man.  The  species  of  Mammals  aro 
with  few  exceptions  the  same  that 
have  been  found  also  in  caverns. 
The  loess  of  the  Rhine  and  the 
valley  formations  of  other  parts  of 
Europe  have  afforded  similar  facts. 
The  European  caves  were  mostly 
caves  of  Bears  (the  great  Ursus 
spelceus  Rosenmiiller),  while  those 
of  England  were  occupied  by  Hy 
enas  (Hyaena  spelcea  Goldf.),  with 
few  bears.  This  Cave  Hyena,  al- 


Caverns  in  Britain 

Fig.  946. 


Canine  tooth  of  the  v!ave  Bear. 


564  CENOZOIC    TIME. 

though  of  unusual  size,  is  now  regarded  as  of  the  same  species  with 
the  Hyaena  crocuta  Zimm.,  of  South  Africa ;  and  the  Cave  Lion,  or 
Felis  spelcea,  as  a  variety  of  Felis  leo  Linn.,  or  the  Lion  of  Africa. 

In  a  cavern  at  Kirkdale,  one  of  the  earliest  explored,  Hyena  bones 
and  teeth  belonging  to  about  three  hundred  individuals  were  mingled 
with  remains  of  extinct  species  of  Elephant  or  Mammoth  (Elephas 
primigemus),  Bear,  Rhinoceros,  Hippopotamus,  Deer,  along  with  the 
Cave  Lion,  the  Brown  Bear  (  Ursus  Arctos  Linn.),  the  Horse,  Hare, 
etc.,  —  all  of  which  then  populated  Britain.  The  Hyenas  hither  dragged 
the  dead  carcasses  they  found,  and  lived  on  the  bones,  and  also  on  the 
bones  of  fellow  Hyenas ;  and  the  bottom  of  the  cave  was  covered 
with  the  fragments.  Calcareous  excrements  are  also  abundant,  quite 
similar  to  the  excrements  of  the  modern  Hyena. 

Kent's  Hole,  near  Torquay,  has  afforded  bones  of  the  Mammoth,  Rhinoceros  (R. 
tichorinus),  Cave  Bear,  Cave  Lion,  Cave  Hyena,  Irish  Deer,  Machcerodus  latidens  Owen, 
besides  relics  of  Man,  in  the  form  of  flint  implements ;  and  the  Brixham  Cave,  in  the 
same  vicinity,  in  addition  to  flint  implements,  bones  of  the  Cave  Bear,  Brown  Bear, 
Grizzly  Bear  ( U.ferox),  Elephant,  Cave  Hyena,  Cave  Lion,  Wolf,  Fox,  Modern  Horse, 
Eeindeer,  Goat,  Irish  Deer,  Elk,  modern  Hare  and  Rabbit,  Wild  Boar,  Layomys  spe- 
Iceus  Owen,  Aurochs  (Bos primiyeniits  Boj.),  etc. 

Some  idea  has  been  given  of  Britain  in  the  age  of  Reptiles  (p.  485).  The  following, 
from  Owen,  gives  a  later  picture  of  England,  —  England  in  the  Middle  Quaternary. 

"  Gigantic  Elephants,  of  nearly  twice  the  bulk  of  the  largest  individuals  that  now 
exist  in  Ceylon  and  Africa,  roamed  here  in  herds,  if  we  may  judge  from  the  abundance 
of  their  remains.  Two-horned  Rhinoceroses,  of  at  least  two  species,  forced  their  way 
through  the  ancient  forests,  or  wallowed  in  the  swamps.  The  lakes  and  rivers  were 
tenanted  by  Hippopotamuses,  as  bulky  and  with  as  formidable  tusks  as  those  of  Africa. 
Three  kinds  of  wild  Oxen,  two  of  which  were  of  colossal  strength,  and  one  of  these 
maned  and  villous  like  the  Bonassus,  found  subsistence  in  the  plains."  There  were 
also  Deer  of  gigantic  dimensions,  wild  Horses  and  Boars,  a  Wild-cat,  Lynx,  Leopard, 
a  British  Tiger,  larger  than  that  of  Bengal,  and  another  Carnivore,  as  large,  of  the 
genus  Machcerodus,  which,  "  from  the  great  length  and  sharpness  of  its  sabre-shaped 
canines,  sometimes  eight  inches  long,  was  probably  the  most  ferocious  and  destructive 
of  its  peculiarly  carnivorous  family."  "  Besides  these,"  continues  Professor  Owen, 
"  troops  of  Hyenas,  larger  than  the  fierce  Hycena  crocuta  Zimm.  of  South  Africa,  which 
they  most  resembled,  crunched  the  bones  of  the  carcasses  relinquished  by  the  nobler 
beasts  of  prey,  and  doubtless  often  themselves  waged  a  war  of  extermination  on  the 
feebler  quadrupeds." 

There  were  also  in  Britain  a  savage  Bear,  larger  than  the  Grizzly  Bear  of  the  Rocky 
Mountains,  Wolves,  a  gigantic  Beaver  (Trogontherium),  and  various  smaller  animals, 
down  to  Bats,  Moles,  Rats,  and  Mice.  The  Horse  (Equusfossilis  Meyer),  though  of  very 
large  size,  is  regarded  as  of  the  same  species  with  the  modern  Horse  (E.  caballus). 

The  more  common  Elephant  of  the  region  was  the  Elephas  primi- 
genius.  It  lived  in  herds  over  England,  and  extended  its  wanderings 
across  the  Siberian  plains  to  the  Arctic  Opean  and  Behring  Straits, 
and  beyond  into  North  America ;  but  it  seems  not  to  have  gone  far 
south  of  the  parallel  of  40°.  It  is  stated  by  Woodward  that  over  two 
thousand  grinders  were  dredged  up  by  the  fishermen  of  the  little  vil 
lage  of  Happisburgh,  in  the  space  of  thirteen  years  ;  and  other  localities 
in  and  about  England  are  also  noted. 


MAMMALIAN   LIFE    OF   THE    QUATERNARY.  565 

This  ancient  Elephant  was  over  twice  the  weight  of  the  largest 
modern  species,  and  nearly  a  third  taller.  The  body  was  covered 
with  a  reddish  wool  and  long  black  hair.  One  of  the  tusks  measured 
twelve  and  one  half  feet  in  length ;  it  was  curved  nearly  into  a  circle, 
though  a  little  obliquely.  The  remains  are  exceedingly  abundant  at 
Eschscholtz  Bay,  near  Behring  Straits,  where  the  ivory  tusks  of 
ancient  generations  of  elephants  are  gathered  for  exportation.  At  the 
mouth  of  the  Lena,  one  of  these  animals  was  found,  at  the  beginning 
of  this  century,  frozen  and  encased  in  ice.  It  measured  sixteen  feet 
four  inches  in  length,  to  the  extremity  of  the  tail,  exclusive  of  the 
tusks,  and  nine  feet  four  inches  in  height.  It  retained  the  wool  on  its 
hide,  and  was  so  perfectly  preserved  that  the  flesh  was  eaten  by  the 
dogs. 

The  common  Rhinoceros  was  the  JR.  tichorinus.  It  spread  from 
England  to  Siberia.  A  frozen  specimen  was  found  near  Wilui,  in 
Siberia,  in  1772.  It  had  a  length  of  eleven  and  a  half  feet,  and  was 
a  hairy  species. 

The  Irish  Deer  (Cervus  megaceros),  was  another  of  the  gigantic 
species.  Skeletons  have  been  found  in  marl,  beneath  the  peat  of 
swamps,  in  Ireland  and  England,  and  fragments  in  the  bone-caverns. 
The  height,  to  the  summit  of  the  antlers,  in  the  largest  individuals, 
was  10  to  11  feet;  and  the  span  of  the  antlers  was  10  feet,  and  in  one 
case  over  12  feet. 

The  Elephant  has  in  all  twenty -four  teeth  (grinders),  but  usually  only  eight  at  a  time, 
two  in  each  side  of  each  jaw.  The  new  teeth  come  up  behind,  and  push  the  others  for 
ward  and  out;  and  thus  there  is  a  succession  until  the  last  has  grown.  Another  Ele 
phant  of  the  era  was  the  E.  antiqmis  Falc.  Both  the  E.  antiquus  and  E.  Africanus 
Cuv.  have  been  found  on  Sicily.  Besides  the  common  hairy  Rhinoceros  tichorinus,  the 
R.  hemit&chus  Falc.  occurs  in  the  British  and  French  bone-caves.  One  of  the  Chain- 
plain  oxen,  the  Aurochs,  still  lives  under  the  protection  of  the  Russian  Czar;  and  the 
other,  Bison  priscus  Ow.,  or  Urus,  was  alive  in  the  time  of  the  Romans. 

Many  species  of  the  present  day  were  associated  with  the  extinct 
kinds  ;  as  is  exhibited  in  the  list  of  species  from  Kent's  Hole. 

2.  America.  —  America  in  the  Quaternary  era  was  inferior  to 
Europe  in  the  number  of  its  Carnivores,  but  exhibited  the  gigantic 
feature  of  the  life  of  the  time  in  its  species. 

In  North  America,  the  mammals  included  an  Elephant,  E.  Ameri- 
canus  Dekay,  as  large  as  the  European,  besides  the  Asiatic  E.  primi- 
genius  Blum.,  in  the  more  northern  latitudes  ;  'a  Mastodon,  M.  Ameri- 
canus  Cuv.,  of  still  greater  magnitude  ;  Horses  much  larger  than  the 
modern ;  species  of  Ox,  Bison,  Tapir,  gigantic  Beavers,  species  of 
Dicotyles  (related  to  the  Mexican  Peccary)  ;  also  animals  of  the  Sloth 
tribe,  of  the  genera  Megatherium,  Mylodon  and  Megalonyx,  of  great 
size,  compared  with  those  now  living.  Amon^  Carnivores,  there  were 


566  CENOZOIC   TIME. 

a  Bear,  a  Lion,  and  a  Raccoon  ;  and  these  were  probably  not  cavern 
species  ;  none  of  the  many  caverns  of  the  country  appear  to  have 
been  the  haunts  of  Carnivores. 

Fig.  947.  Fig.  948. 


Tooth  of  Elephas  Americanus  ( Xx<i).  Tooth  of  Mastodon  Americanus  (X%)- 

The  American  Elephant  ranged  from  Georgia,  Texas,  and  Mexico 
on  the  south  to  Canada  on  the  north,  and  to  Oregon  and  California  on 


Skeleton  of  Mastodon  Americanus  (M.  Ohioticus). 

the  west.     The  species  appears  to  have  been  most  abundant  to  the 
south,  in  the  Mississippi  valley,  it  preferring  a  warmer  climate  than 


MAMMALIAN    LIFE    OF   THE    QUATERNARY.  567 

the  E.  primi genius.  Fig.  947  represents  one  of  the  teeth  (reduced  to 
one-fourth  lineally),  found  in  the  State  of  Ohio. 

The  teeth  differ  from  those  of  the  E.  primigenius,  in  having  the  enamel 
plates  less  crowded. 

Mastodon  remains  (fig.  949)  are  met  with  most  abundantly  over  the 
northern  half  of  the  United  States,  though  occurring  also  in  the  Caro- 
linas,  Mississippi,  Arkansas,  and  Texas.  They  are  found  also  in 
Canada  and  Nova  Scotia.  The  best  skeletons  have  been  dug  out  of 
marshes,  in  which  the  animals  had  become  mired.  Three  perfect  skele 
tons  have  been  obtained  from  the  fresh-water  marshes  of  Orange 
County,  N.  Y. ;  another  from  near  Cohoes  Falls,  on  the  Mohawk  ; 
another  in  Indiana ;  one  from  a  morass  in  New  Jersey  ;  another  on 
the  banks  of  the  Missouri.  In  New  England,  a  few  bones  have  been 
found  near  New  Britain  and  Cheshire,  Connecticut.  The  best  of  the 
skeletons  is  that  set  up  by  Dr.  Warren,  at  Boston :  it  was  obtained 
from  a  marsh  near  Newburgh.  Its  height  is  11  feet;  the  length  to 
the  base  of  the  tail,  17  feet;  the  tusks  12  feet  long,  —  2^  feet  being 
inserted  in  the  sockets.  When  alive,  the  height  must  have  been  12  or 
13  feet,  and  the  length,  adding  7  feet  for  the  tusks,  24  or  25  feet.  Re 
mains  of  the  undigested  food  were  found  between  his  ribs,  showing 
that  he  lived  in  part  on  spruce  and  fir  trees.  Fig.  949,  from  Owen's 
"  British  Mammals,"  represents  the  skeleton  of  this  species  in  the 
British  Museum  ;  and  Fig.  948,  one  of  the  teeth,  one  fourth  the  nat 
ural  size. 

Castoroides  OJiioensis  Foster  was  a  great  Rodent  related  to  the  Beaver  (Cftstor  Cana- 
densls  Kuhl).  The  Beaver  is  an  animal  about  three  feet  long,  exclusive  of  the  tail;  and 
the  Citstoroides  was  almost  or  quite  five  feet.  Its  bones  have  been  found  in  the  States 
of  New  York,  Ohio,  Mississippi  (near  Natchez),  etc. 

Bison  latifrons  L.  was  a  Bison  or  Buffalo,  much  larger  than  the  existing  Buffalo,  which 
lived  in  the  Mississippi  and  Ohio  valleys,  and  over  the  Southern  States  to  Texas.  There 
were  also  species  related  to  the  Musk-ox,  Ovibos  bombifrons  L.  and  0.  cavifrons  L. 

A  Stag,  Cervus  Americanus  Harlan,  whose  bones  were  found  near  Natchez,  equalled, 
if  they  did  not  exceed  in  size,  the  Irish  Deer.  A  Horse  from  the  same  locality  was  also 
gigantic,  — a  fit  cotemporary,  as  Leidy  observes,  of  the  Mastodon  and  Elephant. 

The  Lion,  Felis  atrox  L.,  was  about  as  large  as  that  of  Britain.  Only  a  single  jaw 
bone  of  it  has  been  found  at  the  Natchez  bone-locality,  where  occur  remains  of  species 
of  Bear  (  Ursus  amplidens  L.),  Horse,  Elephant,  Mastodon,  Castoroides,  Meyalonyx,  and 
Mylodon. 

A  vertical  opening  in  the  limestone  strata  at  Port  Kennedy,  eastern  Pennsylvania, 
described  by  C.  M.  Wheatley,  has  afforded  remains  of  a  large  number  of  species  of 
extinct  Mammals,  the  animals  having  fallen  into  it  as  into  a  trap.  As  identified  by 
Cope,  the  bones  belong  to  thirty-four  species  and  seventy-two  individuals,  and  include 
two  Tapirs  ( T.  Americanus  L.  and  T.  Haysn  L.),  a  Bear  (  Ursus  pristinus  L. ),  a  Felis, 
an  Ox,  a  Horse,  the  American  Mastodon,  several  species  of  Meyalonyx,  one  of  Mylodon 
(M.  Harlani  Owen  (  V)),  several  Rodents  and  a  Bat.  Cope  observes  that  eleven  were 
warm-climate  species,  and  three  North  American  Arctic. 

A  cave  in  Wythe  County,  Va.,  and  another  near  Galena,  111.,  contain  some  extinct 
species,  along  with  others  that  are  living.  (Cope,  Proc.  Am.  Phil.  Soc.,  xi.  171). 

In  a  cave  near  Carlisle,  Pennsylvania,  Baird  found  bones  of  all  the  species  of  Mam- 


568 


CENOZOIC   TIME. 


mals  of  the  State,  besides  one  or  two  other  species  not  now  Pennsylvanian,  but  known 
in  regions  not  far  remote :  as  a  general  rule,  the  bones  of  the  cave  appear  to  indicate 
that  the  size  of  the  species  exceeded  that  at  the  present  time. 

In  North  America,  some  of  the  Mammals  appear  to  belong  to  the  Kecent  or  Terrace 
period.  Among  these,  according  to  Holmes  and  Leidy,  there  were  probably  the  modern 
Horse,  or  one  similar  to  the  common  species,  the  Gray  Rabbit  and  the  Tapir;  and  to 
these  Dr.  Holmes  adds  the  Bison,  Peccary,  Beaver,  Musk-rat,  Elk,  Deer,  Raccoon, 
Opossum,  Hog,  Sheep,  Dog,  and  Ox.  The  species,  fiowever,  have  not  in  all  cases  been 
identified  with  certainty;  and  it  is  not  settled  that  the  commingling  of  bones  is  not  of 
more  modern  origin.  In  western  Canada,  Chapman  has  found  remains  of  the  modern 
Beaver,  Musk-rat,  Elk  (Cervus  elaphus),  and  Moose,  in  stratified  gravel  which  contained 
also  bones  of  the  Mammoth  and  Mastodon. 

The  Quaternary  deposits  have  afforded  Marsh  remains  of  the  Birds,  Meleagris  altus 
Mh.,  and  M.  celer  Mh.  (Turkeys),  from  New  Jersey;  Grus  proavus  Mh.,  ibid.;  and 
Catarractes  affinis  Mh.,  from  Maine. 

Remains  of  the  Reindeer  have  been  found  on  Racket  River  and  at  Sing  Sing,  in 
New  York,  near  Vincenttown,  in  New  Jersey,  and  at  Big-bone  Lick,  in  Kentucky. 

The  animals  of  the  Sloth  tribe  are  South  American  in  type.  They 
are  at  the  present  time  mostly  confined  to  South  America,  as  they 
were  also  in  the  Quaternary. 

The  Cetacean,  or  Whale,  Beluga  Vermontana  Thompson,  whose  re 
mains  were  found  on  the  borders  of  Lake  Champlain,  is  supposed  to 


Fig 


Beluga  Yermontana  (X-|). 

have  been  about  fourteen  feet  in  length.  Fig.  950  represents  the  bones 
of  the  head,  reduced  to  one-sixth  the  natural  size.  The  species  closely 
resembles  the  B.  leucas  Gray,  or  small  northern  White  Whale. 

3.  South  America.  —  In  South  America,  over  one  hundred  species 
of  extinct  Quaternary  quadrupeds  have  been  made  out.  The  bones 
occur  in  great  numbers,  over  the  prairies  or  pampas  of  La  Plata,  and 
in  the  caverns  of  Brazil ;  and  they  include  some  thirty  species  of 
Rodents  (Squirrels,  Beavers,  etc.),  species  of  Horse,  Tapir,  Lama, 
Stag ;  a  Mastodon  different  from  the  North  American ;  Wolves,  and1! 
half  a  dozen  Panther-like  beasts,  which  occupied  the  caverns  of  Brazil ; 
and,  among  Edentates,  Ant-eaters,  twelve  or  fourteen  species  related 


MAMMALIAN    LIFE    OF   THE    QUATERNARY.  569 

in  tribe  to  the  Megatherium  (Sloth  tribe),  and  a  dozen  or  more  related 
to  the  Armadillo.  They  number  more  species  than  now  exist  in  that 
part  of  the  continent,  and  include  far  larger  animals. 

The  Edentates  —  including  the  Sloth,  Armadillo,  and  allied  species 
—  were  the  most  remarkable.  The  animals  of  this  order  are  stupid 
in  aspect,  and  lazy  in  movement  and  attitude. 

Fig.  951. 


Megatherium  Cuvieri 


The  Megatherium  (M.  Cuvieri  .  Desmarest,  Fig.  951)  exceeded  in 
size  the  largest  Rhinoceros.  The  length  of  one  of  the  skeletons  is 
eighteen  feet.  Its  massy  limbs  were  more  like  columns  for  support 
than  like  organs  of  motion.  The  femur  was  three  times  as  thick  as 
an  Elephant's;  the  clumsy  tibia  and  fibula  were  soldered  together  ;  the 
huge  tail  was  like  another  hind  leg,  making  a  tripod  to  support  the 
heavy  carcass  when  the  animal  raised  and  wielded  its  great  arms  ;  and 
the  hands  terminating  the  arms  were  about  a  yard  long,  and  ended 
in  long  claws.  The  teeth  had  a  grinding  surface  of  triangular  ridges, 
well  fitted  for  powerful  mastication. 

A  North  American  Megatherium  (M.  miraUle  L.)  has  been  found 
in  Georgia,  at  Skiddaway  Island,  and  in  South  Carolina. 

Megalonyx  is  another  genus  of  these  large  Sloth-like  animals.  Re 
mains  of  species  occur  over  the  Pampas,  to  the  Straits  of  Magellan  ; 
but  the  first  species  known  was  found  in  Virginia,  in  Greenbrier 
County,  and  was  named  Megalonyx  by  Jefferson,  in  allusion  to  its 
large  claws  (Fig.  952).  Its  bones  have  also  been  found  at  Big-bone 
Lick  and  elsewhere. 

Mylodon  is  a  third  genus;  and  three  species  have  been  described,  —two  from  South 
and  one  from  North  America.  The  skeleton  of  one,  M.  robustus  Owen,  is  eleven  feet 
in  length  ;  and  the  animal  was  therefore  much  larger  than  the  western  Buffalo.  The 


570 


CEXOZOIC   TIME. 


North  American,  M.  IJarlani,  has  been  found  both  east  and  west  of  the  Mississippi, 
and  in  Oregon. 

Fig.  952. 


Claw  of  Megalonyx  JeiTersouii,  nut.  size. 


A  fourth  allied  genus  is  Scelidotherium,  of  which  seven  South  American  species  have 
been  made  out,  — one  as  large  as  the  Meyalonyx. 

Of  the  Armadillo  (or  Dasypus)  group,  the  genus  Glypiodon"  (Fig. 
953)  contained  several  gigantic  species.  These  animals  had  a  shell 
something  like  that  of  a  Turtle.  In  the  G.  clavipes  Owen,  the  length 
of  the  shell,  measuring  along  the  curve,  was  five  feet,  and  the  total 

Fig.  953. 


Glyptodon  clavipes  (X  AO- 

length  of  the  animal,  to  the  extremity  of  the  tail,  nine  feet.  The 
genus  Chlamydotherium  included  other  mail-clad  species,  one  of  which 
was  as  large  as  a  Rhinoceros ;  and  the  genus  Pachytherium,  others, 
of  the  size  of  an  Ox. 

Such  were  the  characteristic  animals  of  Quaternary  South  America. 
The  largest  Edentates  of  the  existing  period  are  but  three  or  four  feet 
in  length.  The  Megatherium  probably  exceeded  more  than  one  hun 
dred  fold  the  bulk  of  any  living  Edentate. 

5.  Australia In  Australia,  the  living  species  are  almost  exclu 
sively  Marsupials.  They  were  Marsupials  also  in  the  Quaternary,  but 


CLIMATE   OF   THE    CHAM  PLAIN   PERIOD.  571 

of  different  species  ;  and,  as  on  the  other  continents,  the  moderns  are 
dwarfs  by  the  side  of  the  ancient  tribes.  The  Quaternary  Diprotodon 
was  as  large  as  a  Hippopotamus,  and  somewhat  similar  in  habits,  the 
.skull  alone  being  a  yard  long  ;  and  the  Nototherium  Mitchelli  Ow., 
an  herbivorous  species,  was  as  large  as  a  bullock. 

The  oldest  Quaternary  remains,  referred  to  the  early  part  of  the  Glacial  Period  by 
Dawkins,  are  those  of  the  Cromer  Forest-bed  (p.  556).  They  include,  besides  the  Cave 
Bear,  Elepkas  primigertius,  the  Irish  Deer,  Troyontlierium  Cvvieri  Fischer;  and  several 
modern  species,  as  the  Beaver,  Wolf,  Fox,  Stag,  Aurochs,  Mole,  Wild  Boar,  Horse;  also 
the  European  Pliocene  speoies,  Ursus  Arvemensis,  Cenus  PoUynacus  Robert,  Hippopota 
mus  major  Cuv.,  Rhinoceros  Etruscus,  R.  megarhinus,  Klephas  meridionalis,  with  E. 
antlquus,  and  without  any  remains  of  Man.  The  Machcerodtu  latidens.  found  in  Kent's 
Hole,  is  a  representative  of  an  eminently  Miocene  and  Pliocene  genus. 

The  characteristic  species  of  the  Champlain  period,  are  Man,  the  Cave  Hyena,  Cave 
Bear,  Cave  Lion,  Brown  and  Grizzly  Bears,  Fox,  Wolf,  Cat,  Elephas  primiyenius  and 
E.  antiquus,  Rhinoceros  tichorhinus  Cuv.,  R.  hemitceclius  Falc.,  R.  megarhintu  Christol, 
Hippopotamus  major  Cuvier,  Wild  Boar,  Aurochs,  Urus,  Stag,  Goat,  Cervus  Browni, 
Musk-ox,  Beaver,  Horse,  etc.,  with  few  remains  of  the  Reindeer.  Those  of  the  Rein 
deer  era  are  the  same  species  nearly,  with  very  abundant  remains  of  the  Reindeer, 
Aurochs,  and  Urus,  and  fewer  of  the  extinct  cave  Carnivores,  with  also  the  Lemming, 
and  some  other  northern  species.  (See  further,  pages  576,  577-) 

6.  Conclusions.  —  (1.)   General  features  of  the  Life  of  the  Early  and 
Middle  Quaternary.  —  Viewing  the  globe  as  a  whole,  in  this  Quater 
nary  era,  we  observe,  — 

1.  The  gigantic  size  as  well  as  large  numbers  of  the  species,  —  the 
Elephants,  Lions,  Bears,  and  Hyenas  of   the  Orient  far  larger  than 
the  modern  kinds ;  so  also  the  Horse,  Elephant.  Mastodon,  Beavers, 
and  Lion  of  North  America ;  the  Megatheria  and  other  Edentates  of 
South  America ;  the  Diprotodon  and  other  Marsupials  of  Australia. 

2.  The  characteristic  species  of  each  continent  were  mainly  of  the 
same  type  that  now  characterizes  it.     Both  in  the  Quaternary  and  at 
the  present  time,  the  Orient  is  strikingly  the  continent  of  Carnivores  ; 
North  America,  of  Herbivores ;  South  America,  of  Edentates ;  Aus 
tralia,  of  Marsupials. 

7.  Evidence,  from   the  Life,  with  regard  to  the   Climate  and  the 
Migrations    of    the    Champlain    Period.  —  The    Quaternary   species 
which  have  been   mentioned,  with  a  very  few  exceptions  noted  below, 
must  have  required  a  climate  ranging  between  warm -temperate  on 
one  side,  and  extreme  cold -temperate  on  the  other  ;  and  this  range 
belonged   to   the  wide  region   from    middle  Europe  and   Britain    to 
northern  Siberia,  where  herds  of  Elephants,  hairy  Rhinoceroses,  and 
other  Mammals  found  abundant  vegetation  for  food,  and  a  good  living- 
place.      If   northern    Siberia    had  then    the  mean    temperature   now 
found  in   southern  Scandinavia,  or  40°  F.,  instead  of  its  present  5°  F. 
to    10°  F.,   central   Europe  would  necessarily  have   been   within  the 
warm -temperate  zone.     The  cause  of  such  a   climate  is  found  in  the 


572  CENOZOIC    TIME. 

extensive  submergence  of  northern  lands,  giving  an  unusual  sweep 
northward  to  the  Gulf  Stream  and  the  corresponding  warm  current 
of  the  Pacific.  Perhaps  in  the  earlier  part  of  the  period,  before  the 
glacier  had  disappeared  from  northern  Europe  and  America,  Arctic 
Asia  was  still  very  cold ;  but,  long  before  its  close,  the  Elephants  had 
taken  full  possession,  as  the  vast  abundance  of  their  remains  attests. 

But,  while  these  and  other  Champlain  species  evidently  culminated 
during  that  period,  it  is  probable  that  they  were  in  existence  south 
of  Glacial  latitudes  before  the  Glacial  period  closed.  For,  if  the 
migrations  of  the  species  from  Europe  to  southern  England  had  not 
taken  place  in  the  Glacial  era,  that  is,  during  the  era  of  continental 
elevation  for  the  higher  latitudes,  the  animals  would  not  have  been 
there  in  Champlain  time,  since,  in  this  period,  —  an  era  of  continental 
depression,  —  Britain  was  for  the  most  part  200  to  1,500  feet  below 
its  present  level ;  and  Europe  also  was  at  less  elevation  than  now,, 
and  hence  the  British  Channel  had  much  greater  width. 

The  rarity  of  remains  of  Quaternary  Mammals  in  Scotland  and 
Ireland,  in  contrast  with  England  and  Wales,  where  they  have  been 
found  in  over  one  hundred  and  fifty  localities,  has  been  attributed  by 
Dawkins  to  the  lingering  of  the  ice  longer  about  the  Scotch  and  Irish 
mountains. 

8.  Evidence,  from  the  Life,  with  regard  to  the  Conditions  of  the 
Reindeer  Era,  or  opening  part  of  the  Recent  Period.  —  The  cold  of 
the  second  Glacial  epoch,  —  the  Reindeer  era  of  Lartet,  —  appears  to 
have  brought  destruction  among  the  northern  tribes  of  Europe  and 
Asia,  and,  at  the  same  time,  to  have  driven  southward  the  more  active 
of  survivors,  or  those  which  had  the  best  chance  for  escape.  The  en 
casing  in  ice  of  huge  Elephants,  and  the  perfect  preservation  of  the 
flesh,  shows  that  the  cold  finally  became  suddenly  extreme,  as  of  a 
single  winter's  night,  and  knew  no  relenting  afterward.  The  existence 
of  remains  of  the  Reindeer  in  southern  France,  in  vast  quantities,  of 
the  Marmot,  also  a  northern  species,  and  of  the  Ibex  and  Chamois, 
now  Alpine  species,  is  attributed  by  Lartet  to  the  forced  migration 
thus  occasioned.  In  the  caves  of  Perigord  (Dordogne,  etc.),  the  bones 
of  the  Reindeer,  far  the  most  abundant  kind,  lie  along  with  those  of 
the  Cave  Hyena,  Cave  Bear,  Cave  Lion,  Elephant,  Rhinoceros,  as  well 
as  Horse  and  Aurochs. 

Lartet  says  that,  in  the  Drift  or  valley  -  gravels,  the  Elephant, 
Rhinoceros,  Horse,  and  Ox  are  the  predominant  species,  and  the 
Reindeer  appears  sparingly;  while,  in  the  Dordogne  Caves,  the  Rein 
deer  predominates,  being  associated  in  large  numbers  with  the  Horse 
and  Aurochs,  and  exceptionally  with  remains  of  the  Elephant,  Hyen$ 
etc.  With  the  Mammals  of  the  Reindeer  era,  in  southern  France, 


MAN. 


573 


there  are  also  great  numbers  of  Grouse  and  the  Snowy  Owl,  species 
which  have  since  returned  to  northern  Europe. 

The  elevation  of  the  land  during  the  second  Glacial  epoch,  or  Rein 
deer  era,  probably  made  again  a  dry  land  connection  between  Britain 
and  the  continent,  permitting  of  migration  of  the  later  species.  The 
Reindeer  was  living  in  Scotland,  until  near  the  end  of  the  twelfth 
century. 

The  absence  of  remains  of  the  Reindeer  and  other  Subarctic  species 
from  Spain  and  Italy,  and  the  southern  character  of  the  Champlain 
fauna,  are  evidence  that  the  cold  of  the  second  Glacial  period  did  not 
extend  beyond  the  Alps  and  Pyrenees,  over  southern  Europe.1  At 
the  same  time,  the  presence  of  abundant  remains  of  the  Reindeer  in 
Belgian  deposits  of  this  era,  without  bones  of  the  extinct  Mammals 
may  be  evidence  that  the  cold  of  Belgium  was  severe  enough  to  have 
driven  off  the  old  warm-climate  quadrupeds.  An  isothermal  chart 
shows  that  England  would  have  had  a  warmer  climate  than  Belgium. 

II.  MAN. 

1.  Ancient  Human  relics.  —  The  relics  of  Man,  through  which  his 
geological  history  has  been  deciphered,  are  :  (1)  buried  human  bones  ; 
(2)  stone  arrow-heads,  lance-heads,  hatchets,  pestles,  etc. ;  (3)  flint 
chips,  made  in  the  shaping  of  stone  implements ;  (4)  arrow-heads  or 
harpoon-heads,  and  other  implements,  made  of  horns  and  bones  of 

Fig.  954. 


Elepho.fi  primigenius  ;  engraved  on  ivory  (X-i-)- 

the  Reindeer  and  other  species ;  (5)  bored  or  notched  bones,  teeth, 
or  shells  ;  (6)  cut  or  carved  wood  ;  (7)  bone,  horn,  ivory,  or  stone, 
graven  with  figures  of  existing  animals,  or  cut  into  their  shapes,  — 
one  example  of  which,  found  by  Lartet,  in  the  bone  cave  of  La 

1  On  the  Quaternary  Fauna  of  Britain  and  Europe,  see  papers  by  W.  Boyd  Dawkins, 
in  Quart.  Journ.  Geol.  Soc.,  xxv.  192,  1869;  xxviii.  410,  1872. 


574  CENOZOIC    TIME. 

Maclelaine,   Perigord,   and    representing   the  old  Hairy  Elephant,  is 
here  given  ;   (8)  marrow-bones  broken  longitudinally,  in  order  to  get 
out  the  marrow  for  food;  (9)  fragments  of  charcoal,  and  other  marks 
of  fire  for  warming  or  cooking  ;   (10)  fragments  of  pottery.      Relics  of - 
the  above  kinds  occur  in  the  deposits  of  the  "  Stone  Age." 

In  later  deposits,  occur  bronze  implements,  without  iron  —  marking 
a  "  Bronze  Age  ;  "  and,  still  later,  iron  implements,  or  those  of  the 
"  Iron  Age ; "  and  here  occur,  as  fossils,  coins,  inscribed  tablets  of 
stone,  buried  cities,  such  as  Nineveh  and  Pompeii,  etc. 

The  "  Stone  Age,"  here  referred  to,  is  properly  the  Stone  Age  of 
European  or  Oriental  history.  The  Stone  Age,  in  North  America,  or 
a  large  part  of  it,  continued  in  full  force  till  within  two  centuries  since. 

The  age  has  been  divided  by  Lartet  into  — 

1.  The  PALEOLITHIC   era ;  the  Mammoth  period  of  Dupont ;  the 
Champlain  period. 

2.  The  REINDEER  era,  or  second  Glacial  epoch ;  or  commencement 
of  the  Recent  period. 

3.  The  NEOLITHIC  era ;  a  section  of  the  Recent  period,  following 
the  Reindeer  era,  and  commencing  the  MODERN  era. 

The  terms  Paleolithic  and  Neolithic  were  proposed  by  Lubbock,  who 
recognizes  in  his  work  only  these  two  divisions  in  the  "  age  of  stone." 
The  principal  facts  with  regard  to  human  relics  are  these :  — 

1.  Stone  implements  occur  intimately  associated  with  the  remains 
of  the  Cave  Bear,  Cave  Hyena,  Cave  Lion,  the  old  Elephant  and  Rhi 
noceros  and   other  extinct   species,  with  some  remains  of   the  Rein 
deer  and   other  living  Mammals,  in  deposits  of  the  later  if  not  the 
earlier  part  of  the  Champlain  period,  — the  Paleolithic  era, —  proving 
the  existence  of  Man  at  that  time. 

2.  Similar  implements,  along  with  others  of   horn    and  bone,  and 
drawings  of  animals,  and  other  markings,  occur  in  Southern  France, 
as  well  as  more  to  the  north,  in  caves  and  river-border  deposits,  along 
with  great  numbers  of  bones  of  the  Reindeer,  and  a  number  of  other 
northern  species,  now  existing,  and  also  with   the  remains  of  the  ex 
tinct  Urus,  Elephant,  Cave  Bear,  Cave  Hyena,  Cave  Lion,  etc.,  and  also 
the  now  living  Aurochs,  Ibex,  Elk,  etc.,  the  deposits  being  those  of  the 
Reindeer  era,  and  the  Reindeer  a  colonist  there  from  the  north,  during 
this  second  Glacial   era.     And,  with   these   relics,  human   bones  and 
even  complete  skeletons  have  been  found  :   the  marrow  bones  of  the 
Reindeer  and  Aurochs  so  split  as  to  show  that  they  were  broken  by 
Man  for  the  marrow ;  and  charcoal  and  other  relics  of  fires,  probably 
used  both  for  cooking  and  for  warmth  ;  for  the  weather  must  have  been 
sometimes,  if  not  generally,  cold. 

3.  The  skeletons,  supposed  to  be  Paleolithic,  of  Southern  Europe, 


MAN.  575 

are  in  part  those  of  tall  men.  One  of  them,  that  of  the  cave  of  Men- 
tone  in  the  Mediterranean  (just  east  of  Nice,)  according  to  its 
describer,  Mr.  Riviere,  was  that  of  a  man  six  feet  high,  with  a  rather 
long  but  large  head,  high  and  well  made  forehead,  and  very  large  facial 
angle  —  85°.  The  frontispiece,  from  a  photograph  published  by 
Riviere,  represents  the  skeleton  as  it  lay,  partly  uncovered  from  the 
stalagmite,  with  Mediterranean  shells  and  flint  implements  and  chip- 
pings  lying  around,  and  a  chaplet  of  stag's  canines  across  his  skull.  It 
has  been  regarded  as  one  of  the  oldest  human  skeletons  yet  found.  A 
similar  skeleton  was  obtained  from  the  cave  of  Cro-Magnon,  in  Peri- 
gord,  France,  whose  height  was  five  feet  eleven  inches,  and  another 
at  Grenelle,  about  five  feet  ten  inches.  These  are  referred  to  the 
Reindeer  era ;  and  the  Mentone  skeleton  may  be  of  the  same,  instead 
of  Paleolithic. 

The  human  remains  of  caverns  on  the  Lesse  valley,  in  the  vicinity 
of  Liege,  Belgium,  first  discovered  by  Schmerling  in  1833-1834,  are  re 
garded  as  unquestionably  Paleolithic.  They  belonged  to  less  tall  men  ; 
the  cranium  was  high  and  short,  and  of  good  Caucasian  type,  though  of 
medium  capacity  ;  "  a  fair  average  human  skull,"  observes  Huxley.  But 
one  Belgian  jaw-bone  from  the  cave  of  the  Naulette,  recently  found  by 
Dupont,  has  several  marks  of  inferiority,  for  example,  remarkable 
thickness  and  small  height ;  the  molar  teeth  increasing  in  size  back 
ward,  the  posterior  or  "  wisdom-tooth "  being  the  largest  (besides 
having  five  roots),  while  the  reverse  is  the  case  in  civilized  man  ; 
the  prominence  of  the  chin  wanting.  Fragments  of  crania  and  of 
some  other  bones  were  found  with  the  jaw-bone. 

A  skeleton  of  low  grade  was  found  in  1857  in  the  small  Neander 
thal  Cave,  near  Dlisseldorf,  where  Lyell  thinks  it  may  have  been 
washed  in.  The  mud  in  which  it  lay  contained  no  Quaternary  re 
mains  as  evidence  of  its  antiquity.  Lyell  states  that  the  tusk  of  a 
Bear,  whether  ancient  or  not  is  unknown,  was  found  in  the  mud  of  a 
branch  of  the  cave,  on  the  same  level  with  the  skeleton,  and  that,  at 
the  bottom  of  the  Icess  of  the  region,  Huxley  found  bones  of  the 
extinct  Rhinoceros.  Both  Huxley  and  Lyell  "  think  it  probable  "  that 
it  is  of  the  same  age  with  the  remains  of  the  Liege  caverns  found  by 
Schmerling  ;  and  Lyell  says  that  "  its  position  lends  no  countenance 
whatever  to  the  supposition  of  its  being  more  ancient."  The  forehead 
is  low,  and  the  head  long  ;  the  brow-ridges  very  prominent,  a  little 
ape-like  ;  but  the  cranial  capacity  was  about  seventy-five  cubic  inches, 
or  "  nearly  on  a  level  with  the  mean  between  the  two  human  ex 
tremes  "  and  "  in  no  sense  "  adds  Huxley  u  can  the  Neanderthal  bones 
be  regarded  as  the  remains  of  a  human  being  intermediate  between 
Man  and  the  Apes."  The  bones  of  the  arm  and  thigh  have  the 
ordinary  proportions  in  Man,  though  very  stout. 


576  CENOZOIC   TIME. 

The  human  crania  of  the  caves  of  Furfooz  in  Belgium,  of  the  Rein 
deer  era,  are  described  as  intermediate  between  the  broad  and  long 
types,  and  as  "  Mongoloid,"  approaching  those  of  the  Finns  and  Lap 
landers.  The  height  of  the  men  was  not  over  four  and  a  half  feet, 
and  thus  they  were  like  existing  Man  of  Northern  Europe ;  and  it 
would  seem  as  if  Laplanders  had  been  driven  south  by  the  cold,  as 
well  as  Reindeers.  The  habits  of  the  people,  according  to  Dupont, 
were  like  those  of  the  Esquimaux. 

4.  In   Denmark  and  elsewhere  occur   polished  stone  implements, 
with  broken  pottery,  with  no  remains  of  either  the  extinct  Quaternary 
Mammals  or  the  Reindeer,  but  with  bones  of  existing  quadrupeds,  arid 
among  them  those  of  the  domesticated  Dog.     These  belong  to  the 
Neolithic  era.     The  Neolithic  human  remains  of  Denmark  indicate  the 
same  small,  round-headed  race,  Laplander-like,  that  were  found  in  the 
Reindeer  caves  of  Belgium. 

5.  In  the  same  era,  or  perhaps  a  little  later,  in  the  Neolithic  era, 
existed  the  oldest  of  the  lake-dwellings  of  Switzerland  (dwellings  in 
lakes,  on  piles,  such  as  Herodotus  described  over  two  thousand  years 
since).     They  have  afforded  stone-implements  and  pottery,  with  re 
mains  of  Goats,  Sheep,  the  Ox,  as  well  as  the  Dog,  but  not  the  Rein 
deer  or  any  extinct  species  ;  also,  of  Wheat  and  Barley  ;  also  a  human 
skull,  neither  very  long  nor  very  short,  but,  according   to  Rutimeyer, 
much  like   those-  of  the   modern   Swiss.     These  Neolithic  structures 
occur  mainly  about   the  eastern  lakes,  Constance  and  Zurich,   while 
those  of  the  "  Bronze  Age  "  are  found  in  the  western  lakes. 

Lake-dwellings  or  "  stockaded  islands,"  called  Crannoges,  have  been 
found  in  peat-bogs  in  the  British  Isles,  and  especially  in  Ireland. 
They  belong  to  the  bronze  and  stone  ages,  affording  remains  of  various 
living  species  of  quadrupeds,  with  stone  implements  in  some  of  them. 

1.  Paleolithic.  —  The  river-border  deposits  of  Amiens  and  Abbeville,  in  the  valley  of 
the  Somme  (about  seventy-five  miles  north  of  Paris),  are  here  referred  by  Lartet.  They 
contain,  in  the  lower  parts  of  the  deposits,  flint  implements,  along  with  the  bones  of 
the  old  Elephant,  Rhinoceros,  Hippopotamus,  Ilyen't,  Horse,  and  other  species. 

Various  deposits  in  caverns  and  elsewhere,  in  Great  Britain,  may  be  as  old  —  as  those 
of  Bedford,  and  at  Hoxne  in  Suffolk.  Wookey  Hole  near  Wells,  the  Gower  Caves  in  South 
Wales,  etc.,  where  the  occurrence  of  flint  implements  proves  Man  to  have  been  a  co- 
temporary  of  the  Hyena  that  inhabited  the  caves.  In  Kent's  Hole,  near  Torquay,  which 
may  be  of  later  occupation,  the  flint  arrowheads,  knives,  and  flakes  were  found  at  the  • 
bottom  of  the  cave-deposit,  as  well  as  above,  so  that  there  was  no  ground  for  making 
Man  a  successor  in  occupancy  to  the  Bear,  Cave  Lion,  and  other  wild  beasts  of  the 
country.  Among  the  bones  occurred  remains  of  the  Lion,  Machterodus  latidens. 

In  a  cave  near  Settle,  Yorkshire,  a  human  fibula,  much  like  that  of  the  skeleton  of 
Mentone,  has  been  found,  along  with  remains  of  the  extinct  Elephant,  Bear,  Hyena, 
Rhinoceros,  and  also  the  Bison  and  Elk ;  and  at  the  mouth  of  the  cave  there  is  a  bed 
of  stiff  glacial  clay,  with  scratched  bowlders. 

The  evidence  appears  to  place  Man  in  Britain  and  Europe  at  least  as  early  as  the 
Alluvian  part  of  the  warm  Champlain  era,  and  probably  earlier.  The  jawbone  of  the 


MAN.  577 

Naulette  cave  in  Belgium,  described  above,  pronounced  incontestably  Paleolithic,  oc 
curred  with  remains  of  the  Elephant,  Khinoceros,  Horse,  Wild  Boar,  Chamois,  Goat, 
Reindeer,  Stag,  Marmot,  Squirrel,  Hare,  Water-rat,  Wolf,  Brown  Bear,  and  others, 
and  with  those  of  the  Cave  Hyena,  the  cave  having  been  a  Hyena  cavern,  and  many 
of  the  other  animals  its  prey,  or  that  of  Man. 

2.  The  Reindeer  Era.  —  The  extinct  and  other  Mammals  of  southern  France  are  men 
tioned  on  page  572.     With  the  exception  of  the  skeleton  of  Mentone,  they  have  been 
referred  to  the  Reindeer  era.     With  them  occur  stone  implements,  like  those  of  Amiens, 
only  somewhat  better  fashioned.     Among  the  drawings  on  bones,  of  different  animals, 
are  those  of  Horses  and  one  of  the  Hairy  Elephant  (p.  573).  proving  that  these  species 
were  coteinporaries  of  the   draftsman.     In   one  of  the  Gower  caves  in  South  Wale*, 
called  Bosco's  Den,  no  less  than  one  thousand  antlers  of  the  Reindeer  were  taken  out, 
mostly  shed  horns;  and  Lyell  says  they  had  probably  been  washed  into  the  cavity. 

In  the  cave  of  Cro-Magnon,  near  Les  Eyzies,  bones  were  obtained  belonging  to  three 
of  the  Perigord  human  cave-dwellers.  They  were  of  the  tall  race  mentioned  above ; 
the  cranium  of  one  gave  for  its  capacity  97  cubic  inches,  far  above  that  of  average 
Man.  Neither  the  jaws  nor  the  cheek  bones  were  projecting:  the  tibia  was  much  flat 
tened  (platycnemic). 

The  skeleton  found  in  1872,  in  the  cave  near  Mentone,  was  associated  with  remains 
of  the  same  extinct  Mammals,  the  old  Cave  Lion,  Cave  Bear,  Care  Hyena,  a  Khi 
noceros,  besides  the  Wolf,  Hedyehog,  Aurochs,  Elk,  Stay,  Deer,  etc. ;  but  there  were  no 
Reindeer,  showing  that  the  remains  were  either  Paleolithic,  as  held  by  Lyell,  or  else 
they  were  of  the  Reindeer  era,  and  the  place  too  warm  for  this  northern  species.  The 
height  of  this  extraordinarily  tall  man  is  mentioned  above.  The  length  of  the  radius 
(principal  bone  of  the  forearm),  compared  with  the  humerus  as  100,  was  76'9,  that  of 
the  negro  being  79 -4,  and  that  of  the  typical  European  73-6.  All  the  above  species 
were  found  in  the  bed  of  stalagmite,  six  inches  thick,  above  and  below  the  skeleton. 
The  shells  buried  in  the  same  stalagmite  are  Ctirdium  tuberculatum  Linn.,  Pecten  Jaco- 
bceus  Lam.,  Pecten  maximus  Lam.,  Pectunculus  ylycimeris,  Mytilus  edidis  Linn.,  all 
Mediterranean  species;  and  some  of  them  had  been  perforated  by  Man.  Thus  the 
ancient  skeleton  has  around  it  the  implements,  weapons,  and  ornaments  of  the  man 
who  was  once  its  owner.  Eight  feet  above  the  skeleton,  the  stalagmite  afforded  remains 
of  the  Rhinoceros  tichorimis,  and  all  of  the  species  above  enumerated,  excepting  the 
\Yolf,  Fox,  Weasel,  Wild  Boar,  etc.,  and  some  other  existing  kinds. 

Another  specimen,  found  in  the  Drift  at  Clichy,  was  similar  to  the  above  in  many 
points,  even  to  the  peculiar  platycnemic  tibia;  and  the  latter  feature  belongs  also  to  a 
Gibraltar  specimen. 

The  earliest  observations  in  Southern  France  were  made  in  1828  and  1829  by  Tournal 
and  Christol  (Lyell).  In  the  department  of  Aude,  Southern  France,  in  1828,  Tournal 
found,  in  the  Bize  Cavern,  human  bones,  associated  with  remains  of  species  of  quadru 
peds,  including  the  Reindeer  and  Aurochs;  and  Christol,  at  (he  same  time,  observed 
similar  facts  in  a  cave  near  Nismes,  bones  of  the  Hyena  and  Rhinoceros  being  present, 
and  also  fragments  of  rude  pottery. 

3.  Neolithic  Era,  or  Early  part  of  the  Recent  Period.  —  The  shell-heaps  (Kjiikken- 
modding  or  Kitchenmiddens)  of  the  Danish  Isles  in  the  Baltic,  some  of  which  are  ten 
feet  high,  one  thousand  feet  long,  and  two  hundred  feet  wide,  are  prominent  among  the 
localities  of  Neolithic  man.     Other  remains  of  the  era  occur  in  the  lower  part  of  the 
Danish  peat.     Log  canoes,  found  in  the  peat  of  the  region,  are  supposed  to  have  been 
used  by  the  men  the  refuse  of  whose  sea-food  makes  the  shell  heaps.     (These  heaps  are 
much  like  those  made  by  American  Indians  near  sea-shores.)     The  shells  of  the  shell 
heaps  are  mostly  larger  than  those  of  the  same  species  now  on  the  Danish  shores. 

The  lake-dwellings  of  Europe  are  alluded  to  above.  The  facts  belong  rather  to 
archaeology  than  to  geology ;  and  reference  may  be  had  to  other  works  for  an  account  of 
them. 

4.  Remains  in  America. — In  North  America,  the  facts  brought  to  light  are  for  the 
most  part  less  well  attested,  and  more  scanty.    A  fragment  of  a  human  cranium  was 
reported  in  1857,  by  C.  F.  Winslow,  as  having  been  taken  from  the  auriferous  gravel 

37 


578  CEXOZOIC   TIME. 

of  Table  Mountain,  in  California,  where  this  gravel  underlies  an  extensive  bed  of  lava 
(the  lava  being  the  table-like  top  of  the  mountain.)  According  to  the  statement  of  Col. 
Hubbs  to  Mr.  Winslow,  the  fragment  was  brought  up  from  the  auriferous  Drift  under 
the  lava,  a  shaft  having  been  sunk  into  it.  Bones  of  the  Mastodon  and  Elephant  were 
obtained  from  the  upper  Drift  of  the  same  vicinity. 

Prof.  J.  D.  Whitney  has  described  a  skull  from  a  similar  position,  two  miles  from 
Angelos,  in  Calaveras  County,  but  states  that  the  authenticity  is  not  established  by  the 
positive  knowledge  of  any  scientific  observer,  while  others  have  published  strong  rea 
sons  for  doubt.  The  skull,  according  to  Prof.  Jeffries  Wyman,  resembles  much  that 
of  a  modern  Indian.  If  substantiated  by  further  discovery,  the  facts  would  prove  the 
existence  of  man  there,  after  the  Glacial  period,  but  whether  in  the  earlier  or  the  later 
Champlain  period,  is  not  clear.  The  period  of  eruption  of  the  lava  is  not  ascertained; 
and  the  thickness  is  no  evidence  that  a  long  time  was  taken  for  ejecting  it. 

Flint  arrow-heads  were  reported  by  Dr.  Koch  as  found  by  him  with  charcoal  and 
bones  of  the  Mastodon,  in  the  Osage  Valley  of  Missouri;  and  also  in  the  bottom  of  the 
Pomme-de-Terre  River,  about  ten  miles  above  its  junction  with  the  Osage;  and  charred 
bones  of  the  Mastodon  in  Gasconade  County,  Mo. 

Dr.  Jeffries  Wyman  has  described  a  skull,  from  a  mound  in  Michigan,  the  cranial 
capacity  of  which  was  only  fifty-six  cubic  inches,  and  in  which  the  low  ridges  marking 
the  upper  terminations  of  the  temporal  muscles  were  but  half  an  inch  apart  at  the 
top  of  the  skull,  while  they  are  three  and  a  half  to  four  inches  apart  in  ordinary  men, 
and  meet  in  the  Quadruinana.  But  he  adds  that  two  other  Indian  skulls  from  the  same 
mound  had  no  such  peculiarities,  and  that  this  case  must  therefore  be  considered  ex 
ceptional.  The  oldest  skulls  found  in  other  mounds  confirm  this  opinion.  Dr.  Wyman 
states  (iu  a  letter  to  the  author,  of  November,  1873),  respecting  the  remains  from  con 
solidated  shell-heaps  in  Florida,  that  they  presented  no  marked  deviation  from  the  char 
acteristics  of  the  ordinary  Indian;  that  the  tibia?  were  flattened  (platycnemic),  but  that 
this  was  a  common  fact  among  the  American  Indians,  as  well  as  in  the  prehistoric 
remains  of  Europe. 

In  Brazil,  human  remains  were  found  many  years  since,  by  Lund,  in  caverns,  along 
with  extinct  Quaternary  Mammals ;  and  Clausen  has  reported  the  occurrence  of  pottery 
in  a  bed  of  stalagmite  containing  these  Mammals. 

2.  Man  at  the  head  of  the  System  of  Life.  —  In  the  appearance  of 
Man,  the  system  of  life,  in  progress  through  the  ages,  reached  its 
completion,  and  the  animal  structure  its  highest  perfection.  Another 
higher  species  is  not  within  the  range  of  our  conceptions.  For  the 
Vertebrate  type,  which  began  during  the  Paleozoic  in  the  prone  or 
horizontal  Fish,  became  erect  in  Man,  and  thus  completed,  as  Agassiz 
has  observed,  the  possible  changes  in  the  series,  to  its  last  term.  An 
erect  body  and  an  erect  forehead  admit  of  no  step  beyond. 

But,  besides  this,  Man's  whole  structure  declares  his  intellectual 
and  spiritual  nature.  His  fore-limbs  are  not  organs  of  locomotion, 
as  they  are  in  all  other  Mammals ;  they  have  passed  from  the  loco 
motive  to  the  cephalic  series,  being  made  to  subserve  the  purposes  of 
the  head  ;  and  this  transfer  is  in  accordance  with  a  grand  law  in 
nature,  which  is  at  the  basis  of  grade  and  development.  The  cephal- 
ization  of  the  animal  has  been  the  goal  in  all  progress  ;  and  in  Man 
we  mark  its  highest  possible  triumph. 

Man  was  the  first  being  that  was  not  finished  on  reaching  adult 
growth,  but  was  provided  with  powers  for  indefinite  expansion,  a  will 


MODERN  ERA.  579 

for  a  life  of  work,  and  boundless  aspirations  to  lead  to  endless  im 
provement.  He  was  the  first  being  capable  of  an  intelligent  survey 
of  nature,  and  comprehension  of  her  laws;  the  first  capable  of  aug 
menting  his  strength  by  bending  nature  to  his  service,  rendering 
thereby  a  weak  body  stronger  than  all  possible  animal  force  ;  the  first 
capable  of  deriving  happiness  from  truth  and  goodness  ;  of  appre 
hending  eternal  right ;  of  reaching  toward  a  knowledge  of  self  and 
of  God ;  the  first,  therefore,  capable  of  conscious  obedience  or  dis 
obedience  of  a  moral  law,  and  the  first  subject  to  debasement  through 
his  appetites  and  a  moral  nature. 

There  is,  hence,  in  Man,  a  spiritual  element,  in  which  the  brute  has 
no  share.  His  power  of  indefinite  progress,  his  thoughts  and  desires 
that  look  onward  even  beyond  time,  his  recognition  of  spiritual  exist 
ence  and  of  a  Divinity  above,  all  evince  a  nature  that  partakes  of  the 
infinite  and  divine.  Man  is  linked  to  the  past  through  the  system  of 
life,  of  which  he  is  the  last,  the  completing,  creation.  But,  unlike 
other  species  of  that  closing  system  of  the  past  (significantly  the  Zoic 
era  of  geological  history),  he,  through  his  spiritual  nature,  is  far  more 
intimately  connected  with  the  opening  future. 

5.  MODERN  ERA. 

1.  Modern  relics  of  Man.  —  "While  the  animal  system  is  not  now 
working  onward  to  a  loftier  limit,  except  so  far  as  there  is  improve 
ment  in   the  culminant  species,  Man,  all   other  geological  work  goes 
on  as  in  past  times.     Seas,  rivers,  winds,   and  the  other  agencies  of 
change  are  at  their  old  labors. 

The  following  figures  exemplify  to  the  eye  some  of  the  relics  of  the 
times,  by  way  of  contrast  with  those  of  the  beginning  of  geological 
progress.  Fig.  955  represents  a  human  skeleton,  from  a  shell  lime 
stone  of  modern  origin  and  now  in  progress,  on  the  island  of  Guada- 
loupe.  The  specimen  is  in  the  Museum  at  Paris.  The  British 
Museum  contains  another  from  the  same  region,  but  wanting  the  head, 
which  is  in  the  collection  of  the  Medical  College  at  Charleston  in 
South  Carolina.  They  are  the  remains  of  Caribs,  who  were  killed  in 
a  fight  with  a  neighboring  tribe,  about  two  centuries  since.  Fig.  956 
represents  another  fossil  specimen,  of  the  age  of  Man,  —  a  ferruginous 
conglomerate,  containing  silver  coins  of  the  reign  of  Edward  I.  and 
some  others,  found  at  Tutbury,  England.  It  was  obtained  at  a  depth 
of  ten  feet  below  the  bed  of  the  river  Dove. 

2.  Extinction  of  species  in  Modern  times.  —  Species  are  becoming 
extinct,  as  heretofore,  but  partly  through  the  new  agency,  the  pressure 
of  civilization. 

Among  the   species  recently  exterminated,  there  are   the  Moo,  (Di- 


580 


CENOZOIC   TIME. 


nornis)  and  other  birds  of  New  Zealand,  the  Dodo  and  some  of  its 
associates  on  Mauritius  and  the  adjoining  islands  in  the  Indian  Ocean ; 
Fig.  955.  Fig.  956. 


Human  skeleton,  from  Guadaloupe.  Conglomerate,  containing  coins. 

the  ^Epyornis  of  Madagascar.  The  species  are  of  the  half-fledged  kind, 
like  the  Ostrich.  Fig.  957  (copied  from  Strickland's  "  Dodo  and  its 
Kindred  ")  is  from  a  painting  at  Vienna,  made  by  Roland  Savery  in 
1G28. 

The  Dodo  was  a  large,  clumsy  bird,  some  fifty  pounds  in  weight,  with  loose,  downy 
plumage,  and  wings  no  more  perfect  than  those  of  a  young  chicken.  The  Dutch  navi 
gators  found  it  in  great  numbers,  in  the  seventeenth  century.  But,  after  the  possession 
of  the  island  by  the  French,  in  1712,  nothing  more  is  heard  of  the  Dodo ;  a  head,  two 
feet  and  a  cranium  are  all  that  is  left,  except  some  pictures  in  the  works  of  the  Dutch 
voyagers. 

The  Solitaire  is  another  exterminated  bird,  of  the  same  island. 

The  Moa  (Dinornis  (jiyanteus  Owen),  of  New  Zealand,  exceeded  the  Ostrich  in  size, 
being  ten  to  twelve  feet  in  height.  The  tibia  (drumstick)  of  the  bird  was  thirty  to 
thirty-two  inches  in  length;  and  the  eggs  so  large  that  "  a  hat  would  make  a  good  egg- 
cup  for  them."  The  bones  were  found  along  with  charred  wood,  showing  that  the 
birds  had  been  killed  and  eaten  by  the  natives.  The  name  Dinornis  is  from  <5=u<os,  ter- 
rible,  and  6pvt?,  bird. 

Besides  the  Dinornis  giyanteus,  remains  of  other  extinct  species  of  the  genus  have 
been  found ;  also  extinct  species  of  Palapteryx  and  Notornis.  Palapferyx  is  related  to 
Apteryx  ;  and  both  Apteryx  and  Notornis  have  living  species. 

On  Madagascar,  other  species  of  this  family  of  gigantic  birds  formerly  existed. 
Three  species  have  been  made  out  of  the  genus  ^Epyornis.  From  the  bones  of  the  leg, 
one  is  supposed  to  have  been  at  least  twelve  feet  in  height.  The  egg  was  thirteen  and 
a  half  inches  in  its  longest  diameter. 

The  Great  Auk  of  the  North  Sea  (Alca  impennis  Linn.)  is  reported  to  be  an  extinct 
bird,  bv  Professor  Steenstrup.  The  last  known  to  have  been  seen  were  two  taken 
near  Iceland,  in  1844.  The  bones  occur  in  great  numbers,  on  the  shores  of  Iceland, 
Greenland  and  Denmark,  showing  that  it  was  once  a  common  bird;  and  its  remains 
have  been  found  also  on  the  coasts  of  Labrador,  Maine,  and  eastern  Massachusetts.  They 


MODERN   ERA. 


581 


occur  in  the  shell-heaps  of  Maine,  Wyman  having  found  seven  specimens  of  the  hu- 
merus,  besides  other  bones.  With  these  are  bones  of  other  species,  but  of  none  that  are 
extinct,  and  also  fragments  of  rude  pottery,  and  some  bone-implements. 

A  species  of  Manatee,  Rytina  Stelleri  Cuv.,  known  in  the  last  century  on  the  Arctic 
shores  of  Siberia,  is  supposed  to  be  now  extinct. 

Fig.  957. 


Dodo,  with  the  Solitaire  in  the  background. 

The  Aurochs  (Bison  priscus)  of  Europe,  one  of  the  cotemporaries  of  the  old  Elephant 
(E.primif/enius},  would  have  long  since  been  exterminated  from  Europe,  but  for  the 
protection  of  Man.  Though  once  abundant,  it  is  now  confined  on  that  continent  to  the 
imperial  forests  of  Lithuania,  belonging  to  the  Russian  Czar,  it  is  said  to  exist  also  in 


582  CENOZOIC   TIME. 

the  Caucasus.  The  now  extinct  Bos  primiyenius  is  supposed  to  be  the  same  with  the 
Urus  (Ure-Ox,  or  Bos  Ui-us,  described  by  Caesar  in  his  Commentaries,  and  stated  to 
abound  in  the  Gallic  forests,)  and  is  a  distinct  species  from  the  Aurochs,  with  which  it 
has  been  confounded.  It  is  said  to  have  continued  in  Switzerland  into  the  sixteenth 
century. 

The  American  Buffalo  (Bos  Americnnus  Gm.)  formerly  covered  the  eastern  part  of 
the  continent,  to  the  Atlantic,  and  extended  south  into  Florida,  Texas,  and  Mexico;  but 
now  it  is  never  seen  east  of  the  Missouri,  excepting  its  northern  portion;  and  its  main 
range  is  between  the  Upper  Missouri  and  the  Rocky  Mountains,  and  from  northern 
Texas  and  New  Mexico  to  Great  Martin  Lake  in  latitude  64°  X.  (Baird.) 

The  spread  of  the  farms  and  settlements  of  civilization  is  gradually  limiting,  all  over 
the  globe,  the  range  of  the  wild  animals,  especially  those  of  large  size,  and  must  end  in 
the  extermination  of  many  now  existing. 

Dr.  Asa  Gray  says  that  the  giant  Sequoia  or  Redwood  of  California  is  sure  to  become 
extinct  as  a  native  plant,  and  adds:  "Few  and  evil  are  the  days  of  all  the  forest  likely 
to  be,  while  Man,  both  barbarian  and  civilized,  torments  them  with  fires,  fatal  at  once 
to  seedlings,  and  at  length  to  the  aged  also." 

3.  Changes  of  level  in  the  Earth's  surface.  —  Although  the  earth 
has  now  reached  a  state  of  comparative  stability,  changes  of  level  in 
the  land  are  still  taking  place.  The  movements  are  of  two  kinds  :  — 

1.  Secular,  or  movements  progressing  slowly  by  the  century. 

2.  Paroxysmal,  —  taking  place  suddenly,  in  connection  usually  with 
earthquakes. 

1.  Secular. — The  secular  movements  which  have  been  observed 
are  confined  to  the  middle  and  higher  temperate  latitudes,  and  are 
evidently  a  continuation  of  the  series  which  characterized  the  earlier 
part  of  the  Quaternary  age. 

The  coasts  of  Sweden  and  Finland,  on  the  Baltic,  have  been  proved, 
by  marks  made  under  the  direction  of  the  Swedish  government,  to  be 
slowly  rising.  The  change  is  slight  at  Stockholm,  but  increases 
northward,  and  is  felt  even  at  the  North  Cape,  —  an  extent,  north  and 
south,  of  one  thousand  miles.  Lyell,  in  1834,  estimated  the  rise,  at 
Uddevalla,  at  nearly  or  quite  four  feet  in  a  century,  and  made  it  still 
greater  to  the  north.  The  fact  of  the  slow  elevation  was  first  sus 
pected  a  century  and  a  half  since.  Here,  then,  is  slow  movement  by 
the  century,  such  as  characterized  the  great  changes  of  level  in  past 


Beds  of  recent  shells  are  found  along  the  coast  at  many  places, 
at  heights  from  100  to  700  feet.  Part  of  these  are  of  Quaternary 
date.  Two  miles  north  of  Uddevalla,  Lyell  found  barnacles  on  the 
rocks,  over  100  feet  above  the  sea  ;  and  there  are  shell-beds  at  a  height 
of  400  feet.  The  former,  at  least,  belong  probably  to  the  present  era. 
Southwest  of  Stockholm,  other  beds  of  shells  occur,  and  of  the  same 
dwarfish  species  that  now  live  in  the  partly-freshened  waters  of  the 
Bothnian  Gulf. 

There  are  also,  near   Stockholm,  proofs    of  a  former  subsidence, 


MODERN   ERA.  583 

since  fishing-huts  were  built  on  the  coast.  A  fishing-hut,  having  a 
rude  fireplace  within,  was  struck,  in  digging  a  canal,  at  a  depth  of 
sixty  feet.  It  is  a  common  belief  that  over  southern  Sweden  a  very 
slow  subsidence  is  now  in  progress. 

In  Greenland,  a  slow  subsidence  is  taking  place.  For  six  hundred 
miles  from  Disco  Bay,  near  69°  N.,  to  the  Firth  of  Igaliko,  60°  43', 
the  coast  has  been  sinking  for  four  centuries  past.  Old  buildings  and 
islands  have  been  submerged  ;  and  the  Moravian  settlers  have  had  to 
put  down  new  poles  for  their  boats,  the  old  ones  standing,  Lyell 
observes,  "  as  silent  witnesses  of  the  change." 

On  the  North  American  coast,  south  of  Greenland,  along  the  coasts 
from  Labrador  to  New  Jersey,  it  is  supposed  that  similar  changes  are 
going  on.  G.  H.  Cook  concludes,  from  his  observations,  that  a  slow 
subsidence  is  in  progress  along  the  coasts  of  New  Jersey,  Long  Island, 
and  Martha's  Vineyard ;  and,  according  to  A.  Gesner,  the  land  is 
rising  at  St.  John's,  in  New  Brunswick  ;  sinking  at  the  island  of  Grand 
Manan  ;  rising  on  the  coast  opposite,  at  Bathurst ;  sinking  about  the 
head  of  the  Bay  of  Fundy,  where  there  are  regions  of  stumps,  sub 
merged  thirty-five  feet  at  high  tide,  and  about  the  Basin  of  Mines  in 
Nova  Scotia,  except,  perhaps,  on  the  south  side  ;  arid  rising  at  Prince 
Edward's  Island. 

The  Coral  Islands  of  the  Pacific  are  proofs  of  a  great  secular  sub 
sidence  in  that  ocean.  The  line  C  C  C  (Physiographic  Chart),  be 
tween  Pitcairn's  Island  and  the  Pelews,  divides  coral  islands  from 
those  not  coral ;  over  the  area  north  of  it,  to  the  Hawaian  Islands,  all 
the  islands  are  atolls,  excepting  the  Marquesas  and  three  or  four  of 
the  Carolines.  If  then  the  atolls,  as  will  be  shown  on  a  future  page, 
are  registers  of  subsidence,  a  vast  area  has  partaken  in  it,  —  measuring 
6,000  miles  in  length  (a  fourth  of  the  earth's  circumference),  and 
1,000  to  2,000  in  breadth.  Just  south  of  the  line,  there  are  extensive 
coral  reefs ;  north  of  it,  the  atolls  are  large  ;  but  they  diminish  toward 
the  equator,  and  mostly  disappear  north  of  it ;  and,  as  the  smaller 
atolls  indicate  the  greater  amount  of  subsidence,  and  the  absence  of 
islands  still  more,  the  line  A  A  may  be  regarded  as  the  axial  line  of 
this  great  Pacific  subsidence.  The  amount  of  this  subsidence  may  be 
inferred,  from  the  soundings  near  some  of  the  islands,  to  be  at  least 
3,000  feet.  But,  as  two  hundred  islands  have  disappeared,  and  it  is 
probable  that  some  among  them  were  at  least  as  high  as  the  average 
of  existing  high  islands,  the  whole  subsidence  cannot  be  less  than 
6,000  feet.  This  sinking  may  have  begun  in  the  Tertiary  era. 

Since  this  subsidence  ceased  —  for  the  wooded  condition  of  the 
islands  is  proof  of  its  having  ceased  —  there  have  been  many  cases  of 
isolated  elevations.  The  following  are  some  of  the  islands  that  have 


584 


CENOZOIC   TIME. 


been  elevated:  Oahu  (Hawaian  Islands),  25  feet;  Molokai  (ib.)  300 
feet ;  Elizabeth  Island,  Paumotu  Archipelago,  80  feet ;  Metia,  or  Au 
rora,  250  feet;  Atiu,  Hervey  Group,  12  feet;  Mangaia,  300  feet; 
Rurutu,  150  feet;  P^ua,  Tonga  Group,  nearly  300;  Vavau,  100  ;  Sav 
age  Island,  100.  More  than  twenty-five  others  have  undergone  some 
elevation. 

2.  Paroxysmal.  —  The  changes  of  level  about  Pozzuoli,  near  Na 
ples,  at  Cutch,  in  the  Delta  of  the  Indus,  and  on  the  Chilian  coast, 

Fig.  958. 


Temple  of  Jupiter  Serapis. 

South  America,  are  noted  examples.  The  first  appears  to  have  been 
gradual  in  its  progress  ;  but,  even  if  so,  it  is  not  properly  secular,  in 
the  sense  in  which  that  term  is  used.  The  cases  at  Cutch  and  in  Chili 
were  connected  with  earthquakes ;  the  other  is  in  the  volcanic  region 
of  southern  Italy. 

The  temple  of  Jupiter  Serapis  at  Pozzuoli  (Fig.  958)  was  originally 


GENERAL   OBSERVATIONS,  585 

134  feet  long  by  115  wide;  and  the  roof  was  supported  by  forty-six 
columns,  each  forty-two  feet  high,  and  five  feet  in  diameter.  Three  of 
the  columns  are  now  standing :  they  bear  evidence,  however,  that  they 
were  once  for  a  considerable  time  submerged  to  half  their  height. 
The  lower  twelve  feet  is  smooth  :  for  nine  feet  above  this,  they  are 
penetrated  by  lithodomous  or  boring  shells ;  and  remains  of  the  shells 
(a  species  now  living  in  the  Mediterranean)  were  found  in  the  holes. 
The  columns,  when  submerged,  were  consequently  buried  in  the  mud 
of  the  bottom  for  twelve  feet,  and  were  then  surrounded  by  water 
nine  feet  deep.  The  pavement  of  the  temple  is  now  submerged.  Five 
feet  below  it,  there  is  a  second  pavement,  proving  that  these  oscilla 
tions  had  gone  on  before  the  temple  was  deserted  by  the  Romans.  It 
has  been  recently  stated  that,  for  some  time  previous  to  1845,  a  slow 
sinking  had  been  going  on,  and  that  since  then  there  has  been  as. 
gradual  a  rising. 

At  the  earthquake  in  1819,  about  the  Delta  of  the  Indus,  an  area 
of  2,000  square  miles  became  an  inland  sea ;  and  the  fort  and  village 
of  Sindree  sunk  till  the  tops  of  the  houses  were  just  above  the  water. 
Five  ard  c  half  miles  from  Sindree,  parallel  with  this  sunken  area,  a 
region  was  elevated  ten  feet  above  the  delta,  fifty  miles  long  and  in 
some  parts  ten  broad.  The  natives,  with  reference  to  its  origin,  call 
it  Ullah  Bund,  or  Mound  of  God.  In  1838,  the  fort  of  Sindree  was 
still  half  buried  in  the  sea  ;  and,  during  an  earthquake  in  1845,  the 
Sindree  Lake  was  turned  into  a  salt  marsh. 

In  1822,  the  coast  along  by  Concepcion  and  Valparaiso,  for  1,200 
miles,  was  shaken  by  an  earthquake ;  and  it  has  been  estimated  that 
the  coast  at  Valparaiso  was  raised  three  or  four  feet.  In  February, 
1835,  another  earthquake  was  felt  from  Copiapo  to  Chili,  and  east  be 
yond  the  Andes  to  Mendoza.  Captain  Fitzroy  states  that  there  was 
an  elevation  of  four  or  five  feet  at  Talcahuano,  which  was  reduced  by 
April  to  two  or  three  feet.  The  south  side  of  the  island  of  Santa 
Maria,  near  by,  was  raised  eight  feet,  and  the  north  ten  ;  and  beds  of 
dead  mussels  were  found  on  the  rocks,  ten  feet  above  high-water  mark. 

Thus  the  earth,  although  in  an  important  sense  finished,  is  still  un 
dergoing  changes,  from  paroxysmal  movements  and  prolonged  oscil 
lations.  The  changes,  while  probably  more  restricted  than  in  the  ages 
of  progress,  are  yet  the  same  in  kind. 

III.  GENERAL  OBSERVATIONS  ON  THE  CENOZOIC. 

1.  Time-ratios.  —  Using  the  same  kind  of  data  as  on  p.  381,  for 
determining  the  relative  lengths  of  the  ages  and  periods,  we  have 
for  the  Tertiary  period,  in  North  America  —  in  which  the  maximum 


586  CEXOZOIC   TIME. 

thickness  of  the  deposits  was  fully  16,000  feet,  with  very  little  lime 
stone —  the  length  about  that  of  the  Mesozoic  (p.  481).  But,  as  the 
action  of  rivers  during  the  Cenozoic  greatly  aided  the  ocean  in  wear 
and  transportation,  it  is  probable  that  this  estimate  is  half  too  large. 

The  data  for  the  Quaternary  are  very  uncertain  ;  its  lapse  of  time 
is  more  plainly  marked  in  the  extent  of  the  valleys  made  than  in  the 
thickness  of  the  rock  deposits.  It  must  have  been  at  least  one-third 
as  long  as  the  Tertiary. 

Adopting  these  conclusions,  the  ratio  for  the  Paleozoic,  Mesozoic, 
and  Cenozoic  would  be  12  :  3  :  1. 

2.  Geography.  —  The  geographical  progress  of  the  Tertiary  and  the 
Quaternary  ages  went  forward  in  different  directions. 

A.  Tertiary  Age.  —  In  the  Tertiary,  there  was  (1)  the  finishing  of 
the  rocky  substratum  of  the  continents  ;  (2)  the  expansion  of  the  con 
tinental  areas  to  their  full  limits,  or  their  essentially  permanent  recov 
ery  from  the  waters  of  the  ocean ;   (3)  the  elevation  of  many  of  the 
great  mountains  of  the  globe,  or  considerable  portions  of  them,  through 
a  large  part  of  their  height,  as  the  Alps,  Pyrenees,  Apennines,  Hima 
layas,  Andes,  Rocky  Mountains,  the  loftiest  chains  of  the  globe,  —  a 
result  not  finally  completed  until  the  close  of  the  Tertiary. 

In  North  America,  there  occurred  a  small  extension  of  the  conti 
nent,  on  the  Atlantic  and  Gulf  borders  ;  a  vast  increase  west  of  the 
Mississippi ;  a  small  rising  of  the  land  on  the  east  arid  south ;  an  ele 
vation  of  6,000  to  10,000  feet  in  the  Rocky  Mountains  (nearly  the 
whole  height  of  the  mass),  and  3,000  feet  or  more  on  the  Pacific 
border. 

The  system  of  progress  during  the  Tertiary  was  in  each  respect  a 
continuation  of  that  which  began  with  the  Archaean  era.  In  North 
America,  it  was  enlargement  and  elevation,  especially  to  the  south 
east,  south,  and  southwest,  from  the  original  dry  land  of  the  Archaean 
(p.  160). 

The  mass  of  the  earth  above  the  ocean's  level  was  increased  two 
or  three  fold,  between  the  beginning  and  the  end  of  the  Tertiary 
period. 

B.  Quaternary  Age.  —  In  the  Quaternary,  the  great  events  were  (1) 
the  excavation  of  vallevs  over  the  lifted  mountains  and  plains,  and  the 
shaping  of  the  lofty  summits ;  (2)  the  distribution  of  earth  and  gravel, 
covering   and  levelling  the  rugged  surface  of  the  earth,  laying  the 
foundation  of  prairies,  and  filling  the  broad  valleys  with  alluvium  ;  (3) 
the  finishing  of  the  valleys  and  lake-borders  with  a  series  of  plains  or 
terraces,  and  the  extension  of  flats  along  the  sea. 

There  were  great  oscillations  of  level  in  the  Quaternary,  as  well  as 
in  the  Tertiary  ;  but  those  affecting  the  continents  were  mainly  high- 


GENERAL   OBSERVATIONS.  587 

latitude  oscillations,  being  most  prominent  over  the  colder  latitudes  of 
the  globe,  the  cold-temperate  and  Arctic  ;  (2)  they  were  movements 
of  the  broad  areas  of  the  continents  ;  (3)  they  brought  no  mountain 
ranges  into  existence. 

According  to  the  view  presented  in  the  preceding  pages,  there  was 

(1)  an  upward  oscillation  over  the  higher  latitudes,  in  the  Glacial  period  ; 

(2)  a  downward,  introduciijg  the  Champlain  period,  and  then  (3)  an 
upward   of  moderate    extent,  introducing   the    Recent   period.     The 
Champlain  subsidence  submerged  the  region  about  Montreal  and  the 
Ottawa,  so  that  marine  shell  deposits  were  there  formed,  —  an  event 
which  had  not  previously  occurred  since  the  Lower  Helderberg  period 
in  the  Silurian  age  (p.  216).     It  submerged  a  large  part  of  Britain  to 
500-1,400  feet  below  its  present  level,   and   much  also   of  Europe, 
thereby  giving  an  opportunity  for  the  deposition  of  the  thick  river- 
border  formations    that   prevail    so    extensively.     But    the  elevation 
closing  the  Champlain  period  appears  to  have  gone  on,  in  Europe,  until 
the  continent  stood  above  its  present  level,  and,  in  connection,  a  sec 
ond  Glacial  epoch  intervened,  separating  the  Champlain  and  Recent 
periods  ;  and  it  may  be  that  North  America  also  was  raised  to  a  higher 
level  than  now,  though  with  less  marked  glacial  effects  (p.  561).    Thus 
the  course  of  the  movements  was  diverse  from  that  of  earlier  time,  and 
so  also  their  results. 

During  the  Quaternary,  some  of  the  most  prominent  dynamical  agen 
cies  on  the  globe  were  intensified  vastly  beyond  their  former  power :  — 

(1.)  Owing  to  the  completion  of  the  great  mountain-chains  and  the 
expansion  of  the  continents,  the  heights  for  condensing  moisture,  and 
the  extent  of  slope  for  its  accumulation  into  rivers,  had  augmented 
many  fold.  Moreover,  through  the  union  of  lands  before  isolated  by 
seas,  into  continental  areas,  the  rivers  draining  immense  regions  were 
for  the  first  time  united  into  common  trunks.  The  Quaternary  was 
therefore  eminently  the  era  of  the  jirst  grand  display  of  completed 
river-systems,  —  of  the  first  Amazon,  Mississippi,  Ganges,  Indus,  Nile, 
etc. 

(2.)  The  elevation  of  the  mountains  to  snowy  altitudes  made  gla 
ciers  —  powerful  dynamical  agents. 

(3.)  The  increase  of  cold,  and  the  existence  finally  of  true  frigid 
zones,  due  partly,  at  least,  to  an  increase  of  polar  lands  after  the  close 
of  the  Cretaceous  period  and  through  the  Tertiary,  gave  a  vast  extent 
to  glaciers,  rendering  them  possible  in  regions  where  otherwise  they 
could  not  have  existed. 

(4.)  The  cause  last  mentioned  also  gave  origin  to  icebergs. 

Great  rivers,  glaciers,  and  icebergs  were  especially  characteristic  of 
the  Quaternary  ;  and  the  ice  accomplished  what  was  impossible  for  the 


588  CEXOZOIC    TIME. 

ocean.  In  no  other  period  of  geological  history  have  so  large  masses 
of  stone  been  moved  over  the  earth's  surface  as  in  the  Glacial  and 
Champlain  periods. 

These  Quaternary  agencies  were  active  everywhere  over  the  conti 
nents,  putting  the  finishing  strokes  to  the  nearly  completed  globe. 
There  was  a  development  of  beauty  as  well  as  utility  in  all  these 
later  movements.  Those  conditions  and  special  surface-details  were 
developed  that  were  most  essential  to  the  pastoral,  agricultural,  and 
intellectual  pursuits  which  were  about  to  commence. 

3.  Life.—  Grand  characteristic  of  the  Tertiary  and  Quaternary 
Ages.  —  The  prominent  fact  in  the  life  is  the  expansion  and  culmina 
tion  of  the  type  of  Mammals.  This  culmination,  as  regards  brute 
Mammals,  took  place  in  the  Middle  Quaternary,  when  the  Carnivores, 
Herbivores,  Edentates,  and  Marsupials  far  exceeded  in  number  and 
size  those  of  the  present  time.  It  was  the  great  feature,  not  of  one 
continent  alone,  but  of  all  the  continents,  and  on  each  under  its  own 
peculiar  type  of  Mammalian  life. 

Man  appeared  before  the  Champlain  Mammals  had  gone.  But  an 
era  of  cold  —  the  second  glacial  —  after  a  while  intervened  ;  and  then 
there  went  forward  —  partly,  if  not  wholly,  in  consequence  of  the  cold 
—  the  extermination  of  these  gigantic  species,  leaving  only  smaller 
races  for  the  era  of  man's  development.  In  this,  the  true  Human  era, 
the  Animal  element  is  consequently  no  longer  dominant,  but  Mind,  in 
the  possession  of  a  being  at  the  head  of  the  kingdoms  of  life.  The 
era  bears  the  impress  of  its  exalted  characteristic,  even  in  the  dimin 
ished  size  of  its  beasts  of  prey. 

Range  of  Vertebrate  types.  —  The  following  table  presents  to  the  eye 
the  range  of  the  more  common  Vertebrate  types,  through  the  Mesozoic 
and  Cenozoic,  showing  those  which  began  in  the  Paleozoic,  those  which 
have  their  commencement,  culmination,  and  end  within  these  eras,  and 
those  which  continue  into  the  age  of  Man.  The  symbol  )  (  signifies 
having  biconcave  vertebras.  Under  Tertiary,  the  letters  E.,  M.,  P. 
stand  for  Eocene,  Miocene,  Pliocene  :  Q.  stands  for  Quaternary. 


GENERAL   OBSERVATIONS. 


589 


Fishes.—  Teliosts. 

Ganoids,  Heterocercal 

Homocercal  . 

Selachians  

Cestracionts. . . 
Hybodonts 

Squalodonts  (Modern  Sharks). 
Reptiles.. . 

Labyrinthodonts. 

)  (  Thecodonts 

Enaliosaurs 

Pterosaurs 

Dinosaurs 

Crocodilians 

Genus  Crocodilus 

Chelonians,  or  Turtles..  . . 
Birds. . . 

Mammals,  exclusive  of  Man 

Marsupials. 
Insectivores  .. 
Rodents.  . 
Edentates. 
Chiropters  or  Bats 

Cetaceans 

Herbivores 

Perissodactyls . . 
Artiodactyls.  . 

Sthenorhines 

Proboscidians  (Elephant,  etc.) 
Ruminants,  Stag  family 
Bovine,  or  Ox  family 

Carnivores 

Quadrumana,  or  Monkeys. 


590  GEOLOGICAL  HISTORY. 


GENERAL  OBSERVATIONS   ON    GEOLOGICAL 
HISTORY. 

1.  LENGTH  OF  GEOLOGICAL  TIME. 

On  former  pages  (pp.  371,  575),  estimates  have  been  given  of  the 
relative  lengths  of  the  ages  and  periods,  or  their  time-ratios.  Future 
discovery  will  probably  enable  the  geologist  to  determine  these  ratios 
with  far  greater  certainty  and  precision. 

Although  Geology  has  no  means  of  substituting  positive  lengths  of 
time,  in  place  of  such  ratios,  it  affords  facts  sufficient  to  prove  the 
general  proposition  that  Time  is  long.  A  few  examples  are  here 
given. 

Niagara  has  made  its  gorge  by  a  slow  process  of  excavation,  and  is 
still  prolonging  it  toward  Lake  Erie.  Near  the  fall,  the  gorge  is  200 
to  250  feet  deep,  and  160  feet  at  the  fall,  —  the  lower  80  feet  shale, 
the  upper  80  limestone.  The  waters  wear  out  the  shale,  and  thus  un 
dermine  the  limestone.  The  rocks  dip  fifteen  feet  in  a  mile  up  stream, 
so  that  the  limestone  at  the  fall  becomes  thicker,  as  retrocession  goes 
on.  The  distance  from  Niagara  to  the  Queenstown  heights,  which 
face  the  plain  bordering  Lake  Ontario,  is  seven  miles. 

On  both  sides  of  the  gorge  near  the  whirlpool  (three  miles  below 
the  fall),  and  also  at  Goat  Island,  there  are  beds  of  recent  lake-shells, 
Unios,  Melanias,  and  Pcdudinas,  the  same  kinds  that  live  in  still  water 
near  the  entrance  to  the  lake,  and  which  are  not  found  in  the  rapids. 
The  lake,  therefore,  spread  its  still  waters,  when  these  beds  were 
formed,  over  the  gorge  above  the  whirlpool.  A  tooth  of  a  Mastodon 
has  been  found  in  the  same  beds.  This  locates  the  time  of  deposition 
in  the  Champlain  period.  Moreover,  the  waters  would  not  have  been 
set  back  to  the  height  of  these  beds,  unless  they  extended  on  below 
for  at  least  six  miles  from  the  falls.  Six  miles  of  the  gorge  have 
then  been  excavated,  since  that  Mastodon  was  alive.  There  are  ter 
races  in  the  shell  deposits,  showing  changes  of  level  in  the  lakes. 

There  is  a  lateral  valley,  leading  from  the  whirlpool  through  the 
Queenstown  precipice,  at  a  point  a  few  miles  west  of  Lewiston.  This 
valley  is  filled  with  Drift,  as  stated  on  page  553  ;  and  this  blocking  up 
of  the  channel  forced  it  to  open  a  new  passage. 

If,  then,  the  falls  have  been  receding  six  miles,  and  we  can  ascertain 
the  probable  rate  of  progress,  we  may  approximate  to  the  length  of 
time  it  required.  Hall  and  Lyell  estimated  the  average  rate  at  one 
foot  a  year,  —  which  is  certainly  large.  Mr.  Desor  concluded,  after 


LENGTH   OF   GEOLOGICAL  TIME.  591 

his  study  of  the  falls,  that  it  was  "  more  nearly  three  feet  a  century 
than  three  feet  a  year."  Taking  the  rate  at  one  foot  a  year,  the  six 
miles  will  have  required  over  31,000  years;  if  at  one  inch  a  year, — 
which  is  eight  and  one  third  feet  a  century,  —  380,000  years. 

The  rate  at  which  coral  reefs  increase  in  height  affords  another 
mode  of  measuring  the  past.  From  calculations  elsewhere  stated  by 
the  author,  it  appears  that  the  rate  of  increase  of  a  coral  reef  prob 
ably  is  not  over  a  sixteenth  of  an  inch  a  year.  Now,  some  reefs  are 
at  least  2,000  feet  thick,  which,  at  one  sixteenth  of  an  inch  a  year, 
corresponds  to  384,000  years,  or  very  nearly  a  thousand  years  for  five 
feet  of  upward  increase.  If  the  progressing  subsidence  essential  to 
the  increasing  thickness  were  slower  than  the  most  rapid  rate  at  which 
the  upward  progress  might  take  place,  the  time  would  be  proportion 
ally  longer.  The  reefs  may  have  been  begun  in  the  Tertiary. 

The  use  of  these  numbers  is  simply  to  prove  the  proposition  that 
Time  is  long,  —  very  long,  —  even  when  the  earth  was  hastening  on 
toward  its  last  age.  And  what,  then,  of  the  series  of  ages  that  lie 
back  of  this  in  time  ?  Thousands  of  millions  of  years  have  been 
claimed  by  some  geologists,  for  time  since  life  began.  Sir  Wm. 
Thomson  has  reduced  the  estimate,  on  physical  grounds,  to  one  hun 
dred  millions  of  years  as  a  maximum.  If  the  time  since  the  com 
mencement  of  the  Silurian  were  but  forty-eight  millions,  the  ratio 
12  :  3 :  1,  above  deduced  for  Paleozoic,  Mesozoic,  and  Cenozoic  times, 
would  give  for  each,  severally,  thirty-six  millions,  nine  millions,  and 
three  millions,  of  years. 

In  calculations  of  elapsed  time,  from  the  thickness  of  formations,  there  is  always  great 
uncertainty,  arising  from  the  dependence  of  this  thickness  on  a  progressing  subsidence. 
In  the  case  of  coral  limestone,  the  data  employed  give  the  least  possible  time,  as  is  ob 
vious  from  the  above.  In  estimates  made  from  alluvial  deposits,  when  the  data  are 
based  on  the  thickness  of  the  accumulations  in  a  given  number  of  years,  —  say  the  last 
2,000  years,  —  this  source  of  doubt  affects  the  whole  calculation,  from  its  foundation, 
and  renders  it  almost,  if  not  quite,  worthless.  An  estimate  of  the  length  of  the  Mio 
cene  epoch,  made  from  data  derived  from  observations  on  the  deposits  then  forming  in 
England,  would  have  given  no  idea  of  the  length  of  time  required  for  the  Miocene 
Molasse  of  Switzerland;  and,  in  the  same  manner,  any  such  data  from  observations  at 
the  present  day  must  be  equally  fallacious.  Whoa  the  estimate,  as  from  delta-deposits, 
is  based  on  the  amount  of  detritus  discharged  by  a  stream,  it  is  of  more  value.  But 
even  here  there  is  a  source  of  great  doubt,  in  our  ignorance  of  the  oscillations  the  con 
tinent  may  have  undergone  in  past  time,  which,  especially  if  an  upward  movement, 
would  have  affected  the  amount  of  discharge,  and,  if  attended  with  glaciers,  would  have 
produced  immensely  larger  depositions  in  a  given  time.  This  source  of  doubt  affects 
also  the  calculations  from  the  excavation  of  valleys. 

2.  GEOGRAPHICAL  PROGRESS. 

The  system  of  oscillations  and  progress  in  North  America  during 
the  ages,  to  the  close  of  the  Tertiary  period,  and  the  new  system 


592  GEOLOGICAL   HISTORY. 

which  succeeded  and  characterized  subsequent  time,  have  been  dis 
cussed  in  the  course  of  the  General  Observations  on  the  Archaean. 
Paleozoic,  Mesozoic,  and  Cenozoic  eras  ;  and  the  reader  is  here  re 
ferred  to  pp.  160,  379,  and  576,  a  recapitulation  in  this  place  being 
unnecessary. 

3.   PROGRESS   OF  LIFE. 

Several  general  principles  connected  with  the  progress  of  life  have 
been  illustrated  in  the  course  of  the  preceding  history.  They  are  here 
brought  together  in  brief  review.1 

!The  following  are  some  of  the  Criteria  of  Hank  among  Animals:  — 

(1.)  Under  any  type,  water-species  are  inferior  to  land-species:  as  the  Seals  to  the  ter 
restrial  Carnivores;  the  water-articulates,  or  Worms  and  Crustaceans,  to  land-articu 
lates,  or  Spiders  and  Insects. 

(2.)  Species  of  a  tribe  bearing  some  of  the  characteristics  of  an  inferior  tribe  or  class 
are  inferior  species,  and  conversely.  —  Thus,  Amphibians  show  their  inferiority  to-  True 
Reptiles,  in  the  young  having  gills,  like  Fishes;  the  early  Thecodont  Reptiles,  inferiority 
to  the  later,  in  having  biconcave  vertebrae,  like  Fishes;  the  Marsupials  and  Edentates, 
inferiority  to  other  Mammals,  in  having  the  sacrum  consisting  of  only  two  united  ver 
tebra?,  as  in  most  Reptiles.  On  the  contrary,  the  Dinosaurs  show  their  superiority  to 
other  Saurians,  in  having  the  sacrum  made  of  five  (or  six)  vertebrae,  as  in  the  higher 
Mammals. 

(3.)  As  a  species  in  development  passes  through  successive  stages  of  progress,  relative 
grade  in  inferior  species  may  often  be  determined  by  comparing  their  structures  u-ith  these 
embryonic  stages.  —  As  a  many-jointed  larve,  without  any  distinction  of  thorax  and 
abdomen,  is  the  young  state  of  an  Insect,  therefore  Myriapods,  or  Centipedes,  which 
have  the  same  general  form,  are  inferior  to  Insects.  As  a  young  living  Gar  has  a  ver- 
tebrated  caudal  lobe  (making  an  accessory  upper  lobe  to  the  tail),  which  it  loses  on  becom 
ing  adult,  therefore  the  older  Ganoids,  with  vertebrated  tails  (or  heterocercal ),  are  inferior 
to  the  later,  in  which  the  tails  are  not  vertebrated  (or  are  homocercal).  As  the  young  of  a 
Frog  (a  tadpole)  has  the  tail  and  form  of  a  Salamandrian,  therefore  the  Salamandrians 
are  inferior  to  Frogs.  As  the  number  of  segments  in  the  young  of  Insects  often  exceeds 
much  that  of  the  adult,  therefore  species  of  adult  animals  in  which  there  is  an  exces 
sive  number  of  segments  (beyond  the  typical  number)  have  in  this  a  mark  of  inferiority; 
and  thus  the  Phyllopods  and  Trilobites  among  Crustaceans  bear  marks  of  inferiority, 
the  typical  number  of  segments  in  the  abdomen  of  a  Crustacean  being  but  seven,  and 
in  the  whole  body  twenty-one,  — each  pair  of  members  corresponding  to  one,  commen 
cing  with  the  eyes  as  the  anterior. 

Professor  Agassiz  has  brought  out  and  illustrated  in  his  writings  each  of  the  above 
criteria. 

(4. )  Species  having  the  largest  number  of  distinct  segments  in  the  posterior  part  of  the 
body,  or  having  the  body  posteriorly  prolonged,  are  the  inferior  among  those  under  any 
type.  —Shrimps  and  Lobsters  are  thus  inferior  to  Crabs;  Centipedes,  to  Insects;  Sala 
mandrians,  or  tailed  Batrachians,  to  the  Frogs,  or  tailless  Batrachians;  Snakes,  to  Liz 
ards  ;  the  Ganoids  with  vertebrated  tails,  to  those  with  non-vertebrated.  It  does  not 
follow  on  this  principle  that  Frogs,  although  tailless,  are  superior  to  Lizards;  for  they 
are  of  different  types  of  structure. 

(5.)  Species  having  the  anterior  part  of  the  body  most  compacted  01*  condensed  in  ar 
rangement,  or  having  the  largest  part  of  the  body  contributing  to  the  functions  of  the 
head-extremity,  are  the  superior,  other  things  being  equal. — Thus,  Man  stands  at  the 
head  of  all  Vertebrates,  in  having  only  the  posterior  limbs  required  for  locomotion,  the 
anterior  having  higher  uses ;  and  also  in  having  the  head  most  compacted  in  structure, 


PROGRESS  OF  LIFE.  5 98 

1.  The  fact  of  Progress.  —  The  history  with  which  the  preceding 
pages  are  occupied  has  presented  the  grand  fact  that  the  system  of  life 
began   in  the  simple  sea-plant  and  the  lower  forms  of  animals,  and 
ended  in  Man. 

2.  The  progress  in  climate  and  other  conditions  involved  a  concurrent 
progress  from  the  inferior  living  species  to  the  superior.  —  The  existence 
of  a  long  marine  era,  through  the  Silurian  and  part  of  the  Devonian 
ages,  admitted  of  the  existence  chiefly  of  marine  life.     Hence  the  domi 
nant  type  of  the  Silurian  was  the  Molluscan,  which,  with  the  Radiate, 
is  eminently  marine.     In  addition,  there  were  marine  Articulates  and 
marine  Plants  ;  and,  when  the  Vertebrates  began,  it  was  with  marine 
species,  the  Fishes.     Thus  the  prevalence  of  waters  involved  inferiority 
of   species.     The   increase  of   land,   the    gradual    purification  of   the 
atmosphere,  and  the  cooling  of  the  globe,  prepared  the  way  for  the 
higher  species. 

It  is  probable  that  the  oceanic  waters  were  also  in  an  impure  state, 
compared  with  the  present,  from  containing  an  excess  of  salts  of  lime  ; 
and  this  also  involved  the  existing  of  inferior  species,  —  such  as  Cri- 
noids,  Corals,  and  Mollusks,  a  very  large  proportion  of  whose  weight 
is  in  calcareous  material.  The  removal  of  this  excess  of  lime  from  the 
waters  produced  limestone  strata,  purified  the  waters,  and  fitted  the 
oceans  for  other  species. 

The  great  prevalence,  in  the  Primordial,  of  Lingulce  and  some 
related  Brachiopods,  having  shells  containing  a  large  amount  of  phos 
phate  of  lime,  is  further  evidence  of  the  greater  density  of  the  waters, 
and  seems  to  indicate,  as  stated  by  Hunt,  who  first  made  known  the  fact, 
•the  presence  of  an  excess  of  phosphates. 

3.  The  progress  in  climate  and  in  the  condition  of  the  atmosphere  and 
waters  involved  a  localization  of  tribes  in  time,  or  chronographically^ 
just  as  they  are  now  localized  by  climate  over  the  earth's  surface,  or 
geographically.  —  Living  species  are  always  adapted  to  some  special 
climate  or  condition  of  the  globe ;  and,  when  this  climate  or  condition 
had  been  passed  in  the  earth's  progress,  the  tribes  fitted  for  it  no  longer 

and  brought  into  the  least  compass  consistent  with  the  amount  of  brain.  In  the  same 
manner,  the  Carnivores,  among  the  large  Mammals  (Megasthenes),  are  superior  to  the 
Herbivores,  the  anterior  limbs  not  having  locomotion  as  their  sole  use,  and  the  head 
being  more  compacted  and  condensed,  for  the  size  of  brain.  The  highest  Crabs,  the 
Triangular,  or  Maioids,  are  superior  in  the  same  manner  to  the  lower,  and  far  more  to 
the  Lobster  tribe  and  other  Macrourans;  descending  in  grade  from  the  higher  Crabs,  the 
outer  mouth-organs  become  more  and  more  separated  from  the  mouth,  and,  finally,  in 
many  Macrourans,  they  have  the  form  of  feet,  thus  passing  from  the  head-series  to  the 
foot-series.  Insects  are,  on  this  principle,  — that  of  Cephattzation,  as  it  is  called  by  the 
author,  —  superior  as  a  class  to  Crustaceans,  although  of  so  much  less  size. 

Condensation  anteriorly  and  abbreviation  posteriorly  is  the  law  of  all  progress  in  em 
bryonic  development,  and  also  of  relative  rank  among  species  of  related  groups. 


594  GEOLOGICAL   HISTORY. 

existed.  The  culmination  of  the  Reptilian  and  Molluscan  types  in 
the  Reptilian  age,  arid  of  Trilobites  and  Brachiopods  in  Paleozoic  time, 
are  examples.  The  former,  when  instituted,  had  those  special  relations 
to  climate  that  made  the  Reptilian  age  the  era  of  their  culmination  ; 
just  as,  now,  Palms  and  Bananas  reach  their  perfection  only  in  the 
equatorial  zone ;  Figs,  in  the  tropical  ;  Myrtles  and  Laurels,  in  the 
subtropical ;  and  Pines,  in  the  subarctic.  As  there  are  now  different 
zones  of  living  species  on  going  from  the  equator  to  the  poles,  so  there 
were  successive  phases  in  the  life  of  the  world  passed  over  from  the 
Silurian  —  the  period  of  universal  temperate  climate  —  to  the  present 
age  of  a  frigid  Arctic,  and  a  mean  temperature  of  58°  to  60°  F.  Cli 
mate  was  not  the  only  cause ;  but  it  was  one,  and  of  great  import 
ance. 

4.  The  progress  was  in  accordance  with  system.  —  The  species  fol 
lowed  one  another,  according  to  a  system  of  mutual  relation  or  depen 
dence,  which  is  so  profound  and  comprehensive  that  this  progress  is 
rightly  spoken  of  as  an  evolution  or  development.  This  statement 
is  sustained  by  the  following  considerations :  — 

(1.)  The  same  grander  types  of  structure  that  appeared  in  the  Si 
lurian  age  continued  to  be  the  grander  types  through  all  subsequent 
time.  The  Vertebrate  type,  for  example,  which  was  represented  before 
the  Silurian  age  closed,  presented  in  its  early  species  the  fundamental 
elements  of  all  Vertebrates ;  and  future  progress  was  manifested 
in  modifications  and  complete  developments  of  the  fundamental  idea. 
The  two  pairs  of  fins  in  Fishes  represent  the  two  pairs  of  limbs  of 
higher  species ;  an  air-bladder,  the  lungs ;  a  loose-bone  in  a  closed 
cavity,  the  ear ;  and  so  on  throughout  the  structure  ;  and  this  is  so 
completely  true  that  the  comparative  anatomist,  in  order  to  understand 
the  skeleton  of  the  Mammal,  or  of  Man,  goes  to  the  Fish  for  instruc 
tion.  Thus  the  whole  animal  kingdom  is  the  display  of  a  few  com 
prehensive  structural  types  —  the  simpler  forms  of  which  appeared 
in  early  time,  and  the  more  complex  came  forth  successively  afterward. 
Some  new  organs  were  required  in  the  highest  manifestations  of  a 
type.  But  these  were  only  developments  through  modification  of 
the  older,  or  better  appliances  evolved  from  the  structure  for  carrying 
forward  old  processes. 

Further,  some  of  the  old  Silurian  families  of  Invertebrates  con 
tinued  to  exist  through  all  time  to  the  present.  Thus,  the  most  ancient 
type  of  Mollusks  yet  discovered,  the  Lingula  family,  is  represented  by 
species  in  our  present  seas  ;  and  so  also  the  Discina  and  Nautilus  fami 
lies.  Among  Vertebrates,  some  of  the  ancient  Gars  are  very  much 
like  our  modern  kinds,  and  one  Triassic  genus,  Ceratodus,  is  still  repre- 
resented  in  Australian  Seas.  Such  facts,  coming  up  from  the  past, 


PROGRESS   OF   LIFE.  595 

through  ages  of  unceasing  change,  declare  emphatically  the  unity  of 
system  in  Nature. 

(2.)  This  truth  is  further  manifested,  in  the  fact  of  a  general  paral 
lelism  between  the  progress  of  the  earth's  life  and  the  successive  phases 
in  embryonic  development.  The  almost  egg-like  simplicity  of  the  earli 
est  living  species  of  the  rocks,  —  the  Rhizopods  among  animals,  and 
the  Infusorial  plants,  —  is  the  first  illustration  Geology  presents.  An 
animal  without  limbs,  without  any  sense  beyond  the  general  sense  of 
feeling,  without  a  circulating  system,  without  even  a  stomach,  except 
such  as  it  may  extemporize  when  needed,  and  with  the  work  of  diges 
tion,  respiration,  and  reproduction  performed  by  the  same  protoplasmic 
material  that  makes  up  the  mass  of  the  body  of  the  infinitesimal 
Rhizopod,  is,  as  to  complexity  of  organization,  but  little  removed  from 
a  germ  ;  and  such,  we  have  reason  to  believe,  was  the  beginning  of 
the  system  of  animal  life.  , 

Again,  we  find  some  of  the  earliest  Crustaceans  of  the  Phyllopod 
group  closely  resembling  the  young  of  some  of  the  higher  groups 
of  living  Crustaceans ;  and  the  early  Fishes  having  cartilaginous  skele 
tons,  just  as  is  now  true  of  the  higher  Vertebrates  when  in  the  em 
bryonic  condition. 

Again,  the  Gars  of  the  present  day  have  a  vertebrated  lobe  to 
the  tail,  which  they  lose  on  becoming  adults  ;  and  so  the  Gars  had 
vertebrated  tails  in  the  young  world,  that  is  in  Paleozoic  time,  which 
feature  was  lost  in  the  progress  of  the  Mesozoic  era.  The  Amphib 
ians  afford  a  very  similar  illustration.  So  also  the  Birds  ;  for,  as  the 
young  often  have  a  tail  of  several  disconnected  vertebra?,  which  con 
tracts  much  on  passing  to  the  adult  stage,  so  the  earliest  known  of  the 
Bird  type  had  long,  vertebrated  tails,  such  as  no  modern  Bird  can  boast 
or  complain  of. 

Among  the  modern  free  Crinoids  (Comatulids),  the  young,  for  a 
while,  live  attached  to  some  support ;  and  so,  in  the  young  world,  the 
adult  Crinoids  had  pedicels,  and  were  attached  species.  In  the  ex 
isting  Echini,  as  observed  by  A.  Agassiz,  the  number  of  vertical  series 
of  plates  in  the  shell  of  the  young  is  often  more  than  the  adult  num 
ber,  twenty,  and  the  adult  shows  this  excess  in  the  plates  right  around 
the  mouth,  the  plates  there  being  those  of  the  young ;  and  so,  in  the 
Echini  of  the  young  or  Paleozoic  world,  the  adults  had  an  excessive 
number  of  series  of  plates,  while  later  they  have  only  the  normal  twenty. 

(o.)  The  system  of  progress  was  a  system  of  successive  specializations; 
and  in  this  it  was  parallel  in  idea  with  embryonic  development;  for, 
while  in  the  earliest  species  all  the  functions  were  performed  by  one 
and  the  same  protoplasmic  mass,  as  the  grade  of  species  rose,  these 
functions,  one  after  another,  had  special  organs  to  carry  them  forward. 


596  GEOLOGICAL   HISTORY. 

(4.)  It  was  a  system  of  progressive  cephalization  in  the  Animal 
structure  ;  and  in  this  also  it  was  parallel  with  embryonic  development. 
Several  of  the  facts  already  stated  (p.  595)  illustrate  this.  The  head  of 
an  animal  is  always  the  part  last  perfected.  In  most  Insects,  even 
the  highest,  the  young  is  a  worm-like  larve,  with  its  several  segments 
much  alike  in  kind  and  functions ;  and  the  abdomen  often  serves  for 
locomotion  ;  but,  in  the  adult,  among  the  higher  tribes,  the  abdomen 
and  thorax  have  become  distinct  and  greatly  contracted  ;  the  abdomen 
has  lost  any  locomotive  appendages  it  had ;  and  the  head  has  become 
a  well  denned  organ,  of  improved  structure  and  better  senses.  At  the 
same  time,  the  thorax  bears  the  only  locomotive  organs.  Thus  the  ab 
domen  has  lost  in  forces,  and  the  thorax  and  head  have  gained ;  and 
so  the  forces  of  the  animal  are  in  its  development  thrown  toward  the 
anterior  extremity,  and  the  structure  is  thereby  cephalized.  Now,  in 
the  history  of  the  animal  kingdom,  the  many-jointed  Worms,  with 
segments  almost  all  alike,  preceded  the  Insects,  the  higher  and  more 
cephalized  forms  of  Articulates. 

This  principle  might  be  extensively  illustrated;  for,  throughout 
the  animal  kindom,  wherever  there  has  been  progress,  this  progress 
has  been  attended  with  advance  in  stage  of  cephalization.  Advance 
in  cephalization  necessarily  involves  corresponding  improvements  in 
structure. 

Animals,  high  and  low,  are  in  contact  with  the  outer  world  through 
their  nervous  system,  and  eminently  by  means  of  the  cephalic  ganglion 
(the  brain  in  Vertebrates)  ;  and  it  is  natural,  therefore,  that  progress 
and  cephalization  should  have  gone  forward  together,  the  former  in 
volved  in  the  latter. 

In  Man's  structure,  we  see  the  last  limit  to  which  the  law  of  cephal 
ization  can  carry  the  system  of  life.  The  distinction  is  well  illustrated 
in  the  grades  of  men.  The  retreating  forehead,  long  occiput,  project 
ing  jaws,  and  longer  fore-arm  of  the  negro,  are  all  marks  of  inferior 
cephalization.  Progress  in  the  race  straightens  up  the  forehead,  and 
shortens  in  the  jaws  ;  and  the  abbreviation  of  the  fore-arm  also  is  a 
consequence  of  headward  concentration  in  the  forces  of  the  system. 
Degradation  is  attended  with  a  corresponding  decephalization. 

The  idea  of  system  in  all  structure,  and  of  progress  through  the  ages,  under  laws  of 
specialization  and  cephalization,  according  to  a  scheme  that  may  be  compared  to  the 
opening  of  a  flower,  or  the  development  of  a  germ,  instead  of  being  atheistic,  is  the 
only  view  of  the  history  of  life  that  is  consistent  with  its  Divine  origin.  Were  there 
no  such  order  of  succession,  no  such  unity  of  law  and  structure,  this  Avould  be  complete 
demonstration  that  a  Being  of  infinite  wisdom  had  not  ordered  or  controlled  events. 
Moreover,  a  Divinely  appointed  scheme  of  progress  should  exhibit,  not  merely  system, 
but  an  exact  reference  to  the  external  surroundings  of  the  species,  through  the  succes 
sive  changes  in  the  earth's  physical  history;  and  so  completely,  that  the  succession 
of  life  should  be  the  same,  whether  carried  forward  by  a  system  of  natural  causea 
under  a  Divine  law  established  at  the  beginning,  or  by  successive  Divine  acts. 


PROGRESS    OF   LIFE.  597 

Believing  in  the  unity  and  wisdom  of  the  Divine  plan,  it  is  evident 
that  the  discovery  of  the  "  missing  links  "  in  the  succession  of  living 
species,  or,  in  other  words,  of  the  gradations  between  types,  is  one  of 
the  grandest  aims  of  geological  science;  for  only  after  a  thorough 
knowledge  of  all  the  facts  will  the  system  of  life  be  completely  under 
stood. 

5.  The  comprehensive  character  of  many  of  the  groups  in  past  time.  — 
This  principle  runs  through  all  geological  history,  and  is,  in   fact,  in 
volved  in  those  already  announced. 

The  examples  of  comprehensive  types  illustrate  the  general  truth 
that  the  sub-kingdoms  of  life  were  present  in  early  time,  but  in  a 
more  condensed  or  comprehensive  form  than  now  —  the  grander 
divisions  having  been  defined,  while  the  subordinate  were  often  in  com 
bination  with  one  another,  and  became  afterward  differentiated. 

Among  these  comprehensive  types,  some  are  at  or  near  a  point  of  divergence  of 
lines  in  the  system  of  progress,  as  the  Crinoids,  near  the  point  of  divergence  of  Comat- 
ulids  and  Echinoids;  some  of  the  early  En tomostracans,  near  that  of  modern  Cyclo- 
poids  and  Macrural  Decapods ;  the  earliest  Tetradecapods,  near  that  of  Amphipods  and 
Isopods;  the  earliest  Decapods,  near  that  of  Macrourans  and  Brachyurans;  early 
Neuropterous  Insects,  near  that  of  true  Neuropters  and  Orthopters;  the  Ganoids,  near 
that  of  true  Fishes  and  Reptiles,  etc. 

Others,  like  the  Brachiopods,  Trilobites,  and  Cycads,  are  lines  that  appear  to  continue 
undivided.  There  is  no  reason  to  suppose  that  a  line  from  the  Cycads  led  toward  the 
Palms,  the  structure  of  the  plants  being  wholly  against  it;  the  Trilobites,  before  they 
disappeared,  were  accompanied  by  Tetradecapods ;  and  there  is  nothing  to  support  the 
idea  that  from  the  Trilobites  there  were  lines  to  the  Tetradecapods.  The  Brachiopods 
are  the  earliest  known  of  Mollusks;  but  the  line  has  no  furcations  afterward.  The 
Ascidian  group,  as  it  is  the  most  fundamental  comprehensive  type  under  Mollusks 
(and  could  not  have  been  preserved  in  the  rocks,  since  the  body  has  no  shell),  may 
have  been  the  precursor  of  both  the  Brachiopods  and  ordinary  Mollusks. 

6.  The  progress  involved  not  only   the   expansion  of  types,  hut  also 
the   culmination  and  decline  of  many,  in  the  course   of  the  history.  — 
(1.)  The  tribe  of  Crinoids  began  in  the  Primordial,  culminated  in  the 
Carboniferous  age,  and  is  now  nearly  extinct. 

(2.)  Brachiopods  have  run  a  parallel  course  with  the  Crinoids ;  the 
families  of  the  simple  Lingula  and  Discina,  with  which  the  tribe 
began,  and  a  few  other  kinds  of  low  grade  now  remain  ;  the  genus 
Leptcena,  of  great  prominence  in  Silurian  and  Devonian  time,  had  its 
last  species,  as  large  as  apple-seeds,  in  the  Triassic. 

(3.)  Trilobites  began  at  the  same  time,  in  loose-jointed  or  flabby 
species,  with  very  large  overgrown  bodies  and  poor  heads,  passed  their 
climax  in  number,  and  apparently  in  grade,  in  the  Silurian,  and  dis 
appeared,  according  to  present  evidence,  at  the  close  of  the  Paleozoic. 

(4.)  Ganoid  fishes  began  in  the  Upper  Silurian,  with  vertebrated 
tails ;  rose  out  of  this  inferior  condition,  and  passed  their  climax,  as  to 


598  GEOLOGICAL   HISTORY. 

numbers  and  variety  of  genera,  in  the  Mesozoic ;  and  now  they  are  a 
nearly  extinct  group. 

(5.)  Amphibians,  beginning  in  the  Subcarboniferous,  were,  in  the 
Carboniferous  age  and  the  Triassic  period,  the  most  prominent  kind 
of  Reptilian  life,  and  of  formidable  size,  with  scaly  armor,  and  teeth  ; 
after  that,  they  dwindled ;  and  now  the  tribe  is  represented  only  by 
little,  inferior,  naked-skinned  Frogs  and  Salamanders. 

(6.)  True  ^Reptiles,  which  began  in  the  Carboniferous,  had  posses 
sion  of  the  waters,  the  land,  and  the  air,  in  the  later  Mesozoic,  and 
far  exceeded,  in  size,  in  variety,  and  vastly  also  in  numbers,  the  Reptiles 
of  the  present  era ;  great,  swimming,  snake-like  Mosasaurs,  having  a 
length  of  seventy  five  feet ;  swimming  Enaliosaurs,  of  twenty  to  fifty 
feet ;  Dinosaurs,  sometimes  walking  like  bipeds,  fifteen  feet  high  ;  and 
Pterosaurs,  flying  bat-like,  with,  in  some  cases,  a  spread  of  wings  of 
twenty  to  twenty-five  feet. 

(7.)  Molhjsks  of  the  highest  class  —  that  of  the  Cephalopods  — 
began  in  the  Silurian,  in  kinds  having  straight,  chambered  shells  ; 
coiled  forms  followed ;  and  then,  in  the  Mesozoic,  a  wonderful  variety 
of  the  most  complex  and  largest  kinds,  with  and  without  shells,  existed  ; 
but  nearly  every  genus  with  chambered  external  shells  disappeared  at 
the  close  of  the  Mesozoic ;  and  now  the  only  species  are  three  or  four 
of  the  Silurian  and  all-time  genus,  Nautilus. 

These  examples  are  enough  to  prove  that  the  culmination  of  types, 
and  then  a  dwindling  in  numbers,  size,  and  grade,  have  always  been 
involved  in  the  system  of  progress.  At  the  same  time,  many  tribes, 
on  the  same  principle,  have  their  era  of  culmination  now.  This  is 
true  of  Gasteropods,  among  Mollusks,  of  Birds,  of  the  higher  Insects, 
of  Teliost  Fishes,  probably  of  Crustaceans.  Mammals  culminate  now 
in  Man,  while  brute  Mammals  reached  their  climax  in  the  Champlain 
period  of  the  Quaternary.  Other  examples  of  the  condition  of  some 
of  the  more  prominent  tribes  through  time  are  presented  in  the  tables 
on  pages  386,  589. 

7.  (1.)  The  earliest  species  under  a  type  are  not  necessarily  the  low 
est. —  If  we  may  trust  the  records,  Echinoderms,  or  the  highest  type 
of  Radiates,  were  represented  by  species  (Cystids  and  Crinids),  long 
before  the  inferior  type  of  Polyps  existed;  this  can  hardly  be  ac 
counted  for  satisfactorily  on  the  supposition  that  the  earliest  Polyps 
made  no  calcareous  secretions,  seeing  that  the  ocean's  waters  were  then 
eminently  calcareous.  (2.)  The  highest  group  of  Cryptogams,  the 
Ground  Pines,  were  a  prevailing  form  of  terrestial  vegetation,  long 
before  there  were  Mosses.  (3.)  There  were  huge  Crocodilians  in  the 
world,  long  before  there  were  limbless  Snakes,  like  those  of  the  present 
world.  The  great  Labyrinthodonts  were  vastly  superior  in  every  re- 


PROGRESS    OF   LIFE.  599 

spect  to  modern  Frogs  and  Salamanders.  The  Labyrinthodonts  fol 
lowed  in  the  expanding  line  of  the  Ganoids;  while  the  Frogs  of 
modern  time  are  an  example  of  the  degradation  of  an  old  type.  Thus 
it  is  often  the  case  that  tribes  have  dwindled  below  the  level  of  their 
first  species.  This  necessarily  follows  from  the  principle  stated  on 
page  597.  A  tribe  fitted  to  the  equable  climate  of  Paleozoic  time 
would  naturally  have  become  degraded,  under  a  later  colder  climate  or 
other  untoward  circumstances. 

8.  Peculiarities  in  the  Fauna  or  Flora  of  a  continent  or  region  con 
tinue  on  through  successive  geological  eras.  —  Marked  examples  of  a 
correspondence  between  the  Quaternary  and  existing  life  of  the  con 
tinents  are  mentioned  on  page  571.     Again,  the   Plants  characteristic 
of  the  Cretaceous  era,  in  North  America,  belonged  mainly  to  families 
that  are  characteristic  of  the  present  time.     Cases  of  this  kind  are 
nnmerous  ;  and  exceptions  are  largely  due  to  migrations  on  one  hand, 
and  extinctions  of  groups  on  the  other. 

9.  Tiie  existence  of  Representative  Species  in  different  regions  a  pos 
sible  consequence  of  migration.  —  On  each  continent,  there  have  been, 
in  each  geological  period,  not  only  some  living  species  identical  with 
those  of  another  continent,  but  also  a  larger  number  that  were  closely 
similar    without    being    quite    identical,    and  which  have  hence  been 
called  representative  species ;  at  the  same  time,  these  species  on  either 
continent  have  continental  or  regional  peculiarities  that  look  like  the 
impress  of  the  region.     Such  parallel  lines  of  representative  species 
suggest  the  idea  of  origin  through  migration  in  a  former  period,  and, 
after  that,  gradual  alteration  under  the  new  regional  influences.     On 
the  Atlantic  and   Pacific  sides  of  Central  America,  there  are  many 
such  representative  species ;  and  they  have  been  regarded  as  an  ex 
ample  under  this  principle. 

The  continents,  as  well  as  the  oceans,  radiate  off  from  the  Arctic 
zone ;  and,  consequently,  in  the  period  of  Glacial  cold,  Arctic  species 
were  forced  far  south  along  the  several  continents  and  oceans,  some 
even  to  the  Mediterranean  (pp.  532,  533);  leading  thus  to  the  distribu 
tion  of  the  same  species  over  widely  different  meridians  and  climates, 
and  to  the  formation,  in  each,  of  new  varieties.  In  the  Miocene  Ter 
tiary,  there  was  a  comparatively  mild  climate  in  the  Arctic  zone ;  and 
forests  abounded.  As  the  climate  became  cooler  with  the  progress  of 
the  Tertiary  age  (p.  526),  the  trees  of  the  forests  should  have  spread 
farther  and  farther  south,  along  the  different  continents  or  meridians, 
according  as  the  climate  in  either  direction  was  congenial ;  similar 
kinds  along  eastern  America  and  eastern  Asia,  because  of  the  similarity 
of  climate,  and  other  kinds  along  other  lines.  A  number  of  the 
genera  and  some  of  the  species  that  then  abounded  in  the  Arctic  are 


600  GEOLOGICAL   HISTORY. 

actually  distributed  on  the  plan  here  indicated  (p.  526).  These  facts 
suggest  again  migration  and  subsequent  alteration,  under  the  new 
regional  influences  as  the  cause,  as  urged  by  Professors  Asa  Gray 
and  Heer. 

10.  The  existence  of  Representative  Species  not  always  a  consequence 
of  migration.  —  On    antipodal    continents,  —  as,  for    example,  North 
America  and  Australia,  —  there  were  in  early  time  both  identical  and 
representative  species.     And  now,  in  insular  New  Zealand,  there  are 
Crustaceans  closely  representative  of  some   in  its  antipodes,  insular 
Britain,  in  the  case  of  which  migration  cannot  be  shown  to  be  probable, 
or  hardly  in  any  way  possible.     Such^facts  suggest  that  the  succession, 
in  the  species  of  different  continents,  may  have  been  carried  forward 
independently,  even  to  the  introduction  of  closely  similar  species. 

11.  The  transitions  between  Species,  Genera,  Tribes,  etc.,  in  geological 
history,  are,  with  rare  exceptions,  abrupt.  —  Geological  history   being 
prominently  a  history  of  the  world's  life,  it  is  naturally  looked  to  for 
facts  respecting   the  first  appearance  of  species,   or  the   relations  of 
species,  by  transitions  or  otherwise,  to  one   another.     A  survey  of  the 
history  finds  little  that  is  positive  with  regard  to  these  transitions.     It 
discovers,  as  all  writers  admit,  almost  no  cases  of  the  gradual  passage 
of  one  species  into  another,  riot  nearly  as  many  or  as  close  as  exist  in 
the  present  world.     At  the  same  time,  the  truth  is  apparent  that  the 
geological  record  is  very  imperfect,  so  much  so  as  to  greatly  weaken 
all  its  testimony,  with   regard  to  abrupt  transitions.    It  is  imperfect, 
(1)  because,  under  the  most  favorable  circumstances,  only  a  small  part 
of  the  existing  species  could  have  been  fossilized  ;  (2)  because  in  all 
lands  there  are  great  breaks  in  the  series  of  rocks,  as  we  know  from 
comparing  the  rocks  of  different  continents,  and  even  different  regions 
on    the    same    continent;   (3)   because    fossiliferous  rocks  are  almost 
solely  of  aqueous  origin,  and  consequently  they  contain   exceedingly 
little  of  the  terrestrial  life  of  the  ancient   world  ;  (4)  because,  when 
ever  the  land  was  at  a  higher  level  than  the  present,  the  marine  strata 
then  formed  around  it  are  now  buried  in  the  ocean  and  are  therefore 
inaccessible  ;   (5)  because  only  a  small  part  of  the  rocks  of  a  country 
are  open  to  view ;  and  (6)  because  the  continents  have  not  been  all 
thoroughly  explored. 

For  example :  (a)  in  North  America,  east  of  the  Mississippi,  there 
is  not  a  trace  of  the  life  of  the  seas  of  the  Triassic  and  Jurassic  peri 
ods,  two  thirds  of  all  Mesozoic  time  —  the  Triassic  and  what  there 
is  of  Jurassic  beds  being  of  brackish- water  or  fresh-water  origin,  (b.) 
In  the  American  Triassic  and  Jurassic  beds,  the  jaw-bones  of  two  mar 
supial  Mammals  have  been  found ;  and  these  two  are  the  only  relics 
of  Mammals  from  the  whole  Mesozoic  of  the  continent,  when  the 


PROGRESS    OF   LIFE.  601 

world  was  probably  well  peopled  with  them,  (c.)  Again,  the  Car 
boniferous  age  left  testimony  as  to  the  kinds  of  vegetation  that  grew 
about  and  in  its  great  marshes.  But  it  affords  nothing  with  re 
gard  to  the  forests  that  covered  the  higher  parts  of  the  continent 
in  its  higher  latitudes,  or  west  of  the  100th  meridian.  Again,  in  the 
Triassic  and  Jurassic  periods,  the  land  was,  we  cannot  doubt,  as  abun 
dantly  covered  with  vegetation  as  in  the  Carboniferous  age ;  and  yet 
we  have  only  a  very  meagre  record  from  the  American  rocks,  and  one 
but  little  better  from  those  of  Europe,  (d.)  The  Jurassic  period  in 
P^urope  must  have  had  in  every  part  its  numerous  Birds  ;  and  yet  we 
know  them,  thus  far,  only  from  the  discovery  of  one  single  specimen 
at  Solenhofen. 

A  broken  record  the  geological  undoubtedly  is,  especially  for  ter- 
restial  life.  The  marine  life,  particularly  that  of  the  Paleozoic,  is 
better  displayed;  since  marine  formations  were  then  more  extensively 
in  progress  over  the  Continental  seas  than  later ;  and  the  life  of  the 
world  was  also  much  alike  in  the  two  hemispheres. 

Such  facts  invalidate  the  force  of  geological  testimony,  but  without 
proving  that  abruptness  of  transition  was  not  still  a  general  fact. 

(e.)  The  force  of  the  evidence  is  further  weakened  by  discoveries 
made  from  time  to  time,  that  diminish  some  of  the  wider  gaps  among 
the  abrupt  transitions.  Thus,  the  Horse,  an  animal  with  one  large  toe 
making  the  whole  foot,  and  no  relics  of  other  toes,  excepting  two 
slender  bones  either  side,  —  called  the  splint-bones,  —  has  been  found 
(as  shown  on  page  oOo)  to  have  been  preceded  in  Tertiary  times  by 
other  Horses,  with  real  toes  in  place  of  the  splint-bones ;  and  thus  a 
transition  has  been  made  out  toward  related  animals  with  a  foot  of 
four  or  five  toes.  Again,  the  Birds,  now  standing  apart  so  stiffly,  as 
animals  with  bills  and  feathers  and  short  tails,  in  former  times  had 
teeth  in  their  jaws  (p.  4G6),  and  long  tails  (p.  446),  and,  moreover,  in 
the  Reptilian  age,  there  were  biped  Reptiles,  with  the  hollow  bones 
and  some  other  characteristics  of  Birds  (p.  413). 

Arctic  America  contains,  in  Tertiary  fossils,  remains  of  plants  so 
much  like  species  existing  in  the  forests  of  both  temperate  North 
America  and  Europe  (p.  526),  that  the  former  have  been  pronounced 
the  undoubted  progenitors  of  the  latter. 

But,  while  such  discoveries  have  been  made  in  many  directions, 
they  have  still  left,  with  rare  exceptions,  abrupt  transitions  between 
genera  or  groups  ;  and  in  hardly  a  case  in  the  animal  kingdom  have 
they  yet  filled  out  all  gradations. 

The  admitted  imperfections  in  geological  history,  owing  to  poor 
records,  and  these  not  half  consulted,  lead  the  cautious  geologist  to 
wait,  before  dogmatizing. 


602  GEOLOGICAL    HISTORY. 

(/.)  But  there  are  a  few  breaks  of  extraordinary  character,  deserving 
special  consideration.  The  first  Vertebrates,  Fishes,  start  off  suddenly 
in  the  Upper  Silurian ;  and  no  trace  of  connecting  links  with  Mollusk 
or  Articulate  has  been  found.  The  Ascidian  has  been  put  forward  as 
the  origin  ;  but  no  intermediate  forms  between  the  Ascidian  and  Ver 
tebrate  exist  among  fossils ;  and,  moreover,  as  Verrill  has  observed,  after 
a  thorough  study  of  the  tribe,  the  alleged  relation  to  the  Vertebrates  is 
without  the  slightest  foundation  in  their  structure.  The  modern  Am- 
phioxus,  —  a  very  small  fish  without  a  brain,  —  has  been  made  to  fill 
the  gap.  But,  although  seemingly  fitted  for  the  place,  it  may  be  only 
degradational,  and  of  comparatively  modern  development.  The  rocks 
have  given  us  110  hint  as  to  its  existence  in  Silurian  times,  or  that  of  any 
other  transitional  species.  Thus  the  gap  is  yet  large,  and,  considering 
that  Silurian  rocks  have  afforded  various  embryonic  forms  in  the 
development  of  species  of  Trilobites,  it  is  strange  that  nothing  has 
been  found  to  illustrate  the  successive  steps  in  the  origin  of  the  grand 
sub-kingdom  of  Vertebrates.  It  is  possible  that  further  search  may 
be  successful. 

In  the  Cretaceous  formation  of  North  America,  leaves  of  plants  of 
modern  type  —  the  Angiosperms,  like  the  Willow,  Elm,  Magnolia, 
etc.,  and  the  Palms  —  occur,  and  exhibit  a  totally  different  character 
in  forest  vegetation  from  that  of  the  preceding  period  ;  and  the  same 
abrupt  transition  has  been  observed  in  Europe  and  other  countries.  A 
long  interval  may  have  existed  between  the  Jurassic  and  Cretaceous  in 
some  regions,  but  hardly  in  all ;  and  if,  after  more  complete  investi 
gation,  this  distinction  of  the  Jurassic  and  Cretaceous  periods  remain, 
we  may  have  to  look  to  some  other  reason  for  this  abrupt  transition 
than  that  from  imperfect  records. 

In  the  early  Tertiary,  the  world,  as  the  fossils  show,  was  full  of  true 
Mammals,  related  to  the  Tapirs  and  other  kinds,  many  of  great  size ; 
while  no  such  Mammal  has  yet  been  detected  in  any  earlier  beds. 
It  is  undoubtedly  true  that  the  break  in  the  records,  with  regard  to  the 
era  preceding  the  Tertiary,  is  great ;  but  this  fact  does  not  supply  all 
that  Science  needs  for  a  perfectly  confident  explanation  of  the  break  in 
the  system  of  Mammalian  life.  In  the  coal-bearing  formation  over 
lying  the  Cretaceous,  in  the  Rocky  Mountain  region,  there  are  the 
bones  of  Dinosaurs  ;  while  in  the  Eocene  beds,  resting  on  these,  there 
are  remains  of  a  wonderful  variety  of  Mammals,  some  of  elephantine 
size.  Probably  a  long  time  intervened  between  the  eras  of  the  coal- 
beds  and  of  the  Tertiary  bone-beds.  But  however  long  the  time  that 
may  be  claimed,  the  abruptness  of  the  transition  is  astounding,  and 
needs  facts  for  its  full  elucidation.  The  same  abruptness  in  the  intro 
duction  of  the  Tertiary  Mammals  occurs  in  the  beds  of  other  conti- 


PROGRESS    OF   LIFE.  603 

nents,  as  well  tropical  India  as  colder  Europe.  In  some  regions,  the 
Cretaceous  beds  are  of  deep-water  origin ;  and  hence  they  are  not  the 
place  to  look  for  terrestrial  fossils.  But  this  is  not  true  of  the  Rocky- 
Mountain  or  Atlantic-border  deposits  of  North  America,  nor  of  those 
of  many  localities  on  other  continents. 

(g.}  In  the  case  of  Man,  the  abruptness  of  transition  is  still  more 
extraordinary,  and  especially  because  it  occurs  so  near  to  the  present 
time.  In  the  highest  Man-ape,  the  nearest  allied  of  living  species  has 
the  capacity  of  the  cranium  but  thirty -four  cubic  inches ;  while  the 
skeleton  throughout  is  not  fitted  for  an  erect  position,  and  the  fore- 
limbs  are  essential  to  locomotion  ;  but,  in  the  lowest  of  existing  men, 
the  capacity  of  the  cranium  is  sixty-eight  cubic  inches,  every  bone  is 
made  and  adjusted  for  the  erect  position,  and  the  fore-limbs,  instead  of 
being  required  in  locomotion,  are  wholly  taken  from  the  ground,  and 
have  other  higher  uses.  Forty  years  since,  Schmerling  found  fossil 
bones  of  ancient  Man  in  Europe ;  arid  for  the  past  fifteen  years  active 
search  has  gone  forward  for  the  missing  links  ;  and  still  the  lowest 
yet  found,  —  and  this  probably  not  the  oldest,  —  has  a  cranium  of 
seventy-five  cubic  inches  capacity.  Some  of  the  oldest  yet  discovered 
have  a  large  cranium  and  a  high  facial  angle,  although  rude  in  imple 
ments  and  mode  of  life.  No  remains  bear  evidence  to  less  perfect 
erectness  of  structure  than  in  civilized  man,  or  to  any  nearer  approach 
to  the  Man-ape  in  essential  characteristics. 

The  existing  Man-apes  belong  to  lines  that  reached  up  to  them  as 
their  ultimatum  ;  but,  of  that  line  which  is  supposed  to  have  reached 
upward  to  Man,  not  the  first  link  below  the  lowest  level  of  existing 
Man  has  yet  been  found.  This  is  the  more  extraordinary,  in  view  of 
the  fact  that,  from  the  lowest  limit  in  existing  men,  there  are  all  pos 
sible  gradations  up  to  the  highest ;  while,  below  that  limit,  there  is  an 
abrupt  fall  to  the  ape  level,  in  which  the  cubic  capacity  of  the  brain  is 
one  half  less.  If  the  links  ever  existed,  their  annihilation  without  a 
relic  is  so  extremely  improbable  that  it  may  be  pronounced  impossible. 
Until  some  are  found,  Science  cannot  assert  that  they  ever  existed. 

The  facts  which  have  been  stated  bear  upon  the  question  of  the 
Origin  of  Species.  In  order  to  reach  a  probable  solution  of  the  great 
problem,  various  facts  and  principles  from  other  sources  have  to  be 
considered,  whose  discussion  here  would  be  out  of  place.  In  view  of 
the  whole  subject,  the  following  appear  to  be  the  conclusions  most 
likely  to  be  sustained  by  further  research. 

1.  The  evolution  of  the  system  of  life  went  forward  through  the 
derivation  of  species  from  species,  according  to  natural  methods  not 


604  GEOLOGICAL   HISTORY. 

yet  clearly  understood,  and  with  few  occasions  for  supernatural  inter 
vention.1 

2.  The  method  of  evolution  admitted  of  abrupt  transitions  between 
species ;    as  has  been  argued   by  Hyatt  and   Cope,  from  the  abrupt 
transitions  that  occur   in   the  development  of  animals   that  undergo 
metamorphosis,    and    the    successive  stages   in    the  growth  of  many 
others. 

3.  External    agencies    or   conditions,   while    capable   of  producing 
modifications  of  structure,  have  had  no  more  power  toward  determin 
ing  the  directions  of  progress  in  the  evolution,  than  they  now  have  m 
determining  the  course  of  progress  in  development  from  a  living  germ. 

4.  For  the  development  of  Man,  gifted  with  high  reason  and  will, 
and  thus  made  a  power  above  Nature,  there  was  required,  as  Wallace 
has  urged,  the  special  act  of  a  Being  above  Nature,  whose  supreme 
will  is  not  only  the  source  of  natural  law,  but  the  working  force  of 
Nature  herself. 

1  There  is  here  no  discordance  with  the  Biblical  account  of  Creation,  since,  in  it, 
there  is  one  fiat  for  the  first  introduction  of  life,  and  only  three  others  for  that  of  the 
animal  kingdom;  and,  moreover,  the  language  implies  growth  for  the  rest,  through 
law  established  bj  the  fiats. 


PART  IV. 
DYNAMICAL    GEOLOGY. 


DYNAMICAL  GEOLOGY  treats  of  the  causes  of  events  in  the  earth's 
geological  progress. 

These  events  include  :  the  formation  of  all  rocks,  stratified  and  mi- 
stratified,  with  whatever  they  contain,  from  the  earliest  Archaean  to 
the  modern  beds  of  gravel,  sand,  clay,  and  lava ;  the  oscillations  of  the 
earth's  crust ;  the  increase  of  dry  land,  elevation  of  mountains,  and 
elimination  of  the  surface-features  of  the  globe ;  the  changes  of  cli 
mate  ;  the  changes  of  life. 

The  causes  or  agencies  that  have  been  engaged,  exclusive  of  life, 
have  acted  for  the  most  part  through  the  atmosphere,  waters,  and 
rock-material.  But  they  are  based  necessarily  on  the  general  powers 
of  Nature,  —  Heat,  Light,  Electricity,  and  Attraction.  These  funda 
mental  powers  have  their  universal  laws,  —  as  the  law  of  gravitation, 
according  to  which  falling  bodies  move ;  the  laws  of  chemical  attrac 
tion,  according  to  which  compounds  are  formed  and  decompositions 
take  place  ;  the  laws  of  cohesion  or  crystallization,  according  to  which 
solidification  produces  crystals,  or  a  crystalline  structure  ;  the  laws  of 
heat,  as  regards  conduction,  expansion,  etc.,  and  the  influence  of  heat 
on  chemical  changes  and  growth ;  the  laws  of  light,  as  to  its  nature, 
and  its  action  in  chemical  changes  and  growth,  etc. ;  the  laws  of  elec 
tricity  and  magnetism  :  all  of  which  the  geologist  cannot  understand 
too  well.  But  the  discussion  of  these  topics  belongs  properly  to  a 
treatise  on  Physics.  The  laws  of  solidification  are,  however,  briefly 
considered  in  this  place,  on  account  of  their  bearing  on  the  structure 
of  rocks. 

In  addition  to  the  general  operation  of  forces,  there  are  other  ac 
tions,  that  may  be  embraced  under  the  term  climatological,  which 
proceed  from  the  systematic  arrangement  and  movement  of  heat,  light, 
moisture,  and  electricity  about  the  sphere  (causing  zones  of  tempera 
ture,  varieties  of  climate,  etc.),  and  also  from  the  systems  of  atmos- 


606  DYNAMICAL   GEOLOGY. 

pheric  and  oceanic  circulation.  The  general  facts  on  these  topics  are 
briefly  stated  on  pp.  38-46,  which  may  well  be  reviewed  before  pro 
ceeding  with  the  following  pages.  In  treatises  on  Physical  Geogra 
phy,  these  subjects  may  be  studied  at  greater  length,  by  the  geological 
student,  with  much  advantage. 

The  subject  of  dynamical  geology  is  here  treated  under  the  follow 
ing  heads : — 

1.  Life  ;  2.  Cohesive  and  Capillary  attraction  ;  3.  The  Atmosphere: 
4.  Water  ;  5.  Heat ;  6.  Consequences  of  the  earth's  cooling,  and  the 
Evolution  of  the  general  features  of  the  globe  ;  7.  In  recapitulation, 
Effects  referred  to  their  Causes. 

The  chemistry  of  rocks,  or  the  chemical  processes  concerned  in  their 
origin  and  metamorphism,  embracing  a  consideration  of  Life,  the  At 
mosphere,  Water,  Light,  and  Heat  as  chemical  agents,  would  naturally 
constitute  another  section,  under  the  title  of  Chemical  Geology.  But, 
since  its  proper  elucidation  would  require  a  large  amount  of  space, 
and  its  study  a  minute  knowledge  of  the  principles  of  Chemistry,  the 
subject  is  not  taken  up  in  detail  in  this  Manual.  Some  of  the  more 
common  facts  are  mentioned,  under  the  head  of  Water  as  a  chemical 
agent  (p.  687). 

I.  LIFE. 

1.  PROTECTIVE  EFFECTS. 

The  protective  effects  of  life  come  chiefly  from  vegetation. 

1.  Turf  protects  earthy  slopes  from  the  wearing  action  of  rills  that 
would  gully  out  a  bare  surface  ;  and  even  hard  rocks  receive  protec 
tion  in  the  same  way. 

2.  Tufts  of  grass  and  other  plants  over  sand-hills,  as  on  sea-shores, 
bind  down  the  moving  sands. 

3.  Lines   of  vegetation  along  the  banks   of  streams   prevent  wear 
during  freshets.     When  the  vegetation  consists  of  shrubs  or  trees,  the 
stems  and  trunks  entangle  and  detain  detritus  and  floating  wood,  and 
serve  to  increase  the  height  of  the  margin  of  the  stream. 

4.  Vegetation  on  the  borders  of  a  pond  or  bay  serves  in  a  similar 
manner  as   a  protection   against   the   feebler  wave-action.     In   many 
tropical   regions,  plants   growing   at  the  water's  edge,  like  the  man 
grove,  drop  new  roots  from  the  branches  into  the  shallow  water,  which 
act  like  a  thicket  of  brush-wood,  to  retain  the  floating  leaves,  stems, 
and  detritus  ;  and,   as   the   water   shallows,   other  roots  are   dropped 
farther  out,  which  are  attended  with  the  same  effect ;  and  thus  they 
keep  moving  outward,  and  subserve  the  double  purpose  of  protecting 
and  making  land.     The  coarse  salt-marsh  grasses  along  sea-shores  per- 


LIFE.  607 

form  the  same  kinds  of  geological  work,  being  very  effectual  agents  in 
entangling  detritus,  and  in  protecting  from  erosion. 

5.  Patches  of  forest-trees,  on  the  declivities  in  Alpine  valleys,  serve 
to  turn  the  course  of  the  descending  avalanche,  and  entangle  snows 
that,  but  for  the  presence  of  the  trees,  would  only  add  to  its  extent ; 
and,  in  the  Alps,  such  groves,  wherever  existing,  are  usually  guarded 
from   destruction,  with  great   care.     Forests  also  retard  the   melting 
of  snow  and  ice  in  spring,  and  thus   lessen   the  destructive  effects  of 
floods. 

6.  The  calcareous  Alga?,  called  Nullipores  (p.  135),  served  to  pro 
tect  the  margins  of  coral   reefs   from  wear  ;  and  ordinary    seaweeds 
often  cover  and  protect  the  rocks  of  a  coast  nearly  to  high-tide  level. 

2.  TRANSPORTING  EFFECTS. 

1.  Seeds  are  often  caught  in  the  hair  or  far  of  animals,  and  are  thus 
transported  from  place  to  place. 

2.  Seeds  are  eaten  by  animals  as  food,  or  in  connection  with  their 
food,  which  sometimes  pass  out  undigested,  and  become  planted  in  a 
new  region  ;  and,   in  the  case  of  birds   and  other    animals  on   their 
migration,  they  may  be  carried  far  from  the  place  where  gathered. 

3.  Ova  of  fish,  reptiles,  and   inferior  animals   are   supposed  to   be 
transferred  from   one  region  to  another  by  birds  and  other  animals. 
Authenticated  instances  of  this  are  wanting. 

4.  Floating  logs  or  plants  carry  living  species  from  one  part  of  the 
ocean  to  another,  along  the  courses  of  marine  currents.     Sometimes 
they  carry  land  and  fresh-water  shells,  etc.,  from  rivers  into  estuaries 
or  the  sea,  there  to  become  mingled  with  marine  shells ;  also  stones. 

5.  Migrating   tribes  of  men  carry,  in  their  grain,  or  otherwise,  the 
seeds  of  various  weeds,  and  also,  involuntarily,  rats,  mice,  cockroaches, 
and  smaller  vermin  ;  also  insects  injurious  to   vegetation,   and  other 
kinds.     The  origin  of  tribes  may  often  be  inferred  from  the  species  of 
plants  and  of  domesticated  and  other   animals  found  to   have  accom 
panied  them. 

3.  DESTRUCTIVE  EFFECTS. 

The  destructive  effects  proceed  either  from  living  plants  or  animals, 
or  from  the  products  of  decomposition. 

1.  The  roots  which  come  from  the  sprouting  of  a  seed  in  the  crevice 
of  a  rock,  as  they  increase  in  size,  act  like  wedges,  in  tending  to  press 
the  rock  apart ;  and,  when  the  roots  are  of  large  size,  masses  tons  in 
weight  may  be  torn  asunder  ;  and,  if  on  the  edge  of  a  precipice,  the 
detached  blocks  may  be  pushed  off,  to  fall  to  its  base.  This  is  one  of 
the  most  effective  causes  of  the  destruction  of  rocks.  Many  regions 


DYNAMICAL    GEOLOGY. 

of  massive  and  jointed  rocks  are  thickly  covered  with  huge  blocks, 
looking  like  transported  bowlders,  which  are  the  results  of  this  kind 
of  upturning.  The  opening  of  fissures  by  roots  also  gives  access  to 
moisture,  and  thus  contributes  further  to  rock  destruction. 

2.  Boring  animals,  like  the  saxicavous  Mollusks,  make  holes  often 
as  large  as  the  finger,  and  sometimes  larger,  in  limestone  and  other 
rocks,  along  some  sea-shores.     Species  of  Saxicava,  Pholas,  Petricola, 
Lithodomus,    Gastrochcena,  and  even    some    Gasteropods,    Barnacles, 
Annelids,  Echini,  and  Sponges,  have  this  power  of  boring  into  stone. 
Various  species  also  bore  into  shells  or  corals  ;  arid  the  animal  of  the 
shell  is   thus   often  killed,  and  the  crumbling  of  the  shells  and  corals 
is  much  hastened.     The  Termites  and  many  other  insects,  especially 
in  the   larval  state,  the  Limnnria  among  Crustaceans,  and  the  Teredo 
among  Mollusks,  bore  into  wood. 

3.  The   tunnelling  of  the   earth  done  by  small   quadrupeds,  as  the 
Mole,  and  by  Crustaceans  like  the  Craw-fish,  sometimes  results  in  the 
draining  of  ponds,  and  the  consequent  excavation  of  gullies  or  gorges 
by  the  outflowing  waters.     The  tunnelling  of  the  levees   of  the  Mis 
sissippi  by  Craw-fish  is  one  prominent  cause  of  breaks,  and  thereby 
of  great  floods  over  the  country. 

4.  The  decay  of  vegetation  about  rocks  often  produces  carbonic 
acid    or    different   vegetable  acids,  which   become    absorbed    by   the 
moisture  of  the  soil,  and  thus  penetrate  the  crevices  of  rocks  and  pro 
mote  their   decomposition.      This    is  properly   one  of  the   chemical 
effects  of  life. 

5.  Animals  using  Mollusks  and  Echinoderms  as  food  make  great 
refuse-heaps,  or  beds  of  broken  shells.    The  animals  include  Man,  as 
well  as  other   species ;  and  the  beds  made  by  fishes  off  the  coast  of 
Maine,  as  described  by  Verrill  (who  has  drawn  attention  to  this  mode 
of  making  broken  shells),  are  of  great  extent.     They  might  be  taken 
for  beach-deposits. 

6.  Fungi  attack  dead  plants  and  animals,  and  rapidly  destroy  them. 

7.  The  destruction  also  of  the  vegetation  of  a  region  by  insect  life, 
and  that  of  animals  by  one  another,  are  of  geological  importance. 

4.  CONTRIBUTIONS  TO  ROCK  FORMATIONS. 

The  capability,  on  the  part  of  Life,  of  contributing  to  the  material  of 
rocks,  depends  on  several  considerations,  of  which  the  following  are 
the  more  prominent :  — 

1.  The   conditions  favoring  or  limiting  growth  and  distribution, — 
that  is,  the  laws  of  geographical  distribution  of  living  species. 

2.  The  nature  of  different  organic  products,  and  the  fitness  of  the 
species  affording  them  for  making  fossils  or  rocks. 


LIFE. 


609 


After  discussing  these  subjects,  some  of  the  methods  of  contributing 
to  rock-formations  are  mentioned  under  the  heads,  — 

3.  Methods  of  fossilization  and  concretion. 

4.  Examples  of  the  formation  of  strata  through  the  agency  of  Life. 

1.  Geographical  Distribution. 

The  subject  of  the  geographical  distribution  of  plants  and  animals, 
though  highly  important  in  this  connection,  cannot  be  satisfactorily 
treated  in  a  brief  chapter ;  and  the  student  is  therefore  referred  to 
treatises  on  this  branch  of  science.  Its  general  principles  and  bearing 
are  all  that  can  here  be  explained. 

A.  The  distribution  of  terrestrial  plants  and  animals  is  limited  by 
different  causes. 

1.  Climate.  —  The  temperature  to  which  each  is  adapted  in  its  na 
ture  determines,  within  certain  limits,  its  position  in  the  zones  between 
the  equator  and  the  poles,  and  also,  under  any  zone,  its  special  alti 
tude,  between  the  level  of  the  sea  and  the  height  of  perpetual  snow. 

Meyen  divides  heights,  under  the  equator,  from  the  sea  to  the  level  of  16,200  feet,  — 
that  of  perpetual  snow,  —  into  eight  zones  or  regions,  — beginning  below,  naming  them 

from  the  characteristic  plants:  — 

Feet. 

1.  Palms  and  Bananas, 0 

2.  Tree-ferns  and  Firs 2,020 

3.  Myrtles  and  Laurels, 4,050 

4.  Evergreen  dicotyledonous  trees,  ....  6,120 

5.  European  dicotyledonous  trees,       ....  8,100 

6.  Pines,    .                 10,140 

7.  Rhododendrons, 12,150 

8.  Alpine  plants 14,170 

The  corresponding  zones  in  latitude,  at  the  sea  level,  — setting  aside  variations  from 
special  currents,  are,  — 

1.  Equatorial,     .        .       Lat.  0°-15°        5.  Cold-temperate,       .     Lat.  45°-58° 

2.  Tropical,      .        .        .        15c-23°        6.  Subarctic,    .        .        .        58°-66° 

3.  Subtropical,    .        .        .     23°-34°        7.  Arctic,     ....     66°-78° 

4.  Warm-temperate,        .        34°-45°        8.  Polar,  ....        78°-88° 
Beyond  88°,  vegetation  is  supposed  to  be  at  present  wanting. 

Temperature,  during  the  period  of  flowering  and  fruiting  of  plants, 
and  during  the  reproductive  period  of  animals,  often  determines  their 
geographical  limits. 

Again,  the  amount  of  moisture  for  which  a  species  is  made  deter 
mines  its  position  in  either  a  moist  or  an  arid  region. 

Each  continent  has  its  own  characteristic  climate,  arising  mainly 
out  of  its  special  combination  of  these  two  elements,  temperature  and 
moisture  ;  and  this  is  one  source  of  the  great  diversity  of  life  among 
the  continents.  Another  point  in  which  the  climate  of  continents 
differs  is  the  limit  of  extreme  heat  and  cold.  For  example.  North 


610  DYNAMICAL    GEOLOGY. 

America,  owing  to  its  extent  in  latitude,  from  the  Arctic  circle  to  the 
hot  tropics,  is  remarkable  for  its  very  wide  extremes.  The  severe 
cold  of  winter  passes  over  the  land  to  the  far  south,  destroying  what 
ever  cannot  stand  its  power ;  and  the  summer's  intense  heat  sweeps 
back  again,  with  a  similar  effect ;  so  that  the  continent  cannot  grow 
as  many  kinds  of  terrestrial  plants  or  animals  as  that  on  the  opposite 
side  of  the  Atlantic. 

2.  Continental  idiosyncrasies^  or  peculiarities  that  cannot  be  referred 
to  climate.     Each  continent  has  its  characteristic  types  of  plants  and 
animals.     The  Marsupials,  in  Australia,  and  Edentates  or  Sloth  tribe, 
in  South  America,  are  examples  ;  the   sedate  Platyrrhirie  Monkeys, 
in  South  America,  and   the  nimble  frolicsome  Catarrhines,  in  Africa, 
are  others  ;  so  also  the  abundance  of  Humming-birds  in  the  Occident, 
and  their  absence  in  the  Orient.     Examples  might  be  mentioned  in 
definitely.     Moreover,  the   range  of  animal  life,  or  that  of  vegetable 
life,  has  often  a  continental  feature. 

3.  Diversities  of  soil.  — r  Some  plants  require  wet  soil,  others  mode 
rately  dry,  others   arid  ;  some   rich,  others  sandy,  others  a  surface  of 
rock ;  some   the  presence  of  limestone,   others    of  rocks    containing 
silica,  etc.;  some  the  presence  of  salt,  or  a  salt  marsh. 

B.  The  distribution  of  aquatic  species  is  determined — 1.  By  the 
character  of  the  water,  whether  fresh,  brackish,  or  salt,  pure  or  impure 
from  mixed  sediment ;  and  but  few  species  adapted  for  one  condition 
survive  in  the  other.  Hence,  changing  a  salt  lake  to  a  fresh  one,  or 
even  making  an  addition  of  fresh  waters  which  exceeds  much  the 
amount  lost  by  evaporation  (and  the  reverse),  will  dwindle  or  destroy 
the  living  species.  Most  reef-forming  corals  grow  in  the  purest 
ocean  waters,  where  sediments  make  no  encroachments ;  a  few,  in 
cluding  some  of  the  Porites,  survive  where  there  is  much  sediment. 

The  Aral  and  Caspian  probably  made  formerly  one  great  salt  sea:  owing  to  the 
rivers  that  enter  them,  the  living  species  are  few.  The  shells  are  now  of  but  twelve 
species,  and  mainly  of  the  Cardium  family,  with  Mytilus  edulis  and  a  Dreisscna 
(Mytilus  family);  and  only  two  are  quoted  from  the  Aral,  — Cardium  edule  and  Adacna 
(Cardium)  vitrea.  The  Cardium  and  Mytilus  families  are  hence  capable  of  enduring 
very  wide  extremes  in  the  saline  condition  of  the  waters.  It  is  interesting  to  note  that 
the  earliest  of  American  bivalves  (Acephals)  were  of  the  Cardium  family  (genus  Cono- 
cardium)]  and  the  Mytilus  family  was  but  little  later  in  introduction. 

Certain  species  are  confined  to  excessively  saline  waters.  Artemice  (Crustaceans)  are 
found  in  the  salt  and  alkaline  lakes  of  all  the  continents.  The  larves  under  several 
genera  of  Dipterous  insects  are  other  examples. 

2.  By  temperature.  —  The  reef-forming  corals  grow  in  the  warmer 
ocean-waters,  in  which  the  mean  temperature  for  the  coldest  month 
does  not  fall  below  68°  F.  The  limit  in  depth  also  appears  to  depend 
mainly  on  temperature. 

The  currents  of  the  ocean  distribute  temperature  through  it ;  and, 


LIFE.  611 

when  the  polar  and  tropical  are  alongside,  as  in  some  parts  of  the 
North  Atlantic,  cold-water  and  warm-water  species  are  living  within 
a  short  distance  of  one  another.  Some  species  have  a  wide  range  of 
favorable  temperature,  and  others  a  very  narrow  range. 

The  zones  of  oceanic  temperature  are  marked  on  the  Physiographic 
Chart,  and  are  explained  on  pages  42  to  44,  where  also  facts  are  men 
tioned  illustrating  the  geological  bearing  of  the  subject. 

The  following  zones  in  depth  have  been  recognized  by  Forbes  and  other  observers, 
for  the  convenience  of  marking  the  distribution  of  marine  species:  — 

1.  The  Littoral  zone,  — or  the  tract  between  high-tide  and  low-tide  levels. 

2.  The  Laminarian  zone, — from  low  water  to  fifteen  fathoms  (90  feet).     This  zone 
is  so  named  from  the  fucoidal  sea-weed,  called  sometimes  Tangle-weed,  which  is  of 
the  genus  Lnminaria,  a  plant  especially  of  rocky  shores. 

3.  The  Coralline  zone,  —  from  15  to  about  50  fathoms. 

4.  The  Deep  sea  Coral  zone,  — from  50  to  300  fathoms. 

5.  Abyssal  zone,  —  below  300  fathoms,  the  ocean  abounding  in  life  down  to  a  depth  of 
2,500  fathoms. 

But  the  recent  observation  that  the  same  species  that  live  in  shallow  water  at  the 
north  may  continue  along  the  corresponding  zone  of  temperature  at  various  depths 
down  to  many  hundred  fathoms,  has  lessened  the  importance  attached  to  these  zones, 
and  especially  to  the  two  lower.  For  example,  the  Rhizocrinus  Lofottnsis  Sars,  and 
over  thirty  species  of  other  invertebrates,  including  corals,  occur  in  the  vicinity  of  the 
Lofoten  Islands,  in  the  Scandinavian  seas,  and  also  in  deeper  water  in  the  Atlantic,  and 
in  the  Florida  Channel,  where  they  have  been  dredged  by  Pourtales.  Beyond  a  depth 
of  2,500  fathoms,  life  is  not  abundant. 

A  living  Pleurotoma  has  been  brought  up  from  a  depth  of  2,090  fathoms;  a  Fusus, 
from  1,207  fathoms;  and  Crabs  (Gonoplax  and  Geryon^.  from  808  fathoms;  all  with  good 
eyes;  Lobsters  (Astacus,  etc.),  from  1,000  to  1,900  fathoms,  without  eyes;  other  Crus 
taceans,  from  over  1,000  fathoms  (one  near  Phronima,  three  and  a  half  inches  long), 
with  perfect  eyes.  Mollusks  are  not  common  at  great  depths;  but  there  are  numerous 
Starfishes,  Echini,  and  Crinoids;  and  siliceous  Sponges,  some  of  great  size  and  beauty, 
are  very  common.  The  bottom,  down  to  2,500  fathoms,  is,  to  a  great  extent,  covered 
—  how  deeply  is  unknown  —  with  Foraminifers  (shells  of  Rhizopods),  among  which 
the  Glooigerina  is  very  prominent,  giving  the  name  of  globiyerina  mud  or  ooze  to  the 
material;  the  beds  are  similar  in  nature  and  origin  to  those  of  Chalk.  Microscopic 
calcareous  disks,  called  Coccoliths  (p.  135),  are  also  abundant,  and.  in  large  accumula 
tions,  the  equally  microscopic  siliceous  Diatoms.  Sea-Aveeds,  apart  from  the  micro 
scopic  Alga?,  are  seldom  met  with,  below  50  fathoms. 

Again,  there  are  species  that  grow  in  waters  above  the  ordinary 
temperature.  Some  of  the  simpler  Algag,  and  especially  microscopic 
species,  will  grow  in  waters  even  hot. 

At  the  Hot  Springs  ("Geysers"),  on  Pluton  Creek,  California,  Prof.  Wm.  H. 
Brewer  observed  Confervae,  in  waters  heated  to  140D-149°  F.,  and  simpler  Alga?  where 
the  temperature  was  200°  F.  At  the  same  place,  Dr.  James  Blake  found  two  kinds  of 
Conferva?,  in  a  spring  of  the  temperature  of  198°,  and  many  Oscillatorice  and  two 
Diatoms,  in  one  of  174°.  In  the  waters  of  Pluton  Creek,  of  112°  F.,  the  Alga;  formed 
layers  three  inches  thick.  Dr.  Blake  also  collected  fifty  species  of  Diatoms,  from  a 
spring  in  Pueblo  Valley,  Nevada,  the  temperature  being  163°  F. ;  and  they  were  mostly 
identical  with  those  of  beds  of  infusorial  earth  in  Utah. 

The  various  hot  springs  of  the  several  Geyser  Basins,  in  the  Yellowstone  National 
Park,  contain  very  various  Confervoid  forms.  The  hottest  springs,  up  to  200°  F., 


612  DYNAMICAL    GEOLOGY. 

contain  numerous,  long,  elender,  white  and  yellow  vegetable  fibres,  on  undetermined 
relations,  waving  in  the  boiling  eddies,  and  becoming  buried  in  the  siliceous  deposits 
over  the  bottom,  where  they  often  form  layers  several  inches  thick.  The  bright  green 
forms  appear  to  be  confined  to  lower  temperatures.  VV.  R.  Taggart  reports  that,  at 
the  vents  on  the  shores  of  Lewis's  Lake,  leafy  vegetation  is  limited  to  temperatures 
below  120°.  (Hayden's  Reports,  1871-2.)  Dr.  Josiah  Curtis  found,  in  these  hot  springs, 
siliceous  skeletons  of  verv  numerous  Diatoms;  but  the  vegetable  matter  was  wanting, 
in  all  cases,  where  the  temperature  exceeded  96°  F.  So  many  different  causes  might 
introduce  these  skeletons  to  the  hotter,  pools,  that  their  presence  has  not  necessarily 
any  more  significance  than  that  of  the  grasshoppers  and  butterflies  which  are  frequently 
found  in  the  same  pools.  Living  larves  of  Helicopsyche  were  found,  by  Mr.  Taggart, 
in  a  spring  having  the  temperature  of  180°,  into  which,  however,  they  might  have 
crawled  from  the  river,  which  was  close  by ;  so  that  the  eggs  were  not  necessarily  laid 
at  the  temperature  given. 

At  Bafios.  on  Luzon,  Phillippine  Islands,  the  author  observed  feathery  Confervae,  in 
waters  heated  to  160°  F. 

3.  By  light.  —  Species  are   sometimes  subterranean,  and  have  pecu 
liarities   depending  on   the  absence  of  light,  being  without  sight,  as 
with  the  blind  Fish  and  Crustaceans  of  the  Mammoth  Cave,  etc. 

4.  By  freedom  from  rough  mechanical  agents,  and  the  reverse.  —  The 
occurrence  of  the  siliceous  sponges  especially  over  the  bed  of  the  deep 
oceans,  has  been  accounted  for  on  the  view  that  they  are  too  delicate 
to  exist  where  there  is  much  movement  in  the  waters.     On  the  other 
hand,  some  Corals  and  other  species   seem  to  thrive  best  amid  the 
breakers. 

o.  By  the  character  of  the  bottom  or  shores,  whether  rocky,  sandy,  or 
muddy.  - 

2.   The  nature  of  different   organic  products,  and  the  Jitness  of  the 
species  affording  them  for  making  fossils  and  rocks. 

(a.)  Nature  of  the  organic  produc's  contributed  to  rock-formations.  — 
Some  of  the  general  facts,  relating  to  the  nature  of  the  organic  prod 
ucts  contributed  by  Life  to  the  rocks,  are  mentioned  on  pages  59  to 
62.  The  following  are  additional  facts  :  — 

Plants  afford,  besides  carbon,  oxygen,  hydrogen,  potash,  and  soda,  with  some  sul 
phur  and  nitrogen.  Carbonic  acid  is  one  of  the  important  results  of  their  decomposi 
tion. 

Animal  membranes  and  oil  decompose,  and  pass  off  for  the  most  part  as  gases.  Por 
tions  of  the  carbon  and  hydrogen  often  remain  in  the  bed  in  which  they  are  buried, 
giving  it  a  dark  color,  or  making  sometimes  mineral  oil  or  coal.  Impressions  of  the 
soft  parts  of  animals,  as  of  some  Cephalopods,  and  the  membranous  p:$rt  of  the  wings 
of  Pterodactvls,  have  been  found  in  rocks;  but  they  are  very  rare. 

The  tissues  that  penetrate  shells  and  bones  are  sometimes  in  part  retained  by  the  an 
cient  fossil.  Two  cases  are  mentioned  by  Barrande,  of  the  conversion  of  the  animal 
material,  within  a  Lower  Silurian  Orthoceras,  into  odipocere  (an  animal  substance 
having  the  appearance  of  spermaceti);  and  he  speaks  of  them  as  the  oldest  mummies 
ever  exhumed. 

A  small  percentage  of  phosphates  and  fluorids  is  derived  from  decomposing  animal 
tissues. 


LIFE.  613 

The  Excrements  of  animals  afford  a  considerable  amount  of  phosphates,  and,  by  de 
composition,  ammoniacal  compounds,  as  in  the  case  of  guano.  The  amount  of  phos 
phates,  from  the  life  which  swarms  in  some  muddy  sea  bottoms  and  shores,  must  be 
large.  For  analyses  of  Coprolites,  see  page  61. 

Bones  are  combined  with  so  large  an  amount  of  animal  gelatine  that  they  are  the 
food  of  various  animals;  and  this  is  a  great  source  of  their  destruction.  Again,  Avhen 
the  animal  matter  decays,  the  bones  are  left  very  fragile,  unless  hardened  anew  by  a 
substitution  of  mineral  matter.  In  the  Cartilaginous  fishes,  the  backbone,  when  it  fails 
wholly  of  stony  material,  is  not  found  fossil,  as  in  most  fossil  Ganoids. 

The  teeth  of  Vei'tebrates  contain  much  less  animal  matter  than  bones,  and  also  a 
coating  of  enamel,  in  which  there  is  considerable  phosphate  of  lime.  They  are  there 
fore  exceedingly  durable,  and  the  most  abundant  of  the  remains  of  many  species.  The 
bony  enamelled  scales  of  Ganoid  fishes  are  also  phosphatic,  and  equally  enduring,  differ 
ing  much  in  this  respect  from  the  membranous  scales  of  Teliosts. 

(b.)  The  fitness  of  species  for  becoming  fossilized  or  concreted  into 
rocks  depends  in  part  on  their  place  and  habits  of  growth. 

Aquatic  species  of  plants  and  animals  are  those  most  likely  to  be 
come  fossils,  and  so  to  contribute  to  rock-formations  ;  and,  next,  those 
that  live  in  marshes,  or  along  shores  or  the  borders  of  marshes.  The 
reasons  are  two:  (1)  Because  almost  all  fossiliferous  rocks  are  of 
aqueous  or  marsh  origin  ;  and  (2)  because  organisms  buried  under 
water,  or  in  wet  deposits,  are  preserved  from  that  complete  decompo 
sition  which  many  are  liable  to  when  exposed  on  the  dry  soil,  and  are 
protected  also  from  other  sources  of  destruction.  In  North  America, 
during  the  Cretaceous  period,  the  dry  portions  of  the  continent,  east 
of  the  Mississippi  (see  map,  p.  479),  were  in  all  probability  covered 
with  vegetation  as  densely  as  now  ;  and  yet  we  have  no  remains  of  it, 
excepting  the  few  in  the  Cretaceous  beds  of  the  Atlantic  and  Gulf 
borders.  In  the  Pliocene  Tertiary,  the  species  of  plants  and  birds 
may  have  been  at  least  half  as  numerous  as  now.  Yet  a  few  hun 
dreds  of  the  former  and  hardly  a  score  of  the  latter  are  all  that  have 
thus  far  been  found  fossil.  The  natural  inference  from  these  facts  is 
that,  while  we  may  conclude  that  we  have  a  fair  representation,  in 
known  fossils,  of  the  marine  life  of  the  globe,  we  know  very  little  of 
its  terrestrial  life,  —  enough  to  assure  us  of  its  general  character,  but 
not  enough  for  any  estimates  of  the  number  of  living  species  over  tho 
land. 

Plants  and  all  animal  matter  pass  off  in  gases,  when  exposed  in  the  atmosphere  or  in 
dry  earth;  and  bones  and  shells  become  slowly  removed  in  solution,  when  buried  in 
sands  through  which  waters  may  percolate.  Bones  buried  in  wet  deposits,  especially  of 
clay,  are  sealed  from  the  atmosphere,  and  may  remain  with  little  change,  except  a  more 
or  less  complete  loss  of  the  animal  portion.  Mastodons  have  been  mired  in  marshes, 
and  thus  have  been  preserved  to  the  present  time;  while  the  thousands  that  died  over 
the  dry  plains  and  hills  have  left  no  relics. 

Among  terrestrial  Articulates,  the  species  of  Insects  that  frequent  marshy  regions, 
and  especially  those  whose  larves  live  in  the  water,  are  the  most  common  fossils,  as  the 
Neuropters;  while  Spiders,  and  the  Insects  that  live,  about  the  flowers  of  the  land,  are 
of  rare  occurrence.  Waders,  among  Birds,  are  more  likely  to  become  buried  and  pre- 


614  DYNAMICAL    GEOLOGY. 

served,  than  those  which  frequent  dry  forests.  But,  whatever  their  hahits,  birds  are 
among  the  rarest  of  fossils,  because  they  usually  die  on  the  land,  are  sought  for  as  food 
by  numberless  other  species,  and  have  slender  hollow  bones  that  are  easily  destroyed. 

Vertebrate  animals,  as  fishes,  reptiles,  etc.,  which  fall  to  pieces  when  the  animal  por 
tion  is  removed,  require  speedy  burial  after  death,  to  escape  destruction  from  this 
source  as  well  as  from  animals  that  would  prey  upon  them. 

Fishes  of  the  open  ocean,  having  the  means  of  easy  locomotion  through  the  waters, 
would  be  less  liable  to  destruction  from  changes  of  level  in  the  land  than  the  Mollusks 
of  a  coast;  and  hence  some  of  the  Sharks  of  the  Tertiary  continue  through  two  or  three 
periods. 

The  animals  generally  of  the  ocean  are  little  liable  to  extermination  from  changes  of 
climate  over  the  land;  and  hence  some  marine  invertebrate  species  of  the  early  Terti 
ary,  ninny  of  the  later,  and  all  of  the  Quaternary,  have  continued  on  until  now,  while, 
as  regards  terrestrial  animal  life,  there  have  been  in  this  interval  many  successive 
faunas. 

(c.)  The  lowest  species  of  life  are  the  best  rock-makers,  especially  Co 
rals,  Crinoids,  Mollusks,  Rhizopods,  Diatoms,  and  Coccoliths;  for  the 
reason  that  only  the  simplest  kinds  of  life  can  be  mostly  of  stone,  and 
still  perform  all  their  functions.  Multiplication  of  bulk  for  bu-lk  is 
more  rapid  with  the  minute  and  simple  species  than  with  the  higher 
kinds  ;  for  all  animals  grow  principally  by  the  multiplication  of  cells ; 
and,  when  single  cells  or  minute  groups  of  them,  as  in  the  Rhizopods, 
are  independent  animals,  the  increase  may  still  be  the  same  in  rate  per 
cubic  foot,  or  even  much  more  rapid,  on  account  of  the  simplicity  of 
structure. 

3.  Methods  of  Fossilization  and  Accumulation. 

A.  Fossilization. — In  the  simplest  kind  of  fossilization,  there  is 
merely  a  burial  of  the  relic  in  earth  or  accumulating  detritus,  where  it 
undergoes  no  change.  Examples  of  this  kind  are  not  common.  Sili 
ceous  Diatoms  and  flint  implements  are  among  them. 

In  general,  there  is  a  change  of  some  kind ;  usually,  either  a  loss, 
by  decomposition  of  the  less  enduring  part  of  the  organic  relic,  with 
sometimes  the  forming  of  new  products  in  the  course  of  the  decom 
position,  or  an  alteration,  through  chemical  means,  changing  the  tex 
ture  of  the  fossil, or  petrifying  it,  as  in  the  turning  of  wood  into  stone. 

The  change  may  consist  in  a  fading  or  blanching  of  the  original  colors;  in  a  partial 
or  complete  loss  of  the  decomposable  animal  portion  of  the  bone  or  shell;  a  similar  loss 
of  part  of  the  mineral  ingredients,  by  solvent  waters,  as  of  the  phosphates  and  fluorids 
of  a  bone  or  shell:  or  a  general  alteration  of  the  original  organism,  leaving  behind  only 
one  or  two  ingredients  of  the  whole;  or  a  combining  of  the  old  elements  into  new  com 
pounds,  as  when  a  plant  decays  and  changes  to  coal  or  one  or  more  carbohydrogens,  a 
resin  to  amber,  animal  matter  to  adipocere. 

The  change  may  be  merely  one  of  crystallization.  The  carbonate  of  lime  of  shells  is 
often  partly  in  the  state  of  aragonite;  and,  when  so,  there  is  usually  a  change,  in  which 
the  whole  becomes  common  or  rhombohedral  carbonate  of  lime  (calcite).  Sometimes, 
the  compact  condition  of  the  original  fossil  is  altered  to  one  with  the  perfect  cleavage  of 
calcite,  as  often  happens  in  the  columns  or  plates  of  Crinoids  and  the  spines  of  Echi- 
noids. 


LIFE.  615 

The  change  often  consists  in  the  reception  of  new  mineral  matter  into  the  pores  or 
cellules  of  the  fossil,  as  when  bones  are  penetrated  by  limestone  or  oxyd  of  iron. 

The  change  is  frequently  a  true  petrifaction,  in  which  there  is  a  substitution  of  new 
mineral  material  for  the  original;  as  when  a  shell,  coral,  or  wood  is  changed  to  a  sili 
ceous  fossil,  through  a  process  in  which  the  organism  was  subjected  to  the  action  of 
waters  containing  silica  in  solution.  In  other  cases,  the  organism  becomes  changed  to 
carbonate  of  lime,  as  in  much  petrified  wood ;  and  in  others,  to  oxyd  of  iron  and  py 
rites;  and  more  rarely  to  fluor  spar,  heavy  spar,  or  phosphate  of  lime. 

The  mineral  matter  first  fills  the  cells  of  the  wood,  and  then  takes  the  place  of 
each  particle  as  it  decomposes  and  passes  away,  until  finally  the  original  material  is  all 
gone.  Some  fossil  logs  are  carbonized  at  one  end  and  silicified  at  the  other. 

In  many  silicified  shells,  stems  of  Crinoids,  etc.,  in  the  Subcarboniferous  rocks  of 
Illinois  and  Indiana,  the  shell  or  stem  has  been  split  open,  and  much  enlarged,  by  the 
infiltrating  silica;  owing  apparently  to  successive  depositions  of  silica  between  the 
shell  and  the  first-formed  siliceous  layer  within  the  cavity,  as  the  silicifying  process 
went  forward. 

The  silica  in  most  siliceous  petrifactions  has  come  from  siliceous  organisms  associated 
with  the  fossil  in  the  original  deposit. 

B.  Accumulation  into  Beds.  Calcareous  remains  of  organisms,  as 
shells,  corals,  etc.,  have  very  frequently  been  ground  up  by  the  action 
of  waves  or  by  currents  of  water,  and  thus  reduced  to  a  calcareous 
earth,  —  the  solidification  of  which  (as  explained  on  p.  619),  has  made 
limestones. 

When  the  fossils  are  minute,  like  Rhizopods  and  Diatoms,  the 
simple  concretion  of  the  shells  will  make  a  solid  rock,  as  in  the  case  of 
chalk  and  flint  (p.  478). 

Ehrenberg  estimates  that  about  18,000  cubic  feet  of  siliceous  organisms  annually 
form  in  the  harbor  of  Wismar,  in  the  Baltic;  and  he  has  also  found  that  similar  accumu 
lations  are  going  on  in  the  mud  of  American  and  other  harbors. 

The  bed  of  Rhizopods  accumulating  in  the  North  Atlantic,  mentioned  on  page  477, 
contains,  according  to  Huxley,  about  eighty -five  percent,  of  these  calcareous  shells, 
mostly  of  the  genus  Globiyerinn,  besides  some  siliceous  Diatoms:  it  has  probably  a 
breadth  (between  Ireland  and  Newfoundland)  of  1,300  miles,  and  extends  at  least  some 
hundreds  of  miles  to  the  south.  Ehrenberg  found,  in  a  specimen  examined  by  him, 
eighty-five  species  of  calcareous  Bhizopods,  sixteen  of  Polycystines,  and  seventeen  of 
Diatoms,  with  only  a  few  arenaceous  grains  not  of  organic  origin. 

The  siliceous  shells  of  the  microscopic  Polycystines  have  been  found  not  only  in  the 
frigid  Sea  of  Kamtchatka  (see  Amer.  Jour.  Sci.,  II.  xxii.  pi.  1,  for  figures)  and  the 
North  Atlantic,  but  also  in  the  South  Pacific,  on  both  coasts  of  the  Atlantic,  in  the 
Mediterranean,  and,  within  the  tropics,  at  Barbadoes,  in  the  West  Indies,  and  the  Nicobar 
Islands,  in  the  East  Indies.  Ehrenberg  has  named  282  species  from  a  marl-like  deposit 
at  Barbadoes,  considered  as  Tertiary,  and  100  species  from  the  Nicobar  Islands,  part  of 
them  identical  with  those  of  Barbadoes. 

But,  when  the  fossils  are  comparatively  large,  as  ordinary  corals  and 
shells,  the  intervals  between  them  must  be  filled  with  earth  of  some 
kind,  derived  from  the  wearing  action  of  the  waters.  It  may  be  the 
mud  or  detritus  from  rivers  or  from  wave-action  along  sea-shores ; 
but,  when  calcareous,  it  has  evidently  come  from  the  wear  of  the 
shells,  corals,  or  crinoids  themselves ;  and  hence  any  limestone  rock, 
made  up  of  large  shells,  corals,  or  criuoids,  which  has  the  interstices 


616  DYNAMICAL    GEOLOGY. 

thus  filled  in  with  limestone,  bears  probably  evidence  in  itself  that  it 
has  been  formed,  not  in  the  deep  ocean,  but  within  the  reach  of  current 
or  wave  action. 

The  kinds  of  limestone  made  through  the  agency  of  life  include 
soft  marl  or  calcareous  earth,  chalk,  compact  limestone,  sometimes 
oolitic  or  concretionary  (p.  63),  of  white,  gray,  bluish,  blackish,  and 
other  colors,  —  the  dark  colors  mostly  due  to  the  presence  of  carbon, 
from  animal  or  vegetable  decomposition. 

4.  Examples  of  the  Formation  of  Strata  through  the  Agency  of  Life. 
1.  Peat  Formations. 

Peat  is  an  accumulation  of  half-decomposed  vegetable  matter, 
formed  in  wet  or  swampy  places.  In  temperate  climates,  it  is  due 
mainly  to  the  growth  of  spongy  Mosses,  of  the  genus  Sphagnum. 
This  plant  forms  a  loose  turf,  and  has  the  property  of  dying  at  the 
extremities  of  the  roots,  as  it  increases  above ;  and  it  thus  may  gradu 
ally  form  a  bed  of  great  thickness.  Moreover,  it  is  very  absorbent  of 
moisture.  In  some  limestone  regions,  the  Sphagnous  mosses  are  re 
placed  by  species  of  Hypnum,  as  in  Iowa.  The  roots  and  leaves  of 
other  plants,  or  their  branches  and  stumps,  and  any  other  vegetation 
present,  may  contribute  to  the  accumulating  bed.  The  carcasses  and 
excrements  of  animals  at  times  become  included.  Dust  may  also  be 
blown  over  the  marsh  by  the  winds. 

In  wet  parts  of  Alpine  regions,  there  are  various  flowering  plants 
which  grow  in  the  form  of  a  close  turf,  and  give  rise  to  beds  of  peat, 
like  the  moss.  In  Fuegia,  although  not  south  of  the  parallel  of  56°, 
there  are  large  marshes  of  such  Alpine  plants,  the  mean  temperature 
being  about  40°  F.  On  the  Chatham  Islands  (380  miles  east  of  New 
Zealand),  peat  thus  formed  has  a  depth  of  fifty  feet. 

The  dead  and  wet  vegetable  mass  slowly  undergoes  a  change,  be 
coming  an  imperfect  coal,  of  a  brownish-black  color,  loose  in  texture, 
and  often  friable,  although  commonly  penetrated  with  rootlets.  In 
the  change,  the  woody  fibre  loses  a  part  of  its  gases  ;  but,  unlike  coal, 
it  still  contains  usually  twenty-five  to  thirty-three  per  cent,  of  oxygen. 
Occasionally,  it  is  nearly  a  true  coal. 

Peat-beds  cover  large  surfaces  of  some  countries,  and  occasionally 
have  a  thickness  of  forty  or  fifty  feet.  One-tenth  of  Ireland  is  covered 
by  them  ;  and  one  of  the  "  mosses  "  of  the  Shannon  is  stated  to  be 
fifty  miles  long  and  two  or  three  broad.  A  marsh  near  the  mouth  of 
the  Loire  is  described  by  Blavier  as  more  than  fifty  leagues  in  circum 
ference.  Over  many  parts  of  New  England  and  other  portions  of 
North  America,  there  are  extensive  beds.  The  amount  ill  Massa- 


CORAL  FORMATIONS.  617 

chusetts  alone  has  been  estimated  to  exceed  120,000,000  of  cords. 
Many  of  the  marshes  were  originally  ponds  or  shallow  lakes,  and 
gradually  became  swamps,  as  the  water,  from  some  cause,  diminished 
in  depth.  The  peat  is  often  underlaid  by  a  bed  of  whitish  shell-marl, 
consisting  of  fresh-water  shells  —  mostly  species  of  Sphcerium,  Lim- 
ncea,  Physa,  and  PlanorUs  —  which  were  living  in  the  lake.  There 
are  often  also,  especially  in  regions  of  siliceous  or  metamorphic  rocks, 
beds  of  a  white  chalky  character,  made  of  the  siliceous  shields  of  Di 
atoms. 

Peat  is  used  for  fuel  and  also  as  a  fertilizer.  When  prepared  for  burning,  it  is  cut 
into  large  blocks,  and  dried  in  the  sun.  It  is  sometimes  pressed,  in  order  to  serve  as 
fuel  for  steam-engines.  Muck  is  another  name  for  peat,  especially  impure  kinds,  when 
employed  as  a  manure  ;  any  black  swamp-earth  consisting  largely  of  decomposed 
vegetable  matter  is  so  called. 

Peat-beds  sometimes  contain  standing  trees,  and  entire  skeletons  of 
animals  that  had  sunk  in  the  swamp.  The  peat-waters  have  an  anti 
septic  power.  They  consequently  tend  to  prevent  complete  decay  of 
the  vegetable  matter  of  the  peat  bed  ;  and  flesh  is  sometimes  changed 
by  the  burial  into  adipocere. 

2.  Coral  Formations. 

Coral  formations  are  made  mainly  from  the  calcareous  secretions  of 
coral-making  polyps,  and  are  confined  to  the  warmer  latitudes  of  the 
globe. 

Kinds.  —  Coral  formations,  while  of  one  general  mode  of  origin, 
are  of  two  kinds  :  — 

1.  Coral  islands.  —  Isolated  coral  formations  in  the  open  sea. 

2.  Coral  reefs,  —  Banks  of  coral,  bordering  other  lands  or  islands. 
Distribution.  —  The   limiting  temperature  of  reef-forming  corals  is 

about  68°  F.  ;  that  is,  they  do  not  flourish  where  the  mean  tempera 
ture  of  any  month  of  the  year  is  below  68°.  The  extent  of  the  Coral 
seas  is  shown  by  the  position  of  the  north  and  south  lines  of  68°  F., 
on  the  Physiographic  Chart,  as  already  pointed  out. 

The  exclusion  of  corals  from  certain  tropical  coasts  is  owing  to  dif 
ferent  causes.  —  (1.)  The  cold  extratropical  oceanic  currents,  as  in  the 
case  of  western  South  America  (see  chart).  (2.)  Muddy  or  alluvial 
shores,  or  the  emptying  of  large  rivers  ;  for  coral-polyps  require  clear 
sea-water  and  generally  a  solid  foundation  to  build  upon,  (o.)  The 
presence  of  volcanic  action,  which,  through  occasional  submarine  action, 
destroys  the  life  of  a  coast.  (4.)  The  depth  of  water  on  precipitous 
shores  ;  for  the  reef-corals  do  not  grow  where  the  depth  exceeds  one 
hundred  feet. 

For  the  last-mentioned  reason,  reefs  are  prevented  from  commencing 


618 


DYNAMICAL    GEOLOGY. 


to  form  in  the  deep  ocean.  The  notion  that  coral  islands  are  rising 
from  its  depths  has  no  support  in  facts :  they  must  have  the  land 
within  a  few  fathoms  of  the  surface,  to  begin  upon. 

Coral  formations  are  most  abundant  in  the  tropical  Pacific,  where  there  are  t\vo  hundred 
and  ninety  coral  islands,  besides  extensive  reefs  around  other  islands.  The  Paumotu  Ar 
chipelago,  east  of  Tahiti,  contains  between  seventy  and  eighty  coral  islands;  the  Caro 
lines,  including  the  Kadack,  Kalick,  and  Gilbert  groups,  as  many  more;  and  others  are 
distributed  over  the  intermediate  region.  The  Tahitian,  Samoan,  and  Feejee  Islands  are 
famous  for  their  reefs;  also  New  Caledonia  and  the  islands  to  the  northwest.  There  are 
reefs  also  about  some  of  the  Hawaian  Islands.  The  Laccadives  and  Maldives,  in  the  In 
dian  Ocean,  are  among  the  largest  coral  islands  in  the  world.  The  East  Indies,  the  east 
ern  coast  of  Africa,  the  West  Indies,  and  southern  Florida  abound  in  reefs;  and  Bermuda, 
in  latitude  32°  N.,  is  a  coral  group.  Reef- forming  corals  are  absent  from  western  Amer 
ica,  except  along  the  coasts  of  Central  America,  and  as  far  north  as  the  Gulf  of  Califor 
nia,  and  mostly  from  western  Africa,  on  account  of  the  cold  extratropical  currents  t hat- 
flow  toward  the  equator:  for  the  same  reason,  there  are  no  reefs  on  the  coast  of  China. 
(See  the  Physiographic  Chart. ) 


1.  CORAL  ISLANDS. 

Forms. — Atolls.  —  A  coral  island  commonly  consists  of  a  narrow 
rim  of  reef,  surrounding  a  lagoon,  as  illustrated  in  the  annexed  sketch 
(Fig.  960).  Such  islands  are  called  atolls,  —  a  name  of  Maldive  origin. 


Coral  island,  or  atoll. 

Maps  of  two  atolls  are  given  in  Figs.  961,  962,  showing  the  rim  of 
coral  reef,  the  salt-water  lake,  or  lagoon,  and  the  variations  of  form  in 
these  islands.  They  are  never  circular.  The  size  varies  from  a  length 
of  fifty  miles  to  two  or  three  ;  and,  when  quite  small,  the  lagoon  is 
wanting,  or  is  represented  only  by  a  dry  depression. 


Fig.  962. 


ATOLLS.  — Fig.  961,  Apia,  one  of  the  Gilbert  Islands  ;  962,  Menchikoff,  one  of  the  Carolines. 

The  reef  is  usually  to  a  large  extent  bare  coral  rock,  swept  by  the 
waves  at  high  tide.  In  some,  the  dry  land  is  confined  to  a  few  isolated 
points,  as  in  Menchikoff  Island,  of  the  Caroline  group  (Fig.  962)  ;  in 


CORAL    FORMATIONS.  619 

others,  one  side  is  wooded  continuously,  or  nearly  so,  while  the  other 
is  mostly  hare,  or  is  a  string  of  green  islets,  as  in  Fig.  961,  representing 
Apia,  one  of  the  Gilbert  Islands.  The  higher  or  wooded  side  is  that 
to  the  windward,  unless  it  happens  to  be  under  the  lee  of  another 
island.  On  the  leeward  side,  channels  often  open  through  to  the  la 
goon  (e,  Fig.  961),  which,  when  deep  enough  for  shipping,  make  the 
atoll  a  harbor  ;  and  some  of  these  coral-girt  harbors  in  mid-ocean  are 
large  enough  to  hold  all  the  fleets  of  the  world. 

Fig.  963  represents  a  section  of  an  island,  from  the  ocean  (o)  to  the 
lagoon  (/).  On  the  ocean  side,  from  o  to  «,  there  is  shallow  water  for 
some  distance  out  (it  may  be  a  quarter  or  half  a  mile  or  more)  ;  and, 
where  not  too  deep  (not  over  one  hundred  feet),  the  bottom  is  covered 
here  and  there  with  growing  corals.  Between  a  and  b  there  is  a  plat 
form  of  coral  rock,  mostly  bare  at  low  tide,  but  covered  at  high,  having 

Fig.  903. 


Sectiou  of  a  coral  rslaud,  from  tiie  o^ean  (u)  to  the  lagoon  (/). 

a  width  usually  of  about  a  hundred  yards :  there  are  shallow  pools  in 
many  parts  of  it,  abounding  in  living  Corals  of  various  hues,  Actiniae 
(Sea-anemones),  Star-fishes,  Sponges,  Shells,  Shrimps  and  other  kinds 
of  tropical  life:  toward  the  outer  margin,  it  is  quite  cavernous  :  and  the 
holes  arc  frequented  by  Crabs,  Fishes,  etc.  At  b  is  the  white  beach,  six 
or  eight  feet  high,  made  of  coral  sand  or  pebbles  and  worn  shells  :  b 
to  d  is  the  wooded  portion  of  the  island.  The  whole  width,  from  the 
beach  (b}  to  the  lagoon  (c),  is  commonly  not  over  three  or  four  hun 
dred  yards.  At  c  is  the  beach  on  the  lagoon  side,  and  the  commence 
ment  of  the  lagoon.  Corals  grow  over  portions  of  the  lagoon,  — 
although,  in  general,  a  largo  part  of  the  bottom,  both  of  the  lagoon 
and  of  the  sea  outside,  is  of  coral  sand. 

Beyond  a  depth  of  one  hundred  feet,  there  are  no  growing  corals, 
except  some  kinds  that  enter  but  sparingly  into  the  structure  of  reefs, 
the  largest  of  which  are  the  Dendrophylliae. 

Coral-reef  Rock.  —  The  rock  forming  the  coral  platform  and  other 
parts  of  the  solid  reef  is  a  white  limestone,  made  out  of  corals  and 
shells.  Its  composition  is  like  that  of  ordinary  limestones. 

In  some  parts,  it  contains  the  corals  imbedded  ;  but,  in  others,  it  is 
perfectly  compact,  without  a  fossil  of  any  kind,  unless  an  occasional 
shell.  In  no  case  is  it  chalk.  The  compact  non-fossiliferous  kinds 
are  formed  in  the  lagoons  or  sheltered  channels  ;  the  kinds  made  of 
broken  corals,  on  the  seashore  side,  in  the  face  of  the  waves  ;  those 


620  DYNAMICAL   GEOLOGY. 

made  of  corals  standing  as  they  grew,  in  sheltered  waters,  where  the 
sea  has  free  access. 

The  following  are  the  principal  kinds  of  coral  rocks :  — 

1.  A  fine-grained,  compact,  and  clinking  limestone,  as  solid  and  flint-like  in  fracture  as 
any  Silurian  limestone,  and  with  rarely  a  shell  or  fragment  of  coral. 

This  variety  is  very  common ;  and,  where  coral  reefs  or  islands  have  been  elevated, 
it  often  makes  up  the  mass  of  the  rock  exposed  to  view.  The  absence  of  fossils,  while 
the  rock  was  evidently  made  out  of  corals  and  shells,  is  a  remarkable  and  instructive 
fact. 

2.  A  compact  oolyte,  consisting  of  rounded  concretionary  grains,  and  generally  with 
out  any  distinct  fossils. 

3.  A  rock  equally  compact  and  hard  with  No.  1,  but  containing  imbedded  fragments 
of  corals  and  some  shells. 

4.  A  conglomerate  of  broken  corals  and  shells,  with  little  else,  —  very  firm  and  solid ; 
many  of  the  corals  several  cubic  feet  in  size. 

5.  A  rock  consisting  of  corals  standing  as  they  grew,  with  the  interstices  filled  in 
with  coral  sand,  shells,  and  fragments.     In  general,  the  rock  is  exceedingly  solid;  but 
in  some  cases  the  interstices  are  but  loosely  filled. 

Coral  Beach-rock.  —  The  beach-rock  is  made  from  the  loose  coral 
sands  of  the  shores,  which  are  thrown  up  by  the  waves  and  winds. 
The  sands  become  cemented  into  a  porous  sandstone,  or,  where  pebbly, 
into  a  coral  pudding-stone.  It  forms  layers,  or  a  laminated  bed,  along 
the  beach  of  the  lagoon,  arid  also  on  the  sea-shore  side,  sloping  gener 
ally  at  an  angle  of  five  to  eight  degrees  toward  the  water,  but  some 
times  at  a  larger  angle,  this  depending  on  the  slope  of  the  beach  at 
the  place. 

Formation  of  the  Coral  Reef.  —  A  reef-region  is  a  plantation  of  living 
corals,  in  which  various  species  are  growing  together,  —  at  one  place, 
in  crowded  thickets,  at  another,  in  scattered  clumps,  over  fields  of  coral 
sand.  There  is  the  same  kind  of  diversity  that  exists  in  the  distribu 
tion  of  vegetation  over  the  land.  Some  of  the  kinds  branch  like  trees 
of  small  size,  or  shrubs  (Madrepores)  ;  others  form  closely-branched 
tufts  (PociUiporce,  many  Porites)  ;  others  resemble  clustered  leaves 
(Merulince,  Montiporce),  or  tufts  of  pinks  (Tubiporce),  or  lichens  and 
fungi  (Agaricice,  etc.)  ;  others  grow  in  hemispherical  or  subglobular 
forms  (Astrcece,  Meandrince  and  some  Porites}  ;  and  others  are  groups 
of  slender,  brilliantly-colored  twigs  (Gorgonice). 

When  alive  in  the  water,  all  these  corals  are  covered  throughout 
with  expanded  polyps,  emulating  in  beauty  of  form  and  colors  the 
flowers  of  the  land. 

Each  of  the  polyp-cells  in  these  corals  corresponds  to  a  separate  animal  or  polyp  (p. 
130).  In  the  Madreporce,  the  polyps  when  expanded  have  twelve  rays,  or  tentacles, 
and  a  diameter  of  an  eighth  to  a  quarter  of  an  inch.  Those  of  the  Pocillipoi-ce  and 
Porites  are  also  twelve-rayed,  but  smaller.  The  Astrcew  have  an  indefinite  number  of 
rays,  or  tentacles:  in  some  species  of  the  family,  the  expanded  flower-like  polyp  is  an 
inch  or  more  in  diameter.  In  the  Meandrince  and  related  kinds,  the  polyps  coalesce  in 


CORAL    FORMATIONS.  621 

lines;  there  is  a  series  of  mouths  along  the  centre  of  each  furrow,  and  a  border  of  ten 
tacles  either  side.  The  Funyice  have  the  form  of  broad,  circular,  or  oblong  disks;  the 
disk  corresponds  to  a  single  polyp,  and  has  a  diameter  in  some  cases  of  ten  or  twelve 
inches. 

In  the  Milleporce,  as  stated  on  page  130,  the  animals  are  Acalephs,  and  not  true 
Polyps. 

Corals  of  the  different  groups  here  mentioned  grow  together  promiscuously  at  different 
depths,  up  to  low-tide  level.  The  largest  Astrcece,  Meandrince,  and  Porites,  with  many 
Madreporce  and  other  kinds,  have  been  seen  by  the  author  constituting  the  upper  part 
of  the  growing  reef.  At  Tongatabu,  there  were  single  masses  of  Porites,  twenty-five 
feet  in  diameter,  along  with  Astrcece  and  Meandrince,  ten  to  fifteen  feet.  But,  while 
these  different  groups  do  not  correspond  to  different  zones  in  depth,  there  are.  without 
doubt,  species  in  them  which  belong  to  the  deeper  waters,  and  others  to  the  more 
shallow. 

The  Porites,  with  some  species  of  the  Astrcea,  Jfadrepora,  and  Pocittipora  groups,  con 
tinue  to  grow  a  little  above  low-tide  level,  equal  to  about  one-third  the  height  of  the 
tide,  —  as  they  will  endure  a  temporary  exposure  to  the  sun  without  serious  injury. 
The  Porites  are  an  especially  hardy  group;  for  the  corals  suffer  less  from  impurity  or 
silt  in  the  waters  than  the  species  of  other  groups. 

The  polyp-corals  have  the  power  of  growing  indefinitely  upward,  while  death  is  going 
on  at  equal  rate,  either  at  the  base  of  the  structure  (as  in  the  moss  of  which  peat  is 
made)  or  through  its  interior,  and  are  only  stopped  in  upward  progress  by  reaching  the 
surface  of  the  water.  The  hemispherical  Astrcece,  many  feet  in  diameter,  although 
covered  throughout  with  living  polyps,  may  be  alive  to  a  depth  of  only  half  or  three- 
quarters  of  an  inch,  and  the  huge  Porites  to  a  depth  of  less  than  a  quarter  of  an  inch: 
that  is,  only  a  thin  exterior  portion  of  the  mass  is  really  living. 

Besides  corals  and  shells,  there  are  also  some  kinds  of  calcareous 
vegetation,  called  Nullipores,  both  branching  and  incrusting  in  form, 
which  add  to  the  accumulation.  They  grow  well  over  the  edge  of  the 
reef,  in  the  face  of  the  breakers,  and  attain  considerable  thickness. 
Even  the  delicate  branching  kinds  sometimes  made  thick  beds,  as  ob 
served  by  Agassiz  in  the  Florida  seas.  Bryozoans  add  a  little  to  the 
material,  occasionally  making  large  massive  corals.  In  Paleozoic  time, 
both  branching  and  massive  kinds  contributed  largely  to  limestone 
formations. 

Action  of  the  Waves.  —  The  waves,  especially  in  their  heavier  move 
ments,  sweeping  over  the  coral  plantations,  may  be  as  destructive  as 
winds  over  forests.  They  tear  up  the  corals,  and,  by  incessant  tritu- 
ration,  reduce  the  fragments  to  a  great  extent  to  sand  ;  and  the  debris 
thus  made  and  ever  making  is  scattered  over  the  bottom,  or  piled  upon 
the  coast  by  the  tide,  or  swept  over  the  lower  parts  of  the  reef  into 
the  lagoon.  The  corals  keep  growing ;  and  this  sand  and  the  frag 
ments  go  on  accumulating :  the  consolidation  of  the  material  thus  ac 
cumulated  makes  the  ordinary  reef-rock.  Thus,  by  the  help  of  tho 
waves,  a  solid  reef-structure  is  formed  from  the  sparsely-growing  corals. 

Where  the  corals  are  protected  from  the  waves,  they  grow  up  bodily 
to  the  surface,  and  make  a  weak,  open  structure,  instead  of  the  solid 
reef-rock  ;  or,  if  it  be  a  closely-branching  species,  so  as  to  be  firm,  it 
still  wants  the  compactness  of  the  reef  that  has  been  formed  amid  the 
waves. 


622  DYNAMICAL   GEOLOGY. 

History  of  the  emerging  Atoll.  —  The  growing  corals  and  the  accu 
mulating  debris  reach,  at  last,  low-tide  level.  The  waves  continue  to 
pile  up  on  the  reef  the  sand  and  pebbles  and  broken  masses  of  coral, 

—  some  of  the  masses  even  two  or  three  hundred  cubic  feet  in  size, 

—  and  a  field  of  rough  rocks  begins  to  appear  above  the  waves.    Next, 
a  beach  is  completed  ;  and  the  sands,  now  mostly  above  the  salt  water, 
are  planted  by  the  waves  with  seeds ;  and  trailing  shrubs  spring  up : 
afterward,  as  the  soil  deepens,  palms  arid  other  trees  rise  into  forests  ; 
and  the  atoll  comes  forth  finished. 

The  windward  side  of  such  islands  is  the  highest,  because  here  the 
winds  and  waves  act  most  powerfully  ;  and,  where  the  leeward  side  of 
one  part  of  the  year  is  the  windward  of  another,  there  may  not  be 
much  difference  between  the  two.  The  water  that  is  driven  by  the 
winds  or  tides  over  the  reef,  into  the  lagoon,  tends,  by  its  escape,  to 
keep  one  or  more  passages  open,  which,  when  sufficiently  deep,  make 
entrances  for  shipping. 

2.  CORAL  REEFS. 

The  coral  reefs  around  other  lands  or  islands  rest  on  the  bottom 
along  the  shores.  They  are  either  fringing  or  barrier  reefs,  according 
to  their  position.  Fringing  reefs  are  attached  directly  to  the  shore, 
while  barrier  reefs,  like  artificial  moles,  are  separated  from  the  shore 
by  a  channel  of  water. 

Fig.  964  represents  an  island  with  a  fringing  reef  (/)  a  barrier 
reef  (&),and  an  intervening  channel.  Just  to  the  right  of  the  middle, 
the  reef  is  wanting,  because  of  the  depth  of  water  ;  and,  farther  to 
the  right,  there  is  only  a  fringing  reef.  Fig.  966  is  a  map  of  an  island 

Fig.  964. 


View  of  a  high  island  with  barrier  and  fringing  reefs. 

with  a  fringing  reef;  and  Figs.  967-969,  others,  with  barrier  reefs.  At 
two  points  through  the  barrier  reef,  in  Fig.  964,  there  are  openings  to 
harbors  (A).  Such  harbors  are  common,  and  generally  excellent.  The 
channels  uniting  them  around  an  island  are  sometimes  deep  enough 
for  ship  navigation,  and  occasionally,  as  oflf  eastern  Australia,  fifty  or 
sixty  miles  wide.  On  the  other  hand,  they  may  be  too  shallow  for 
boats  ;  in  which  case,  the  barrier-reefs  coalesce  with  the  fringing  reefs. 


CORAL    FORMATIONS.  623 

The  barrier  sometimes  becomes  wooded  for  long  distances,  like  the 
reef  of  an  atoll ;  but  the  wooded  portion,  when  there  is  any  at  all,  is 
usually  confined  to  a  few  islets. 

The  barrier  and  fringing  reefs  are  formed  precisely  like  the  atoll 
reefs ;  and  special  explanations  are  needless. 

The  absence  of  reefs  from  parts  of  coasts  of  islands,  within  coral-reef  seas,  is  due  to 
several  causes:  (1)  to  the  depth  of  water,  for  corals  fail  if  the  depth  exceeds  one  hun 
dred  feet;  (2)  to  fresh-water  streams,  especially  if  bringing  in  detritus,  which  destroys 
the  living  corals;  as  such  fresh  waters  flow  over  the  surface  of  the  salt,  they  do  not  pre 
vent  the  corals  from  growing  below,  unless  impure  with  detritus;  (3)  tidal  and  other 
currents,  which  keep  passages  open,  by  means  of  the  detritus  they  often  bear  along 
their  course.  These  are  the  principal  causes  that  prevent  the  harbors  from  becoming 
filled  with  corals  and  thereby  destroyed. 

The  growth  of  the  different  parts  of  a  reef,  or  its  prolongation  in  one  direction  or  an 
other,  depends  much  on  the  tidal  and  other  currents  that  sweep  through  the  channel  or 
by  the  side  of  the  island.  As  in  the  case  of  silt  along  other  sea-shores,  the  coral  detri 
tus  made  by  the  waves  is  distributed  by  these  currents:  and  hence  the  increase  of  a 
reef  is  not  dependent  solely  on  the  number  of  growing  corals  over  its  surface,  or  their 
kinds. 

Breadth  of  Reefs.  —  The  reefs  adjoining  lands  have  sometimes  great 
width.  On  the  north  side  of  the  Feejees,  the  reef-grounds  are  five  to 
fifteen  miles  in  width.  In  New  Caledonia,  they  extend  one  hundred 
and  fifty  miles  north  of  the  island,  and  fifty  south,  making  a  total 
length  of  four  hundred  miles.  Along  northeastern  Australia,  they 
stretch  on,  although  with  many  interruptions,  for  one  thousand  miles, 
and  often  at  a  distance,  as  just  stated,  of  fifty  or  sixty  miles  from  the 
coast,  with  a  depth  between  of  fifty  or  sixty  fathoms.  But  the  reefs, 
as  they  appear  at  the  surface,  even  over  the  widest  reef-grounds,  are 
in  patches,  seldom  over  a  mile  or  two  broad.  The  patches  of  a  single 
reef-ground  are,  however,  connected  by  the  coral  basement  beneath 
them,  which  is  struck,  in  sounding,  at  a  depth  usually  of  ten  to  forty 
or  fifty  feet. 

The  transition  in  the  inner  channels,  from  a  bottom  of  coral  detritus 
to  one  of  common  mud  or  earth,  derived  from  the  hills  of  the  encir 
cled  island,  is  often  very  abrupt.  Streams  from  the  land  bring  in  this 
mud,  and  distribute  it  according  to  their  courses  through  the  channels. 

Thickness  of  Reefs.  —  The  thickness  of  a  coral  formation  is  often 
very  great.  From  soundings  within  a  short  distance  of  coral  islands, 
it  is  certain  that  this  thickness  is  in  some  cases  thousands  of  feet. 
Within  three-quarters  of  a  mile  of  Clermont  Tonnerre,  in  a  sounding 
made  by  Hudson,  the  lead  struck  and  brought  up  an  instant  at  two 
thousand  feet,  and  then  fell  off  and  ran  out  to  three  thousand  six  hun 
dred  feet,  without  finding  bottom ;  and  seven  miles  from  the  samo 
island,  no  bottom  was  found  at  six  thousand  feet. 

The  barrier  reefs  remote  from  an  island  must  stand  in  deep  water. 


624 


DYNAMICAL    GEOLOGY. 


Supposing  the  slope  of  the  bottom  at  the  Gambler  Islands  only  five 
degrees,  we  find,  by  a  simple  calculation,  that  the  reef  has  a  thickness 
of  twelve  hundred  feet.  In  a  similar  manner,  we  learn  that  it  must 
be  at  least  two  hundred  and  fifty  feet  at  Tahiti,  and  two  or  three  thou 
sand  at  the  Feejees. 

3.  ORIGIN  OF  THE  FORMS  OF  REEFS, —  THE  ATOLL  AND  THE 
DISTANT  BARRIER. 

The  origin  of  the  atoll  form  of  reefs  was  first  explained  by  Darwin. 
According  to  the  theory,  each  atoll  began  as  a  fringing  reef,  around 
an  ordinary  island ;  and  the  slow  sinking  of  the  island  till  it  disap 
peared,  while  the  reef  continued  to  grow  upward,  left  the  reef  at  the 
surface,  a  ring  of  coral  around  a  lake. 

The  proofs  arc  — - 

1.  As  reef-forming  corals  grow  only  within  depths  not  greater  than 
one  hundred  feet,  the  bottom  on  which  they  began  must  have  been  no 
deeper  than  this;  and   as -such  a  shallow  depth  is  to  be  found,  with 
rare  exceptions,  only  around  the  shores  of  lands  or  islands,  the  reef 
formed  would  be  at  first  nothing  but  a  fringing  reef. 

2.  A  fringing  reef  being  the  first  step  in  coral  formations,  slow  sub 
sidence  would  make  it  a  barrier-reef. 

In  Fig.  965,  a  section  of  a  high  island  with  its  coral  reefs  is  repre 
sented,  the  horizontal  line  1  being  the  level  of  the  sea,/  a  section 
of  the  fringing  reef  on  the  left,  and  fr  of  that  on  the  right.  The 
growing  reef  depends  for  its  upward  progress  on  the  growth  of  the 
coral,  and  on  the  waves.  The  waves  act  only  on  the  outer  margin  of 
a  reef,  while  the  dirt  and  fresh  water  of  the  land  directly  retard  the 

Fig.  965. 


Section  of  an  island  bordered  by  a  coral  reef,  to  illustrate  the  effects  of  a  subsidence. 

inner  part.  Hence  the  outer  portion  would  increase  the  most  rapidly, 
and  would  retain  itself  at  the  surface,  during  a  slow  subsidence  that 
would  submerge  the  inner  portion.  The  first  step,  therefore,  in  such 
a  subsidence,  is  to  change  a  fringing  reef  into  a  barrier-reef  (or  one 
with  a  channel  of  water  separating  it  from  the  shore).  The  continued 
subsidence  would  widen  and  deepen  this  channel ;  then,  as  the  island 


CORAL   FORMATIONS. 


625 


began  to  disappear,  the  channel  would  become  a  lake,  with  a  few  peaks 
above  its  surface  ;  then,  a  single  peak  of  the  old  land  might  be  all  that 
was  left  ;  and  finally  this  would  disappear,  and  the  coral  reef  come 
forth  an  atoll,  with  its  lagoon  complete. 

Referring  again  to  the  figure  :  if,  in  the  subsidence,  the  horizontal 
line  2  become  the  sea-level,  the  former  fringing  reefy  is  now  at  b,  a 
barrier  reef,  and  ff  is  at  &',  and  ch,  chr,  ch!r  are  sections  of  parts  of 
the  broad  channel  or  area  of  water  within  ;  over  one  of  the  peaks,  P, 
of  the  sinking  island,  there  is  an  islet  of  coral,  i  :  when  the  subsidence 
has  made  the  horizontal  line  3  the  sea-level,  the  former  land  has  wholly 
disappeared,  leaving  the  barrier-reef,  t,  tf,  alone  at  the  surface,  around 
a  lagoon,  ///,  with  an  islet,  u,  over  the  peak  T,  which  was  the  last 
point  to  disappear. 

These  steps  arc  well  illustrated  at  the  Feejees.     The  island  Goro 
(Fig.  966)  has  a  fringing  reef;  Angau  (Fig.  967),  a  barrier;  Explor 
ing  Isles  (Fig.  968),  a  very  dis 
tant   barrier,   with   a   few  islets  ; 
Numuku  (Fig.  969),  a  lake  with 
a   single    rock.      The   disappear 
ance  of  this  last  rock  would  make 
the  island  a  true  atoll. 

Whenever  the  subsidence  ceases, 
the  waves  build  up  the  land  above 
the  reach  of  the  tides;  seeds  take 
root;  and  the  reef  becomes  cov- 
ered  with  foliage. 

The  atoll  Menchikoff  (Fig.  962)  was  evidently  formed,  as  explained 
by  Darwin,  about  a  high  island,  consisting  of  two  distinct  ridges  or 
clusters  of  summits,  like  Maui  and  Oahu  in  the  Hawaian  group. 

If  the  subsidence  be  still  continued,  after  the  formation  of  the  atoll, 
the  coral  island  will  gradually  diminish  its  diameter,  until  finally  it 
may  be  reduced  to  a  mere  sand-bank,  or  become  submerged  in  the 
depths  of  the  ocean. 

The  rate  of  subsidence  required  to  produce  these  results  cannot  exceed  the  rate  of 
upward  increase  of  the  reef-ground.  On  page  591,  some  estimates  are  given  with  re 
gard  to  the  exceeding  slowness  of  the  movement.1 

As  coral  debris  is  distributed,  by  the  waves  and  currents,  according  to  the  same  laws 
that  govern  the  deposition  of  silt  on  sea-coasts,  it  does  not  necessarily  follow  that  the 
existence  of  a  reef  in  the  form  of  a  barrier  is  evidence  of  subsidence  in  that  region. 
On  page  670,  the  existence  of  sand-barriers  of  similar  position  is  shown  to  be  a  com- 

1  For  further  information  on  the  subject  of  Corals  and  Coral  Islands,  the  reader  may 
refer  to  the  author's  Exploring  Expedition  Report  on  Zoophytes,  740  pp.,  4to,  and  61 
plates  in  folio,  3846,  and  to  his  recent  work  on  Corals  and  Coral  Islands,  398  pp.,  8vo, 
1872;  also  to  Darwin  on  the  Structure  and  Distribution  of  Coral  Reefs,  214  pp.,  8vo, 
with  maps  and  illustrations,  London,  1842. 
40 


Islands  of  the  FeeJee  srouP:  Fis-  966'  Gor°; 

967,  Angau  ;   968,  Exploring  Tsles  ;  969,  Nu- 

muku. 


626  DYNAMICAL    GEOLOGY. 

mon  feature  of  coasts  like  that  of  eastern  North  America.  In  the  cases  of  the  barriers 
about  the  islands  of  the  Pacific,  however,  there  is  no  question  on  this  point.  Such  bar 
riers  do  not  form  about  so  small  islands.  Moreover,  the  great  distances  of  the  reefs 
from  the  shores,  in  many  cases,  and  the  existence  of  islands  representing  all  the  steps 
between  that  with  a  fringing  reef  and  the  true  atoll,  leave  no  room  for  doubt.  The  re 
moteness  of  the  Australian  barrier  from  the  continent,  and  the  great  depth  of  water  in 
the  wide  channel,  show  that  this  reef  is  unquestionable  proof  of  a  subsidence,  —  though 
it  is  not  easv  to  determine  the  amount.  Along  the  shores  of  continents,  the  question 
whether  a  barrier  coral  reef  is  evidence  of  subsidence  or  not  must  be  decided  by  the 
facts  connected  with  each  special  case. 

Recapitulation.  —  The  following  are  some  of  the  points,  connected 
with  the  formation  of  limestone  strata,  illustrated  by  coral  reefs :  — 

1.  The  narrow  geographical  limits  of  coral-reef  rocks  at  the  present 
time,  owing  to  the  existing  zones  of  oceanic  temperature. 

2.  The    narrow  limit  in   depth  of   the  reef-making  corals,  —  this 
depth  not  exceeding  one  hundred  feet. 

3.  The  promiscuous  growth  of  the  corals  over  the  reef-grounds. 

4.  The  perfect  compactness    and  freedom    from  fossils  of  a  large 
proportion  of  the  coral  rock,  although  made  within  a  few  hundred  feet 
of  living  corals  and  shells  ;  the  oolitic  structure  of  part  of  this  com 
pact  kind ;  while  a  variety  made  of  broken  corals  cemented  together 
is  common  on  the  seaward  side  of  a  reef,  and  another,  made  of  stand 
ing  corals  with  the  interstices  filled,  forms  where  there  is  shelter  from 
the  ocean's  waves. 

5.  The  aid  of  the  waves  of  the  ocean  necessary,  for  making  a   solid 
limestone  out  of  corals  or  ordinary  marine  shells. 

6.  The  great  extent  and  thickness  of  single  reefs. 

7.  The  action  of  tidal  currents  and  those  arising  from  the  piling  in 
of  the   waves  during  stormy  weather,  in  keeping  open  channels  and 
harbors,  and  determining,  the  distribution  of  the  coral  detritus. 

8.  The  close  proximity,  along   shores   bordered  by  barrier-reefs,  of 
deposits    of  coral    material    and  deposits  of  river  or  ordinary  shore 
detritus. 

9.  An  exceedingly  slow  subsidence,  in  progress  during  the  growth 
of  the  corals,  the  cause  of  the  change  of  a  fringing  reef  into  a  barrier, 
and  later  into  an  atoll. 

10.  The  necessity  of  this  subsidence,  for  giving  great  thickness  to 
such  limestones. 

The  making  of  limestones  from  shells  or  crinoidal  remains  is  similar 
to  that  from  corals,  the  waves  wearing  them  or  part  of  them  to  sand 
or  mud,  and  then  consolidation  taking  place.  The  rate  of  formation  of 
limestones  from  shells  is  slower  than  that  of  Coral  or  Crinoidal  lime 
stones,  since  Mollusks  produce  in  their  calcareous  secretions  much  less 
carbonate  of  lime  in  proportion  to  their  bulk. 


COHESIVE   ATTRACTION.  627 


II.  COHESIVE  AND  CAPILLARY  ATTRACTION;    GRAV 
ITATION. 

1.  CRYSTALLIZATION.  — The  power  of  cohesion  acting  in  solidifica 
tion,  and  that  in  crystallization,  appear  to  be  identical.  Snow,  ice,  bar- 
iron,  trap,  granyte  and  even  solid  spermaceti  are  crystallized  in  their 
intimate  structure.  Iron  and  granyte  show  it  in  the  angular  grains 
which  make  up  the  mass,  and  which  may  be  observed  on  a  surface  of 
fracture ;  and  ice,  in  the  frosty  covering  of  windows,  and  the  prisms 
which  shoot  across  a  surface  on  freezing,  as  well  as  in  the  vertical 
columns  into  which  it  sometimes  breaks  when  the  ice  of  a  pond  melts 
in  spring.  Quartz  exhibits  it  in  its  prismatic  and  pyramidal  crystals 
(p.  55).  The  fact  can  thus  be  proved  for  all  mineral  solids,  except  it 
be  those  of  a  glassy  nature  ;  and  even  these  are  probably  no  excep 
tion  to  the  principle  that  solidification  is  crystallization. 

Crystallization  is  exhibited  (1)  in  the  angular  solids  it  produces, 
called  crystals,  and  (2)  in  the  tendency  to  cleave  or  divide  in  one  or 
more  directions,  called  cleavage. 

Crystals.  —  Some  of  the  forms  of  crystals  are  illustrated  on  the 
early  pages  of  this  work  (pp.  53-59).  Crystals  are  formed  when 
substances  cool  from  fusion  (as  when  melted  sulphur  cools)  ;  or 
solidify  from  solution  (as  in  the  evaporation  of  a  solution  of  alum)  ; 
or  become  condensed  from  the  state  of  vapor  (as  in  the  formation  of 
snow  from  vapor  of  water).  But  it  is  usually  requisite  for  perfection 
that  the  process  should  go  forward  with  extreme  slowness,  free  from 
all  disturbing  causes,  and  with  space  for  the  crystals  to  expand.  Cav 
ities  in  rocks  are  often  lined  with  crystals,  while  the  rock  itself  is  but 
a  compact  mass  of  crystalline  grains. 

Long-continued  heat,  short  of  fusion,  favoring  a  slow  aggregation 
of  the  particles,  sometimes  produces  crystals,  or  a  crystalline  structure. 
Heating  steel  to  a  certain  temperature,  short  of  that  required  for 
fusion,  changes  the  fineness  of  the  grains,  —  which  is  a  change  of  crys 
talline  texture. 

Cleavage.  —  Cleavage  is  usually  parallel  to  one  or  more  planes  or 
diagonals  of  the  fundamental  form. 

The  minerals  mica  and  gypsum  are  examples  of  very  easy  cleavage. 
Calcite  has  easy  cleavage  in  three  directions,  making  a  fixed  angle 
(105°  5')  with  one  another,  parallel  to  the  faces  of  the  fundamental 
rhombohedron.  Feldspar  has  easy  cleavage  in  one  direction,  and  in 
another  a  second  cleavage,  a  little  less  perfect,  at  right  angles,  or 
nearly  so,  with  the  first.  Quartz  has  no  distinct  cleavage. 

Cleavage  in  rocks.  —  Rocks  may  derive  a  cleavage-structure   from 


628  DYNAMICAL    GEOLOGY. 

one  of  the  constituent  minerals.  Thus,  mica  schist  cleaves  into  thin 
laminre,  because  of  the  abundance  of  the  very  cleavable  mineral  inica. 
Mica  may  give  cleavage  even  to  a  quartz  rock.  Granyte  often  has  a 
direction  of  easiest  fracture,  due  to  the  fact  that  the  feldspar  crystals 
have  approximately  a  uniform  position  in  the  rock,  bringing  the 
cleavage-planes  into  parallelism. 

Cleavage-structure  must  not  bo  confounded  with  the  existence  of 
planes  of  fracture  in  rocks,  called  joints.  Mineral  coal,  trap,  sand- 
stone  often  break  into  angular  blocks  ;  but,  were  there  true  cleavage, 
the  cleavage-structure  would  be  general  along  some  one  or  more 
fixed  directions  in  the  mass  or  block,  and  not  be  limited  to  certain 
planes  of  fracture.  Cleavage  follows  particular  directions,  but  not 
particular  planes. 

The  cleavage-structure  of  a  rock  like  mica  schist,  due  to  a  cleav 
able  mineral,  is  usually  called  foliation,  to  distinguish  this  character 
from  slaty  cleavage.  (See  p.  89.) 

2.  CONCRETIONARY  STRUCTURE.  —  Examples  of  concretionary 
forms  arc  given  on  pages  85-88.  There  is  a  general  tendency  in  matter 
to  concrete  around  centres,  whether  solidifying  from  fusion,  solution,  or 
vapors.  These  centres  may  be  determined  (1)  by  foreign  substances 
which  act  as  nuclei,  or  (2)  by  the  circumstances  of  solidification,  which, 
according  to  a  general  law,  favor  a  commencement  of  the  process  at 
certain  points  in  the  mass,  assumed  at  the  time.  As  the  solidifying 
condition  is  just  being  reached,  instead  of  the  whole  simultaneously 
concreting,  the  process  generally  begins  at  points  through  the  mass ; 
and  these  points  are  the  centres  of  the  concretions  into  which  the 
mass  solidifies. 

The  concretions  in  the  same  mass  arc  usually  of  nearly  equal  size : 
hence,  (3)  the  points  at  which  solidification  in  any  special  case  begins 
are  usually  nearly  equidistant.  The  great  uniformity  of  size  in  the 
concretions  of  most  beds  of  rock  shows  that  foreign  bodies  do  not 
generally  determine  the  positions  of  the  centres,  although  they  often 
act  as  nuclei. 

Basaltic  columns  are  a  result  of  concretionary  structure  formed  in 
cooling  (p.  87),  in  accordance  with  the  principles  just  explained:  each 
column  corresponds  to  separate  concretionary  action.  The  size  of  the 
columns  is  determined  by  the  distance  apart  of  the  points  which  take 
the  lead  (these  points  lying  in  the  centres  of  the  columns)  ;  and  this 
is  determined  by  the  rate  of  cooling ;  and  this,  mainly,  by  the  thick 
ness  of  the  mass  to  be  cooled  :  the  thicker  the  mass,  the  slower  the 
cooling,  and  the  larger  the  columns.  The  cracks  separating  the  col 
umns  from  one  another  are  due  to  contraction  on  cooling. 

Iron-stone,  sandstone,  and  clayey  concretions  in  beds  of  rock,  are 


COHESIVE   ATTRACTION.  629 

examples  in  which  the  concreting  is  due  to  a  mineral  solution  pene 
trating  a  stratum  of  clay  or  sand.  A  solution  containing  silica  would 
make  siliceous  concretions  :  so  also  a  calcareous  or  a  ferruginous  solu 
tion  may  be  the  concreting  agent.  In  either  case,  the  process  is  as 
has  been  explained :  the  distances  between  the  centres,  being  first  fixed 
in  the  concreting  process,  determine  the  size  of  the  concretions  ;  and 
the  equality  of  these  distances,  the  uniformity  of  size. 

Spherical  and  flattened  Concretions.  —  A  mineral  solution  (or  any 
liquid)  naturally  spreads  equally  in  all  directions,  through  a  sandy  or 
earthy  stratum,  and  makes,  therefore,  spherical  concretions ;  but,  in  a 
clayey  rock,  it  spreads  laterally  most  rapidly,  and  so  leads  to  flattened 
concretions.  The  vertical  and  horizontal  diameters  of  the  concre 
tions  will  be  to  one  another  as  the  rate  of  spreading  in  the  two 
directions. 

Hollow  Concretions.  —  Flattened  Rings.  —  In  a  concretionary  mass, 
the  drying  of  the  exterior,  by  absorption  around,  may  lead  to  its  con 
creting  first.  It  then  forms  a  shell,  with  a  wet  un solidified  interior. 

o 

The  drying  of  the  interior,  since  the  shell  is  unyielding,  contracts  it ; 
and  consequently  it  becomes  much  cracked,  as  in  Figs.  72,  73  ;  or,  if 
the  interior  undergoes  no  solidification,  it  may  remain  as  loose  earth  ; 
or,  if  it  solidify  at  the  centre,  by  the  concreting  process,  before  the 
shell  forms,  or  after,  it  may  form  a  ball  within  a  shell,  with  loose  earth 
between. 

The  circumstances  that  would  produce  hollow  balls  among  sphe 
roidal  concretions  produce  rings  among  flattened  concretions,  or  in 
clayey  layers.  They  arise  from  the  solidification  commencing  first 
around  the  circumference  of  the  concretions,  and  then  the  circle  thus 
begun  acting  as  a  nucleus  about  which  the  concreting  is  continued. 

The  concentric  coats  in  many  concretions  are  due  to  an  intermittent 
action  in  the  concreting  process.  If  a  drop  of  a  weak  solution  of 
sugar  dry  upon  a  slab  of  stone  in  the  air,  there  will  result  concentric 
rings.  The  outer  edge  of  the  circular  spot  dries  most  rapidly  ;  and, 
when  solidification  begins  along  it,  the  liquid  inside  of  it,  for  a  limited 
distance,  is  drawn  to  the  concreting  circle,  exhausting  the  sugar  for 
that  distance  inward  ;  then  the  spot  of  dissolved  sugar,  thus  made 
smaller,  concretes  again  at  its  outer  edge,  and  forms  in  the  end  a  new 
circle  ;  and  so  it  goes  on  until  all  is  evaporated.  A  concentric  ar 
rangement  of  colors  and  of  layers  is  often  thus  produced  in  ferrugi 
nous  concretions,  the  outer  shell  first  drying  and  concreting,  and  after 
ward  successive  concentric  shells,  to  the  centre. 

3.  CAPILLARY  ATTRACTION.  —  The  process  resulting  in  concentric 
coats,  described  in  the  preceding  paragraph,  is  due  partly,  as  is  seen, 
to  capillary  attraction.  In  the  drying  of  the  soil  during  dry  seasons, 


630  DYNAMICAL    GEOLOGY. 

the  loss  of  moisture  at  the  surface  is  attended  by  a  rise  of  moisture, 
through  capillary  attraction,  from  the  deeper  part  of  the  soil ;  and  thus 
vegetation  is  often  sustained  through  a  long  drought.  If  the  waters 
below  contain  soluble  saline  substances,  these  salts  are  brought  to  the 
surface,  there  to  crystallize,  and  make  what  are  called  efflorescent 
crusts  ;  and,  in  a  dry  climate,  like  that  of  Nevada  and  many  other 
regions,  such  a  crust  may  become  quite  thick.  This  crust  the  rains 
may  afterward  dissolve  and  wash  away,  or,  if  the  region  is  a  basin, 
make  by  means  of  it  a  salt  lake.  The  saline  substances  referred  to 
include  common  salt,  carbonate  of  soda,  sulphate  of  soda  (Glauber 
salt),  alum,  sulphate  of  magnesia  (Epsom  salt),  borax,  gypsum,  car 
bonate  of  soda  and  lime  (gay-lussite),  etc. 

When  infiltrating  waters  cause  the  superficial  decomposition  of  a 
rock,  the  drying  of  the  surface  tends  to  bring  whatever  is  dissolved  to 
the  surface,  and  thus  produce  a  film  over  it.  Limestone,  if  it  contains 
any  iron,  is  sometimes  covered  in  this  way  with  a  brownish -vellow  film, 
or,  if  any  manganese,  a  black  film,  the  film  in  each  of  these  cases  being 
an  oxyd  of  the  metal  present. 

4.  GKAVITATION.  —  Gravitation  is  concerned  in  all  the  mechanical 
changes  carried  on  over  the  globe,  influencing  the  arrangement  and 
positions  of  material,  and  having  a  controlling  action  over  all  move 
ments.  In  the  case  of  slopes  of  dry,  falling  sand  or  stones,  gravitation 
and  friction  are  the  chief  causes  of  the  positions  assumed.  Such  an 
accumulation  at  the  foot  of  a  bluff  is  called  a  talus  ;  and  those  of  vol 
canic  cinders,  about  a  vent  of  eruption,  a  volcanic  cone.  A  talus  of 
dry  sand  may  have  an  angle  of  32°  to  35°,  it  slipping  easily  if  at  a 
higher  angle  ;  one  of  angular  stones,  such  as  forms  at  the  base  of  a 
bluff  of  trap,  38°  to  40°  ;  volcanic  cinders  about  40°.  Assumption 
Island,  one  of  the  northern  Ladrones,  and  a  cone  of  this  kind,  has,  as 
observed  by  the  author,  a  slope  scarcely  varying  from  40°.  Where 
abundant  waters  from  rains  accompany  the  fall,  the  slope,  if  the  mate 
rial  is  earth  or  sand,  will  be  diminished  to  different  angles,  from  30° 
to  15°,  according  to  the  amount  of  water;  and,  with  a  very  free 
supply,  to  a  much  smaller  angle, 

m.   THE  ATMOSPHERE. 

The  following  are  some  of  the  mechanical  effects  connected  with 
the  movements  of  the  atmosphere. 

1.  Destructive  effects,  from  the  transportation  of  sand,  dust,  etc.  —  The 
streets  of  most  cities,  as  well  as  the  roads  of  the  country,  in  a  dry 
summer  day,  afford  examples  of  the  drift  of  dust  by  the  winds.  The 
dust  is  borne  most  abundantly  in  the  direction  of  the  prevalent  winds, 


THE   ATMOSPHERE.  631 

and  may  in  the  course  of  time  make  deep  beds.  The  dust  that  finds 
its  way  through  the  windows  into  a  neglected  room  indicates  what 
may  be  done  in  the  progress  of  centuries,  where  circumstances  are  more 
favorable. 

The  moving  sands  of  a  desert  or  sea-coast  are  the  more  important 
examples  of  this  kind  of  action. 

On  sea-shores,  where  there  is  a  sea-beach,  tho  loose  sands  composing 
it  are  driven  inland  by  the  winds,  into  parallel  ridges  higher  than  the 
beach,  forming  drift-sand  hills.  They  are  grouped  somewhat  irregu 
larly,  owing  to  the  course  of  the  wind  among  them,  and  little  inequali 
ties  of  compactness  or  protection  from  vegetation.  They  form  espe- 
ciallv  (1)  where  the  sand  is  almost  purely  siliceous,  and  therefore  not 
at  all  adhesive  even  when  wet,  and  not  good  for  giving  root  to  grasses ; 
and  (2)  on  windward  coasts.  They  arc  common  on  the  windward 
side,  and  especially  the  projecting  points,  even  of  a  coral  island,  but 
never  occur  on  the  leeward  side,  unless  this  side  is  the  windward 
during  some  portion  of  the  year.  On  the  north  side  of  Oahu,  they 
are  thirty  feet  high,  and  made  of  coral  sand.  Some  of  them,  which 
stand  still  higher  (owing  to  an  elevation  of  the  island),  have  been 
solidified ;  and  they  show,  where  cut  through,  that  they  consist  of  thin 
layers  lapping  over  one  another  ;  they  evince  also,  by  the  abrupt 
changes  of  direction  in  the  layers  (see  Fig.  61  G?),  that  the  growing 
hill  was  often  cut  partly  down  or  through  by  storms,  and  again  and 
again  completed  itself  after  such  disasters. 

This  style  of  lamination  and  irregularity  is  characteristic  of  the 
drift-sand  hills  of  all  coasts.  On  the  southern  shore  of  Long  Island, 
there  are  series  of  sand-hills,  of  the  kind  described,  extending  along 
for  a  hundred  miles,  and  five  to  thirty  feet  high.  They  are  par 
tially  anchored  by  straggling  tufts  of  grass.  The  coast  of  New  Jersey, 
down  to  the  Chesapeake,  is  similarly  fronted  by  sand-hills.  In  Nor 
folk,  England,  between  Hunstanton  and  Weybourne,  the  sand-hills 
are  fifty  to  sixty  feet  high. 

2.  Additions  to  land,  by  means  of  drift-sands  —  The  drift-sand  hills 
arc  a  means  of  recovering  lands  from  the  sea.     The  appearance  of  a 
bank  at  the  water's   edge,  off  an  estuary  at  the  mouth  of  a  stream,  is 
followed  by  the  formation  of  a  beach,  and  then  the  raising  of  the  hills  of 
sand  by  the  winds,  which  enlarge  till  they  sometimes  close  up  the  estu 
ary,  exclude  the  tides,  and  thus  aid  in  the  recovery  of  the  land  by  the 
depositions   of  the  river-detritus.     Lyell  observes  that,  at  Yarmouth, 
England,  thousands  of  acres  of  cultivated  land  have  thus  been  gained 
from  a  former   estuary.     In  all  such  results,  the  action  of  the  waves 
iu  first  forming  the  beach  is  a  very  important  part  of  the  whole. 

3.  Destructive  effects  of  drift-sands.  —  Dunes.  —  Dunes  are  regions 


632  DYNAMICAL    GEOLOGY. 

of  loose  drift-sand,  near  the  sea.  In  Norfolk,  England,  between  Hun- 
stanton  and  Weybourne,  the  drift-sands  have  travelled  inland,  with 
great  destructive  effects,  burying  farms  and  houses.  They  reach,  how 
ever,  but  a  few  miles  from  the  coast-line  ;  and,  were  it  not  that  the 
seashore  itself  is  being  undermined  by  the  waves,  and  is  thus  moving 
landward,  the  effects  would  soon  reach  their  limit. 

In  the  desert  latitudes,  drift-sands  are  more  extended  in  their  effects. 

4.  Sand-scratches.  —  The  sands  carried  by  the  winds,  when  passing 
over  rocks,  sometimes   wear  them  smooth,  or  cover  the  surface  with 
scratches  and  furrows,  much  like  glacier  scratchings  and  ploughings,  as 
observed  by  Wm.  P.  Blake  over  granyte  rocks,  at  the   Pass  of  San 
Bernardino   in   California.      Even   quartz  is   polished ;    and    garnets 
are  left  projecting,  upon  pedicels  of  feldspar.     Limestone  is  so  much 
worn  as  to  look  as  if  the  surface  had  been  removed  by  solution.     The 
glass  in  windows  on  Cape  Cod  is  worn  through  by  the  same  means. 
This  principle  is  now  put  to  practical  use,  in   the  grinding  and  carv 
ing  of  glass,  gems,  and  even  granyte,  steam  being  used  for  blowing 
a  jet  of  sand  against  the  surface  on  which  designs  are  to  be  made,  and 
also,  in  most  operations,  issuing  with  the  sand,  in  order  to  soften  the 
material.    In  this  way,  the  deep  carvings  of  a  granyte  frieze  have  been 
made  in  six  hours,  that  would  have  required  two  months  of  work  by 
hand. 

5.  Dust-showers.  —  Sands  are  sometimes  taken  up  by  whirlwinds  or 
in  heavy  gales,  into  the  higher  regions  of  the  atmosphere,  and  trans 
ported  to  great  distances. 

In  1812,  volcanic  ashes  were  carried  from  the  island  of  St.  Vincent 
to  Barbadoes,  sixty  to  seventy  miles  ;  and  in  1835,  from  the  volcano 
of  Coseguina,  in  Guatemala,  to  Jamaica,  eight  hundred  miles. 

Showers  of  grayish  and  reddish  dust  sometimes  fall  on  vessels  in 
the  Atlantic  off  the  African  coast,  and  over  southern  Europe ;  and, 
when  they  come  down  with  rain,  they  produce  "  blood-rains."  Ehren- 
berg  has  found  that  the  dust  of  these  showers  is  to  a  great  extent 
made  up  of  microscopic  organisms.1  The  figures  on  the  adjoining 
page  represent  the  species  from  a  single  shower,  which  came  down 
about  Lyons,  on  October  17,  1846.  The  amount  which  fell  at  the 
time  was  estimated  by  Ehrenberg  at  720,000  Ibs. ;  and  about  one 
eighth  consisted  of  these  organisms,  making  90,000  Ibs.  of  them. 

The  species  figured  by  Ehrenberg  include  thirty-nine  species  of  siliceous  Diatoms 
(Figs.  1-65);  twenty-five  of  what  he  calls  Phytolitharia  (Figs.  66-104),  besides  eight  of 
Khizopods.  The  following  are  the  names  of  the  Diatoms. 

Figs.  1,  2,  Melosira  yranulata  ;  3,  M.  decussrtta ,;  4,  M.  Marcliica;  5-7,  M.  distnns; 

1  See  his  work  entitled  Passctt-staub  und  Blut-reyen,  4to,  1847,  and  Amer.  Jour.  Sri., 
II.  xi.  372. 


THE   ATMOSPHERE. 
Figs.  1-105  (970-1075). 


633 


19  A        A  feM-iVVvW  ?• 
\J  \  >;  'c  i  "   '••'  •*   »"•• 


Diatoms  and  other  microscopic  organisms  of  a  dust-shower. 


634  DYNAMICAL   GEOLOGY. 

8,9,  Coscinodiscus  atmospherica ;  10,  Cosdnodiscus  (?) ;  11,  Trachelomonas  levis ;  12, 
Campylodiscus  clypeus ;  13-15,  Gomphonema  yradle, ;  16,  17,  Cocconema  cymbiforme  ; 
18,  Cymbdla  maculata ;  19,  20,  Epithemia  lonyicornis  (frustule  of  E.  Art/us);  21,  22. 
E.  lonyicornis;  23,  E.  Art/us;  24,  E.  lonyicornis ;  25,  Eunotia  yranulata  (?) ;  26,  E. 
zebrina  (?) ;  27.  Himantidium  Monodon  (?) ;  28-32,  Eunotia  amphioxys  ;  33,  34,  Epithemia 
yibberuld;  35,  Eunotia  zebrina  (?);  36,  E.  zyyodon  (?) ;  37,  Epithemin  yibba ;  38,  Eu 
notia  trident  ula ;  39,  E.(?)  levis;  40,  Ilimantidium  arcus ;  41,  42,  Tabellarin ;  43, 
Odontidium  (?) ;  44,  Coccone'is  lineata  ;  45,  C.  atmospherica  ;  46,  Navicula  badllum ;  47, 
JV.  amphioxys ;  48,  49,  AT.  semen;  50,  JV.  serians;  51,  Pinnularia  borealis ;  52,  P. 
viridula;  53,  P.  viridis ;  54,  Mastoyloia  (? ) ;  55,  Pinnulnria  (equally  (?) ;  56,  Surirdla 
cruticula  (?) ;  57,  58,  Synedra  ulna ;  59,  Odontidium  (?) ;  60,  Frttyilaria  pinnata  (?) ;  61 
Mastoyloia  (?) ;  62-65,  doubtful. 

A  shower  which  happened  near  the  Cape  Verdes,  and  has  been  described  by  Darwin, 
had  by  his  estimate  a  breadth  of  more  than  1,600  miles,  —  or,  according  to  Tuckey,  of 
1,800  miles,  —  and  reached  800  or  1,000  miles  from  the  coast  of  Africa.  These  numbers 
give  an  area  of  more  than  a  million  of  square  miles. 

Dust  from  a  shower  over  Italy,  in  1803,  afforded  Ehrenberg  forty -nine  species  of 
organisms,  and  another,  in  1813,  over  Calabria,  sixty-four  species;  and  the  two  had 
twenty-eight  species  in  common. 

In  1755,  there  was  a  "blood-rain  "  near  Lago  Maggiore,  in  northern  Italy,  covering 
about  two  hundred  square  leagues  ;  and  at  the  same  time  nine  feet  of  reddish  snow  fell 
on  the  Alps.  The  earth-deposit  in  some  places  was  an  inch  deep.  Supposing  it  to 
average  but  two  lines  in  depth,  it  would  be  for  each  square  mile  an  amount  equal  to 
2,700  cubic  feet.  The  red  color  of  the  "  blood-rain  "  is  owing  to  the  presence  of  some 
red  oxyd  of  iron. 

Ehrenberg  enumerates  a  very  large  number  of  tliese  showers,  referring  to  Homer's 
Iliad  for  one  of  the  earliest  known.  With  such  facts  before  us,  how  many  millions 
of  hundred-weight  of  microscopic  organisms  have  reached  Europe  since  the  period  of 
Homer?  The  whole  number  of  species  made  out  is  over  three  hundred. 

The  species, so  far  as  ascertained,  are  not  African;  fifteen  are  South  American.  But 
the  origin  of  the  dust  is  yet  unknown.  The  zone  in  which  these  showers  occur  covers 
southern  Europe  and  northern  Africa,  with  the  adjoining  portion  of  the  Atlantic,  and 
the  corresponding  latitudes  in  western  and  middle  Asia. 

6.  CJtanges  of  Atmospheric  Pressure. —  A  local  change  of  atmospheric 
pressure,  from  a  passing  storm,  has  an  effect  on  any   large  body  of 
water  beneath  it,  a  diminution  of  pressure  causing  the  water  directly 
beneath  to  rise  from  the  greater  pressure  elsewhere.     A  variation  of 
one  inch  in  the  mercury  column  of  a  barometer  is  equivalent  to  13.4 
inches  in  a  column  of  water.     Captain  J.  C.  Ross  has  observed,  in  the 
Arctic  regions,  that  a  change  of  pressure  of  this  kind  was  perceptible 
in  the  tides.     Observations  through  forty-seven  days  gave  a  variation 
in  the  water  of  nine  inches,  corresponding  to  two  thirds  of  an  inch  in 
the  barometer. 

The  wind  during  storms  produces  sometimes  an  elevation  of  the 
water  in  the  leeward  part  of  a  lake,  at  the  expense  of  that  in  the 
other,  as  has  often  been  observed  in  the  Great  Lakes  of  North  Amer 
ica.  Great  waves  on  the  ocean  and  extraordinary  tides  on  sea-coasts 
are  other  effects  of  the  same  cause.  The  subject  of  waves  is  treated 
of  under  the  head  of  Water. 

7.  Chemical  action.  —  The  atmosphere  also  plays  an  important  part 


FRESH-WATER   STREAMS.  635 

in  geological  changes,  through  the  chemical  action  of  its  elements. 
But  these  effects  properly  come  under  the  head  of  Chemical  Geology. 
The  operation  loosens  the  grains  of  the  surface,  and  thus  gives  a 
chance  to  the  winds  to  do  work  of  erosion,  which  would  otherwise  be 
impossible.  The  crumbling  of  the  softer  decomposable  layers,  in  a 
series  of  horizontal  beds,  may  result,  and  thus  the  firmer  strata  be 
undermined,  so  that  gravitation  has  a  chance  to  carry  forward  the 
work  of  destruction,  and  thus  make  vertical  and  overhanging  bluffs. 
In  the  decompositions  and  recompositions  in  which  the  air  takes  part, 
the  presence  of  moisture  is  generally  essential ;  and  the  subject  is 
therefore  considered  under  the  head  of  Water. 

IV.   WATER. 

Subdivisions  of  the  subject. 

1.  FRESH  WATERS  ;  including  especially   Rivers  and   the   smaller 
Lakes. 

2.  The  OCEAN  ;  including  the  larger  Lakes,  whether  salt  or  fresh 
water,  —  the  general  facts  being  similar,  excepting  such  as  depend  on 
the  tides  and  the  kind  and  density  of  the  water. 

3.  FROZEN  WATERS,  or  Glaciers  and  Icebergs. 

4.  WATER  AS  A  CHEMICAL  AGENT. 

1.    FRESH  WATERS. 

The  Superficial  waters  and  the  Subterranean  may  bo  separately 
considered. 

A.   SUPERFICIAL    WATERS:    RIVERS. 
1.    GENERAL    OBSERVATIONS    ON   RIVERS. 

1.  Water  of  Rivers.  —  The  fresh  waters  of  the  land  come  from  the 
vapors  of  the  atmosphere ;  and  these  are  largely  furnished  by  the 
ocean.  They  rise  into  the  upper  regions  of  the  atmosphere  and,  be 
coming  condensed  into  drops,  descend  about  the  hills  and  plains,  and 
so  begin  their  geological  work,  —  gravity  being  the  moving  power. 

The  amount  of  water  in  a  river  depends  on  (1)  the  extent  of  the 
region  it  drains;  (2)  the  amount  of  rain,  mist,  or  snow  of  the  region; 
(3)  its  climate,  —  heat  and  a  dry  atmosphere  increasing  the  loss  by 
evaporation  ;  (4)  its  geological  nature,  —  absorbent  and  cavernous 
rocks  carrying  off  much  of  the  water;  (5)  its  physical  features, —  a 
flat,  open,  unwooded  country  favoring  evaporation. 

The  annual  discharge  of  the  Mississippi  River  averages  nineteen 
and  a  half  trillions  (19,500,000,000,000)  of  cubic  feet,  varying  from 


636  DYNAMICAL   GEOLOGY. 

eleven  trillions  in  dry  years  to  twenty-seven  trillions  in  wet  years. 
This  amount  is  about  one-quarter  of  that  furnished  by  the  rains.  The 
river  is  3,500  feet  wide  at  St.  Louis,  4,000  off  the  mouth  of  the  Ohio, 
and  about  2,500  at  New  Orleans. 

The  mean  annual  discharge  of  the  Missouri  River  is  about  three  and  three-quarter 
trillions,  or  Jifteen-hundredtk*  of  the  amount  of  the  rains  over  the  region.  The  corre 
sponding  amount  for  the  Ohio  is  five  trillions,  which  is  one-quarter  the  amount  of  rain. 
(Humphreys  £  Abbott.) 

Floods.  —  The  larger  part  of  the  geological  work  done  by  rivers  is 
carried  forward  in  times  of  flood.  Streams  that  are  sluggish  and 
impotent  in  the  dry  season,  or  even  burrow  out  of  sight,  become  tor 
rents  of  tremendous  power  during  rains.  The  rivers  of  some  dry 
countries,  as  Australia,  spread  out  in  immense  floods  in  the  rainy  sea 
son,  although  but  strings  of  pools  in  the  dry. 

Bursting  of  Lakes.  —  The  floods  made,  when  the  banks  of  a  lake 
suddenly  give  way,  have  the  character  of  those  arising  from  a  sudden 
precipitation  of  rain  in  the  mountains,  but  sometimes  with  vaster 
results,  the  water  ploughing  profoundly  into  the  slopes  before  it,  and 
spreading  the  gravel  or  earth,  uprooted  trees,  and  the  contents  of  the 
lake  basin,  far  and  wide. 

2.  Amount  of  Pitch  or  Descent  in  Rivers.  —  The  average  descent  of 
large  rivers,  excluding  regions  of  cascades,  seldom  exceeds  twelve 
inches  to  a  mile,  and  is  sometimes  but  half  this  amount. 

The  following  facts  on  this  point  are  from  Humphreys  &  Abbot's  Report  on  the  Mis 
sissippi  Basin.  The  descent  per  mile  is  given  in  inches;  L.  stands  for  the  low-water 
pitch,  and  II.  for  the  liiyli-water  pitch. 

L.  II. 

Mississippi  R.    Mouth  to  Memphis  (855  m.)  4'82  in.     5'23  in. 

Mouth  to  Cairo,  at  mouth  of  Ohio  (1088  m.)  6 '94          5'96 

Above  the  Missouri  to  source  (1330  m.)  11"74 

Missouri  R.        Mouth  to  St.  Joseph  (484  m.)  9 '24 

St.  Joseph  to  Sioux  City  (358  m.)  10'32 

Sioux  City  to  Fort  Pierre  (404  m.)  12'12 

Fort  Pierre  to  Fort  Union  (648  m.)  13'20 

Fort  Union  to  Fort  Benton  (750  m.)  10'56 

Fort  Benton  is  2,644  miles  above  the  mouth  of  the  Missouri.  The  whole  Missouri, 
from  its  highest  source,  a  distance  of  2,908  miles,  has  a  descent  of  about  6,800  feet, — 
or  28  inches  per  mile. 

During  floods  (1),  the  pitch  of  the  surface  of  a  stream,  when  the 
bottom  has  in  the  main  a  regular  descent,  and  the  channel  is  broad 
and  open,  is  increased  in  amount  arid  uniformity.  But,  in  the  Missis 
sippi,  below  the  mouth  of  the  Ohio,  it  is  less  than  the  low-water  pitch, 
because  the  lower  part  of  this  river,  for  200  miles  from  the  Mexican 
Gulf,  is  horizontal,  or  very  nearly  so.  The  waters  are  raised  less  near 


FRESH-WATER    STREAMS,  637 

the  ocean  than  in  the  interior  of  tho  country,  because  of  the  easy 
discharge  through  the  mouth.  Owing  to  the  height  of  the  waters, 
which  often  cover  the  banks,  the  course  loses  some  of  its  minor  bends ; 
arid  the  whole  distance  is  therefore  less  ;  while  the  inequalities  of  pitch 
between  the  still  water  and  more  rapid  portions  tend  to  disappear  in 
a  broad  open  channel.  When  a  river  runs  through  a  narrow,  rocky 
gorge,  the  waters  above  the  entrance  of  the  gorge  are  partially  held 
back,  and  have  less  pitch  during  freshets  than  at  low  water  ;  and  con 
sequently  the  pitch  through  the  course  of  the  gorge  is  increased. 

3.  Flow  of  a  Stream.  —  The  above  conditions  affect  directly  the 
velocity  of  the  stream,  as  this  varies  with  the  pitch  and  depth  of 
water.  The  sudden  expansion  in  size  and  depth  of  a  river-channel,  as 
when  a  lake  intervenes,  also  affects  the  velocity,  often  producing  seem 
ingly  a  state  of  nearly  perfect  quiet.  The  water-level  becomes  for 
the  interval  nearly  horizontal.  The  quiet  at  the  whirlpool,  in  the 
rapids  below  the  Falls  of  Niagara,  is  accounted  for  on  the  ground  of 
the  great  increase  of  depth  and  the  abrupt  expansion  in  breadth. 

The  movement  of  a  stream  is  most  rapid  near  the  surface.  The 
bottom,  sides,  and  air  retard  by  friction  the  layer  in  contact  with 
them  ;  and  other  adjoining  layers  are  retarded  through  the  cohesion 
between  the  particles  of  the  water.  The  velocity  is  greater,  the  less 
the  extent  of  the  upper  (or  air)  and  bottom  surfaces,  —  the  surfaces 
of  friction.  When  two  streams  unite,  the  waters  have  the  surfaces  of 
friction  of  one  stream  instead  of  two,  and  there  is  consequently  an 
increased  rate  of  flow;  and,  besides,  owing  to  the  greater  velocity, 
the  united  waters  do  not  occupy  a  space  equal  to  the  sum  of  those 
which  they  occupied  before  the  union. 

Other  characteristics  of  rivers  are  brought  out  in  the  following 
pages. 

2.  MECHANICAL  EFFECTS  OF  RIVKRS. 
The  mechanical  effects  of  fresh  waters  are,  — 

1.  Erosion,  or  wear. 

2.  Transportation  of  earth,  gravel,  stones,  etc. 

3.  Distribution  of  transported  material,  and  the  formation  of  frag- 
mental  deposits. 

1.  Erosion. 

1 .  General  Statement  of  the  Effects  of  Erosion.  — The  effects  of  erosion 
are  seen,  first,  in  the  imprint  of  the  falling  rain-drop,  —  a  trifling 
matter  to  most  eyes,  but  not  so  to  the  geologist ;  for  it  remains  among 
the  records  of  the  earliest  and  latest  strata,  to  show  that  it  rained 
then  as  now,  and  to  teach  us  where  the  lands  at  the  time  lay  above 


638 


DYNAMICAL   GEOLOGY. 


the  ocean.  It  is,  therefore,  a  part  of  the  markings  in  which  the  geo 
graphical  history  of  the  globe  is  registered. 

Second.  The  gathering  drops  make  the  rill,  and  the  rill  its  little 
furrow  ;  rills  combine  into  rivulets,  and  rivulets  make  a  gully  down 
the  hill-side  ;  rivulets  unite  to  form  torrents,  and  these  work  with 
accumulating  force,  and  excavate  deep  gorges  in  the  declivities.  Other 
torrents  form  in  the  same  mariner  about  the  mountain-ridge,  and 
pursue  the  same  work  of  erosion,  until  the  slopes  are  a  series  of 
valleys  and  ridges,  and  the  summit  a  bold  crest,  overlooking  the  erod 
ing  waters. 

2.  Progress  of  erosion  in  the  Formation  of  Valleys  or  River-courses.  — 
The  mist  and  rains  about  the  higher  parts  of  mountains  are  usually 
the  main  source  of  the  water.  As  the  first-made  streamlets  are 
gathering  into  larger  streams,  through  the  course  of  the  descent,  and 
are  largest  below,  the  torrent  has  its  greatest  force  toward  the  bot 
tom  of  the  steep  declivity ;  and  there  the  valley  first  takes  shape  and 
size. 

Let  A  B  (Fig.  1076)  represent  a  profile  of  a  declivity.  As  the 
erosion  goes  on,  a  valley  is  formed  along  I  m,  on  the  principle  just 
stated,  so  that  the  course  of  the  waters  on  the  profile  corresponds  to 
Aim.  At  m.  the  most  of  the  descent  of  the  declivity  is  made :  the 
waters  have,  therefore,  but  little  eroding  power  at  bottom  ;  and  they 
flow  off  at  a  small  angle  to  B,  along  the  line  m  B.  At  m,  moreover, 
the  stream,  ceasing  to  erode  much  at  bottom,  commences  to  erode 

Fig.  1076.  Fig.  1077. 


laterally  during  freshets,  undermining  the  cliffs  on  either  side,  when 
the  rocks  admit  of  it,  thus  widening  the  valley  and  making  a  'k  flood- 
plain,"  or  "  bottom-lands,"  through  which  the  stream  when  low  has 
its  winding  channel. 

The  river,  in  this  state,  consists  of  its  torrent-portion,  A  m,  and  its 
river-portion,  m  B.  Along  the  former,  a  transverse  section  of  the 
valley  is  approximately  V-shaped,  and  along  the  latter  nearly  U-shaped, 
or  else  like  a  V  flattened  at  bottom.  The  river-portion  usually  ex 
hibits,  even  in  its  incipient  stages,  its  two  prominent  elements,  —  a 
river -channel,  occupied  by  the  waters  in  ordinary  seasons,  and  the 
alluvial-flat,  or  flood-ground,  which  is  mostly  covered  by  the  higher 


FRESH-WATER    STREAMS.  639 

freshets.  The  two  go  together,  whenever  the  course  of  the  stream  is 
not  over  and  between  rocks  that  do  not  admit  of  much  lateral  erosion 
and  a  widening  thereby  of  the  river-valley. 

In  the  farther  progress  of  the  stream,  A  n  o  becomes  the  torrent- 
portion,  and  o  B  the  river-portion.  Later,  the  valley  commences  from 
the  summit  A. 

As  the  waters  continue  their  work  of  erosion  about  the  summits, 
where  the  mists  and  rains  are  most  abundant  and  often  almost  per 
petual  through  the  year,  the  next  step  is  the  working  down  of  a  preci 
pice  under  the  summit,  or  toward  the  top  of  the  declivity,  making 
the  course  of  the  waters  A  p  q  B,  and  later,  A  r  s  B.  The  stream 
in  this  state  has  (1)  a  cascade-portion  and  (2)  a  torrent-portion,  be 
sides  (3)  its  river-portion.  The  precipices  thus  formed  are  sometimes 
thousands  of  feet  in  height ;  and  the  waters  often  descend  them  in 
thready  lines,  to  unite  below  in  the  torrent.  The  mountain-top  is 
chiselled  out,  by  these  means,  into  a  narrow,  crest-like  ridge.  Each 
separate  descending  rill  frequently  makes  its  own  recess  in  the  side 
of  the  precipice  ;  and  together  they  may  face  it  with  a  series  of  deep 
alcoves  and  projecting  buttresses. 

The  next  step  in  the  progressing  erosion  is  the  wearing  away  of  the 
ridge  that  intervenes  between  two  adjoining  valleys.  This  takes  place 
about  the  higher  portions,  nearest  the  mountain-crest,  where  the  de 
scending  waters  are  most  abundant.  Gradually  the  ridge  thins  to 
a  crest,  and  finally  becomes  worn  away  for  somo  distance,  so  that 
two  valleys  (or  more  by  the  wear  of  more  ridges)  have  a  common 
head.  In  Fig.  1077,  A  r  s  B  represents  the  course  of  the  stream,  as  in 
Fig.  1076  ;  and  A  e  f  B  the  eroded  ridge,  which  has  lost  at  e  much  of 
its  height.  The  erosion,  continuing  its  action  around  the  precipitous 
sides  of  the  united  head  of  the  valleys,  may  widen  it  into  a  vast 
mountain  amphitheatre,  out  of  which  the  stream  may  pass,  below, 
between  closely  approaching  walls  of  rock. 

This  is  theoretically  the  history  of  valley-making,  and  the  actual 
history  when  the  course  is  not  modified  by  the  structure  of  the  rocks. 

A  model  of  this  system  of  erosion  is  often  admirably  worked  out  in 
the  earthy  slopes  along  a  road-side,  —  the  little  rill  having  its  cascade- 
head,  then  its  torrent-channel,  and  below  its  flat  alluvial  plain,  with 
the  winding  rill-channel ;  some  of  the  ridgelets,  in  their  upper  parts, 
worn  away  until  two  or  more  little  valleys  coalesce  ;  then,  in  some 
cases,  the  head  of  the  coalesced  valleys  widened  into  an  amphitheatre, 
and  the  walls  fluted  into  a  series  of  alcoves  and  buttresses. 

The  system  is  illustrated  on  a  grand  scale  among  the  old  volcanic  islands  of  the 
Pacific,  where  the  slope  of  the  rocks  at  a  small  angle  (five  to  ten  degrees),  from  a  centre, 
has  favored  a  regular  development.  On  Mount  Kea  (Hawaii),  nearly  14,000  feet  high, 


640  DYNAMICAL   GEOLOGY. 

the  valleys  extend  about  half-way  to  the  summit,  having  made  only  this  much  of  prog 
ress  upward  since  the  volcano  became  extinct.  On  Tahiti,  the  old  mountain  is  reduced 
to  a  mere  skeleton.  The  valleys  lead  up  to  amphitheatres,  bounded  by  precipices  of 
2,000  to  3,000  feet,  directly  under  the  peak;  and  the  ridges  between  the  valleys,  though 
1,000  to  2,000  feet  high,  are  reduced  in  the  interior  to  mere  knife-edges,  impassable 
except  as  they  are  balustraded  by  shrubbery;  and  in  some  cases,  adjoining  the  central 
heights,  they  are  worn  down  to  a  low  wall  or  pinnacled  crest,  partially  separating  two 
of  the  valleys.  Tin  traveller,  ascending  one  of  the  valleys  along  the  bed  of  the 
stream,  finds  himself  at  last  at  the  base  of  inaccessible  heights,  with  numberless  cas 
cades  before  him,  and  a  range  of  buttressed  walls  of  remarkable  grandeur.1  Something 
of  this  buttressed  character  of  precipices  is  seen  in  Fig.  1079. 

The  nature  of  the  rocks  causes  modifications  in  these  results.  If 
there  are  harder  beds  at  intervals,  in  the  course  of  the  stream,  or  any 
impediment  to  even  wear,  the  impediment  becomes  the  head  of  a  water 
fall  and  precipice,  whose  height  increases  rapidly,  from  the  force  of  the 
falling  waters,  until  some  other  similar  impediment  below  limits  the 
farther  erosion.  Many  waterfalls  and  rapids  are  thus  made  in  the 
cascade-portion  of  a  stream  ;  and  they  are  not  absent  from  the  river- 
portion.  Another  effect  of  this  cause  is  that  the  stream  is  set  back 
for  some  distance  above  a  waterfall,  and  has  in  this  part  more  or  less 
extensive  flood-plains. 

If  the  rocks  arc  in  horizontal  strata,  and  easily  worn,  the  waters 
work  rapidly  down  to  the  level  of  the  river-portion,  so  that  the  cas 
cade  and  torrent  portion  are  each  short,  or  are  hardly  distinguishable. 
The  streamlets  descending  the  walls  of  such  soft  rocks  will  easily 
widen  the  head  of  the  valley  into  an  extensive  amphitheatre ;  while, 
in  the  farther  course  of  the  valley,  beyond  the  limit  of  the  rainy 
region,  the  valley  may  be  only  a  narrow  gorge,  with  nearly  vertical 
walls,  hundreds,  or  perhaps  thousands,  of  feet  deep.  Here  in  these 
depths,  the  stream  meanders  through  a  ribbon  of  alluvial  land,  rich  in 
verdure  at  one  season,  and  in  others  mostly  flooded.  Examples  of  all 
these  peculiarities  of  river-valleys  might  be  described,  from  among  the 
rivers  of  North  America,  especially  the  streams  of  the  Mississippi 
Valley  and  those  of  the  slopes  of  the  Rocky  Mountains,  where  the  rocks 
are  in  general  stratified,  and  often  not  far  from  horizontal  in  position. 

The  features  of  the  remarkable  caiion  of  the  Colorado,  between  the  meridians  of  111° 
and  115°  W.  longitude,  have  been  described  by  J.  S.  Newberry,  in  the  Reports  of  Ives' 
Expedition.  The  principal  facts  are  these:  A  length  of  200  miles,  and,  through  the 
whole,  nearly  vertical  walls  of  rock,  3,000  to  6,000  feet  in  height;  these  rocks  lime 
stone  and  other  strata  of  Carboniferous  age,  others  of  older  Paleozoic,  and  below  these 
generally  the  solid  granite,  making  from  500  to  1,000  feet  of  the  gorge;  and,  in  some 
places,  the  granite  rising  in  pinnacles  out  of  the  waters  of  the  stream;  finally,  all 
the  tributaries  or  lateral  streams  with  similar  profound  gorges  or  chasms.  The  view 

i  See  the  Author's  Expl  Exped.  Geol.  Rep.,  pp.  290,  384,  and  Am.  J.  Set.,  II.  ix.  48 
and  289. 


FRESH-WATER   STREAMS. 


641 


represented  in  Fig.  1078  was  taken  at  the  junction  of  the  Colorado  and  the  Green 
Rivers,  near  the  meridian  of  113°30'.  It  shows  well  the  narrow  and  profound  chasm 
in  which  the  waters  of  the  Colorado  flow,  although  not  doing  justice  to  the  depth,  which 
at  this  place  is  about  3,000  feet.  Some  distance  up  the  stream,  the  two  rivers  conic 
together,  the  Colorado  from  far  to  the  right,  and  Green  River  from  the  left;  and,  every 
where  over  the  great  plain,  there  are  the  profound  lateral  chasms  or  side-canons  of  the 
tributaries. 

Fig.  1079  is  another  view  from  the  same  remarkable  region,  illustrating  especially  the 
side-cafions.  It  is  from  the  Report  of  Lieutenant  J.  C.  Ives,  the  commander  of  the  ex 
pedition  with  which  Dr.  Newberry  was  connected. 

Newberry  attributes  these  profound  gorges,  and  beyond  doubt  correctly,  to  erosion, 
each  stream  having  made  its  own  channel.  The  cliffs  are  so  high  that  in  general  no 
undermining  can  set  back  the  walls  far  enough  to  allow  of  alluvial  plains  along  the 
bottom,  even  when  the  water  is  not  too  rapid;  and, when  a  channel  is  cut  in  granite, 
lateral  wear  is  always  small. 

In  the  more  distant  part  of  Fig.  1078,  there  is  a  higher  level  of  rock,  —  the  overlying 

Fig.  1078. 


Canon  of  the  Colorado  near  its  junction  with  Green  River. 

gypsiferous  red  sandstone,  probably  Triassic  or  Jurassic  (p.  407).  It  is  in  isolated 
tables,  and  in  some  places  in  columns,  needles,  and  towers,  the  greater  part  of  the 
formation  having  been  swept  off  by  erosion,  due  partly  at  least  to  fresh  waters.  Still 
farther  to  the  east,  beyond  the  range  of  the  view,  another  still  more  elevated  level  is 
formed  by  Cretaceous  strata:  the  existing  surface-features  are  similar  to  those  of  the 
older  red  sandstone. 

Owing  to  the  rapid  increase  of  ratio  in  the  power  of  running  water, 
41 


642 


DYNAMICAL   GEOLOGY. 


attending  increase  of  velocity,  the  eroding  action  of  water  during 
freshets  becomes  immense.  Many  examples  are  on  record  of  gorges, 
hundreds  of  feet  deep,  cut  out  of  the  solid  rock  by  two  or  three 


FRESH-WATER    STREAMS.  643 

centuries  only  of  work.  Lyell  mentions  the  case  of  the  Simeto,  in 
Sicily,  which  had  been  dammed  up  by  an  eruption  of  lavas  in  1603. 
In  two  and  a  half  centuries,  it  had  excavated  a  channel  fifty  to  several 
hundred  feet  deep,  and  in  some  parts  forty  to  fifty  feet  wide,  although 
the  rock  is  a  hard  solid  basalt.  He  also  describes  a  gorge  made  in  a 
deep  bed  of  decomposed  rock,  three  and  a  half  miles  west  of  Milledge- 
ville,  Georgia,  that  was  at  first  a  mud-crack  a  yard  deep,  in  which  the 
rains  found  a  chance  to  make  a  rill,  but  whioh,  in  twenty  years,  was 
300  yards  long,  20  to  180  feet  wide  and  55  feet  deep;  and  Liais 
describes  a  similar  gorge,  of  twice  the  length,  in  Brazil,  made  in  forty 
years.  These  erosions  of  soft  material  show  what  may  be  done  in 
hard  rocks,  when  time  for  the  work  is  given.  The  most  of  the  valleys 
of  the  world  have  been  formed  entirely  by  running  water.  Subterra 
nean  movements  have  sometimes  made  fissures  that  have  determined 
the  direction  of  the  water  ;  but  this  has  not  been  ordinarily  the  case. 
At  Tahiti,  where  the  valleys  are  one  to  three  thousand  feet  deep,  they 
all  terminate  before  reaching  the  sea,  showing  that  they  have  been 
formed  while  the  land  has  stood,  as  now,  above  the  ocean,  and  there 
fore  that  they  are  due  to  fresh-water  streams. 

The  windings  of  the  stream,  in  large  alluvial  flats,  are  most  numer 
ous  where  the  current  is  exceedingly  slow  ;  for  slight  obstacles  change 
the  course,  throwing  the  current  from  one  side  to  the  other.  Between 
the  mouth  of  the  Ohio  and  the  Gulf  of  Mexico  (Head  of  the  Passes), 
the  length  of  the  Mississippi  is  1,080  miles  ;  and  the  actual  distance 
in  a  straight  line  about  500  miles. 

Pot-holes  are  incident  to  the  process  of  erosion,  when  the  waters 
flow  in  rapids  over  a  bed  of  hard  rocks.  The  rushing  waters  make 
the  large  loose  masses  to  rock,  and  this  wears  the  surface  beneath,  and 
gradually  deepens  it ;  and  then  the  whirl  begins  which  carries  around 
stones  and  pebbles,  and  hastens  the  wear.  Or,  where  the  waters  are 
made  to  whirl  by  the  position  of  the  rocks  of  the  bottom,  the  whirled 
stones  are  at  once  set  about  the  work  of  excavation.  The  "  Basin,"  in 
the  Franconia  Notch  (White  Mountains),  is  a  pot-hole  in  granite, 
fifteen  feet  deep  and  twenty  and  twenty-five  feet  in  its  two  diameters. 
There  are  many  pot-holes  at  Bellows  Falls,  on  the  Connecticut; 
others  on  White  River,  in  the  Green  Mountains,  and  elsewhere.  One 
of  those  on  the  White  River  is  fifteen  feet  deep  and  eighteen  in 
diameter  ;  another,  twelve  feet  deep  and  twenty-six  in  diameter. 

4.  Flood-plain.  —  The  facts  connected  with  the  flood-plains  derive 
a  special  importance  from  their  bearing  on  the  subject  of  terraces. 

The  breadth  of  the  flood-plain  of  a  stream  depends  (1)  on  the  general  features  of  a 
country,  and  (2)  on  the  stream's  capability  of  encroaching  laterally  on  the  hills  either 
side.  In  some  cases,  this  breadth  is  ten  to  twenty  miles,  and  even  fifty  miles  along 


644  DYNAMICAL    GEOLOGY. 

such  rivers  as  the  Sacramento.  .In  the  case  of  these  broad  plains,  the  valley  is  seldom 
one  of  erosion  simply,  but  generally  a  yeosyndinal  trough,  or  an  interval  between  sep 
arate  mountain  ranges.  When  a  stream  crosses  a  series  of  synclinal  valleys,  the  Hood- 
plain  generally  expands  as  it  enters  each,  and  contracts  at  the  passage  from  one  to  the 
other. 

The  surface  of  a  flood-plain  is  only  approximately  flat.  (1)  The  margin  along  a 
stream  is  often  higher  than  the  part  back  of  it;  (2)  some  portions  are  frequently  within 
the  reach  of  only  the  very  highest  freshets;  (3)  others  are  quite  low,  and  are  sometimes 
occupied  by  ponds  of  water  or  lagoons,  fed  from  the  river  by  percolation  through  the 
soil.  The  variation  of  height  from  these  sources  is  often  equal  to  two  thirds  of  the 
whole  average  height  of  the  flood-plain  above  the  river.  The  surface  is  sometimes 
changed  much  in  height  during  freshets,  by  the  wearing  away  of  one  part  and  the  in 
crease  of  others. 

The  height  and  pitch  of  the  flood- plain  are  essentially  that  of  the  stream  at  flood- 
height,  and  will,  therefore,  be  affected  by  the  causes  mentioned  on  page  637-  It  will 
be  comparatively  low,  toward  the  ocean.  It  will  be  diminished  by  any  abrupt  expan 
sion  of  the  river-valley,  by  which  the  waters  spread  laterally  to  great  distances,  and 
consequently  have  diminished  vertical  height.  Conversely,  the  height  will  be  increased 
by  a  narrowing  of  the  valley,  and  especially  before  the  entrance  of  a  contracted  gorge. 

While,  therefore,  there  is  a  general  parallelism  between  a  stream  at  low  water  and 
its  flood-plain,  there  are  wide  variations  from  this  parallelism. 

The  occurrence  of  waterfalls  in  the  course  of  a  stream  causes  the  flood-plain  above 
to  stand  at  a  higher  level  than  that  below,  equal  at  least  to  the  height  of  the  fall,  and 
somewhat  above  this  height  if  the  fall  occurs  in  a  gorge,  which  would  set  the  waters 
back  during  a  flood. 

If  the  erosion  of  some  thousands  of  years  or  less  deepen  the  bed  of  a  stream  fifty 
feet,  the  flood-plain  would  sink  correspondingly  to  a  lower  level;  and  thus,  in  the  lapse 
of  time,  without  other  geographical  change  than  the  one  mentioned,  a  terrace  would  be 
formed,  some  portion  of  the  old  plain  being  left,  as  would  naturally  happen,  at  its 
former  height.  If  a  waterfall  were  gradually  obliterated,  the  flood-plain  would  undergo 
a  corresponding  change.  If  the  barrier  that  caused  the  existence  of  a  lake  along  a 
river  were  removed,  there  would  be  a  sinking  of  the  river's  channel,  and  a  sinking  by 
erosion  also  of  the  flood-plain.  If,  from  any  cause — as  a  mountain-slide  —  a  barrier 
were  thrown  across  a  stream,  and  a  lake  made,  the  flood-waters  would  stand  at  a  cor 
respondingly  higher  level  than  before,  and  would  spread  more  widely,  making  new 
flood-plains,  above  the  former  level.  If  the  progressing  erosion  be  very  much  less  on 
one  part  of  a  stream  than  on  another  (from  the  nature  of  the  country,  or  that  of  the 
rocks,  etc.),  the  changes  in  the  level  of  the  later  flood-plain  would  have  the  same 
differences.  Small  streams,  working  the  same  length  of  time,  would,  of  course,  sink 
their  channels  by  erosion  less  than  the  large  ones  to  which  they  are  tributary,  provided 
the  pitch  be  the  same  and  the  bed  similar  in  material ;  and  even  a  large  pitch  will  not 
often  compensate  for  a  very  great  difference  in  the  amount  of  water. 

These  are  changes  in  the  flood-plain  which  may  take  place  from  the  ordinary  inci 
dents  to  which  rivers  are  exposed. 

Finally,  if  a  continent  undergo  an  elevation  which  is  greatest  about  the  headwaters 
of  the  stream,  or  if  an  equable  elevation  and  the  pitch  of  the  bottom  off  its  mouth  is 
large,  the  pitch  of  the  river  is  increased,  and  new  erosive  power  is  given  it;  and,  with 
the  progress  of  the  elevation,  new  flood-plains  would  form,  at  lower  and  lower  levels. 
This  subject  is  already  explained  on  page  558.  The  only  case  in  which  the  rivev  would 
not  have  a  greater  pitch  after  such  an  elevation,  is  when  the  coast-region,  added  by  the 
elevation,  slopes  seaward  at  the  same  angle  with  that  of  the  stream  before  the  elevation, 
or  at  a  less  angle  than  this. 

Topographical  Effects  of  Erosion.  —  The  topographical  effects  of 
erosion  depend  on  several  conditions,  —  as  (1)  the  durability  of  the 
rocks,  (2)  their  structure,  and  (3)  their  stratification. 


TOPOGRAPHICAL    EFFECTS    OF   EROSION.  645 

1.  Durability  of  the  Hocks.  — Granite   is  well  known  to  run  up  into  lofty  needles  (or 
aiguilles),  as  in  the  Alps  and,  still  better,   the  Organ  Mountains  of  Brazil,  and  some 
peaks  in  the  Castle  Rock  range,  a  few  miles  southwest  of  Mount  Shasta,  California. 
But  there  are  varieties  crumbling  easily  on  exposure;  and  these  occur  only  in  broad, 
massive  elevations.     The  hard  argillyte  (roofing-slate)  often  forms  bold,  craggy  heights, 
while  soft  argillaceous  shales  make  only  tame  hills  and  undulating  plains. 

The  refractory  quartzytes  and  grits,  which  make  little  or  no  soil,  stand  up  in  rude 
piles  and  massy  brows  or  nearly  bare  rock. 

2.  Structure.  —  When  there  are  no  planes  of  structure,  as  in  true  granite,   the  rock 
may  rise  into  lofty  peaks,  with  rounded  surfaces.     Slow  denudation  goes  on  over  all  sides 
of  the  peak,  either  from  trickling  waters  or  from  frosts,  and  may  gradually  narrow  it  into 
the  model  aiguille.     But,  when  the  rock  has  a  cleavage-structure,  like  the  schists  and 
slates,  its  heights  are  rough  and  angu'ar,  and  its  aiguilles,  if  any  are  formed,  are  more 
apt  to  be  pyramidal  than  conical. 

The  joints  in  slates  or  sandstones  often  lead  to  forms  resembling  walls  and  battle 
ments,  when  exposed  in  cliffs  (Fig.  88,  p.  88).  The  architectural  effect  of  the  columnar 
cleavages  of  trap  or  basalt  is  shown  in  Fig.  115,  p.  108. 

3.  Stratification.  —  The  results  with  stratified  rocks  differ  according  to  (1)  the  position 
of  the  strata,  and  (2)  their  nature. 

If  the  strata  are  horizontal,  or  nearly  so,  and  hard  and  similarly  so  throughout,  the 
elevations  have  generally  table  summits,  with  vertical  rocky  brows  facing  the  lower 
lands.  The  river-valleys  are  profound,  and  often  inaccessible  for  long  distances,  owing 
to  the  boldness  of  the  precipices.  The  flooded  waters  of  the  valley  wear  the  rocks  at 
the  base  of  the  precipice,  and  so  undermine  it,  and  make  avalanches  of  rock  which  keep 
the  front  nearly  vertical.  Some  varieties  of  these  valleys  are  shown  in  Figs.  1078,  1079. 
Other  topographical  effects  are  described,  in  the  remarks  on  the  erosion  of  valleys,  p. 
640.  If  the  rock  is  firm,  like  most  limestones,  it  may  rise  into  lofty,  few-angled  sum 
mits,  especially  when  erosion  has  been  preceded  by  fractures ;  as  in  the  Alpine  heights 
of  the  Wetterhorn  and  its  associates,  near  Grindelwald,  in  the  Bernese  Oberland. 

If  horizontal,  or  nearly  so,  but  of  unequal  hardness,  the  softer  strata  are  easily  worn 
away,  undermining  the  harder  strata ;  the  table-lands  have  a  top  of  the  harder  rock, 
and  the  declivities  are  usually  banded  with  projecting  shelves  and  intervening  slopes. 
Figs.  1080,  1081  represent  the  common  character  of  such  hills.  A  number  are  shown 

Fig.  1080.  Fig.  1081. 


in  Fig.  1079 ;  in  the  Colorado  region,  they  have  been  called  Mesas,  from  the  Spanish  for 
table*  In  some  parts  of  the  Rocky  Mountain  slopes,  the  thick  gravel  deposits  are  covered 
with  streams  of  lava  of  great  thickness ;  and  table  mountains  are  common  is  such  regions. 

Elevations  thus  left  prominent,  after  denudation  around,  have  been  called  hills,  or 
mountains,  of  circumdenudation.  Figs  1082,  1083  are  other  examples. 

When  the  beds  are  inclined  between  5°  and  30°,  and  are  alike  in  hardness,  there  is  a 
tendency  to  make  hills  with  a  long  back  slope  and  bold  front;  but.  with  a  much  larger 
dip,  the  rocks,  if  hard,  often  outcrop  in  naked  ledges. 

When  the  dipping  strata  are  of  unequal  hardness,  and  lie  in  folds,  there  is  a  wide 
diversity  in  the  results  on  the  features  of  elevations. 

Figs.  1082,  1083  represent  the  effects  from  the  erosion  of  a  synclinal  elevation  con 
sisting  of  alternations  of  hard  and  soft  strata.  The  protection  of  the  softer  beds  by  the 
harder  is  well  shown.  This  is  still  further  exhibited  in  Figs.  1084-1087. 


i  For  Figs.  1080-1091,  and  the  views  they  illustrate,  the  author  is  indebted  to  the 
volume  on  Coal  and  its  Topography,  by  Lesley.  In  a  long  chapter  on  "Topography 
as  a  science,"  this  author  has  given  the  results  of  extensive  personal  observation. 


646 


DYNAMICAL    GEOLOGY. 


Anticlinal  strata  give  rise  to  another  series  of  forms,  in  part  the  reverse  of  the  pre 
ceding,  and  equally   varied.     Figs.   1088-1C91   represent  some  of  the  simpler  cases. 


1082 


Figs.  1082-1087. 


When  the  back  of  an  anticlinal  mountain  is  divided  (as  in  Figs.  1088-1090),  the  moun 
tain  loses  the  anticlinal  feature ;  and  the  parts  are  simply  monoclinal  ridges.    As  the 

Figs.  1088-1091. 

1090 


1088 


anticlinal,  in  the  progress  of  its  formation,  is  almost  sure  to  have  its  back  fractured, 
from  the  strain  on  the  bending  rocks,  the  removal  of  the  upper  and  central  portion, 
making  a  broad  valley  in  its  place,  is  the  common  fact. 

In  Fig.  1091,  the  anticlinal  character  is  distinct  in  the  central  portion,  while  lost  in  the 
parts  either  side.  To  the  right,  in  this  figure,  is  shown  a  common  effect  of  the  protection 
afforded  to  softer  layers  by  even  a  vertical  layer  of  hard  rock :  the  vertical  laver  forms 
the  axis  of  a  low  ridge. 

Fig.  1092  represents  some  remarkably  slender  columns  of  Tertiary  sandstone,  from 
Fio:  1092  ^ie  ^ePort  °f  Dr.  Hayden  for  1873.    There 

_   _  are  here  two  layers  harder  than  the  rest; 

and  one  has  been  left  to  make  the  top  of 
the  taller  column,  while  another  caps  a 
shorter  series.  These  examples  of  nature's 
modelling  are  very  numerous  in  Colo 
rado,  over  what  has  been  called  Monument 
Park.  The  erosion  is  due  to  the  rains,  or 
the  rills  they  produce,  and  the  later  part 
gj  to  the  gentler  action  of  rain-drops,  together 
with  the  action  of  the  winds  and  frosts. 
Lyell  has  described  a  remarkable  example 
of  erosion  by  rains,  of  a  thick  deposit  of 
reddish  indurated  mud,  containing  scat 
tered  bowlders,  really  a  moraine,  occurring 
near  Botzen  in  the  Tyrol,  in  which  the  re 
sult  is  a  region  of  many  hundreds  of  slen 
der  pillars  and  columns  of  half  consolidated 
earth,  twenty  to  a  hundred  feet  in  height, 
and  each  capped  with  a  bowlder,  —  some 
of  the  stones  two  or  three  feet  in  diameter. 
He  gives  a  view  of  one  such  scene  in  his 
Erosion,  Monument  Park,  Colorado.  "  Principles,"  chapter  xv. 

The  above  are  the  simple  results  from  the  erosion  of  folded  rocks.  They  serve  as  a 
key  to  the  complexities  of  features  common  through  a  large  part  of  the  Appalachians 
and  other  regions  of  folded  rocks,  where  synclinal  and  anticlinal  axes  are  in  numberless 
complicated  combinations,  rendered  doubly  puzzling  by  faults.  See,  further,  pages 
93-98. 


FRESH-WATER    STREAMS.  647 

Extent  of  Erosion.  —  The  outlining  of  mountain-ridges  and  val 
leys  has  been  in  part  produced  by  subterranean  forces,  uplifting  and 
fracturing  the  strata  ;  but  the  final  shaping  of  the  heights  is  due  to 
erosion,  and  mostly,  as  has  been  stated,  to  erosion  by  fresh  waters. 
This  cause  has  been  in  action  ever  since  continents  began  to  be ;  and 
it  has  been  thus  making  earth  and  gravel  for  stratified  rocks,  as  well 
as  gorging  hills  and  mountains.  The  Appalachians  have  lost  by 
denudation  much  more  material  than  they  now  contain.  Mention  has 
been  made  of  faults  of  ten  thousand  feet  or  more,  along  the  course  of 
the  chain,  from  Canada  to  Alabama.  In  such  a  fault,  one  side  was  left 
standing  ten  thousand  feet  above  the  other,  enough  to  make  alone  a 
lofty  mountain  ;  and  yet  now  the  whole  is  so  levelled  off  that  there  is 
no  evidence  of  the  fault  in  the  surface-features  of  the  country.  The 
whole  Appalachian  region  consists  of  ridges  of  strata  isolated  by  long 
distances  from  others  with  which  they  were  once  continuous.  Fig. 
103,  page  96,  represents  a  common  case  of  this  kind.  The  anthracite 
coal-fields  of  central  Pennsylvania  were  once  a  part  of  the  great 
bituminous  coal-field  of  western  Pennsylvania  and  Virginia  (Fig.  £13, 
p.  310).  They  now  form  isolated  patches  ;  and  formations  of  great 
extent  have  been  removed  from  over  the  intervening  country.  The 
coal-region  of  Great  Britain  is  broken  into  many  patches,  in  con 
sequence  of  similar  denudation  and  uplifts. 

In  New  England,  there  is  evidence  of  erosion  on  a  scale  of  vast 
magnitude,  since  the  crystallization  of  its  rocks.  On  the  summit-level 
between  the  head-waters  of  the  Merrimac  and  Connecticut,  there  are 
several  pot-holes  in  hard  granyte ;  one,  as  described  by  Professor  Hub- 
bard,  is  ten  feet  deep  and  eight  feet  in  diameter,  and  another  twelve 
feet  deep.  They  indicate  the  flow  of  a  torrent  for  a  long  time,  where 
now  it  is  impossible  ;  and  the  period  may  not  be  earlier  than  the 
Quaternary.  Many  other  similar  cases  are  described  by  Hitchcock. 

These  examples  of  denudation  are  sufficient  for  illustration.  The 
other  continents  furnish  cases  that  are  no  less  remarkable.  Scotch  val 
leys  and  mountains  gave  to  Hutton  the  first  right  ideas  on  the  subject. 

In  the  work  the  ocean  has  taken  some  part,  as  explained  beyond. 

2.  Transportation  by  Rivers. 

The  materials  transported  by  running  water  are  (1)  stones,  pebbles, 
sand,  and  clay;  (2)  logs  and  leaves  from  the  forests,  and  sometimes 
trees  that  have  been  torn  up  or  dislodged  by  the  current ;  (3)  mollusks 
or  their  shells,  worms,  insects,  etc.,  attached  to  the  logs  or  leaves ; 
(4)  occasionally  larger  animals,  that  have  been  surprised  and  drowned 
by  freshets,  or  bones  that  have  been  exhumed  by  the  waters. 

The  fine  earthy  material  deposited  by  streams,  or  their  sediment,  is 


648  DYNAMICAL    GEOLOGY. 

called  silt,  or  detritus.  In  accordance  with  the  law  with  regard  to  the 
transporting  power  of  water,  stones  and  pebbles  make  the  bed  of  rapid 
streams,  and  in  general  earth  or  silt,  where  the  current  is  slow. 

The  amount  of  transportation  going  on  over  a  continent  is  beyond 
calculation.  Streams  are  everywhere  at  work,  rivers  with  their  large 
tributaries  and  their  thousand  littlo  ones  spreading  among  all  the  hills 
and  to  the  summit  of  every  mountain.  And  thus  the  whole  surface 
of  a  continent  is  on  the  move  toward  the  oceans.  In  the  rainy  sea 
sons,  the  streams  increase  immensely  their  force,  streamlets  in  the 
mountains,  that  are  almost  dry  in  summer,  becoming  destructive  tor 
rents  during  the  rains. 

The  process  of  transportation  is  also  one  of  wear.  The  stones  are 
reduced  to  sand  and  fine  earth,  by  the  friction.  The  silt  is  nothing  but 
the  coarse  material  of  the  upper  waters,  ground  up.  The  soil  of  tho 
plains  and  sand  of  the  sea-shore  are  the  pulverized  rocks  of  the  moun 
tains,  —  running  waters  being  the  moving-power,  and  the  mutual  fric 
tion  of  stone  upon  stone,  or  grain  of  sand  upon  grain,  the  means  of 
grinding.  The  word  detritus  means  worn  out,  and  is  well  applied  to 
river-depositions.  On  large  rivers,  stones  and  pebbles  disappear  from 
the  alluvium,  long  before  they  reach  the  sea,  and  partly  for  the  reason 
here  mentioned.  The  process  is  sometimes  aided  by  the  partial  de 
composition  of  the  rocks. 

The  amount  of  silt  carried  to  the  Mexican  Gulf  by  the  Mississippi, 
according  to  the  Delta  Survey  under  Humphreys  &  Abbot,  is  about 
l-1500th  the  weight  of  the  water,  or  l-2900th  its  bulk  ;  equivalent 
for  an  average  year  to  812,500,000,000,000  pounds,  or  a  mass  one 
square  mile  in  area  and  two  hundred  and  forty-one  feet  deep. 

The  following  table  contains  the  ratio  of  sediment  to  water  by  weight,  as  obtained 
by  the  Delta  Survey,  and  also  the  results  of  other  investigations.  It  is  from  Humphreys 
&  Abbot's  Report  (p.  148):  — 

Ratio.  Time. 

Mississippi  R.,  at  Carrollton,   by  Delta  Survey,  1  :  1808     12  mos.,  1851-1852. 
Mississippi  R.,  at  Carrollton,   by  Delta  Survey,  1  :  1449    12  mos.,  1852-1853. 
Mississippi  R.,  at  Columbus,    by  Delta  Survey,  1  :  1321       9  mos.,  1858. 
Mississippi  R.,  at  Mouths,  by  Mr.  Meade,  1  :  1256      2  mos.,  1838. 

Mississippi  R.,  at  Mouths,  by  Mr.  Sidell,  1  :  1724    1838. 

Mississippi  R.,  at  Various  places,  Prof.  Riddell,  1  :  1245  14  days,  summer  of  1843. 
Mississippi  R.,  at  New  Orleans,  Prof.  Riddell,  1  :  1155  35  days,  summer  of  1846. 
Rhone,  at  Lyons,  by  Mr.  Surell,  1  :  17000  1844. 

Rhone,  at  A*rles,  Messrs.  Gorsse  &  Subours,  1  :  2000      4  mos.,  1808-1809. 

Rhone,  in  Delta,  Mr.  Surell,  1  :  2500 

Ganges,  by  Mr.  Everest,  1  :  510      12  mos. 

The  bulk  may  be  calculated,  by  taking  1'9  as  the  specific  gravity  of  the  material. 

The  total  annual  discharge  of  sediment  from  the  Ganges  has  been  estimated  at 
6,368,000,000  cubic  feet. 

Besides   the  material  held  in  suspension,  as  these  authors  observe, 


FRESH-WATER    STREAMS.  649 

the  Mississippi  pushes  along  into  the  Gulf  large  quantities  of  earthy 
matter ;  and,  from  observations  made  by  them,  they  estimate  the  an 
nual  amount  thus  contributed  to  the  Gulf  to  be  about  750.000,000 
cubic  feet,  —  which  would  cover  a  square  mile  twenty-seven  feet  deep ; 
and  this,  added  to  the  241  feet  above,  makes  the  total  268  feet. 

The  quantity  of  wood  brought  down  by  some  American  rivers  is 
very  great.  The  well-known  natural  "  raft,"  obstructing  Red  River, 
had  a  length,  in  1854,  of  thirteen  miles,  and  was  increasing  at  the 
rate  of  one  and  a  half  to  two  miles  a  year,  from  the  annual  accessions. 
The  lower  end,  which  was  then  fifty-three  miles  above  Shreveport, 
had  been  gradually  moving  up  stream,  from  the  decay  of  the  logs,  and 
formerly  was  at  Natchitoches,  if  not  still  farther  down  the  stream. 
Both  this  stream  and  others  carry  great  numbers  of  logs  to  the  delta. 

3.  Distribution  of  transported  Material. 

1.  Alluvial  Formations  in  River-valleys.  —  Alluvial  formations  cover 
usually  a  broad  area,  on  one  or  both  sides  of  a  river.  They  are  in 
general  the  basis  of  the  flood-plain ;  and  the  features  of  this  plain,  as 
already  described,  are  the  exterior  characteristics  of  the  alluvium. 
They  are  made  from  the  material  brought  down  by  the  stream,  espe 
cially  during  freshets,  and  consist  of  earth  and  clay,  sometimes  thinly 
laminated,  with  some  beds  of  pebbles,  and  occasionally  stones.  These 
coarser  beds  are  most  abundant  along  the  upper  portions  of  the 
stream  ;  while,  toward  the  mouth,  —  particularly  in  the  case  of  large 
rivers,  —  the  material  may  be  wholly  a  fine  silt.  When  the  floods  are 
very  great  and  of  long  continuance,  as  during  the  melting  of  the 
glacier  in  the  Champlain  period,  the  finer  depositions  may  have  no 
distinct  bedding,  where  the  waters  flow  quietly,  or,  on  the  contrary,  in 
case  of  a  violent  plunging  flow,  the  flow-and-plunge  structure  described 
on  page  83. 

The  material,  whether  coarse  or  fine,  is,  in  general,  simply  pulverized  rock  —  the 
rocks  of  earlier  time  ground  to  powder,  by  the  attrition  undergone  through  the  moving 
waters.  So  that  a  mud  often  consists  of  the  very  same  minerals,  and  in  the  same  pro 
portions,  as  the  granyte  or  gneiss  from  which  it  was  derived;  in  such  a  case,  the  feld 
spar  is  present  as  feldspar,  this  being  proved  by  the  presence  of  potash  or  soda,  which 
ingredients  are  lost  when  feldspar  undergoes  decomposition.  Most  of  the  shales  and 
slates  of  the  world  are  made  from  muds  or  clays  of  this  kind.  But,  in  other  cases,  the 
feldspar  has  undergone  more  or  less  complete  decomposition;  and  then  the  muds  or 
clays  have  a  different  constitution,  the  alkalies  being  absent. 

Again,  since,  in  the  flow  of  water,  softer  materials  are  worn  out,  and  also  the  lighter 
borne  on  to  stiller  regions,  quartz  sands  are  often  left  by  themselves,  and  the  finer  silt 
carried  to  make  deposits  of  its  own :  and  thus  again  the  deposits  are  made  to  differ  in 
constitution  from  the  rocks  whence  they  are  derived.  The  facts  here  stated  are  true 
also  of  glacial  and  marine  depositions. 

Logs  and  leaves  are  in  some  cases  distributed  through  alluvial  de- 


650  DYNAMICAL    GEOLOGY. 

posits,  but  always  sparingly ;  for  they  are  mostly  destroyed  by  wear 
or  by  decay.  They  rarely  if  ever  accumulate  in  beds  fitted  for  mak 
ing  coal,  being  widely  scattered  by  the  currents.  Fresh-water  and 
land  shells  are  occasionally  found  in  the  beds.  Remains  of  other 
animals  are  also  distributed  by  the  waters,  and  buried,  though  seldom 
escaping  destruction,  unless  carried  into  a  quiet  portion  of  the  flood- 
plain.  Thus  the  fossils  of  river-deposits  may  have  come  from  a  region 
of  very  wide  range. 

In  the  case  of  the  bursting  of  lakes,  the  fishes  of  the  waters  and 
the  material  of  the  bottom,  including  its  shells,  are  sometimes  trans 
ferred  to  a  level  below,  far  distant  from  the  source.  Lyell  says  that 
bogs,  on  bursting,  have  sent  forth  great  volumes  of  black  mud,  which 
has  flowed  slowly  along,  making  a  deposit  sometimes  fifteen  feet  thickr 
and  overwhelming  cottages  and  forests. 

As  the  range  of  height  within  which  river-waters  can  work  has 
narrow  limits,  the  thickness  of  the  alluvial  formations  made  by  a 
stream,  in  any  given  condition  of  it,  is  necessarily  small.  Even  the 
whole  of  the  river-flat,  above  the  level  of  its  bottom,  may  not  have 
been  deposited  by  the  river  in  its  existing  state  ;  for  the  channel  and 
flood-plain  may  be  excavated  in  the  alluvium  or  river-border  forma 
tion  of  an  earlier  period,  so  that  its  upper  surface  alone  may  be  of  recent 
origin  (p.  560).  If,  however,  the  land  were  undergoing  a  very  slow 
subsidence,  which  should  diminish  the  pitch  of  the  stream,  a  deposition 
of  detritus  would  take  place,  that  would  raise  both  its  bed  and  flood- 
plain  ;  and  the  thickness  might  thus  go  on  increasing  so  long  as  the 
subsidence  continued.  Moreover,  when  rivers  flow  rather  sluggishly 
through  plains,  they  tend  to  raise  the  bottom  by  the  deposit  of  sedi 
ment  ;  and,  consequently,  the  dikes  that  may  be  built  to  prevent  the 
spread  of  the  waters  over  the  flat  country  during  floods  have  to  be 
correspondingly  raised,  to  prevent  catastrophe. 

The  deposition  of  detritus,  which  takes  place  along  the  course  of  a  river,  usually  raises 
the  borders  of  the  channel  above  the  general  level  of  the  flood-plain.  Along  the  Lower 
Mississippi,  the  pitch  of  the  plain  awav  from  the  river  amounts,  on  an  average,  to 
seven  feet  for  the  first  mile.  (Humphreys  &  Abbot.) 

The  fine, earthy  alluvium,  which  is  formed  bv  a  slow  deposition  of  detritus  by  annual 
floods,  consists  of  thin,  even  layers.  A  vibration  or  wave-movement,  in  the  waters  of  a 
vat  in  which  a  sediment  is  falling,  tends  to  arrange  that  sediment  in  layers,  each  layer 
corresponding  to  a  wave  movement,  and  showing,  by  a  difference  of  texture  in  its  under 
and  upper  portions,  the  progress  of  the  wave.  But  the  thin  layers  of  alluvium  usually 
mark  the  depositions  of  successive  floods. 

The  pebbles  or  stones,  forming  beds  in  alluvium,  are  brought  in  by  the  upper  waters 
and  lateral  tributaries,  during  floods.  The  course  of  a  tributary  across  the  river-plain 
is  often  marked  by  a  wide  bed  of  stones.  The  sweep  of  a  freshet,  over  the  earthy 
flood-plain,  may  carry  away  the  finer  earth,  and  leave  a  surface  of  pebbles.  The  bank 
of  a  river,  struck  by  a  strong  current,  may  in  a  similar  way  be  made  pebbly,  while  the 
opposite  is  muddy, or  has  a  sand-bank  funning,  from  the  earth  carried  across. 


FRESH-WATER    STREAMS.  651 

Still  other  irregularities  result  from  changes  in  the  river-channel.  The  transfer  of 
material,  from  one  side  of  a  stream  to  the  other,  ends  often  in  making  a  long  bend,  and 
finally  in  cutting  off  the  bend  and  turning  it  into  an  island,  and  ultimately  into  a  part 
of  the  mainland,  by  the  tilling  up  of  the  old  channel. 

The  islands  in  the  large  rivers  are  also  very  unstable.  In  the  Mississippi,  as  Hum 
phreys  &  Abbot  observe,  they  often  begin  in  the  lodging  of  drift-wood  on  a  sand-bar; 
this  causes  the  accumulation  of  detritus;  a  growth  of  willow  succeeds;  the  height  of  the 
alluvium  still  increases,  until  finally  the  island  reaches  the  level  of  high  water,  or  rises 
even  above  it,  and  becomes  covered  with  a  growtli  of  cotton-wood,  willow,  etc.  By  a 
similar  process,  the  island  may  be  united  to  the  mainland;  or,  "  by  a  slight  change  of 
direction  of  the  current,  the  underlying  sand-bar  is  washed  away,  the  new-made  land 
caves  into  the  river,  and  the  island  disappears." 

Alluvial  Fans.  When  a  flooded  stream  descends  along  a  steep  ravine,  the  detritus 
carried  down  is  piled  up  at  the  foot  of  the  slope  over  the  plain,  making  a  section  of  a 
very  low  cone,  usually  3°  or  less  to  8°  or  10°,  called  by  Drew,  from  their  shape,  Alluvial 
fans.  The  streams  producing  these  "  tans"  are  small  ones,  having  more  transporting 
than  denuding  power.  The  material  is  bedded,  but  concentrically,  or  parallel  with  the 
curved  surface.  When  such  "fans"  are  afterward  cut  through  by  the  little  stream, 
and  then  partly  worn  away  by  the  floods  of  the  river  in  the  valley  which  they  border, 
and  then  formed  anew  at  an  outer  and  lower  level,  and  so  on,  the  bedding  becomes 
quite  complex  in  its  directions  and  abrupt  transitions;  and  there  are  parts  of  successive 
'•  fans  "  at  different  levels.  (Q.  Jour.  Gcol.  Soc.,  xxix.  441,  187-3). 

2.  Delta  Formations.  —  The  larger  part  of  the  detritus  of  a  river  is 
carried  to  the  ocean  (or  lake)  into  which  it  empties  ;  and  it  goes  to 
form,  about  the  mouth  of  the  stream,  more  or  less  extensive  flats. 
Such  flats,  when  large  and  intersected  by  a  network  of  water-channels, 
are  called  deltas ;  they  reach  a  large  size,  only  where  the  tides  are 
quite  small  or  are  altogether  wanting.  They  are  formed  from  the 
conjoined  action  of  the  river  and  the  ocean,  and  are  sometimes  called 
fluvio-marine  formations.  Great  streams,  like  the  Amazon,  carry 
their  muddy  waters  hundreds  of  miles  into  the  ocean  ;  but  far  the 
greater  part  of  the  detritus,  even  in  the  case  of  the  largest  rivers,  is 
beaten  back  by  the  waves  on  soundings,  and  by  the  shore  currents, 
and  either  falls  in  the  shallow  waters,  or  is  thrown  upon  the  coast 
near  by.  In  floods,  the  river-water  of  the  Mississippi  is  distinguish 
able  in  the  Gulf,  at  the  distance  of  twenty  or  twenty-five  miles  from 
the  bar ;  in  low  water,  at  the  distance  of  only  five  or  ten  miles. 
(Humphreys  &  Abbot.) 

The  eastern  North  American  coast,  from  Texas  to  Florida,  and 
from  Florida  to  New  Jersey,  is  nearly  a  continuous  range  of  fluvio- 
mariue  formations. 

Only  a  single  example  —  that  of  the  Mississippi  delta  —  need  here  be  referred  to. 
The  annexed  map  (Fig.  1093)  presents  its  general  features.  It  commences  below  the 
mouth  of  Red  River,  where  the  Atchafalaya  "  bayou  "  begins,  —  the  first  of  the  many 
side-channels  that  open  through  the  great  flats  to  the  Gulf.  The  whole  area  is  about 
12,300  square  miles;  and  about  one-third  is  a  sea-marsh,  only  two-thirds  lying  above 
the  level  of  the  Gulf.  Professor  E.  W.  Hilgard  has  shown  that,  about  New  Orleans, 
the  modern  alluvium  has  a  depth  of  only  thirty-one  to  tifty-six  feet,  there  existing  be 
low  this  the  alluvial  clay,  etc.,  of  the  Port  Hudson  group  (p.  5J8). 


652 


DYNAMICAL   GEOLOGY. 


On  p.  649,  the  amount  of  detritus  is  mentioned  which  the  river  annually  furnishes 
toward  the  extension  of  the  delta. 


According  to  Humphreys  &  Abbot,  the  outer  crest  of  the  bar  of  the  Southwest  Pass 
Jthe  principal  one)  of  the  Mississippi  advances  into  the  Gulf  338  feet,  over  a  width  of 
11,500  feet,  annually;  and  the  erosive  power  is  only  about  one  tenth  of  its  depositing 
power.  The  depth  of  the  Gulf,  where  the  bar  is  now  formed,  being  100  feet,  the  profile 
and  other  dimensions  of  the  river,  in  connection  with  the  above-mentioned  rate  of  de 
posit,  give  for  the  difference  between  the  cubical  contents  of  yearly  deposit  and  erosion 
255,000,000  cubic  feet,  or  a  mass  one  mile  square  and  nine  feet  thick:  this,  therefore, 
is  the  volume  of  earthy  matter  pushed  into  the  Gulf  each  year  at  the  Southwest  Pass. 
The  quantities  of  earthy  matter  pushed  along  by  the  several  passes  being  in  proportion 
to  their  volumes  of  discharge,  the  whole  amount  thus  carried  yearly  to  the  Gulf  is 
750, 000,01  ;0  cubic  feet,  or  a  mass  one  mile  square  and  twentv-seven  feet  thick.  As  the 
cubical  contents  of  the  whole  mass  of  the  bar  of  the  Southwest  Pass  are  equal  to  a  solid 
one  mile  square  and  400  feet  thick,  it  would  require  fifty-five  years  to  form  the  bar  as 
it  now  exists,  or,  in  other  words,  to  establish  the  equilibrium  between  the  advancing 
rates  of  erosion  and  deposit. 

The  deltas  of  the  Nile,  Ganges,  Amazon  and  other  large  streams  are  equally  interest- 


SUBTERRANEAN   WATERS.  653 

ing  subjects  of  study.     But  it  is  not  necessary  to  enter  into  details  respecting  them  in 
this  place,  as  they  illustrate  no  new  principles. 

As  the  forms  and  stratification  of  delta-deposits  depend  partly  upon  wave-action,  this 
subject  comes  up  again,  under  the  head  of  Tlie  Ocean. 

B.   SUBTERRANEAN    WATERS. 

It  is  an  obvious  fact  that  a  considerable  part  of  the  water  which 
reaches  the  earth's  surface  descends  into  the  soil,  and  becomes  in  a 
sense  subterranean.  There  are  also  subterranean  streams,  which  have 
their  rise  in  hills  and  mountains,  and  are  fed,  like  ordinary  rivers, 
by  the  rains  and  snows,  and  especially  those  that  fall  about  elevated 
regions.  These  waters  become  under-ground  streams,  by  following  the 
dip  of  tilted  strata,  or  by  infiltrating  through  pervious  or  loosely  ag 
gregated  deposits  ;  and  they  flow  over  some  impervious  layer.  The 
layers  of  stratified  rocks  are  often  so  porous  that  water  easily  perco 
lates  through  them,  down  to  a  stratum  that  will  hold  it ;  and  seldom 

O 

fit  so  closely  together  that  it  cannot  find  its  way  between  them. 

Again,  there  is  a  small  percentage  of  moisture  in  all  or  nearly  all 
strata,  which  is  mechanically  inert,  that  may  properly  be  included 
under  the  head  of  subterranean  waters. 

1.  SUBTERRANEAN  STREAMS. 

The  large  size  of  some  of  the  under-ground  rivers  is  proved  by 
direct  observation  in  caverns,  where  they  have  the  variety  of  cascades 
and  quiet  waters  which  characterizes  the  streams  of  the  surface.  The 
Mammoth  Cave,  of  Kentucky,  and  the  Adelsberg,  twenty-two  miles 
northeast  of  Trieste,  in  Austria,  are  examples.  And  again,  as  in  the 
Appalachians,  and  the  Jura  Mountains,  they  sometimes  come  out  of 
the  hills  with  sufficient  force  and  volume  to  turn  the  wheel  of  a  large 
mill.  All  wells  and  springs  are  tappings  of  these  subterranean  waters. 
Some  small  lakes  receive  their  supply  of  water  mainly  from  springs, 
or  subterranean  flows. 

The  outward  flow  of  the  under-ground  waters  of  a  continent  pre 
vents,  on  sea-shores,  the  in-flow  of  the  salt  water.  Springs  are  common 
on  shores  ;  occasionally,  their  waters  rise  in  large  volume  in  a  harbor, 
or  out  at  sea,  some  miles  distant  from  a  coast. 

If  subterranean  streams  have  their  rise  in  elevated  regions,  their 
inferior  portions,  beneath  the  plains  of  a  country,  must  be  under  hydro 
static  pressure  ;  and  this  should  appear,  whenever  a  boring  is  made  to 
the  waters,  by  their  rising  toward  the  surface,  or,  if  the  pressure  is 
great,  above  it,  in  a  jet.  Borings  of  this  kind  have  been  made  in 
many  parts  of  Europe  and  America,  with  this  effect.  They  were  first 
attempted  in  France,  and  are  called  Artesian  wells,  from  the  district 
of  Artois,  in  France,  where  they  were  early  used.  In  Fig.  1094,  a  b 
represents  an  argillaceous  stratum,  on  which  the  water  descends,  and 


654 


DYNAMICAL    GEOLOGY. 


b  c  the  boring  ; 


b  c  d  is  the  jet  of  water.      The  rise  of  the  jet  falls 
far  short  of  the    height    of   the 


Fig.  1094. 


Section  illustrating  the  origin  of  Artesian  wells. 


source,  because  of  the  great  amount 
of  friction  along  the  irregular 
rocky  bed  of  the  stream,  and  also 
the  resistance  of  the  air. 

In  some  cases,  subterranean 
waters  are  under  pressure,  from  a 
stratum  of  gas  over  them,  which 
is  sufficient  to  send  them  to  the 
surface  without  other  aid. 


The  Artesian  well  of  Grenelle,  near  the  Hotel  des  Invalides,  in  Paris,  is  2,000  feet 
deep.  At  1,798  feet,  water  was  struck;  and  it  darted  out  to  a  height  above  the  surface 
of  112  feet,  and  at  the  rate  of  nearly  one  million  of  gallons  a  day.  The  pressure  indi 
cated  by  the  jet  Avas  equal  to  that  of  a  column  of  water  2,612  feet  high,  or  1,160  pounds 
to  the  square  inch.  Another,  in  the  north  of  Paris,  has  been  carried  down  to  a  depth 
exceeding  2,000  feet,  with  a  diameter  of  more  than  four  feet  to  the  bottom.  All  but 
157  feet  of  it  is  below  the  sea-level. 

Another  well,  in  Westphalia  in  Germany,  is  2,385  feet  deep. 

An  Artesian  boring  at  St.  Louis  has  been  carried  to  a  depth  of  3,843^  feet,  but  with 
out  obtaining  a  flow  of  water  to  the  surface ;  the  last  250  feet  were  in  granyte  of  the 
Archaean,  so  that  the  whole  of  the  Paleozoic  of  the  region,  from  the  Carboniferous 
downward,  was  passed  through.  (Broadhead.)  A  well  at  Louisville,  Kentucky,  2,086 
feet  deep,  supplies  an  abundance  of  water,  though  a  little  brackish.  In  California, 
Artesian  wells  have  been  resorted  to  successfully,  for  agricultural  purposes. 

Borings  are  often  successful  in  alluvial  regions,  fifty  or  one  hundred  miles  from  any 
high  land.  A  second  boring  in  the  same  region  sometimes  seriously  lessens  the  amount 
of  water  afforded  by  the  first,  by  giving  the  same  subterranean  stream  a  new  place  of 
exit.  The  layer  from  which  the  boring  and  jet  rise  may  be  gradually  worn  through  by 
the  flow,  and  the  water,  or  part  of  it,  become  lost  by  being  thus  let  off  to  a  lower  level. 

The  stratified  sands  and  gravel  of  a  region  have  often,  at  some  depth  below  the  sur 
face,  a  half-consolidated  layer  called  hard-pan  (often  consolidated  by  oxyd  of  iron, 
through  the  aid  of  percolating  waters),  which  holds  the  water  above  it,  and  thereby 
makes  an  underground  stream  or  basin  for  the  supply  of  wells.  The  same  result  comes 
also  from  the  presence  of  a  clayey  layer.  Artesian  borings  to  this  water-layer  some 
times  secure  a  flow  to  the  surf  ace,  and  a  jet  of  moderate  height. 

Subterranean  streams  produce  erosion,  like  running  water  above 
ground,  and  may  excavate  a  channel  in  the  same  way.  Caverns  are 
made  partly  by  erosion  and  partly  by  the  dissolving  action  of  water. 
A  common  effect  of  such  excavations  is  the  production  of  subsidences 
of  the  soil  and  overlying  rocks,  and  the  formation  of  sink-holes.  Small 
shakings  of  the  earth  may  be  a  consequence  of  the  fractures  of  under 
mined  strata. 

2.  MECHANICAL  EFFECTS,  FROM  THE  SOFTENING  OR  LOOSENING 

OF  BEDS. 

Subterranean  waters  act  mechanically,  also,  by  softening  or  loosen 
ing  permeable  beds  of  rock -material,  and  adding  to  their  weight.  The 
following  are  among  the  consequent  results  :  — 


SUBTERRANEAN    WATERS.  655 

1.  Land-slides.  —  Land-slides  are  of  the  three  kinds  :  — 
(1.)  The  mass  of  earth  on  a  side-hill,  having  over  its  surface,  it  may 
be,  a  growth  of  forest  trees,  and,  below,  beds  of  gravel  and  stones, 
may  become  so  weighted  with  the  waters  of  a  heavy  rain,  and  so 
loosened  below,  by  the  same  means,  as  to  slide  down  the  slope  by 
gravity. 

A  slide  of  this  kind  occurred,  during  a  dark,  stormy  night,  in  August,  1826,  in  the 
White  Mountains,  back  of  the  Willey  House.  It  carried  rocks,  earth,  and  trees  from  the 
heights  to  the  valley,  and  left  a  deluge  of  stones  over  the  country.  The  frightened 
Willey  family  fled  from  the  house,  to  their  destruction  :  the  house  remains,  as  on  an 
island  in  the  rocky  stream. 

(2.)  A  clayey  layer,  overlaid  by  other  horizontal  strata,  sometimes 
becomes  so  softened  by  water  from  springs  or  rains,  that  the  superin 
cumbent  mass,  by  its  weight  alone,  presses  it  out  laterally,  provided 
its  escape  is  possible,  and,  sinking  down,  takes  its  place. 

Near  Tivoli,  on  the  Hudson  River,  a  subsidence  of  this  kind  took  place  in  April, 
1862.  The  land  sunk  down  perpendicularly,  leaving  a  straight  wall  around  the  sunken 
area,  sixty  or  eighty  feet  in  height.  An  equal  area  of  clay  was  forced  out  laterally  un 
derneath  the  shore  of  the  river,  forming  a  point  about  an  eighth  of  a  mile  in  circuit, 
projecting  into  the  cove.  Part  of  the  surface  remained  as  level  as  before,  with  the  trees 
all  standing.  Three  days  afterward,  the  slide  extended,  partially  breaking  up  the  sur 
face  of  the  region  which  had  previously  subsided,  and  making  it  appear  as  if  an  earth 
quake  had  passed.  The  whole  area  measured  three  or  four  acres. 

(3.)  When  the  rocks  are  tilted,  and  form  the  slope  of  a  mountain, 
the  softening  of  a  clayey  or  other  layer  underneath,  in  the  manner 
just  explained,  may  lead  to  a  slide  of  the  superincumbent  beds  down 
the  declivity. 

In  1806,  a  destructive  slide  of  this  kind  took  place  on  the  Rossberg,  near  Goldau,  in 
Switzerland,  which  covered  a  region  several  square  miles  in  area  with  masses  of  con- 
.glomerate,  and  overwhelmed  a  number  of  villages.  The  thick  outer  stratum  of  the 
mountain  moved  bodily  downward,  and  finally  broke  up  and  covered  the  country  with 
ruins,  while  other  portions  were  buried  in  the  half-liquid  clay  which  had  underlaid  it 
and  was  the  cause  of  the  catastrophe. 

Similar  subsidences  of  soil  have  taken  place  near  Nice,  on  the  Mediterranean.  On 
one  occasion,  the  village  of  Roccabruna,  with  its  castle,  sunk,  or  rather  slid  down,  with 
out  destroying  or  even  disturbing  the  buildings  upon  the  surface. 

Besides  (1)  the  transfer  of  rocks 
and  earth,  land-slides  also  cause  (2)  a 
scratching  or  planing  of  slopes,  by  the 
moving  strata  and  stones ;  (3)  the 
burial  of  animal  and  vegetable  life; 
(4)  the  folding  or  crumpling  of  the 
clayey  layer  subjected  to  the  pressure, 
where  the  effect  does  not  go  so  far  as 
to  produce  its  extrusion  and  destruction ; 

'While    the    beds    between    Which    it   lies  Plated  dayey  layer. 


656  DYNAMICAL    GEOLOGY. 

are  only  slightly  compacted,  or  are  unaltered.  Fig.  1095  is  a  reduced 
view  of  a  layer  thus  plicated,  from  the  Post-tertiary  of  Booneville, 
N.  Y.  Vanuxem  illustrates  the  facts  there  observed  by  him,  with 
this  and  other  figures  (N.  Y.  Geological  Report),  and  attributes  the 
plications  to  lateral  pressure,  while  the  layer  was  in  a  softer  state 
than  those  contiguous. 

2.  Mud-lumps,  Mud-volcanoes.  —  The  shallow  waters  within  one  to 
three  miles  of  the  main  channel  or  mouth  of  the  Mississippi  River 
(see  map,  p.  652)  are  dotted  with  what  are  called  mud  lumps,  —  con 
vex  or  low-conical  elevations,  sometimes  100  feet  or  more  in  diameter, 
—  showing  their  tops  at  the  surface.  They  originate  in  upheavals 
of  the  soft  bottom.  Once  formed,  they  discharge  mud  from  the  top, 
which  gives  to  the  material  of  the  low  cone  the  structure  of  a  volcanic 
cone,  the  successive  layers  being,  however,  of  mud,  and  but  a  fraction 
of  an  inch  thick.  They  finally  collapse ;  and  then  the  cavity  of  the 
cone  sometimes  becomes  the  site  of  a  pool  of  salt-water,  like  the  lake 
in  an  extinct  volcano.  They  are  formed,  according  to  Prof.  E.  W.  Hil- 
gard  (from  whose  description  in  the  u  American  Journal  of  Science," 
III.  i.,  the  facts  here  given  are  cited,  and  who  adopts,  in  the  main  point, 
the  view  of  Lyell),  through  the  pressure  of  the  surface  deposits  on  a 
layer  of  mud  which  overlies  the  Port  Hudson  clay,  or  Champlain  al 
luvium  (p.  547).  Some  carbo-hydrogen  gas  is  given  out,  arising  from 
the  decomposition  of  animal  or  vegetable  matters  in  the  mud. 

3.  MOISTURE  CONFINED  IN  ROCKS. 

The  amount  of  moisture  in  different  rocks  varies  with  their  kinds 
and  compactness  of  texture. 

In  1853,  Durocher  published  some  results  of  experiments  with  regard  to  the  amount 
of  water  contained  in  different  crystallized  minerals,  giving,  among  them,  -0028  to 
•0269  per  cent,  for  orthoclase,  or  common  feldspar;  -0127  for  porphyry;  '0203  for 
euryte,  a  feldspathic  granyte,  etc.  Delesse  made  further  examinations  of  rocks,  in 
1861,  and  found  the  amount  of  moisture  in  coarse  granyte  0-37  per  cent  ;  in  euryte, 
0*07;  in  milky  quartz,  from  a  vein,  0-08;  in  flint,  from  the  chalk  at  Meudon,  0*12;  in 
a  compact  Tertiary  limestone  (Calcaire  grossiere),  3'11;  in  chalk,  from  Meudon,  nearly 
20  per  cent.;  in  a  quartzose  sandstone  (gres  de  Fontainebleau,  near  Meudon),  2'73. 
Hunt,  in  some  experiments,  the  results  of  which  were  published  in  1865,  obtained 
for  the  amount  of  moisture  absorbed,  after  drying  at  a  temperature  between  150°  and 
200°  F. :  for  Potsdam  sandstone,  three  specimens,  2'26  to  2-71  per  cent.;  other  three, 
6-94-9-35;  for  Trenton  limestone,  0  32  to  1*70,  the  former  for  a  black  variety;  for  the 
Chazy  rock,  an  argillaceous  limestone,  6-45  to  13'55;  a  crystallized  dolomite,  of  the 
Calciferous  formation,  four  specimens,  1-89  to  2-53;  two  other  specimens,  5"90  to  7"22; 
for  the  Medina  argillaceous  sandstone,  two  specimens,  8-37  to  10-06.1 

The  facts,  as  first  suggested  by  Saemann,  early  in  1861,  and  after 
ward  at  more  length  by  Delesse,  show  that  the  thickening  of  the 

1  Durocher,  Bull.  Soc.  Geol.,  x.  431,  1853;  Delesse,  ibid.,  xviii.,  64,  1861;  Hunt, 
Amer.  Jour.  Sd.,  II.  xxxix.  193. 


THE    OCEAN.  657 

supercrust,  by  the  addition  of  sedimentary  beds,  has  been  attended  by 
the  withdrawal  of  water  from  the  oceanic  and  other  superficial  basins. 
The  metamorphism  of  strata  has  expelled  this  moisture,  to  a  large 
extent,  from  the  beds  thus  altered,  yet  not  wholly.  The  average 
amount,  in  granyte,  syenyte,  porphyry,  and  all  Archaean  rocks,  is  not 
over  0-06  per  cent.  ;  while  in  other  rock  formations  it  may  be  2-5 
per  cent. ;  and  in  superficial  clays  and  gravels  it  is  at  least  10  per 
cent. 

If  the  thickness  of  the  supercrust  over  the  continental  portion  of 
the  globe  averages  five  miles,  and  the  average  amount  of  moisture  in 
the  formations,  both  metamorphic  and  unaltered,  be  2*5  per  cent.,  the 
whole  amount  of  water  absorbed  and  confined  would  be  a  fortieth  of 
five  miles,  or  about  650  feet  in  depth,  for  the  area  of  the  continents. 
The  deposits  over  the  oceanic  basins  have  relatively  little  thickness. 
Whatever  reasonable  allowance  be  made  for  them,  the  whole  loss  to 
the  ocean  waters,  in  depth,  from  this  source,  will  not  exceed  400  feet. 
This  confined  water,  while  a  feeble  agent  of  change  at  the  ordinary 
temperature,  is  one  of  immense  importance  when  much  heat  is  present. 

As  Delesse  states,  the  water  confined  in  terrestrial  plants  and  animals  is  another 
part  taken  permanently  from  the  oceans,  since  the  commencement  of  Paleozoic  time. 

The  average  thickness  of  the  deposits,  along  the  central  portions  of  the  Appalachian 
region,  has  been  estimated  at  seven  miles.  .But,  above  the  Archaean,  that  of  the 
region  east  of  it  is  very  thin;  and  west  of  it,  to  the  Mississippi  and  for  600  miles 
beyond,  it  will  not  average  one  mile.  In  the  Rocky  Mountains,  there  is  a  large  crest 
range,  with  no  deposits  above  the  Archaean :  but,  farther  west,  the  mean  thickness  may 
possibly  be  eight  miles.  To  the  north  of  the  eastern  United  States,  there  is  a  very  large 
area  of  uncovered  Archaean  rocks.  The  mean  thickness  for  the  whole  surface,  there 
fore,  will  not  exceed  five  miles. 

2.    THE   OCEAN. 
1.  OCEANIC  FORCES. 

The  ocean  exerts  mechanical  force,  by  means  of  its  — 

1.  General  system  of  currents. 

2.  Tidal  waves  and  currents. 

3.  Wind-waves  and  currents. 

4.  Earthquake-waves. 

The  force  of  moving  salt  water  is  the  same  as  for  fresh  water,  ex 
cept  the  difference  arising  from  the  greater  density  of  the  former,  — 
its  specific  gravity  being  one-thirty-fifth  to  one-fortieth  more  than  that 
of  fresh  water. 

The  specific  gravity  of  sea-water  varies  for  different  parts  of  the  ocean.  For  the 
waters  of  the  southern  ocean,  it  is  1-02919;  the  northern,  1-02757;  equator,  1.02777; 
Mediterannean  Sea,  1-0293;  Black  Sea,  1-01418  (Marcet).  In  most  seas  receiving 
large  rivers,  and  in  bays,  the  density  is  least.  The  specific  gravity  of  the  water  of 
East  River,  off  New  York  City,  at  high  tide,  is  1-02038  (BeckJ. 
42 


658  DYNAMICAL    GEOLOGY. 


1.  General  System  of  Currents. 

The  system  of  oceanic  currents  is  briefly  explained  on  pages  38— 
42.  It  is  part  of  the  organic  structure  of  the  globe,  irrespective  of 
its  age  or  condition ;  for,  whatever  the  temperature  of  the  poles,  there 
must  always  have  been  a  warmer  tropics,  under  the  path  of  the  sun. 

The  prominent  characteristics  of  these  currents,  bearing  on  their 
mechanical  effects  in  geological  history,  are  the  following :  — 

1.  The  rate  of  movement  is  slow.  —  The  maximum  velocity  of  the 
Gulf  Stream  is  five   miles  an  hour,  and  the  average  less   than  one 
mile  and  a  half. 

The  Gulf  Stream  is  most  rapid  off  Florida,  where  the  hourly  rate  is  three  to  five 
miles;  off  Sandy  Hook,  it  is  one  mile  and  a  half.  The  rate  of  flow  of  the  polar  cur 
rent  is  less  than  one  mile  an  hour.  Kane,  while  shut  up  in  the  Arctic,  was  carried 
south  by  the  current,  some  days,  about  half  a  mile  an  hour.  The  great  oceanic 
current  of  the  eastern  South  Pacific  varies  from  three  miles  an  hour  to  a  fraction  of  a 
mile ;  and  across  the  middle  of  the  ocean  it  is  barely  appreciable.  The  current  in  the 
Indian  Ocean,  where  most  rapid,  has  the  hourly  rate  of  two  miles  and  a  quarter. 

In  past  geological  ages,  the  rapidity  of  these  great  oceanic  currents 
must  have  been  less  than  now,  if  there  was  any  difference,  because 
of  the  less  difference  of  temperature  between  the  equator  and  the 
poles,  and  hence  feebler  trade-winds. 

2.  The  currents  are  generally  remote  from  coasts,  and  are  seldom 
appreciable  where  the  depth  is  less  than  one  hundred  feet,  and  very  feeble 
where  less  than  one  hundred  fathoms.  —  Owing  to  the  great  depth  of 
the  oceanic  movement,  the  waters  are  diverted  along  the  borders  of 
the   oceans,  by  the  deep-sea  slopes  of  the  continents.      In  the  case 
of  the  Gulf  Stream,  these  approach  the  coast  at  Cape  Florida,  and 
somewhat  nearly  at  Cape  Hatteras  and  Cape  Cod  ;  but,  off  New  Jer 
sey,  they  are  eighty  to  one  hundred  miles  distant ;  and  here  runs  the 
western  limit  of  the  stream. 

The  polar  or  Labrador  current,  which  is  mostly  a  sub-current,  comes 
to  the  surface  along  the  same  slope,  west  of  the  limit  of  the  Gulf 
Stream,  and  is  slightly  apparent  on  the  shore-plateau,  but  rather  by 
its  temperature  than  by  the  movement  of  the  waters.  The  more 
western  position  of  the  limit  of  the  polar  current  is  explained  on  page 
39.  The  fact  that  it  has  not  more  rapid  movement,  on  the  great 
shore-plateau,  is  evidence  that  it  belongs  to  the  deep  water.  This 
appears,  further,  in  the  current's  underlying  the  Gulf  Stream,  and  its 
banding  the  stream  with  colder  and  warmer  waters,  as  shown  by  the 
Coast  Survey,  under  Professor  Bache.  The  observations  of  the  sur 
vey  have  proved  that  there  are  mountain-ridges  apparently  parallel 
with  the  Appalachians,  along  the  course  of  the  stream,  in  its  more 


THE   OCEAN.  659 

southern  part,  off  the  Carolinas,  and  that,  above  these  ridges,  the  sur 
face-waters  are  cooler,  owing  to  the  lifting  upward  of  the  polar  current 
by  the  submarine  elevations.  The  fact  that  the  cold  waters  produce 
a  temperature  of  35°  F.,  at  a  depth  of  six  hundred  fathoms,  off 
Havana  (as  stated  by  Bache),  is  proof  of  the  great  magnitude  of  the 
polar  current. 

Where  the  current  flows  close  along  a  coast  or  submarine  bank,  or 
by  an  oceanic  island,  it  may  produce  some  eroding  effects. 

3.  As  the  position  of  the  main  flow  of  the  currents  is  determined 
partly  by  the  trend  of  the  continents,  their  courses  may  have  been  differ 
ent  in  former  time  from  what  they  are  now,  provided  the  continents,  or 
large  portions  of  them,  were  sufficiently  submerged.  —  Small  subsidences 
would  not  suffice  to  produce  a  diversion  from  their  present  courses,  for 
the  reason  just  given.  Even  the  barrier  of  Darien  might  be  removed, 
by  submergence  to  a  depth  of  five  hundred  feet,  and  probably  one 
thousand,  without  giving  passage  to  much,  if  any,  of  the  Gulf  Stream. 
If,  however,  the  straits  were  so  deeply  sunk  that  the  Gulf  Stream 
passed  freely  into  the  Pacific  (the  West  India  islands  being  also  in  the 
depths  of  the  ocean,  as  would  be  necessary  for  the  result),  a  great 
change  would  thereby  be  produced  in  the  temperature  of  both  the 
Atlantic  and  the  Pacific,  —  a  loss  of  heat  to  the  former  and  a  gain  to 
the  latter.  (See  Physiographic  Chart.)  But  no  facts  yet  observed 
prove  this  supposition  to  have  been  a  realized  fact  since  the  opening 
of  the  Silurian  age.  A  shallow-water  connection  across  the  isthmus 
between  the  two  oceans  probably  existed  as  late  as  the  Cretaceous,  as 
has  been  inferred  from  the  parallel  series  of  representative  species  now 
existing  on  the  two  sides. 

Besides  the  general  system  of  currents,  which  has  been  considered,  there  are  currents 
between  the  ocean  and  some  confined  seas  opening  into  it,  which  are  due  to  the  evap 
oration  going  on  over  the  surface  of  those  seas.  The  consequent  diminution  of  water 
causes  a  flow  at  surface  from  the  ocean,  to  supply  the  loss.  This  happens  at  the  Straits 
of  Gibraltar,  opening  into  the  Mediterranean.  At  bottom,  there  is  a  nW  outward, of  the 
denser  water.  In  many  seas  of  this  kind,  the  accessions  from  rivers  more  than  supply 
the  amount  removed  by  evaporation ;  and  these  produce  an  out-current  at  the  entrance. 
The  Black  Sea,  by  losing  much  of  its  salt,  is  rendered  less  dense  than  the  ^Egean,  to 
the  south,  and  hence  there  is  an  under-current  into  it  at  the  Dardanelles. 

2.  Tidal  Waves  and  Currents. 

1.  Rise  and  Fall  of  Tides.  —  The  simplest  of  tidal  actions  is  the 
periodical  rising  of  the  waters  on  a  coast.  The  in-flow  acts  like  a 
dam,  in  setting  back  the  waters  of  springs  and  rivers.  It  floods  large 
areas  on  flat  coasts,  which  are  thereby  made  salt-marshes. 

The  height  of  the  tide  is  less  in  mid-ocean  than  along  the  continents, 
and  is  greatly  augmented  where  two  coast-lines  converge,  as  on  enter- 


660  DYNAMICAL    GEOLOGY. 

ing  a  bay,  and  especially  where  there  is  free  entrance  to  a  channel 
from  two  directions.  In  the  middle  Atlantic,  at  St.  Helena,  it  is  two 
or  three  feet ;  at  the  Azores,  three  feet ;  on  the  Atlantic  coast  of  the 
United  States,  from  five  to  twelve  feet ;  but  in  the  Persian  Gulf  the 
highest  tide  at  the  extremity  is  thirty-six  feet ;  at  the  mouth  of  the 
Severn,  forty-five  feet ;  at  the  Bay  of  St.  Michael  (west  coast  of  Nor 
mandy),  France,  forty -five  to  forty -eight  feet ;  in  the  Bay  of  Fundy, 
forty  to  sixty-nine  feet ;  in  the  gulfs  of  San  Jorge  and  Santa  Cruz,  at 
the  entrance  of  the  Straits  of  Magellan,  forty-eight  to  sixty-six  feet. 
In  the  central  Pacific,  the  height  is  two  to  four  feet ;  and  at  Tahiti 
high  tide  occurs  always  at  noon. 

2.  Translation  Character  of  the  Tidal  Waves. —  The  tidal  waves  which 
succeed  one  another  around  the  globe  become  appreciably  translation 
or  propelling  waves,  on  soundings  ;  and  directly  upon  a  coast,  espe 
cially  along  its  deeper  bays  or  inlets,  they  constitute  a  force  of  great 
energy.     The  borders  of  all  the  continents  and  islands  feel  this  power, 
and  exhibit  its  effects. 

3.  In-flowing  Tidal  Currents.  —  The  in-coming  tide  has  a  progres 
sive  movement  along  a  coast,  varying  in  its  effects,  according  to  the 
trend  of  the  coast  with  reference  to  the  course  of  the  tidal  wave. 

If  a  bay  at  the  mouth  of  a  river  has  a  long  projecting  cape  on  the 
side  from  which  the  wave  comes,  it  will  have  usually  a  good  depth 
and  entrance,  the  detritus  brought  down  by  the  outflowing  tide  beinij 
carried  out  so  far  as  to  be  swept  off  to  leeward.  But  if  the  cape  is 
on  the  opposite  side,  the  bay  or  mouth  of  the  river  will  commonly  be 
choked  up  by  sand-banks,  made  of  the  detritus  thrown  into  it  by  the 
unparried  in-flowing  tide. 

The  tidal  current  becomes  one  of  great  strength,  where  there  are 
narrow  channels  to  receive  and  discharge  the  waters.  The  movement 
may  have  the  violence  of  a  river-torrent,  when  the  entrance  to  bays 
is  of  a  kind  to  temporarily  dam  up  the  waters,  until  the  far-advanced 
tide  has  so  accumulated  them  that  they  overcome  the  resistance  and 
pass  on  in  a  body.  In  the  Bay  of  Fundy,  the  waters  of  the  in 
coming  tide  are  raised  high  above  their  natural  elevation,  so  that,  as 
they  advance,  they  seem  to  be  pouring  down  a  slope,  making  a  turbid 
waterfall  of  majestic  extent  and  power,  without  foam. 

In  some  cases,  the  whole  tide  moves  in  all  at  once,  in  a  few  great 
waves.  This  happens  especially  at  the  mouths  of  rivers,  where  there 
is  obstruction  from  sand-bars,  and  other  favoring  circumstances  about 
the  entrance.  The  phenomenon  is  called  an  eagre  or  bore.  The  flow 
of  the  tides  at  the  Bay  of  Fundy  has  something  of  the  character  of 
an  eagre.  But  the  most  perfect  examples  are  afforded  at  the  mouths 
of  the  rivers  Amazon,  Hoogly  (one  of  the  mouths  of  the  Gauges), 


THE   OCEAN.  661 

and  Tsien-tang,  in  China.  In  the  case  of  the  last-mentioned  river,  the 
wave  plunges  on  like  an  advancing  cataract,  four  or  five  miles  in 
breadth  and  thirty  feet  high,  and  thus  passes  up  the  stream,  to  a  dis 
tance  of  eighty  miles,  at  a  rate  of  twenty-five  miles  an  hour.  The 
change  from  ebb  to  flood- tide  is  almost  instantaneous.  Among  the 
Chusan  Islands,  just  south  of  the  bay,  the  tidal  currents  run  through 
the  funnel-shaped  frith  with  a'  velocity  of  sixteen  miles  an  hour. 
(Macgowan.) 

In  the  eagre  of  the  Amazon,  the  whole  tide  passes  up  the  stream  in 
five  or  six  waves,  following  one  another  in  rapid  succession,  and  each 
twelve  to  fifteen  feet  high. 

4.  Out-flowing  Currents.  —  The  ebbing  tide  causes  an  out-flowing 
current,  which  is  directly  the  counterpart  of  the  in-flowing  current. 
It  is  more  quiet  than  the  latter  in  its  movement ;  but  it  is  often  a 
rapid  and  powerful  current,  because  more  contracted  in  width  than 
that  of  the  flow,  —  and  especially  so  in  bays  in  which  the  waters  of  a 
river  add  to  the  volume  of  the  ebb. 

The  piling  of  the  tide-waters  to  an  unusual  height  in  converging 
bays,  raising  them  far  above  their  level  outside,  is  another  cause  of 
out-flowing  currents.  The  flow  is  along  the  bottom ;  and  it  often  has 
great  power. 

3.    Ordinary  Wind-waves  and  Currents. 

1.  Waves.  —  The  winds  are  almost  an  incessant  wave-making  power. 
Even  in   the  calmest  weather,   there   is   some  breaking   of  wavelets 
against  the  rocky  headlands  or  the  exposed  beach  ;  and,  with  ordinary 
breezes,  the  beaches  and  rocks  are  ever  under  the  beating  waves,  night 
and  day,  from  year  to  year.     Most  seas,  moreover,  have  their  storms ; 
and  in  some,  as  those  about  Cape  Horn,  gales  prevail  at  all  seasons. 
The  breakers  on   the   shores  of  the  Pacific  are  especially  heavy,  on 
account  of  its  extent  and  depth. 

Through  a  large  part  of  the  ocean,  the  winds  are  constant  in  direc 
tion  either  for  the  year  or  half-year. 

Stevenson,  in  his  experiments  at  Skerry vore  (west  of  Scotland), 
found  the  average  force  of  the  waves  for  the  five  summer  months  to 
be  611  pounds  per  square  foot,  and  for  the  six  winter  months  2,086 
pounds.  He  mentions  that  the  Bell  Rock  Lighthouse,  one  hundred 
and  twelve  feet  high,  is  sometimes  buried  in  spray  from  ground-swells, 
when  there  is  no  wind,  and  that,  on  November  20,  1827,  the  spray  was 
thrown  to  a  height  of  one  hundred  and  seventeen  feet,  —  equivalent 
to  a  pressure  of  nearly  three  tons  per  square  foot. 

2.  Surface-currents.  —  Winds  also  cause  currents.     The  prevailing 
winds  of  an  ocean,  like  the  trades  (p.  43),  cause  a  parallel  movement 


DYNAMICAL    GEOLOGY. 

in  the  surface-waters  ;  and, when  the  direction  is  reversed  for  half  the 
year,  as  in  the  western  half  of  the  tropical  Pacific,  the  current  is 
changed  accordingly.  These  currents  become  marked  along  shores, 
and  especially  through  open  channels  ;  the  great  currents  of  the  ocean 
are  attributed  by  some  physicists  to  the  force  of  the  prevailing  winds. 
Prolonged  storms  often  produce  their  own  currents,  even  in  mid-ocean, 
and  more  strikingly  still  among  the  bays  and  inlets  of  a  coast. 

These  currents  made  by  the  winds  are  inferior  in  power  to  the  tidal 
currents,  among  the  inlets  and  islands  of  a  continental  coast;  but, 
about  oceanic  islands,  they  are  often  of  greater  strength. 

3.  Under -currents. — The  forcing  of  waters  into  bays,  whether  by 
regular  winds  or  by  storms,  causes  a  strong  under-current  outward,  like 
that  from  the  tides.  This  happens  when  the  entrance  of  the  bay  is 
broad,  so  as  to  allow  of  an  in-flow  over  a  wide  area,  while  the  deep- 
water  channel  is  narrow,  and  especially  so,  if  the  entrance  to  the  bay 
is  narrowed  by  a  bar  or  reef.  In  some  cases,  ships  lying  at  anchor 
feel  this  under-current  so  strongly  as  to  "  tail  out "  the  harbor,  in  the 
face  of  a  gale  which  is  blowing  in. 

In  the  ordinary  breaking  of  waves  on  a  beach  or  in  rocky  coves, 
there  is  an  under-current  (or  uiider-tow)  flowing  outward  along  the 
bottom.  The  wave  advances  and  makes  its  plunge ;  and  then  its 
waters  flow  back  beneath  those  of  the  next  wave,  which  is  already 
hastening  on  toward  the  beach. 

4.  Earthquake  Waves. 

In  an  earthquake,  the  movement  of  the  earth  may  be  either  (1)  a 
simple  vibration  of  a  part  of  the  earth's  crust ;  or  (2)  a  vibration  with 
actual  elevation  or  subsidence.  In  each  case,  the  ocean-waves,  which 
the  earthquake,  if  submarine,  may  produce,  have  an  actual  forward  im 
pulse,  and  are,  therefore,  forced  or  translation-waves.  They  have  great 
power  ;  and,  as  there  is  no  narrow  limit  to  the  amount  of  elevation 
which  may  attend  an  earthquake,  such  a  wave  may  be  of  enormous 
height.  An  earthquake  at  Conception,  Chili,  set  in  motion  a  wave 
that  traversed  the  ocean  to  the  Society  and  Navigator  Islands,  3,000 
and  4,000  miles  distant,  and  to  the  Hawaian  Islands,  6,000  miles  ;  and 
on  Hawaii  it  swept  up  the  coast,  temporarily  deluging  the  village  of 
Hilo.  An  earthquake  at  Arica,  and  other  parts  of  southern  Peru, 
August  14,  1868,  sent  a  wave  across  the  Pacific,  westward  to  New 
Zealand  and  Australia,  northwestward  to  the  Hawaian  Islands,  north 
ward  to  the  coast  of  Oregon. 


THE    OCEAN.  663 

2.    EFFECTS  OF  OCEANIC  FORCES. 

The  effects  of  oceanic  forces  are  here  treated  under  the  heads  of  — 
(1)  Erosion;  (2)  Transportation;  (3)  Distribution  of  Material,  or 
Marine  and  Fluvio-marine  formations. 

1.  Erosion. 

Erosion  by  Currents.  —  But  little  erosion  can  be  produced  by  the 
great  oceanic  currents,  on  account  of  their  slow  rate  of  motion,  and 
their  distance  from  the  land.  Still,  the  Labrador  current,  with  its 
westward  tendency  (p.  40),  acting  against  the  submerged  border  of 
the  continent,  may  have  produced  some  results  of  this  kind  in  past 
time,  if  not  doing  so  now.  It  has  been  supposed  that  the  course  of 
the  steep  outer  slope  of  this  submerged  border  (p.  11)  has  been  deter 
mined  by  the  oceanic  currents  ;  but  it  is  more  probable  that  the  posi 
tion  of  the  slope  has  directed  the  courses  of  the  currents. 

The  tidal  flow  and  upper  wind-currents  may  produce  results  similar 
to  those  of  fresh-water  streams  of  equal  velocity. 

The  ebbing  tide  and  the  wider-currents  act  on  the  bottoms  of  inlets 
and  harbors,  and  especially  their  channels,  and  are  an  important 
means  of  keeping  them  open  to  the  ocean,  and  of  modelling  their 
forms. 

2.  Erosion  by  Waves.  —  The  waves  bring  to  bear  the  violence  of  a 
cataract  upon  whatever  is  within  their  reach,  —  a  cataract  that  girts 
all  the  continents  and  oceanic  islands.  In  stormy  seas,  they  have  the 
force  of  a  Niagara,  but  with  far  greater  effects  ;  for  Niagara  falls  into 
a  watery  abyss,  while,  in  the  case  of  the  waves,  the  rocks  arc  made 
bare  anew  for  each  successive  plunge.  It  is  not  surprising,  therefore, 
that, in  regions  like  Cape  Horn  or  the  coast  of  Scotland,  where  storms 
are  common  and  the  bordering  seas  deep,  the  cliffs  should  undergo 
constant  degradation,  and  be  fronted  by  lofty  castellated  and  needle- 
shaped  rocks.  The  action  of  the  ordinary  breakers  is  sufficient  to 
wear  away  rocky  shores,  and  reduce  stones  to  gravel  and  sand,  besides 
grinding  the  sands  of  beaches  to  a  finer  powder. 

The  cliffs  of  Norfolk  and  Suffolk,  England,  afford  an  example  that  has  been  long 
under  observation,  as  the  country  is  one  of  houses  and  cultivated  fields.  Lyell  states 
that  in  1805,  when  an  inn  at  Sherringham  was  built,  it  was  fifty  yards  from  the  sea, 
and  it  was  computed  that  it  would  require  seventy  years  for  tlie  sea  to  reach  the 
spot  —  the  mean  loss  of  land  having  been  calculated,  from  former  experience,  to  be 
somewhat  less  than  one  yard  annually.  But  it  was  not  considered  that  the  slope  of 
the  ground  was/rom  the  sea.  Between  the  years  1824  and  1829,  seventeen  yards  were 
swept  away,  bringing  the  waters  to  the  foot  of  the  garden ;  and  in  1829  there  was 
depth  enough  for  a  frigate  (twenty  feet),  at  a  spot  where  a  cliff  of  fifty  feet  stood  forty- 
eight  years  before.  Farther  to  the  south,  the  ancient  villages  of  Shipden,  Wimpwell, 
and  Eccles  have  disappeared.  This  encroachment  of  the  sea  has  been  going  on  from 


664  DYNAMICAL   GEOLOGY. 

time  immemorial.     Many  examples  might  be  cited  from  the  American  coast;  but  none 
so  remarkable  have  yet  been  described. 

These  effects  of  the  sea  on  coasts  depend  on  (1)  the  height  of  the 
tides ;  (2)  strength  and  direction  of  tidal  currents  ;  (3)  direction  of 
the  prevalent  winds  and  storms  ;  (4)  force  of  the  waves  ;  (5)  nature  of 
the  rock  of  the  shores  ;  (6)  outline  of  the  coast. 

Soft  sandstones,  in  horizontal  layers,  and  beds  of  gravel  or  earth 
are  easily  removed.  The  harder  kinds  of  granyte,  gneiss,  quartz  rock 
and  trap  or  basalt,  undergo  usually  but  slow  wear,  while  other  kinds, 
looking  as  firm  but  really  subject  to  easy  decomposition,  fall  away 
rapidly  before  the  plunging  waters.  Projecting  headlands,  which  stand 
out  so  that  the  sea  can  batter  them  from  opposite  directions,  are  es 
pecially  exposed  to  degradation,  and  particularly  those  on  windward 
coasts. 

3.  The  wearing  action  of  waves  on  a  coast  is  mainly  confined  to  a 
height  between  high  and  low  tides.  —Since  a  wave  is  a  body  of  water 
rising  above  the  general  surface,  and  when  thus  elevated  makes  its 
plunge  on  the  shore,  it  follows  that  the  upper  line  of  wearing  action 
may  be  considerably  above  high-tide  level. 

Again,  the  lower  limit  of  erosion  is  above  low-tide  level ;  for  the 
waves  have  their  least  force  at  low  tide,  and  their  greatest  during  the 
progressing  flood ;  and,  when  the  waves  are  in  full  force,  the  rocks  be 
low  are  already  protected  by  the  waters,  up  to  a  level  above  low-tide 
mark.  There  is,  therefore,  a  level  of  greatest  wear,  which  is  a  little 
above  half -tide,  and  another  of  no  wear,  which  is  just  above  low-tide. 

This  feature  of  wave-action,  and  the  reality  of  a  line  of  no  wear, 
above  the  level  of  low  tide,  are  well  illustrated  by  facts  on  the  coasts 
of  Australia  and  New  Zealand. 

In  Figure  1096  (representing  in  profile  a  cliff  on  the  coast  of  New 
South  Wales,  near  Port  Jackson),  the  horizontal  strata  of  the  foot  of 
the  cliff  extend  out  in  a  platform,  a  hundred  yards  beyond  the  cliff. 

Fig.  1096.  Fig.  1097. 


Cliff,  New  South  Wales.  "  The  Old  Hat,"   New  Zealand. 

The  tide  rises  on  the  platform;  and  the  waves,  unable  to  reach  its 
rocks  to  tear  them  up.  drive  on  to  batter  the  lower  part  of  the  cliff. 
At  the  Bay  of  Islands,  New  Zealand,  the  rocks  have  no  horizontal 
stratification  ;  and  still  there  is  the  same  seashore  platform  ;  and  an 
island  in  the  bay  (Fig.  1097)  is  called  "  The  Old  Hat."  The  seashore 


THE   OCEAN.  665 

platform  of  coral  islands  has  the  same  origin.     The  stability  of  sand- 
flats  in  the  face  of  the  sea  is  owing  to  this  cause. 

In  seas  of  high  tides  and  frequent  storms,  the  platform  is  narrow  or 
wanting,  owing  to  the  tearing  action  of  the  heavier  waves. 

2.    Transportation. 

1.  Transportation  by  Currents.  —  The  great  oceanic  currents  are  too 
feeble  to  transport  any  material  coarser   than  the  finest  detritus,  and 
too  remote  from  coasts  to  receive  detritus  of  any  kind,  except  sparingly 
from  the  very  largest  of  rivers,  like  the  Amazon.     Whatever  sinks, 
in  the  main  course  of  the  Gulf  Stream,  is  carried  some  distance  south 
ward  again,  by  the  polar  current  beneath  it. 

Sea-weeds  are  borne  on  by  the  Gulf  Stream  in  great  quantities,  and 
thrown  off  on  the  inner  side  of  the  current,  into  the  great  area  of  still 
water  about  the  centre  of  the  North  Atlantic,  called,  from  the  common 
name  of  the  plant  (a  species  of  Fucus),  the  Sargasso  Sea.  With  the 
sea-weeds,  which  grow  as  they  float,  there  is  a  profusion  of  small  life, 
—  Fishes,  Crabs,  Shrimps,  Bryozoans,  etc. 

In  polar  seas,  where  there  are  glaciers  and  icebergs,  large  quantities 
of  gravel,  earth,  and  bowlders  are  often  floated  off  on  the  bergs. 
From  the  Arctic  region,  they  are  borne  south  by  the  polar  current  to 
the  Banks  of  Newfoundland  ;  there  the  icebergs  encounter  the  edge 
of  the  Gulf  Stream,  and  melt,  dropping  their  freight  over  the  bottom. 

Tidal  and  wind  currents  have  the  same  powers  of  transportation  as 
rivers  of  equal  velocity. 

2.  Transportation  by  Waves.  —  As  follows  from  the  force  of  waves 
against  shores,  stated  on  page  663,  they  have  great  transporting  power ; 
but  their  action  is  confined  to  narrow  limits  of  depth,  and  is  exerted 
mainly  when  the  plunging  waters  strike  upon  a  sandy  or  rocky  coast. 
Large  rocks   often  have   their   buoyancy  increased    by  the  sea-weeds 
attached  to  them. 

Stevenson  reports  that  a  block  of  gneiss,  of  504  cubic  feet  (about  forty -two  tons), 
lying  on  a  beach  (in  Scotland),  was  moved  five  feet  by  the  waves  during  one  storm,  and 
was  then  so  wedged  in  that  its  farther  progress  was  prevented.  The  in-coming  wave, 
as  it  strudk  it,  gave  it  a  shove,  and,  pushing  on,  buried  it  from  sight,  making  a  per 
pendicular  rise  of  thirty-nine  or  forty  feet;  and,  in  the  back-run,  the  mass  was  again 
uplifted  with  a  jerk. 

Marine  animals,  or  their  relics,  and  sea-weeds  are  thrown  abun 
dantly  on  coasts  by  the  waves  ;  and,  in  some  regions,  whales  that  ven 
ture  too  near  the  land  are  carried  up  and  left  floundering  on  the  sand. 
This  happens  not  un frequently  about  the  Chusan  Islands,  in  the  China 
Seas,  where  the  tidal  currents  have  great  force  (p.  661). 

In  the  case  of  the  heaviest  waves,  and  especially  earthquake-waves, 


666  DYNAMICAL    GEOLOGY. 

the  waters  first  retreat  to  an  unwonted  distance,  and  then  advance  in 
their  might,  striking  deep,  and  tearing  up  strata  that  at  other  times  are 
under  the  protection  of  the  waters. 

In  the  wave-movement  on  soundings,  and  not  close  in-shore,  the  pro 
pulsion  of  each  wave  is  very  small ;  and  its  power  of  accomplishing 
great  transporting  effects  lies  in  its  incessant  action.  The  waves  thus 
beat  back  the  detritus  thrown  out  by  rivers,  and  cause  them  to  be  de 
posited  mainly  over  the  bottom,  in  the  shallower  waters,  and  against 
the  shores,  and  so  prevent  their  being  lost  to  the  land  by  sinking  in 
the  depths  of  the  ocean. 

In  the  passage  of  the  great  wave  of  the  eagre  on  the  Tsien-tang  (p.  661 ),  the  boat?  float 
ing  in  the  middle  of  the  stream  rise  and  fall  on  the  tumultuous  waters,  but  are  carried 
only  a  verv  short  distance  forward.  Yet,  along  the  sides  of  the  river,  the  wave  tears 
away  the  banks,  and  at  times  sends  a  deluging  flood  over  the  shores.  (Am.  Jour.  Sci., 
II.  xx.  305.) 

It  follows,  from  the  facts  stated,  that  no  continent  can  contribute  to 
the  detrital  accumulations  of  another  continent,  except  through  the 
aid  of  icebergs.  Had  there  formerly  existed  a  continent  in  the  midst 
of  the  present  North  Atlantic,  America  would  have  receive/!  from  it 
little  or  no  rock-material.  The  tides  and  waves,  and  tidal  and  wave 
currents,  all  work  shoreward. 

3.  Distribution  of  Material,   and  the  Formation  of  Marine  and 
Fluvio-mariiie  Deposits. 

1.    Oceanic  Formations. 

Since  oceanic  currents  can  transport  only  the  finest  detritus,  the  depo 
sitions  from  them  can  be  of  no  other  kind  ;  no  conglomerates  or  coarse 
sandstones  can,  therefore,  be  made  from  them.  The  Gulf  Stream  has 
little  power  in  making  such  deposits,  as  it  carries  along  scarcely  any 
detritus.  The  bottom  of  the  Atlantic,  between  Ireland  and  Newfound 
land,  consists  almost  solely  of  the  shells  of  microscopic  organisms  (p. 
615)  ;  and  in  the  deeper  waters,  3,000  fathoms  down,  as  examined  by 
Wyville  Thomson,  there  is  a  red  ooze,  with  little  life  and  no  sand. 

By  means  of  icebergs,  the  currents  of  the  ocean  may  distribute 
widely  the  coarsest  of  rock-material ;  but  nearly  all  the  icebergs  of 
the  North  Atlantic  drop  their  loads  of  gravel  and  stone  in  the  vicinity 
of  the  American  continent,  and  not  in  mid-ocean.  The  deposits  made 
by  icebergs  consist  of  gravel,  sand,  and  stones  of  all  sizes,  up  to  many 
tons  in  weight,  promiscuously  mingled,  without  stratification.  They 
are  thus  unlike  the  ordinary  rock-formations  over  the  continent. 

Mr.  Babbage  has  shown  that,  taking  four  kinds  of  detritus,  of  such 
a  size,  shape,  and  density  that  they  would  sink  —  the  first  kind  10  feet 
an  hour,  the  second  8,  the  third  6,  the  fourth  4,  then,  if  a  stream  con- 


THE    OCEAN.  667 

taining  this  detritus  were  100  feet  deep  at  mouth,  and  entered  a  sea 
having  a  uniform  depth  of  1,000  feet,  and  a  rate  of  motion  of  two 
miles  an  hour,  the  first  kind  would  be  carried  1 80  miles,  before  the 
first  portions  would  reach  bottom,  and  would  be  distributed  along  for 
20  miles ;  the  corresponding  numbers  for  the  others  would  be  —  (2) 
225  and  25;  (3)  360  and  40;  (4)  450  and  50.  Thus,  four  kinds  of 
deposits  would  be  formed  from  the  same  stream,  at  different  distances 
from  its  mouth. 

2.  Formations  on  Soundings^  and  along  Coasts. 

1.  Origin  of  tlte  Material.  —  The  material  of  sea-shore  formations 
is  derived  from  two  sources:   (1)  the  detritus  of  rivers,  which  is  at 
present  the  principal  one,  though  not  so  in  Paleozoic  time ;   (2)  the 
wear  of  coasts. 

All  the  rivers  entering  an  ocean  bring  in  more  or  less  detritus, 
especially  during  freshets.  The  quantity  from  the  Mississippi  is  stated 
on  page  648.  The  amount  thus  contributed  to  the  ocean  depends  on 
the  geographical  extent  of  the  river-systems  bordering  it,  and  the 
annual  amount  of  rain,  snow,  etc.  In  both  these  respects,  North  and 
South  America  exceed  the  other  continents ;  and  the  ocean  which 
receives  the  most  detritus  is  the  Atlantic. 

2.  Distribution  and  Accumulation.  —  The  distribution  and  accumu 
lation  of  the  material   may  take  place  (1)  from-  the  action  of  waves 
alone;    (2)  from    waves   and   tidal   or  wind  -  currents ;    (3)  from  the 
waves,  the  shore-currents,  and  the  currents  of  rivers. 

(1.)  The  accumulations  made  by  leaves  are  in  the  form  either  of 
beaches  or  of  off-shore  deposits  of  detritus.  As  the  plunge  of  the 
wave  is  analogous  to  that  of  a  torrent,  its  waters,  while  grinding  the 
material  upon  which  they  act,  wash  out  the  finer  portion,  and  carry  it 
away  by  means  of  the  under-tow.  The  beach  consequently  consists 
of  more  or  less  coarse  material,  according  to  the  strength  of  the 
waves  :  it  may  be  sand,  pebbles,  or  even  large  stones,  if  the  rocks  of 
the  coast  are  of  a  nature  to  afford  them.  In  sheltered  bays,  where 
the  waves  are  small,  trituration  is  gentle  ;  and  the  material  of  the 
beach  may  be  a  fine  mud  or  silt. 

The  material  added  by  the  waters  is  deposited  partly  over  the 
sloping  surface,  and  partly  at  the  top  of  the  beach,  where  thrown  by 
the  toss  of  the  waves,  especially  in  storms.  The  former  is  necessarily 
bedded  or  laminated  parallel  to  the  beach  surface  ;  and  the  bedding 
has  consequently  its  slope,  or  ordinarily  5°  to  8°. 

The  height  of  a  beach  depends  on  the  height  of  the  tides  and  the 
strength  of  the  waves.  The  sands  thrown  beyond  the  farthest  reach 


668 


DYNAMICAL    GEOLOGY. 


of  the  waves  are  often  accumulated  into  higher  ridges,  and  make  the 
wind-drifts  and  dunes  described  on  page  631. 

(2.)  The  tidal  and  wind  currents  give  directions  to  the  material 
taken  up  by  the  waters.  This  material  may  be  the  sands,  pebbles, 
etc.,  of  a  beach,  or  the  finer  material  from  the  bottom,  or  the  mud 
stirred  up  from  greater  depths,  down  even  to  one  hundred  fathoms,  by 
the  heavy  waves  of  storms.  The  currents,  their  general  course  being 
otherwise  determined,  flow  where  they  find  the  freest  and  deepest 
passage,  and  drop  their  detritus  wherever  there  is  a  diminution  of 
velocity.  This  precipitation  takes  place  in  the  waters  thrown  ofPeither 
side  of  the  current,  and  especially  the  shoreward  side,  toward  which 
the.  waves  set  the  floating  material  ;  also,  where  capes  make  a  lateral 
eddy,  arid  where  any  obstruction  tends  to  retard  the  waters.  A  vessel 
sunk  in  the  passage  may  divert  the  waters  a  little  to  one  side,  where 
they  may  have  an  easier  flow,  and  become  itself  the  basis  of  an  accu 
mulating  sand-bank.  The  flow  of  the  tidal  wave  or  current  along  any 
coast,  while  aiding  in  fixing  the  limit  of  the  barrier,  often  transfers 
detritus  up  or  down  the  coast,  according  to  the  direction  of  the  move 
ment  ;  and  it  thus  tends  to  make  the  barrier  follow,  for  long  distances, 
a  nearly  even  line ;  so  that,  however  indented  such  a  coast  may  be 
after  a  change  of  level,  it  will  become  straightened,  if  the  waters  out 
side  are  shallow,  through  the  forming  barrier,  while  the  waters  shut  in 
by  the  barrier  may  still  have  an  irregular  inner  shore-line.  The  same 
action  assists  the  ebbing  tide  in  giving  form  and  length  to  sandspits, 
like  Sandy  Hook.  The  Hook,  according  to  A.  D.  Bache,  has  been 
elongating  at  the  rate  of  u  one  sixteenth  of  a  mile  in  twelve  years,'* 
since  the  first  precise  observations  were  made. 

This  point  is  well  illustrated  by  Captain  Davis,  in  his  excellent  paper  on  the  geolog 
ical  effects  of  tidal  action.  He  mentions  the  cases  of  long  points  thus  made  on  the 
eastern  extremity  of  Nantucket,  where  the  current  on  the  outside  of  the  island  sets 
from  the  west  to  the  east,  and  from  the  south  to  the  north.  Vessels  wrecked  on  the 

south  side  of  the  island  have  been  carried  by 

Fig.  1098.  it,  by  piecemeal,  eastward  and  then  northward, 

to  the  beach  north  of  Sankaty  Head.  The 
coal  of  a  Philadelphia  vessel,  lost  at  the  west 
end  of  the  island,  was  carried  around  by  the 
same  route  to  the  northern  extremity. 

Where  the  wind-current .  changes 
semi-aunually,the  accumulations  made 
by  the  current  when  flowing  in  one 
direction  are  sometimes  transferred  to 
another  side  of  an  island  or  point,  dur 
ing  the  next  half-year. 


_R 


THE    OCEAN. 


669 


J.  D.  Hague  states,  that  at  Baker  Island  (of  coral),  in  the  Pacific  (0°  15'  N.,  176°  22' 
W.),  this  fact  is  well  exhibited.  In  Fig.  1098.  I  I  I  is  the  southwest  point  of  the 
island,  and  II  R  K,  the  outline  of  the  coral-reef  platform,  mostly  a  little  above  low- 
tide  level;  its  width,  c  d,  100  yards.  In  the  summer  season,  when  the  wind  is  from 
the  southeast,  the  beach  has  the  outline  s,  s,  s ;  during  the  winter  months,  when  the 
wind  is  northeast,  the  material  is  transferred  around  the  point,  and  has  the  position 
«?,  w,  u-,  having  a  width  at  a  b  of  200  feet.  A  vessel  wrecked  in  summer,  and 
stranded  at  Y,  was  transferred  to  V  in  the  course  of  the  month  of  November. 


Fig.  1099. 


(3.)  The  combination  of  wave-action  and  marine  currents  ivith  the 
currents  of  rivers  produces  results  analogous  to  those  proceeding  from 
marine  currents  and  waves  alone,  but  with  greater  complication,  and, 
in  the  present  age,  of  far  greater  extent,  because  rivers  add  so  vastly 
to  the  material  of  deposits  by  their  detritus. 

The  flow  of  rivers  and  the  movements  of  the  ocean  are,  in  general, 
in  direct  opposition.  The  in-flowing  tide  sets  back  the  rivers,  quiets 
the  waters,  and  floods  the  adjoin 
ing  tidal  flats  ;  and,  consequently,  a 
deposition  of  detritus  takes  place 
over  the  flats,  and  especially  about 
the  mouth  of  the  stream.  The  turn 
of  the  tide  sets  the  river  again  in 
full  movement;  and  it  takes  up 
the  detritus  deposited  over  its  bed 
(but  only  little  of  what  fell  over 
the  flats),  and  bears  it  to  the  ocean. 
Here,  the  current  loses  much  of  its 
velocity,  in  the  face  of  the  waves, 
and  with  the  spreading  of  the  wa 
ters  ;  and  hence  a  deposition  of  de 
tritus  goes  on  in  the  shallow  sea, off 
the  mouth  of  the  stream ;  and  this 
continues  until  the  next  tidal  flow 
dams  up  the  fresh-water  stream 
anew.  Between  the  tidal  currents, 
especially  the  in-flowing,  and  the 
river,  there  is  a  region  of  com 
parative  equilibrium  in  the  two 
movements ;  and  there  the  accu 
mulations  Of  sand  Or  detritus  take  riuvio-mariue  formation  along  the  coast  of 

place,  forming  sand-bars.  North  Carolina. 


Humphreys  and  Abbot  observe,  in  speaking  of  the  Mississippi  delta,  that,  as  the  river- 
water  rises  above  the  salt  water,  from  its  low  density,  there  is  a  dead  angle  between  the 
two.  The  current  out  of  the  Passes  pushes  sand  and  earth  before  it,  until,  reaching,  it 


C70  DYNAMICAL    GEOLOGY. 

begins  to  ascend  upon  the  salt  water  of  the  Gulf;  and  here  this  material  "is  left  upon 
the  bottom,  in  the  dead  angle  of  salt  water.  A  deposit  is  thus  formed,  whose  Surface 
is  along  or  near  the  line  upon  which  the  fresh  water  rises  on  the  salt  water,  as  it  enters 
the  Gulf  ;  and  this  action  produces  the  bar." 

The  distance  of  these  sand-bars  or  barriers,  off  the  mouth  of  a 
river,  will  depend  on  the  size  and  strength  of  the  rivers  on  one  side, 
and  the  height  and  force  of  the  tides  on  the  other.  Small  streams 
are  often  blocked  up  entirely,  by  a  sand-bar  across  their  mouths  ; 
and  the  waters  reach  the  ocean  only  by  percolation  through  the  beach. 
Large  streams  make  distant  sand-reefs  and  barriers,  even  in  the  face 
of  the  ocean.  The  North  American  coast,  from  Long  Island  to 
Florida,  is  fronted  by  ranges  of  barrier  reefs,  shutting  in  extended 
sounds  or  narrow  lagoons. 

The  preceding  map  of  Pamlico  Sound  and  the  region  about  Cape 
Hatteras  (Fig.  1099)  illustrates  this  feature  of  the  continent. 

The  numerous  rivers  of  this  well-watered  coast  carry  great  quan 
tities  of  detritus  to  the  ocean,  part  of  which  is  borne  out  to  sea,  to 
raise  the  great  submarine  plateau  of  the  coast ;  and  another  part  is 
added  to  the  barrier  and  to  the  banks  and  flats  of  the  Sound.  The 
contraction  of  the  Sound,  which  is  going  on  by  the  additions  to  the 
flats  and  over  its  bottom,  gradually  prolongs  the  channel  of  the  river 
toward  the  ocean.  This  gives  greater  force  to  the  river-current ;  and 
it  acts  in  conjunction  with  the  strong  ebb-tide,  against  the  inner  side  of 
the  barrier,  in  slowly  wearing  it  away.  At  the  same  time,  the  outflow 
ing  stream  and  tidal  current  carry  a  greater  quantity  of  detritus  into 
the  ocean,  contributing  sand  to  the  beach  and  finer  detritus  to  the 
plateau,  the  nature  of  wave-action  on  a  beach  being  such  as  to  leave 
only  the  sand  or  coarser  material.  Thus,  by  a  slow  process,  the  main 
land  gains  in  breadth,  and  the  river  in  length  ;  and  the  barrier  moves 
gradually  seaward.  In  other  cases,  the  lagoons  inside  of  the  barrier 
become  filled ;  and  a  continuous  marsh,  and  ultimately  dry  land,  is 
made,  out  to  the  barrier.  All  the  low  lands  along  the  eastern  coast  of 
the  continent,  and  that  bordering  on  the  Gulf  of  Mexico,  in  most 
parts  many  scores  of  miles  in  breadth,  have  been  made  in  the  manner 
here  pointed  out. 

When  the  tides  are  very  small,  or  foil  altogether,  the  rivers  may 
reach  the  sea  by  many  mouths,  without  the  formation  of  barriers,  or, 
in  other  words,  may  form  true  deltas.  The  height  of  the  tide  of  the 
Mexican  Gulf,  along  the  north  shore,  is  but  twelve  to  fifteen  inches  ; 
and,  consequently,  while  most  of  the  streams,  before  even  this  small 
tide,  have  their  bars  and  barriers,  the  great  Mississippi  sends  its  many 
arms  far  out  into  the  Gulf,  prolonging  its  channels  in  the  face  of 
winds,  waves,  and  tide  (Fig.  1093,  p.  652).  Incipient  sandbars  at  times 


THE    OCEAN.  671 

form  ;  but  these  serve  only  to  divide  one  of  the  great  channels,  and 
make  a  new  branch. 

The  structure  of  the  formations,  made  from  river  and  oceanic  action 
combined,  has  been  described  in  connection  with  the  remarks  on  deltas, 
on  page  651.  Sand-flat  formations  are  made  of  sand,  because  the 
movement  of  the  waves  is  sufficient  in  force  to  carry  off  the  finer 
material.  The  stratification,  or  bedding,  is  parallel  to  the  general  sur 
face  of  the  flat,  because  the  successive  additions  are  laid  over  this  sur 
face  ;  consequently,  the  bedding  will  be  horizontal,  or  nearly  so.  The 
sand-beds,  where  in  shallow  waters,  and  washed  over  by  the  tidal  cur 
rents,  have  often  the  layers  obliquely  laminated  (Fig.  61,  p.  82)  ; 
and,  as  the  in-going  tidal  current  moves  with  the  greatest  force,  this 
lamination  usually  dips  toward  the  direction  from  which  this  current 
comes,  or  rises  in  the  opposite  direction.  The  deposits  in  shallow 
waters  off  a  coast  are  usually  of  sand  or  mud  —  river  detritus  and  the 
detritus  from  the  wear  of  the  sands  and  pebbles  of  the  sea-shores  being 
the  material  of  which  they  consist.  They  have  sometimes  great  breadth, 
as  over  the  submerged  plateau  off  the  coast  of  New  Jersey,  which  is 
fifty  to  eighty  miles  wide.  And,  as  the  bottom  varies  inappreciably 
from  horizontality,  the  stratification  or  lamination  will  be  equally  hori 
zontal.  Where  there  are  strong  flows  of  the  tide  between  islands  and 
the  mainland,  or  among  groups  of  islands,  the  material  may  be  in  part 
pebbly  ;  and  oblique  lamination  may  be  a  feature  of  the  beds.  Over  in 
terior  oceanic  basins,  as  well  as  off  a  coast  in  quiet  depths,  fifteen  or 
twenty  fathoms  and  beyond,  the  deposits  are  mostly  of  fine  silt,  fitted 
for  making  fine  argillaceous  rocks,  as  shales  or  slates.  When,  however, 
the  depth  of  the  ocean  falls  off  below  a  hundred  fathoms,  the  deposi 
tion  of  silt  in  our  existing  oceans  mostly  ceases,  unless  in  the  case  of 
a  great  bank  along  the  border  of  a  continent. 

As  heretofore  stated,  the  material  of  the  bottom  of  the  submerged  plateau,  above 
referred  to,  outside  of  a  depth  of  one  hundred  feet,  consists  at  surface  largely  of 
Rhizopod  shells.  Off  southern  New  England,  at  depths  between  300  and  550  feet, 
from  a  region  southeast  of  Montauk  Point  to  that  southeast  of  Cape  Henlopen,  the 
soundings,  according  to  Bailey  (Smithsonian  Contrib.,  ii.,  and  Am.  Jour.  Sci.,  II.  xvii. 
176,  xxii.  282),consist  chiefly  of  these  shells.  At  greater  depths,  beyond  the  limit  of  the 
plateau,  Pourtales  found  almost  a  pure  floor  of  Rhizopods  (Trans.  Am.  Assoc.  for  1850, 
84,  and  Rep.  Coast  Survey  for  1853  and  1858);  and  the  facts  have  been  confirmed  by 
later  investigation.  The  species  are  deep-water  forms,  differing  thus  from  those  of  the 
New  Jersey  Cretaceous  beds.  Pourtales  observes,  in  a  letter  to  Professor  Bache  (dated 
May  17,  1862),  that,  along  the  plateau  between  the  mouth  of  the  Mississippi  and  Key 
West,  for  two  hundred  and  fifty  miles  from  the  mouth,  the  bottom  consists  of  clay, 
with  some  sand  and  but  few  Rhizopods;  but,  beyond  this,  the  soundings  brought  up 
either  Rhizopod  shells  alone,  or  these  mixed  with  coral  sand,  Nullipores,  and  other 
calcareous  organisms. 

As  microscopic  life  abounds  in  harbors  where  rivers  make  frequent  depositions  of 
sediment,  the  presence  of  a  considerable  proportion  of  Rhizopods  is  consistent  with  an 
annual  increase  of  the  plateau  from  sedimentary  depositions. 


672  DYNAMICAL    GEOLOGY. 

Ripple-marks  are  often  made  by  the  waves  over  the  finer  beach- 
sands,  where  they  are  low  and  partly  sheltered,  and  also  over  mud 
flats.  The  flowing  water  pushes  up  the  sand  into  a  ridgelet,  as  high 
as  the  force  can  make,  and  then  plunges  over  the  little  elevation  and 
begins  another ;  and  thus  the  succession  is  produced.  The  height  and 
breadth  of  the  intervening  space  will  depend  on  the  force  and  velocity 
of  the  flowing  water,  and  the  ease  with  which  the  sand  or  mud  is 
moved.  Ripple-marks  may  be  made,  by  the  vibration  of  waves,  even 
at  depths  of  300  to  500  feet. 

When  a  wave  dies  out  on  a  beach,  it  sometimes  leaves  a  tracing  of 
its  sweep  on  the  sand,  as  a  wave-line  ;  and  the  returning  waters,  flow 
ing  by  any  half-buried  shell  or  stone,  may  make  rills  in  the  sand,  or 
rill-marks  (Fig.  63,  p.  83). 

Broken  shells,  and  other  marine  relics  in  fragments,  are  common  in 
beach-deposits.  Below  high-tide  level,  there  may  be  the  vertical  bor 
ings  of  sea-worms,  of  certain  Crustaceans  (as  species  of  the  Callia- 
nassa  family),  and  of  some  Mollusks.  In  the  off-shore  shallow  waters, 
occur  beds  of  living  Mollusks,  and  other  kinds  of  animals,  as  well  as 
plants,  varying  according  to  the  depth. 

4.    Action    of  the    Oceanic  Waters   over   a   submerged    Continent, 
and  during  a  progressing  Submergence  or  Emergence. 

1.  Marine  Deposits.  —  The  most  obvious  effect  of  the  slow  submer 
gence  of  a  continent  beneath  the  waters  of  the  ocean  would  be  the 
working  over,  by  the  waves   and  marine  currents,  of  the  loose  earth, 
gravel,  and  alluvium  of  the  surface,  thereby  changing  them  into  marine 
deposits.     The  depth  to  which  this  alteration  would  extend  would,  for 
the  most  part,  be  much  less,  probably,  than  a  hundred  feet.     What 
ever  the  extent,  the  ocean,  besides  exterminating  living  species,  would 
obliterate  most  of  the  remains  of  terrestrial  life  in  the  altered  deposits, 
and  introduce  its  own  living  Mollusks  and  other  tribes,  throughout  the 
new  continental  seas. 

2.  Features  of  the   surface   not  altered  by  an  excavation  of  valleys, 
but  by  a  diminution  of  its  heights  and  a  filling  of  preexisting  valleys. 

It  might  be  supposed,  at  first  thought,  that  the  ocean  would  wash 
through  the  valleys  with  great  excavating  force,  and  make  deep 
gorges  over  the  surface.  The  real  effect  will  be  best  learned  from  the 
present  action  on  sea  coasts  ;  for,  with  every  foot  of  submergence,  the 
sea-beach  would  be  set  a  little  farther  inland,  so  that  the  whole  would 
successively  pass  through  the  conditions  of  a  seashore.  On  existing 
seashores,  the  action  in  progress,  instead  of  tending  to  excavate  val 
leys,  produces  just  the  contrary  effect.  It  is  everywhere  wearing  off 
exposed  headlands,  and  filling  up  bays.  The  salt  waters,  in  fact,  enter 


THE   OCEAN.  673 

but  a  short  distance  the  river-valleys  of  a  coast,  because  they  are  ex 
cluded  by  the  out-Howing  stream.  The  bottom  of  the  Hudson  is 
below  the  sea-level,  for  a  long  distance  beyond  the  limit  to  which  the 
pure  ocean-water  extends :  the  same  is  true  of  the  St.  Lawrence,  and 
of  many  other  rivers  along  the  coast.  During  a  progressing  sub 
mergence,  therefore,  the  ocean  would  have  no  power  of  excavating 
narrow  valleys,  unless  they  happened  to  be  open  at  both  ends,  so  as  to 
allow  the  oceanic  currents  to  sweep  through. 

As  the  submergence  progressed,  there  would  be,  through  wave- 
action,  extensive  degradation  of  the  ridges  and  mountains  over  the 
surface,  and  a  distribution  of  the  detritus  through  the  intervening  de 
pressions.  In  a  subsequent  emergence  of  the  land,  the  mountains  and 
ridges  would  be  still  further  degraded,  and  the  valleys  filled  by  their 
debris.  The  laws  of  sea-coast  action  would  again  come  into  play,  and 
the  wear  of  all  new  headlands,  and  the  filling  of  bays,  continue  to  be 
the  result,  so  long  as  the  emergence  was  in  progress. 

3.  Formation  of  marine  deposits,  when  a  continent  is  mostly  without 
mountain-ranges  and  valleys. 

If  the  continent  were  to  a  large  extent  without  mountains,  the 
broad  flat  surface  might  then  lie  slightly  above  or  below  tide-level 
at  once,  or  rlearly  simultaneously,  so  that,  under  a  small  change  of 
level,  the  waves  could  sweep  across  the  whole  area.  It  has  been 
shown  that  the  Appalachian  Mountains  were  not  raised  until  after  the 
Carboniferous  age,  and  the  greater  part  of  the  Rocky  Mountains  not 
before  the  close  of  the  Cretaceous  period.  The  North  American  con 
tinent  was,  therefore,  in  early  time,  in  the  condition  here  supposed  ; 
and  the  older  formations  have  a  corresponding  extent  and  character. 
The  tidal  arid  oceanic  currents  were  almost  the  only  transporters  of 
detritus  ;  and  these  agents  worked,  in  one  place  or  another,  according 
to  all  those  various  methods  which  have  been  above  described.  There 
were  continental  oscillations,  causing  slight  emergences  of  large  areas 
to  alternate  with  varying  submergences ;  and,  through  such  changes, 
the  variations  in  the  formations  were  produced,  differences  of  depths 
and.  differences  of  currents  causing  transitions  from  arenaceous  to 
argillaceous  or  to  pebbly  accumulations;  and  the  differences  required 
for  such  changes  were  so  small  that  the  probability  of  finding  the 
cotemporaneous  fragmental  deposits  of  Europe  and  America,  or  even 
of  distant  parts  of  one  continent,  alike  arenaceous,  argillaceous,  or 
pebbly,  is  exceedingly  small. 

The  ocean,  like  fresh-water  streams,  has  been  greatly  aided  in  its 
geological  work  by  slow  chemical  change,  going  on  over  the  surfaces 
of  exposed  rocks,  often  causing  them  to  crumble  slowly,  or  to  peal 

43 


674  DYNAMICAL    GEOLOGY. 

off  in  slabs.  It  also  owes  much  of  its  efficiency  to  the  fact  that  even 
the  hardest  rocks  are  generally  much  jointed,  that  is,  full  of  pro 
found  cracks,  which  give  the  waters  a  chance  to  gain  entrance  arid 
leverage.  It  has  had  further  help  in  the  frequent  alternation  of  softer 
strata  with  the  hard ;  so  that  a  little  hammering  at  the  former,  if 
nearest  the  water's  edge,  would  bring  the  latter  down  in  fragments 
within  reach. 

The  features  resulting  from  degradation  are,  for  the  most  part,  the 
same  that  are  described  on  pages  645,  646,  as  consequences  of  denu 
dation  from  river  action. 

3.  FREEZING  AND  FROZEN  WATER. 

Water  performs  part  of  its  geological  work  in  the  act  of  freezing, 
and  another  part  when  frozen,  in  the  condition  of  snow  and  ice. 

1.  WATER  FREEZING. 

Rending  and  Disintegration  from  Expansion.  —  Since  fresh  water 
expands  as  the  temperature  falls  below  39i°  F.,  until  it  freezes,  freezing 
in  the  seams  of  rocks  opens  those  seams,  tears  rocks  asunder,  and 
tumbles  fragments  and  masses  down  precipices  ;  or,  in  porous  strata, 
it  crumbles  off  the  surface,  and  causes  disintegration.  Consequently, 
bluffs  in  a  cold  climate,  like  the  trap  hills  of  Connecticut  and  the 
Highlands  of  the  Hudson,  have  a  long  talus  of  broken  stone,  made 
mainly  by  this  means,  —  while,  in  a  tropical  climate,  the  precipices  are 
generally  free  from  fragments.  This  kind  of  degradation  goes  on 
incessantly  in  all  icy  regions,  where  there  are  melting  and  freezing,  and 
may  have  originated  much  of  the  soil  and  drift  material  of  the  globe. 

2.  ICE  OF  RIVERS  AND  LAKES. 

Ice,  forming  along  streams  in  which  there  are  stones,  envelops  the 
stories  in  shallow  water,  even  to  a  depth  of  two  or  three  feet,  or  more 
in  the  colder  climates.  Other  stones  and  earth  fall  on  the  ice  from 
the  banks.  When  the  floods  of  spring  raise  the  stream,  and  break  up 
the  ice,  both  ice  and  stones  often  float  down  stream  with  the  current, 
or  are  drifted  up  the  banks  high  above  their  former  level,  of  are 
spread  over  the  river-flats. 

Ice  sometimes  forms  about  stones  in  the  bottom  of  rivers,  when  the 
rest  of  the  water  is  not  frozen,  and  is  then  called  anchor-ice.  In  this 
condition,  it  may  serve  as  a  float  to  raise  the  stones,  and  to  transport 
them,  with  the  aid  of  the  current. 

The  same  modes  of  transportation  are  exemplified  in  lakes  as  in 
rivers,  except  that  there  is  less  current ;  and  the  stones  are  mostly  set 


ICE.  675 

back  up  the  shore.     Large  accumulations  of  stray  stones  far  above 
the  ordinary  level  of  the  lake  are  in  some  places  thus  made. 

Ice'  over  a  pond,  when  thick,  by  its  expansion  often  pushes  with 
great  force  against  the  shores,  moving  what  is  movable  on  it,  or,  if 
it  be  confined  by  a  narrow  bank,  will  sometimes  push  the  bank  out 
of  place. 

3.  GLACIERS. 

I.  General  Features,  Formation,  and   Movement  of  Glaciers. 

1 .  Nature  of  Glaciers.  —  Ordinary  glaciers  are  accumulations  of  ice, 
descending  by  gravity   along  valleys  from   snow-covered  elevations. 
They  arc  ice-streams,  200  to  5,000   feet   deep  or  more,  fed  by  the 
snows  and  frozen  mist  of  regions-  above  the  limits  of  perpetual  frost. 
They  stretch  on  4,000  to  7,500  feet  below  the  snow-line  (limit  of  per 
petual  snow),  because  they  are  so   thick  masses  of  ice  that  the  heat 
of  the  summer  season  is  not  sufficient  to  melt  them.     Some  of  them 
reach  down  between  green  hills  and  blooming  banks,  into  open  culti 
vated  valleys.     The  extremities  of  the  glaciers  of  the  Grindelwald 
and  Chamouni  valleys  lie  within   a  few  hundred   feet  of  the  gardens 
and  houses  of  the  inhabitants.     Each  glacier  is  the  source  of  a  stream, 
made  from  the  melting  ice.     The  stream  begins  high  in  the  mountains, 
from  the  waters  that  descend  through  the  crevasses  to  the  ground 
beneath,  and  often  makes  a  tunnel  in  the  ice  above  its  course  ;  finally, 
it  gushes  forth  from  its  crystal  recesses,  a  full  torrent,  and  hurries 
along  over  its  stony  bed  down  the  valley. 

2.  Glacier  Regions  —  The  best  known  of  glacier  regions  is  that  of 
the    Alps.      West   of  the   head-waters    of  the    Rhone,  the   chain    is 
divided  into  two  nearly  parallel  ranges,  a  southern  and  a  northern. 
The  latter  includes,  besides  minor  areas,  two  large  glacier  districts,  — 
the  Mt.  Blanc,  and  the  Mt.  Rosa  or  Zermatt  district ;  and  the  former, 
one  of  equal  extent,  though  its  peaks  are  less  elevated,  —  that  of  the 
Bernese  Oberland.     There  is  another  district  of  glaciers  at  the  head 
waters  of  the  Rhone,  and  others  farther  eastward. 

Glaciers  occur  also  in  the  Pyrenees,  the  mountains  of  Norway, 
Spitzbergen,  Iceland,  the  Caucasus,  the  Himalayas,  the  southern  ex 
tremity  of  the  Andes,  in  Greenland,  and  on  Antarctic  lands.  One 
of  the  Spitzbergen  glaciers  stretches  eleven  miles  along  the  coast,  and 
projects  in  icy  cliffs  100  to  400  feet  high.  The  great  Humboldt 
glacier  of  Greenland,  north  of  79°  20',  has  a  breadth  at  foot,  where  it 
enters  the  sea,  of  forty-five  miles ;  and  this  is  but  one  among  many 
about  that  icy  land.  Some  American  glaciers  are  alluded  to  on  page 
536. 

3.  Many  Glaciers  from  one  Glacier  District.  —  The  following  map 


676  DYNAMICAL   GEOLOGY. 

(Fig.  1100)  represents  the  Mt.  Blanc  glacier-region,  excepting  a 
small  part  at  its  southwestern  extremity.  The  vale  of  Chamoimi 
along  the  river  Arve  bounds  it  on  the  northwest,  and  the  valley  of 

Figs.  1100-1104. 


Fig.  1100.  —  Part  of  the  glacier-district  of  Mt.  Blanc,  the  lighter  middle  portion  of  the  map  six 
teen  miles  long,  out  of  twenty-two  miles  the  whole  length ;  river  on  the  northwest  side,  the  Arre, 
in  the  valley  of  Chamouni,  and  that  on  the  southeast  side,  the  Doire  ;  B,  Mt.  Blanc;  G,  Aiguille 
du  Geant ;  J,  the  Jardin  ;  T.  Aig.  du  Tour  ;  V,  Aig.  Verte  ;  a,  Argentiere  Glacier  ;  ba,  Br^nva 
Gl.  ;  bn,  Bossons  Gl. ;  bs,  Bois  Gl.  ;  g,  Geant  or  Tacul  Gl. ;  /,  Lechaud  Gl.  ;  m,  Mer  de  Glace,  up 
per  part  of  the  Bois  Gl.  ;  mg,  Miage  Gl.  ;  ta,  Talefre  Gl. ;  tr,  Tour  Gl. ;  tt,  Trient  Gl. 

Fig.  1101.  —Section  of  the  Mer  de  Glace,  near  m  of  Fig.  1100,  or  opposite  Trelaporte  ;  1102,  sec 
tion  of  same,  near  bs  of  Fig.  1100,  or  opposite  Montauvert ;  1103,  View  of  the  Rhone  Glacier;  1104, 
profile  of  same.c,  r,  etc.,  being  the  transverse  crevasses,  fading  out,  and  becoming  curved  after 
passing  the  cascade  at  m  n . 


GLACIERS. 


677 


the  river  Doire  on  the  southeast.  This  mountainous  area,  though  one 
vast  field  of  snow,  gives  origin  to  numerous  glaciers  on  its  different 
sides,  —  each  principal  valley  having  its  ice-stream.  The  series  of 
dotted  curves  show  the  courses  of  the  several  glaciers.  B  is  Mt. 
Blanc  ;  bs,  the  Glacier  des  Bois,  or  Bois  Glacier  (so  named  from  a 
village  near  the  foot  of  the  glacier)  ;  m,  the  Mer  de  Glace,  an  upper 
portion  of  this  glacier.  The  river  Arveiron  issues  from  the  extremity 
of  the  glacier,  and,  after  a  short  course,  joins  the  Arve  near  the 
village  of  Chamouni.  The  glaciers  «  du  Ge'anf  (#),  "du  Talefre" 
(#«),  and  "  de  Lechaud  "  (/),  are  the  three  largest  of  the  upper  glaciers 
which  combine  to  form  the  Mer  de  Glace.  The  Glacier  du  Talefre 
heads  in  two  valleys  ;  and  at  J,  on  the  ridge  between,  is  the  Jardin,  a 
spot  with  some  verdure,  often  visited  by  travellers.  The  depth  of  the 
Mer  de  Glace  is  about  350  feet. 

4.  General  Appearance.  —  Fig.  11 05  is  a  reduced  copy  of  a  sketch 
in  Agassiz'  great  work,  representing  the  Glacier  of  Zermatt,  or  the 
Gorner  Glacier,  in  the  Mt.  Rosa  region.  This  grand  glacier  receives 

Fig.  1105. 


The  Corner  Glacier. 


some  of  its  tributaries  from  the  right,  but  the  larger  part  from  beyond 
the  Riffelhorn,  the  near  summit  on  the  left.     The  dark  bands  on  the 


678  DYNAMICAL    GEOLOGY. 

glacier  are  lines  of  stones  and  earth,  called  moraines.  The  longitudi 
nal  lines  on  Fig.  1101  represent  moraines  on  the  Mer  de  Glace;  the 
bands  correspond  to  different  tributaries  of  this  glacier,  and  the  broad 
est  one  to  the  right  is  that  of  the  Geant  Glacier.  The  ice  of  a  glacier 
is  intersected  by  fractures  or  crevasses,  made  by  its  movement  through 
the. irregular  valley. 

Glaciers  descend  slopes  of  all  angles  ;  and,  as  with  water  or  pitch, 
will  move  over  a  horizontal  surface,  provided  the  supply  of  material  is 
constant  and  sufficiently  great.  There  are  cataracts  and  cascades  among 
them,  as  well  as  among  rivers.  One  of  the  large  tributaries  of  the 
Mer  de  Glace,  the  Glacier  du  Geant  (#,  Fig.  1100),  descends  in  an 
immense  ice-cascade  from  the  plateau  of  the  Col  du  Geant,  over  a  ver 
tical  rock  wall  of  the  Tacul,  into  the  valley  below,  making  a  plunge 
of  140  feet.  The  Glacier  of  the  Ehone  —  one  of  the  grandest  in  the 
Alps  —  is  another  ice-cataract.  As  the  glacier  commences,  its  steep 
descent,  it  becomes  broken  across ;  and  thus  great  sections  of  it  plunge 
on  in  succession,  separated  partly  by  profound  traverse  chasms.  Fig. 
1103  gives  the  outline  of  the  lower  part  of  the  glacier,  am  being  the 
cataract,  mb,  its  terminal  portion  or  foot,  from  the  extremity  of  which 
the  river  Rhone  issues,  and  c,  c,  c,  transverse  crevasses  of  the  cascade. 
The  same  is  shown  in  profile  in  Fig.  1104,  in  which  c,  c,  c  are  the 
transverse  crevasses. 

Other  glaciers,  in  some  of  the  higher  valleys  of  the  Alps,  reach  the 
edges  of  precipices,  to  descend,  perhaps  thousands  of  feet,  in  crashing 
avalanches,  in  which  the  ice  is  broken  to  fragments. 

5.  Formation  of  Glaciers.  —  The  uppermost  portion  of  a  glacier 
consists  of  snow  and  frozen  mist,  deposited  in  successive  portions,  and 
usually  more  or  less  distinctly  stratified.  This  part  is  called  tliejirn, 
or  neve.  At  a  lower  limit,  the  snow  becomes  compacted  into  ice, 
by  pressure,  owing  to  the  depth  of  the  accumulations  ;  and  here  the 
true  glacier-portion  begins.  Below  the  limit  of  perpetual  frost  there 
is  occasional  melting  in  summer,  with  alternate  freezing ;  and  this  pro 
cess  aids  in  changing  the  mass,  as  well  as  the  surface-snow,  to  ice.  The 
stratification  of  the  neve  is  not  generally  distinct  in  the  icy  glacier. 

The  following  circumstances  are  essential  to,  or  injluence,  the  forma 
tion  of  glaciers. 

(1.)  The  region  must  extend  above  the  line  of  perpetual  congela 
tion. 

(2.)  Abundant  moisture  is  as  important  as  for  rivers ;  and  hence 
one  side  of  a  chain  of  mountains  may  have  glaciers,  while  the  opposite 
is  bare.  Abundant  precipitation  in  winter  especially  favors  their 
formation. 

(3.)  A  difference  of  temperature  and  moisture  between  summer  and 


GLACIERS.  679 

winter  is  requisite ;  for  otherwise  the  snows  will  be  melted  to  the  same 
line  throughout  the  year,  and  will  not  descend  much  below  the  line  of 
perpetual  congelation. 

The  level  of  the  snow-line,  or  that  below  which  the  snow  annually 
precipitated  melts  away  during  the  year,  and  the  distance  to  which 
glaciers  descend,  depend  mainly  on  the  mean  temperature  and  moisture 
of  the  region,  and  especially  the  mean  temperature  of  summer  as  con 
trasted  with  that  of  winter.  The  height  of  the  snow-line  on  the  north 
side  of  the  Alps  is  about  8,000  feet,  and  on  the  southern  side  about 
8,800  feet.  Below  this  limit,  the  glaciers  descend  4,500  to  5,300  feet, 

The  snow-line  in  the  Pyrenees  is  8,950  feet  above  tide  level;  in  the  Caucasus,  10,000 
to  11,000  feet;  on  the  south  side  of  the  Himalayas,  12,980  feet,  and  on  the  north, 
16,620  feet;  at  the  equator,  in  the  Andes,  15,980  feet;  in  Bolivia,  18,520  feet  in  the 
western  Cordillera,  and  15,920  in  the  eastern;  in  Mexico,  14,760  feet;  in  Chili,  near 
Santiago,  12,780  feet;  in  Norway,  5,000  feet  in  its  middle  portion,  and  2,300  feet  at  its 
northern  extremity;  in  Kamchatka,  5,200  feet;  in  Alaska,  5,500  feet. 

The  lower  limit  of  a  glacier  sometimes  varies  several  miles, in  the 
course  of  a  series  of  years.  A  succession  of  moist  years  increases 
the  thickness  of  the  glacier,  and  thereby  its  tendency  downward  ; 
while  dry  years  have  the  reverse  effect.  If  the  moist  years  have  also 
long,  hot  summers,  the  descent  and  lengthening  of  the  glacier  will  be 
further  promoted,  —  since  glaciers  move  most  rapidly  in  summer. 
But  hot,  dry  years  would  shorten  it,  bv  diminishing  the  ice,  and  espe 
cially  at  the  lower  end. 

Lowering  the  mean  temperature  of  a  place,  by  cooling  the  summers,  would  lower  the 
glacier-limit.  Great  Britain  and  Fuegia  are  in  nearly  the  same  latitude ;  and  yet,  in 
Fuegia,  the  snow-line  is  only  3,000  feet  above  the  sea.  If,  by  any  means,  the  climate 
of  Great  Britain  could  be  reduced  to  that  of  Fuegia,  it  would  cover  the  Welsh  and  Irish 
mountains  with  glaciers  that  would  reach  the  sea,  the  snow-line  being  but  1,000  to  2,000 
feet  above  it;  and  the  same  cause  would  place  the  snow-line  in  the  Alps  at  5,000  to 
6,000  feet  above  the  sea.  instead  of  9,000.  This  change  of  temperature  involves  a 
removal  of  tropical  sources  of  heat,  or  an  increase  of  arctic  sources  of  cold. 

6.  The  Law,  Rate,  and  Method  of  Flow.  —  The  law  of  flow  is  essen 
tially  that  of  rivers. 

(1.)  The  movement  in  a  glacier  is  most  rapid  at  or  near  the  middle 
line  of  the  stream,  and  least  so  along  the  sides,  because  of  friction 
along  the  sides. 

(2.)  The  movement  is  most  rapid  at  top  and  least  so  at  bottom,  be 
cause  of  the  friction  at  bottom.  No  atmospheric  friction  retards  the 
movement  at  surface,  owing  to  its  extreme  slowness. 

(3.)  Where  there  is  a  bend  in  the  stream,  the  movement  is  more 
rapid  on  the  convex  side  of  the  glacier  than  on  the  concave  ;  and  the 
medial  line  of  greatest  rapidity  is  nearest  the  convex  side. 

(4.)  When  the  stream  abruptly  narrows,  the  ice  just  above  becomes 


680  DYNAMICAL   GEOLOGY. 

more  or  less  heaped,  and  slower  in  movement ;  and  then  it  moves 
through  the  narrows  below,  with  a  consequently  increased  rate  of 
flow. 

(5.)  The  rate  of  movement  of  the  glacier  as  a  whole  depends  on  the 
following  conditions  :  — 

(a.)  The  amount  and  rate  of  supply  of  moisture  precipitated  as 
snow. 

(5.)  The  slope  of  the  upper  surface  of  the  glacier  :  which  slope  is 
determined,  in  ordinary  cases,  partly  by  the  supply  of  snow  to  the 
glacier,  over  its  upper  portions,  and  partly  by  the  slope  and  form  of 
the  land  beneath  ;  but  the  latter  slope  is  not  a  prerequisite  to  move 
ment,  as  explained  on  page  536,  just  as  it  is  not  for  the  movement  of 
water  or  pitch. 

(c.)  The  presence  or  absence  of  6bstructions,  in  the  valley  or  region 
along  which  it  moves. 

All  these  points  have  been  demonstrated  by  observation  and  experi 
ment.  The  greater  rapidity  of  the  middle  portion  is  shown  by  the 
fact  that  the  transverse  ridges  made  at  an  ice-cascade,  like  that  of  the 
Rhone,  and  the  lines  of  earth  and  sand  in  the  chasms,  become  after 
ward  arched  in  front,  as  shown  in  Fig.  1103,  in  which  the  crevasses  c 
are  at  first  transverse,  but  curve  below  the  cascade.  The  arch  is 
sometimes  very  much  elongated,  almost  to  a  triangular  form,  as  in  the 
Geant  portion  of  the  Mer  de  Glace.  This  is  well  illustrated  in  Figs. 
1101,  1102,  from  Tyndall:  the  right-hand  half  of  the  figure,  corre 
sponding  to  the  Geant  Glacier  (the  cascade  which  is  alluded  to  on 
p.  678),  has  the  transverse  bands  (carrying  dirt  and  stones)  elongated 
into  triangles,  while  in  the  other  half  of  the  Mer  de  Glace  there  are 
no  such  bands,  as  the  tributaries  making  it  do  not  descend  in  cas 
cades. 

The  view  that  the  movement  of  glaciers  was  essentially  like  that  of  rivers  or  "  soft 
ened  wax  "  was  announced  by  Bordier  in  1773;  and  afterward  more  fully,  with  a  spe 
cific  recognition  of  the  idea  of  plasticity  in  the  ice,  and  of  the  influence,  on  the  move 
ment,  of  friction  at  bottom  and  along  the  sides,  by  Rendu,  in  a  memoir  read  before  the 
Academy  of  Sciences  of  Savoy,  in  1841.  Hugi,  in  1827,  built  a  hut  on  the  Aar  glacier, 
to  determine  its  rate  of  motion ;  and  found  the  movement  330  feet  in  three  years,  and 
2,354  feet  in  nine  years;  and  afterward  Agassiz  observed  that  in  fourteen  years  it  had 
jnoved  4,712  feet  below  its  first  position.  Agassiz  commenced  in  1841  his  grand  series 
of  observations  on  the  Aar  glacier,  measuring  the  rate  of  movement  in  a  section  across 
the  glacier;  and,  on  July  4,  1842.  his  first  results,  proving  the  more  rapid  flow  of  the 
middle  portion  (his  six  poles  in  the  line  across  having  moved  severally  160,  225,  269, 
240,  210,  and  120  feet),  were  published  in  the  "Comptes  Rendus."  His  investigations 
were  continued  for  several  years  afterward;  and  in  1847  appeared  his  first  great  work, 
entitled  "  Systeme  Glaciaire."  Prof.  Forbes  visited  Agassiz  at  his  work  on  the  Aar,  in 
1841,  and  in  the  summer  of  1842  undertook  an  independent  investigation  on  the  Mer  de 
Glace,  near  Chamouni;  and  in  October  of  1842  his  measurements,  confirming  those  of 
Agassiz,  were  published.  A  year  afterward,  in  1843,  appeared  his  "Travels  in  the 
Alps,"  in  which  his  various  careful  observations  are  given  ia  detail,  and  the  theory  of 


GLACIERS. 


681 


glaciers,  on  the  principle  that  the  ice  moves  like  a  viscous  fluid,  is  fully  elucidated.  His 
later  writings  on  the  subject  are  contained  in  a  volume  entitled  "Occasional  papers  on 
the  Theory  of  Glaciers."  Later,  Tyndall  (from  whom  these  historical  notes  are  taken) 
made  a  further  series  of  measurements  and  observations  in  the  Alps,  demonstrating  the 
influence  of  bends  in  a  glacier,  and  explaining  other  glacial  phenomena.  His  views 
are  contained  in  "The  Glaciers  of  the  Alps,"  1860,  and  "The  Forms  of  Water,"  1872. 

The  rate  of  descent  in  the  mass  of  a  glacier  varies  from  one  or  two 
inches,  to  over  fifty  a  day  ;  and  the  rate  is  about  half  less  in  winter 
than  in  summer.  Ten  to  twenty  inches  a  day  in  the  warm  season  is 
most  common  ;  twelve  inches  corresponds  to  three  hundred  and  sixty- 
five  feet  a  year,  or  one  mile  in  about  fourteen  and  a  half  years.  It 
takes  the  ice  of  the  Col  du  Geant  one  hundred  and  twenty  years  to 
reach  the  lower  end  of  the  Mer  de  Glace. 

Opposite  Montanvert,  where  there  is  a  bend  in  the  stream,  Tyndall  found  the  move 
ment  per  day,  at  eleven  stakes,  from  the  east  to  the  west  side,  20,  23,  29,  30,  34,  28,  25, 
25,  18,  9  inches,  the  first  and  last  being  near  the  opposite  sides.  Descending  from  Tre- 
laporte  to  Montanvert,  the  rate  increases  from  twenty  to  thirty-four  inches  a  day.  At 
Trelaporte,  the  three  tributary  glaciers  of  the  Col  du  Geant,  Lechaud,  and  Talefre  have 
become  one ;  and  the  ice  moves  in  a  channel  but  half  as  wide  as  the  sum  of  the  widths 
of  these  three  tributaries.  The  rate  of  movement  above  this  narrowing  is  hence  slow; 
Tyndall  found  the  movement  per  day,  across  the  lower  part  of  the  Col  du  Ge"ant,  11, 
10,  12,  13,  12,  13,  11,  10,  9,  5  inches;  across  the  lower  part  of  the  Lechaud  glacier,  5,  8, 
10,  9,  9,  8,  G,  9,  7,  6. 

Forbes  deduced,  from  his  measurements,  made  at  two  stations  on  each  of  the  Bois  and 
Bossons  Glaciers,  the  following  results.  The  first  station  on  the  Bois  Glacier  was  near 
its  upper  part,  where  the  rapidity  is  unusually  great,  and  the  other  near  its  lower  ex- 
tremitv. 


Bois  I. 

Bois  II. 

Boss.  I. 

Boss.  II. 

Motion  from  November,  1844,  to  Novem 
ber,  1845              .  .    . 

847-5  ft. 

220-8  ft. 

657-8  ft. 

489-1  ft. 

Mean  dailv  motion.                  .             ... 

27'8  in. 

7*3  in. 

21-6  in. 

16-1  in. 

Mean  daily  motion  in  summer,  April  to 
October  
Mean  daily  motion  in  winter,  October  to 
April.  .  , 

37-7  in. 
19-1  in. 

9-9  in. 
4-7  in. 

28-0  in. 
15-8  in. 

22-2  in. 
10-7  in. 

The  winter  movement  of  the  Mer  de  Glace  is  not  over  half  that  of  the  summer. 
Forbes  found  for  the  maximum  in  July,  at  his  upper  station  on  the  Bois  Glacier,  52-1 
inches  a  day,  and  in  December  11-5  inches. 

(6.)  The  capability  of  motion  in  a  glacier  is  attributed  to  — 
(a.)  A  kind  of  plasticity  in  ice.  Ice  may  be  made,  through  simple 
pressure,  to  copy  a  seal  or  mould,  like  wax  ;  or  to  take  the  form  of  a 
long  cylinder,  by  pressing  it  through  holes  ;  and,  if  the  ice,  in  such  an 
experiment,  is  added  in  fragments,  it  comes  out  solid.  The  ice,  when 
thus  under  pressure,  is  somewhat  clouded,  by  the  incipient  fractures 
in  it ;  but,  when  the  pressure  ceases,  it  is  quite  clear,  owing  to  rege- 
lation  along  all  such  microscopic  fractures.  Kane  mentions,  in  his 
"  Arctic  Explorations,"  the  case  of  a  table  of  ice,  eight  feet  thick  and 
twenty  or  more  wide,  supported  only  at  the  sides,  which,  between  the 


6&2  DYNAMICAL   GEOLOGY. 

middles  of  the  months  of  March  and  May,  became  so  deeply  bent  that 
the  centre  was  depressed  five  feet.  The  temperature  during  the  in 
terval  was  at  all  times  many  degrees  below  the  freezing-point. 

(b.)  The  facility  with  which  ice  breaks,  and  then  mends  its  fractures 
by  revelation ;  that  is,  by  a  freezing  together  again  of  the  surfaces 
that  are  in  contact.  This  fact,  first  noticed  by  Faraday,  and  applied 
to  glaciers  by  Tyndall,  is  of  prominent  importance.  Any  one  may 
test  it,  by  breaking  a  piece  of  ice  and  then  pressing  lightly  the  parts 
together  again  :  the  surfaces,  if  moist,  will  become  firmly  united.  A 
glacier  moves  on,  breaking  and  mending  itself  through  its  whole 
course.  The  multitudes  of  fractures  made  on  steep  slopes  may  all 
disappear  below,  where  the  motion  becomes  slow,  and  the  ice  feels  the 
pressure  from  above. 

(c.)  The  capability  of  sliding  along  its  bed,  but  only  portions  at  a 
time. 

The  first  of  these  causes  acts  universally  throughout  the  mass  of  the 
ice,  while  the  second  serves  to  do  the  immense  amount  of  mending  that 
is  required.  The  third  is  of  less  importance.  The  temperature  of 
the  mass  of  a  glacier  is  at  32°  F.  throughout  the  year,  its  non-con 
ducting  nature  preventing  any  accession  of  cold  during  the  winters. 
"  Thus,"  as  Helmholtz  observes,  "  the  interior  of  the  masses  of  neve, 
as  well  as  of  the  glacier,  remains'  permanently  at  the  melting  point." 

(7.)  Crevasses.  —  Along  the  sides  of  a  glacier,  especially  when  passing 
prominent  angles  in  the  valley,  or  over  places  in  the  valley  where  there 
is  an  increase  in  the  angle  of  slope,  the  crevasses  are  deep  and  numer 
ous.  The  ordinary  direction  of  these  crevasses  is  obliquely  up  stream, 
or  at  an  angle  of  forty  to  fifty  degrees  with  the  margin,  being  at  right 
angles,  nearly,  to  the  lines  of  greatest  tension  in  the  descending  glacier. 
The  crevasses  at  a  bend  form  especially  on  the  convex  side  of  the 
stream,  the  ice  undergoing  a  stretching  on  that  side  and  a  compression 
on  the  opposite.  Deep  transverse  crevasses,  and  others  of  irregular 
courses,  are  made  when  a  glacier  is  forcing  its  way  through  narrow 
passes  in  a  valley,  or  descending  rapid  slopes.  Afterward,  on  reaching 
a  broader  portion  of  the  valley,  the  ice  may  return  to  a  solid  mass, 
with  a  comparatively  even  surface,  having  fractures  only  toward  the 
sides.  Forbes  mentions  one  chasm,  500  feet  wide,  extending  quite 
across  the  Mer  de  Glace. 

7.  Veined  Structure.  —  The  ice  of  a  glacier,  as  first  observed  by 
Guyot,  is  often  vertically  laminated,  parallel  to  its  sides,  and  some 
times  so  delicately  so  that  the  ice  appears  like  a  semi-transparent 
striped  marble  or  agate.  This  is  well  seen  either  side  of  the  middle 
portion  of  the  Mer  de  Glace,  and  in  the  Brenva  and  Aar  glaciers. 
The  layers  are  alternations  of  cellular  (or  snowy)  ice  and  clear  bluish 


GLACIERS.  683 

solid  ice.  The  melting  of  the  surface  sometimes  leaves  the  more  solid 
layers  projecting.  The  structure  is  due,  as  shown  by  Tyndall,  to  the 
pressure  to  which  the  glacier  is  subjected,  in  making  its  way  between 
the  walls  of  a  valley,  especially  where  there  is  a  contraction  in  width, 
or  a  projecting  point  against  which  pressure  is  exerted,  and  particularly 
below  a  place  of  steep  descent.  It  may  be  formed  when  two  great 
glaciers  unite,  the  pressure  between  the  meeting  streams  being  here 
the  cause.  In  the  lower  part  of  the  glacier  of  the  Rhone,  the  lam 
inated  structure  is  produced,  according  to  Tyndall,  between  the  capes  m 
and  n  (Fig.  1103,  p.  676),  — the  structure-mill,  in  his  language.  It  ap 
pears  first  in  the  section  s,  and  is  fully  developed  in  the  following  one, 
s'.  The  radiating  lines  in  the  view  represent  crevasses.  The  resis 
tance  to  motion  in  a  glacier  is  not  continuously  overcome,  as  in  the 
case  of  a  perfect  fluid,  but  intermittently.  This  is  evinced  in  the 
successive  transverse  crevasses  of  a  cascade-glacier,  like  that  of  the 
Rhone,  or  in  the  dirt-bands  which  are  registers  of  the  successive 
crevassing.  Each  movement,  moreover,  must  cause  a  series  of  vibra 
tions,  of  great  force,  in  the  ice.  Such  intermittent  action  is  especially 
calculated  to  produce  a  laminated  structure.  As  Tyndall  has  observed, 
the  air-cells  appear  to  have  been  in  part  expelled  from  the  bluish  lay 
ers  by  the  pressure,  and  in  part  to  have  been  obliterated  by  an  incipient 
liquefaction  and  refreezing  of  the  layer. 

II.  Transportation  and  Erosion. 

1.  Transportation.  —  The  moraines  of  glaciers  are  made  from  (1) 
the  stones  and  earth  which  fall  from  the  cliffs  along  their  borders  ; 
(2)  the  material  received  from  falling  avalanches ;  (3)  that  which  is 
taken  up  by  the  ice  from  the  surface  of  the  valley  against  which 
it  moves.  They  form  in  all  the  stages  of  progress  of  a  glacier, 
though  usually  the  least  in  the  region  of  the  neve,  where  the  area  of 
bare  peaks  is  often  small,  compared  with  the  extent  of  snow.  The 
surface  in  this  upper  part  is  always  peculiarly  white  and  clean,  owing 
to  the  frequent  falls  of  snow. 

From  their  mode  of  origin,  it  follows  that  moraines  are  situated 
primarily  along  the  margin  of  a  glacier.  But,  when  two  glaciers 
coalesce,  the  two  uniting  sides  join  their  moraines  in  one  ;  and  this 
one  is  remote  from  the  borders,  and  may  be  central  —  as  in  the  glacier 
of  the  Aar  —  if  the  two  coalescing  streams  are  about  equal.  It  fol 
lows  from  the  above  that  the  number  of  moraines  on  a  glacier  can 
never  exceed  the  number  of  coalesced  glaciers  by  more  than  one. 

The  nearest  moraine,  in  the  view  of  the  Glacier  of  Zermatt,  on  page 
677,  is  that  of  the  Riffelhorn  ;  the  second  is  a  union  of  moraines  of 
the  Gornerhorn  and  Porte  Blanche ;  the  third,  a  union  of  two  mo- 


684  DYNAMICAL    GEOLOGY. 

rallies  from  two  Mt.  Rosa  Glaciers  ;  the  fourth,  the  great  moraine  of 
the  Breithorn,  the  summit  in  the  middle  of  the  view.  Other  moraines 
may  be  seen  on  the  distant  part  of  the  glacier.  In  Fig.  1101,  on 
page  676,  representing  a  section  of  the  Bois  Glacier  near  Trelaporte, 
there  are  six  distinct  moraines. 

Toward  the  lower  extremity  of  a  glacier,  the  several  moraines 
usually  lose  their  distinctness,  through  the  melting  of  the  ice ;  for  this 
brings  the  stones  and  earth  that  were  distributed  at  different  depths  to 
one  level,  and  thus  produces  a  coalescence  of  the  whole  over  the  sur 
face. 

The  stones  are  both  angular  and  rounded  ;  the  former  are  the  more 
abundant  in  the  Alps,  and  the  latter  about  the  much  larger  Greenland 
glaciers.  Many  are  of  great  magnitude.  One  is  mentioned,  contain 
ing  over  200,000  cubic  feet,  or  equal  in  size  to  a  building  one  hun 
dred  feet  long,  fifty  wide,  and  forty  high.  As  the  large  masses  shade 
the  ice  below  from  the  sun,  and  so  protect  it  from  melting,  they  are 
often  left  capping  a  column  of  ice. 

At  the  glacier  of  the  Aar,  the  central  moraine  is  raised  100  to  140 
feet  above  the  general  surface  either  side  ;  but  this  is  partly  owing  to 
the  pressing  up  of  the  ice  itself,  by  the  mutual  pushing  of 'the  two 
combined  glaciers  of  which  it  is  made.  The  breadth  where  narrowest 
is  250  feet ;  and  from  this  it  increases  to  750  feet,  half-way  to  the 
termination  of  the  glacier,  and  to  treble  this  below. 

The  final  melting  of  a  glacier  leaves  vast  piles  of  unstratified  stones 
and  earth,  or  moraines,  along  its  sides,  toward  and  about  its  lower  ex 
tremity.  The  stream  which  proceeds  from  the  glacier  works  over  all 
that  comes  within  its  reach,  carrying  it  onward  down  the  valley,  and 
making  deposits  on  its  banks  which  are  usually  more  or  less  perfectly 
stratified. 

2.  Erosion.  —  (1.)  The  movement  of  a  glacier  is  attended  with  so 
much  wrenching  of  the  ice,  that  the  blocks  have  their  angles  more  or 
less  blunted  or  rounded  by  mutual  attrition. 

(2.)  As  the  glacier  has  its  sides  and  bottom  here  and  there  set  with 
stones  of  large  and  small  size,  it  is  a  tool  of  vast  power  as  well  as 
magnitude,  scratching,  ploughing,  and  planing  the  rocks  against  or 
over  which  it  moves.  Besides  this,  it  pushes  along  gravel  and  stones, 
between  itself  and  the  rocks,  with  the  same  kind  of  effect.  The  rocky 
cliffs  and  ledges  in  the  vicinity  of  the  glaciers  are  in  many  places  fur 
rowed,  planed,  and  rounded,  over  their  whole  exposed  surfaces. 

The  rounded  knolls  of  rock  along  the  track  of  a  glacier  have  been 
called  sheep-backs  (roches  moutonnees)  in  allusion  to  their  forms.  They 
are  a  prominent  feature  of  all  glacier  regions  ;  and  those  of  the 
Glacial  period  (p.  531),  when  they  were  formed  over  a  vast  extent  of 


GLACIERS. 


685 


Country,  are  sometimes  preserved  to  the  present  time  in  great  perfec 
tion.     The  view  below,  copied  from   the   Report   of  Dr.  Hayden  for 

Fig.  1106. 


View  on  Roehe-Moutonnee  Creek,  Colorado. 

1873.  represents  a  portion  of  an  immense  crouching  flock  of  them, 
covering  the  side  of  the  valley  leading  down  from  the  "  Mountain  of 
the  Holy  Cross,"  one  of  the  prominent  summits  (12,485  feet  high),  in 
the  Crest  range  of  the  Rocky  Mountains,  Colorado ;  they  extend  up 
the  slope  for  nearly  2,000  feet,  and  have  suggested  to  Hayden  &  Gard 
ner,  for  the  stream  of  the  valley  (a  tributary  of  Eagle  River,  and  that 
of  Grand  River),  the  appropiate  name  of  Roche- Moutonnee  Creek. 

The  furrowings  or  gougings  have  a  direction  corresponding  with  that 
of  the  movement  of  the  ice  ;  and  sometimes  two  or  more  directions, 
indicating  glacier-movements  of  different  periods. 

(3.)  The  stones  which  have  produced  the  furrowing  are  smoothed, 
polished  on  one  or  more  sides,  and  often  scratched. 

(4.)  The  grinding  of  the  stones  against  one  another,  and  those  of 
the  bottom  against  the  underlying  rocks,  produces  very  fine  powder, 
which  makes  the  waters  of  the  underflowing  stream  milky,  and  pro 
duces  clay-like  deposits  (the  bowlder  clay).  Lake  Geneva  owes  its 
blue  color,  according  to  Tyndall,  to  the  presence  of  infinitesimal  (gla 
cier-made)  particles. 

Other  facts  connected  with  this  subject  are  mentioned  on  page  53 1. 
See  also  the  works  of  Agassiz,  Forbes,  Tyndall,  and  Helmholtz. 


686  DYNAMICAL    GEOLOGY. 

Glaciers,  as  these  facts  show,  are  efficient  means  of  widening  and 
deepening  valleys ;  and  in  this  work  the  torrents  of  water  they  beget 
take  a  prominent  part.  The  thickness  of  the  ice  in  the  Alps  nowhere 
exceeds  500  feet.  Let  it  be  2,000  feet,  as  now  in  some  Greenland 
glaciers,  or  twice  this,  as  in  many  regions  during  the  Glacier  period, 
and  the  work  of  erosion  accomplished  would  be  vastly  greater,  since  it 
is  directly  proportioned  to  the  thickness. 

The  snow  and  ice  of  Alpine  valleys  often  cause,  indirectly,  violent 
erosion  and  transportation  of  material,  by  damming  up  streams.  In 
no  other  way  can  barriers  be  thrown  so  readily  across  profound  val 
leys  ;  and  the  deluges  caused  by  the  accumulated  waters,  when  they 
break  loose,  are  often  very  destructive.  The  Alps  are  full  of  examples. 
Again,  the  valleys  are  sometimes  dammed  up  by  great  moraines,  mak 
ing  lakes ;  and  such  lakes  sometimes  break  through  their  barriers,  and 
flood  the  valley  below  with  tearing  waters. 

4.  ICEBERGS. 

A  glacier  on  a  sea-coast  often  stretches  out  its  icy  foot  into  the 
ocean ;  and,  when  this  part  is  finally  broken  off,  by  the  movement  of 
the  sea,  or  otherwise,  it  becomes  an  iceberg.  Greenland  is  the  great 
region  of  icebergs,  no  less  than  of  glaciers.  They  carry  away  the 
stones  and  earth  with  which  the  glacier  was  covered  during  its  land- 
progress,  and  transport  them  often  to  distant  regions,  whither  they  are 
borne  by  the  polar  oceanic  currents. 

Dr.  Kane  describes  the  great  pack  of  icebergs  that  occupies  the 
centre  of  Baffin's  Bay,  and  mentions  that  some  were  300  feet  high, 
and  large  numbers  over  200  feet.  There  were  280  icebergs  of  the 
first  magnitude  (the  most  of  them  over  250  feet)  in  sight  at  one  time. 

In  the  Antarctic,  Captain  Wilkes  observed  a  long  ice  barrier,  having 
a  height  above  the  sea  of  150  to  200  feet;  and  some  of  the  bergs 
were  300  feet  high.  The  ice  of  the  barrier  was  stratified ;  and,  ac 
cording  to  Wilkes,  this  was  owing  to  the  constant  increase  from  the 
freezing  mists  over  it. 

As  the  specific  gravity  of  ice  is  0*918  (at  32°  F.),  the  proportion  in 
weight  of  the  mass  out  of  water  is  about  one-twelfth. 

The  icebergs  of  the  Atlantic  melt  mostly  about  the  Banks  of  New 
foundland,  or  between  the  meridians  of  44°  and  52°.  They  have  been 
observed  in  this  ocean  as  far  south  as  36°  10'. 

Icebergs  are  (1)  a  means  of  transporting  stones  and  earth  from  one 
region  to  another  (see  p.  534).  (2)  When  grounded  on  rocks,  they 
may  scratch  the  surface ;  but  closely-crowded  and  regular  scratches 
like  those  of  glaciers,  over  large  areas,  could  hardly  be  made.  The 
currents  of  Baffin's  Bav  flow  southward  on  the  west  side,  and  north- 


WATER   AS  A   CHEMICAL   AGENT.  687 

ward  on  the  other,  —  which  would  give  great  irregularity  there  to  the 
scratches  of  grounded  bergs.  An  iceberg  "  rocked  by  the  swell  of  the 
sea,  and  sometimes  turning  over,"  could  not  be  good  at  scoring  sub 
merged  rocks.  Moreover,  these  rocks,  in  the  seas  in  which  icebergs 
melt  and  drop  their  freight  of  stones,  would  seldom  be  uncovered. 

4.  WATER   AS   A   CHEMICAL   AGENT. 

Water  does  its  chemical  work  among  the  rocks,  either  — 
(1.)   Through  its  capacities  as  water, 
(2.)  Through  the  affinities  of  its  elements,  directly. 
(3.)   By  means  of  the  substances  it  takes  into  solution. 
This  work  is  either  destructive  or  formative.     The  air  aids  largely 
in  the  results ;  and  hence  its  chemical  effects  are  here  in  part  included. 


I.  DESTRUCTIVE  WORK. 

1.  THROUGH  ITS  CAPACITIES  AS  WATER. 

1.  At  the  ordinary  Temperature.  —  It  takes   50,000  parts  of  pure 
water,  at  the  ordinary  temperature,  to  dissolve  one  part  of  calcite  or 
carbonate  of  lime  :    over   200,000   for  one  of  a  silicate  of  alumina ; 
7,500  for  one  of  silica  in  its  gelatinous  condition ;  460  for  one  of  sul 
phate  of  lime,  or  gypsum.     With  heated  water,  the  amount  for  sul 
phate  of  lime  is  the  same. 

With  the  exception  of  gypseous  rocks,  there  is  consequently  no  ap 
preciable  erosion,  through  the  action  of  pure  water  ;  but  these  are 
rapidly  worn  away. 

Many  minerals  tend  to  combine  with  water,  and  thus  become  altered 
in  constitution. 

Anhydrite;  or  anhydrous  sulphate  of  lime,  changes  to  gypsum,  or  hydrous  sulphate 
of  lime ;  and  great  beds  of  the  latter  mineral  have  been  made  out  of  the  former.  Mica 
and  many  other  minerals  often  take  in  two  or  three  per  cent,  of  water,  through  incipi 
ent  change.  Feldspar,  according  to  Hunt,  may  owe  its  decomposition  and  change  to 
porcelain  clay,  or  kaolin,  to  a  tendency  to  combine  with  water.  In  most  of  these  cases 
of  hydration,  carbonic  acid  has  accompanied  the  action  of  the  infiltrating  waters,  and 
has  been  essential  to  the  process. 

2.  At  an  elevated  Temperature.  —  Water  at  high  temperatures,  espe 
cially  above  the  boiling  point,  as  superheated  vapor,  has  great  dissolv 
ing  and  destroying  power.     No  silicate  will  withstand  it.     The  feld 
spars,  the  most  universal  of  silicates,  yield  before  it  with  great  facility. 
It  takes  the  alkalies,  and  also  the  silica,  making  the  siliceous  waters 
of  most  hot-spring  regions.     At  the  present  time,  the  disaggregation 
of  rocks  going  on  by  this  means  is  small ;  but  in  all  regions  of  meta- 


688  DYNAMICAL   GEOLOGY. 

morphism  in  the  Earth's  history,  this  has  been  a  prominent  source  of 
the  changes. 

Water  in  a  superheated  state  is  present  in  the  conduits  of  all  vol 
canoes  ;  and  it  is  supposed  that  the  apparent  liquidity  of  the  lava  is  in 
part  only  a  mobility  among  the  grains,  produced  by  this  means. 

2.  THROUGH  THE  ELEMENTS  OF  WATER  DIRECTLY. 

Water  consists  of  oxygen  and  hydrogen,  in  the  proportion,  by 
weight,  of  8  O  to  1  H.  The  oxygen  is  the  element  of  chief  import 
ance.  But  water  has  acted  conjointly  with  atmospheric  air,  in  these 
changes  ;  and  the  oxygen  produced  through  their  united  action  has 
often  come  from  the  air  instead  of  the  water.  Water  alone  is  usually 
a  protector  of  the  rocks  it  covers. 

A.    OXYDATION    AT     THE    ORDINARY     TEMPERATURE. The    Cases 

of  oxydation  of  widest  geological  influence  are  those  of  the  sulphids 
of  iron,  pyrite  (FeS2)  and  pyrrhotite  (Fe7S8),  and  those  of  carbo 
nates  containing  iron.  In  each,  iron  is  the  principal  oxydizing  element. 
The  oxyds  of  iron  concerned  are  the  protoxyd,  FeO ;  the  sesquioxyd, 
Fe203,  or  hematite,  which  has  a  red  powder  ;  and  the  hydrous  sesqui 
oxyd,  Fe2O3  -J-  1^H2O,  which  has  a  brownish-yellow  powder,  and  is 
called  limonite)  or  sometimes  brown  hematite. 

1.  The  Sulphids  of  Iron.  —  The  oxydation  of  these  sulphide  is  one 
of  the  most  universal  means  of  rock  destruction ;    for  there  are  few 
rocks  that  do  not  contain  pyrite,  in  disseminated  grains  or  crystals ; 
and  only  the  firmer  and  smaller  crystals  of  pyrite  withstand  the  ten 
dency  to  change.     Under  the  combined  influence  of  moisture  and  the 
atmosphere,  both  the  iron  and  sulphur  undergo  oxydation,  and  often 
produce  sulphate  of  iron  ;  or,  if  bases  are  at  hand,  like  lime,  or  alka 
lies  and  alumina,  the  acid  takes  the  lime  to  make  sulphate  of  lime,  or 
the  alkalies  and  alumina  to  make  alum ;  and  the  iron,  thus  left  free, 
becomes  a  sesquioxyd,  and  usually  the  hydrous  sesquioxyd,  or  limonite. 
Thus    the   decomposition    is    doubly    destructive.     Whenever    taking 
place  in  a  granular  rock,  the  oxyd,  becoming  distributed  among  the 
grains,  tends  to  pry  them  apart,  and  so  disaggregate  the  rock ;  while 
the  acid  aids  in  decomposing  the  other  ingredients  present. 

2.  Carbonates  containing  Iron.  —  Carbonate  of  iron  is  the  ore  of 
iron  called  siderite  or  spathic  iron.     Under  exposure  to  air  and  mois 
ture,  the  iron,  which  the  mineral  contains  in  the  protoxyd  state,  under 
goes    oxydation,  becoming   brown,  and    changing  to    limonite.     The 
alteration  goes  on  rapidly,  to  the  depth  that  water  and  air  succeed  in 
penetrating.     Any  rock,  through  which  this  carbonate  is  distributed, 
will  undergo  rapid  alteration   and   destruction   at   surface.     A  ferrif- 


WATER   AS   A    CHEMICAL   AGENT.  689 

erous  carbonate  of  lime,  or  carbonate  of  lime  and  magnesia  (in  which 
iron  replaces  part  of  the  calcium  or  magnesium),  undergoes  the  same 
kind  of  destruction,  though  less  rapidly.  The  rock  often  becomes  re 
duced  to  a  bed  of  more  or  less  pure  limonite.  Crystalline  limestones 
usually  undergo  this  change  more  readily  than  common  massive  lime 
stone,  because  more  permeable  to  moisture. 

3.  Other  Cases  of  Oxyda tion.  —  The  oxydation  of  carbon,  hydroyen,  and  other  in 
gredients  of  vegetable  and  animal  matter,  is  another  important  means  of  geological 
change,  through  the  oxygen  of  water  and  air.  The  fallen  unburied  leaves  and  stems 
of  the  forest  have  their  carbon  changed  by  this  means  to  carbonic  acid,  and  so,  in  a 
true  sense,  consumed;  and  if  buried,  the  air  being  to  a  great  extent  excluded,  part  of 
the  carbon  will  be  preserved  to  make  coal,  while  other  portions  will  be  lost  by  this  sort 
of  combustion  (p.  363).  Animal  matters  are  subject  to  an  analogous  change. 

On  the  evaporation  of  water  from  a  moist  surface,  or  after  a  rain,  it  has  been  ob 
served  that  there  is  a  production  of  ozone  over  the  surface,  and,  Schonbein  says, 
of  nitrite  of  ammonia.  Whatever  the  chemical  effects  of  such  a  cause,  they  must  be 
of  wide  influence.  But, while  water  is  essential  to  the  result,  the  ozone  is  probably 
from  the  oxygen  of  the  air  present.  In  the  production  of  nitrates  in  covered  places  or 
caverns,  the  same  production  of  ozone  has  been  supposed  to  be  a  step,  it  leading  to  the 
oxydation  of  the  nitrogen  of  the  atmosphere,  or  of  organic  substances  present.  The 
production  of  such  nitrates  has  considerable  mechanical  effect,  in  disintegrating  the 
outer  portion  of  loosely  aggregated  rocks  in  covered  places ;  and  there  must  be  chemical 
effects  besides,  yet  to  be  studied. 

B.  COMBINATIONS  OF  THE  HYDROGEN  OF  WATER,  AT  THE  ORDINARY  TEMPERA- 
TURK.  —When  pyrite  is  undergoing  oxydation,  through   the  decomposition  of  water, 
the  hydrogen  of  the  decomposed  water  will  form  sulphid  of  hydrogen  with  the  sulphur, 
and  so  give  origin  to  "sulphur   springs."     This  sulphid  of  such  springs  may  also  be 
come  oxydized,  the  sulphur  making  with  the  oxygen  sulphuric  acid,  and  the  hydrogen 
producing  wafer,  and  thus  may  be  produced  sulphuric  acid  springs  ;  though  this  acid  is 
so  strong  in  its  affinities  that  it  seldom  is  allowed  to  remain  free. 

C.  EFFECTS  AT  AN  ELEVATED  TEMPERATURE.  —  In  volcanoes,  the  vapors  of  water, 
in  connection  with  sulphur  vapors  from  sulphids,  give  origin  to  sulphurous  acid  or  sul 
phuretted  hydrogen;  and  the  acid  is  destructive  to  the  volcanic  rocks  within  its  reach. 

1).  EFFKCTS  THROUGH  THE  DISSOCIATED  ELEMENTS  OF  WATER.  —  At  tempenitures 
about  1800°  F.,  the  elements  of  water  are  separated.  In  the  process  of  metamorphism, 
this  temperature  has,  beyond  doubt,  been  sometimes  concerned.  But, as  the  moisture 
present  was  under  high  pressure,  and  pressure  raises  the  temperature  of  dissociation,  it 
is  not  certain  that  this  means  of  change  has  been  an  actual  one,  at  least  since  the  earth's 
crust  was  first  formed. 

3.  DESTRUCTIVE    EFFECTS    THROUGH    OR    BY    THE    AID    OF    SUB 
STANCES  HELD  IN  SOLUTION  IN  WATER. 

A.  CARBONIC  ACID.  —  The  most  important  agent  of  destruction,  as 
well  as  of  construction,  among  the  substances  dissolved  in  water,  is  car 
bonic  acid  gas ;  and  it  starts  for  its  work  mostly  from  the  atmosphere, 
although  constituting  but  four  parts  in  10,000  of  air.  In  Archrean 
time,  as  stated  on  page  156,  its  effects  were  far  greater  than  now,  o wing- 
to  the  much  larger  proportion  of  carbonic  acid  in  the  atmosphere;  and 
from  that  time  they  have  gradually  diminished.  It  is  carried  from  the 
air  to  the  earth's  rocky  surface  in  all  precipitated  moisture,  and  is  con- 
44 


690  DYNAMICAL   GEOLOGY. 

sequently  present  in  all  streams,  lakes,  and  oceans.  Other  prominent 
sources  of  this  gas  in  the  earth's  waters,  and  in  the  soil,  are:  (1)  the 
respiration  of  aquatic  and  underground  animals,  carbonic  acid  con 
stituting  a  large  part  of  the  air  exhaled;  (2)  vegetable  and  animal 
decomposition,  carbonic  acid  being  an  ultimate  product,  as  it  is  of  the 
combustion  of  coal ;  (3)  chemical  agents  (mentioned  beyond),  sepa 
rating  carbonic  acid  from  carbonate  of  lime. 

1.  Eroding  Action.  —  Carbonic  acid  has  a  strong  affinity  for  potash, 
soda,  lime,  magnesia,  and  iron.     If  waters  containing  carbonic  acid  are 
made  to  pass  through  powdered  feldspar,  mica,  hornblende,  pyroxene, 
limestone,  and  other  mineral  materials  containing  these  substances, 
portions  of  them  will  be  taken  up  and  carried  off;  and  the  disorgani 
zation  thus  begun  is  attended  by  a  loss  also  of  silica  and  alumina,  and 
ends  in  the  destruction  of  the  rock  made  of  these  minerals,  so  far  as  it 
is  subjected  to  the  process.      Professors  W.  B.  and  R.  E.  Rogers  found, 
in  their  experiments  on  the  action  of  carbonated  waters,  0'4  to  one  per 
cent,  of  the  whole  mass  under  digestion  dissolved  away  in  only  forty- 
eight  hours.1 

Some  granites  and  gneisses  are  decomposed  to  a  depth  of  fifty  or 
sixty  feet ;  and  in  tropical  countries,  like  Brazil,  where  a  warm  climate 
favors  activity  in  nature's  chemistry,  and  no  glacial  agent  has  worn 
off  the  earthy  surface  of  the  country,  the  depth  of  altered  rock,  accord 
ing  to  Liais,  is  sometimes  a  hundred  yards.  The  decomposition  has 
been  attributed  mainly  to  atmospheric  carbonic  acid  and  moisture,  and 
to  a  great  extent  by  the  process  just  pointed  out.  The  decomposi 
tion  of  the  sulphids  of  iron,  when  present,  would  also  aid  in  the 
destruction. 

Limestones  are  worn,  through  the  same  atmospheric  agents.  Waters 
containing  carbonic  acid  will  dissolve  readily  carbonate  of  lime,  making 
of  it  the  soluble  bicarbonate  of  lime  ;  1,000  parts  of  such  water  taking 
up  one  of  carbonate  of  lime.  Carbonic  acid  from  other  sources  aids 
in  this  work,  and  especially  in  the  case  of  limestones  ;  that  produced 
within  the  soil  is  an  important  contribution  to  underground  waters, 
and  a  means  thereby  of  making  caverns  in  limestone  formations. 

2.  By  preparing  the  way  for  Oxydation. —  Carbonic  acid  helps  on 
destruction,  also,  by  giving  iron  a  chance   to  oxydize.     On  dissolving 
out  the  iron  from  an   iron-bearing  mineral,  in  the  manner  above  ex 
plained,  it  forms  with  this  iron  carbonate  of  iron  ;  and  then   imme 
diately   the   oxydation    of  this    carbonate    of  iron   goes   forward,  as 
already  stated,  and  with  the  same  result.     This  process,  on  the  part 
of  carbonic  acid,  of  robbing  minerals  of  their  iron,  and  then  the  next 
instant  losing   the  iron  by  its   becoming  an  oxyd,  is  usually  going  on 

1  American  Journal  of  Science,  II.,  v.,  401. 


WATER  AS  A  CHEMICAL  AGENT.  691 

more  or  less  slowly,  whenever  rocks  containing  these  iron-bearing 
minerals  are  accessible  to  air  and  moisture.  The  action  of  the  car 
bonic  acid  cannot  be  perceived  ;  but  the  oxydation  of  the  iron,  the 
secondary  result,  is  very  manifest  in  the  brownish  or  reddish  color 
which  the  exposed  rock  acquires,  and  also  in  its  disaggregation.  In 
the  case  of  a  close-textured  rock,  like  much  doleryte  (trap),  the 
change  gradually  extends  from  the  surface  inward,  making  a  dis 
colored  crust.  This  crust  loses  at  surface  at  the  same  rate  that  it  pro 
gresses  inward ;  and  hence  its  thickness,  for  a  given  variety  of  rock,  is 
nearly  uniform. 

B.  ORGANIC  ACIDS.  —  The  work  here  attributed  to  carbonic  acid 
is   also   performed,  though  to   a  less  extent,  by  organic  acids,  made 
from  vegetable  or  animal    decomposition.      They   contribute    to  the 
solution  and  erosion  of  limestones,  and  also   to  the  process  of  oxyda 
tion. 

C.  SILICA.  —  Silica   is  present,  in   minute  traces,  in  most  natural 
waters.     7,500  parts  of  water  will  dissolve  one  part  of  silica  in  the 
gelatinous  or  soluble  state  ;  and  the  shells  of  Diatoms,  which  are  pres 
ent  over  the  bottoms  of  most  waters,  are   silica  in  this  soluble  state. 
If  the  waters   are  at  all  alkaline,  the  proportion  of  silica  that  may  be 
taken  up  is  much  larger. 

The  geological  effects  of  the  silica  of  cold  solutions  appear  to  be 
of  only  infinitesimal  importance  ;  while  the  siliceous  solutions  made 
by  heated  waters,  like  those  of  geyser  and  other  hot-spring  regions, 
have  great  destroying  power,  though  at  the  present  time  confined  to 
small  areas.  They  act  on  limestones,  expelling  carbonic  acid,  and 
making  silicates  containing  lime  ;  and  this  is  probably  a  prominent 
source  of  the  carbonic  acid  gas  given  out  in  some  solfataras,  and  also 
of  that  which  has  made  the  region  of  Yellowstone  Park  as  remark 
able  for  its  calcareous  as  for  its  siliceous  waters. 

D.  SULPHURIC  ACID  AND   SOLUBLE  SULPHATES.  —  Waters  hold 
ing  in  solution  sulphuric  acid  or  soluble  sulphates  (alums,  vitriols,  etc., 
made  through  the  decomposition  of  sulphids),  act  erosively  on  most 
rocks  within  reach,  and  especially  on  limestones. 

II.  FORMATIVE  WORK. 

The  destructive  work  in  geology  is  all  preparatory  to  new  forma 
tions. 

1.  Through  Calcareous  Waters.  —  The  carbonate  of  lime  taken  up 
by  carbonated  waters,  making  them  calcareous,  is  the  means  by 
which  limestones  have  been  consolidated ;  even  sea-water  contains 
enough  carbonic  acid  to  take  up  some  carbonate  of  lime.  The  cal 
careous  sands  of  a  beach  washed  over  by  the  tides,  and  thereby 


692 


DYNAMICAL    GEOLOGY. 


alternately  wet  and  dry,  become  coated  with  a  deposit  of  carbonate 
of  lime  from  the  waters  ;  and  finally  all  are  united  into  a  solid  mass. 
Sands  and  pebbles  of  other  kinds  are  treated  in  the  same  way  ;  and, 
on  shores  bordered  by  coral  reefs,  the  pebbles  of  basalt,  and  other 
kinds,  often  have  a  milky  exterior,  from  a  film  of  carbonate  of  lime. 

The  calcareous  mud  and  sand  of  the  reef  under  water  become 
solidified  apparently  without  other  means  than  the  carbonated  sea- 
waters. 

Beds  of  limestone  are  sometimes  made  by  depositions  from  calca 
reous  waters,  though  small  beds,  compared  with  those  of  organic  origin. 
The  travertine  of  Tivoli,  near  Rome,  is  a  large  deposit  along  the  Anio 
(p.  75),  whose  waters  are  there  strongly  calcareous.  On  the  banks 
of  Gardiner's  River,  in  the  region  of  the  Yellowstone  Park,  in  the 
Rocky  Mountains,  thick  limestone  deposits  have  been  made,  from 
the  waters  of  numerous  and  large  hot  springs  and  geysers,  as  well 
illustrated  and  described  in  the  Reports  of  Dr.  I  lay  den.  The  cal 
careous  waters,  in  descending  the  slopes  of  the  hills,  have  made  a 
series  of  parapets  at  different  levels,  inclosing  basins,  over  which  the 
water  drips  or  plunges  on  its  way  to  the  bottom,  as  illustrated  in  the 

Fig.  1107. 


Travertine  deposits  on  Gardiner's  River. 


sketch  above,  from  a  photograph  by  W.  II.  Jackson.  Travertine  is 
throughout  concretionary,  and  in  many  parts  cavernous,  and  com 
monly  wholly  unlike  the  even-grained  material  of  ordinary  limestone 


WATER   AS   A   CHEMICAL   AGENT.  693 

strata.  Leaves,  stems,  and  nuts  are  often  petrified  by  the  calcareous 
waters. 

The  waters  dripping  into  limestone  caverns  produce,  by  their  calca 
reous  depositions,  the  pendent  stalactites  of  the  roof  of  the  cavern,  and 
the  stalagmite  of  the  floor.  The  stalagmite  shows,  in  a  cross  frac 
ture,  the  fact  of  its  gradual  deposition,  by  the  bandings  in  its  colors. 
The  deposit  from  such  waters  sometimes  has  a  soft  chalky  texture. 

Some  sand  and  clay  beds  owe  their  consolidation  to  carbonate  of  lime 
derived  from  the  remains  of  shells  present  in  them. 

2.  Through  Siliceous  Waters.  —  Siliceous  waters  have  done  far  the 
larger  part  of  the  consolidation  of  sandstones,  conglomerates  and  clay 
beds.  The  silica  has  commonly  been  taken  up  from  feldspars  distrib 
uted  throughout  the  rock  itself,  or  from  the  siliceous  relics  of  Diatoms 
and  Sponges  present  in  it,  by  the  heat  and  moisture  penetrating  it ; 
and  then  consolidation  has  taken  place  as  the  temperature  lowered. 
Such  solutions  have  filled  fissures  and  cavities  in  rocks  with  quartz, 
making  quartz  seams  and  veins.  They  have  also  been  the  means  by 
which  mineral  silicates  have  been  formed  in  the  process  of  meta- 
morphism  (p.  726). 

They  have  also  produced  extensive  deposits  of  silica  in  regions  of 
hot  springs,  remarkable  examples  of  which  occur  in  the  Yellowstone 
Park,  and  also  in  Iceland  and  New  Zealand.  The  silica  in  these  de 
posits  is  mostly  in  the  state  of  common  opal.  When  the  depositions 
cease,  from  the  failure  of  the  hot  waters,  much  of  the  material  soon 
crumbles,  and  loses  its  peculiar  external  features. 

Wood,  shells,,  and  insects,  arc  often  petrified  by  such  siliceous 
waters,  so  that  silicified  stumps  are  common  over  large  portions 
of  the  Pacific  slope,  one  of  the  most  remarkable  regions  of  igneous 
eruption  in  the  world.  Portions  of  trunks  of  more  than  a  hundred 
silicified  trees,  one  of  them  twelve  feet  in  diameter,  lie  prostrate  to 
gether,  according  to  Marsh,  in  a  thick  bed  of  tufa,  about  five  miles 
southwest  of  Calistoga  Hot  Springs,  in  the  Coast  Range,  north  of  San 
Francisco,  California  —  a  locality  first  made  known  by  C.  II.  Denison. 
The  trees  are  described  as  probably  all  Conifers.  They  received  the 
silica  from  the  tufaceous  deposit,  and  probably  while  it  was  penetrated 
by  heat  and  moisture,  if  not  comprised  within  the  range  of  true  hot 
springs ;  and  the  tufa  had  its  origin  in  a  shower  of  volcanic  cinders 
(from  some  unascertained  vent)  settling  down  over  the  forest  region. 

Siliceous  solutions  have  moreover  silicified  the  fossils  of  many  of  the 
earth's  limestones  and  other  strata,  and  made  flint  or  hornstone  nodules 
in  them,  though  without  silicifying  the  limestone  itself. 

The  most  of  the  above  results  have  been  produced  by  hot,  or  at 
least  warm,  solutions.  But,  in  the  case  of  the  fossils  and  hornstone  in 


694  DYNAMICAL    GEOLOGY. 

limestones,  —  of  which  the  chalk  affords  an  example,,  —  even  a  low 
heat  could  hardly  have  been  necessary.  The  silica  was  distributed 
through  the  calcareous  mud  of  the  sea  bottom,  in  the  form  of  Diatoms, 
Polycystines,  and  siliceous  spicules  of  Sponges,  and  therefore  was  in 
the  soluble  state  ;  and  the  solution  of  this  silica  took  place  within  the. 
mass  of  the  deposit.  The  tendency  of  matter  of  one  kind  to  concrete 
together  led  to  the  forming  of  flint-nodules  and  the  silicifying  of  shells 
and  other  foreign  substances. 

3.  Through  Oxydation.  —  The  oxydation  of  the  iron  of  ferriferous 
minerals,  in  the  destruction  of  rocks  described  above,  is  also  a  forma 
tive  process.  It  usually  results,  as  has  been  stated,  in  making  the 
brown  hydrous  oxyd,  limonite,  unless  either  the  climate  is  a  dry  one, 
or  the  temperature  is  near  or  above  the  boiling  point,  when  the  red 
oxyd,  hematite,  is  formed.  Further,  accumulations  of  iron  ores  in 
great  beds  have  been  thus  made.  Carbonates  containing  iron  and 
sulphids  of  iron  have  been  the  chief  sources  of  the  ore;  but,  where 
these  were  present  to  start  the  process,  all  other  iron-bearing  minerals 
at  hand  have  contributed  to  the  end. 

In  a  large  number  of  cases,  the  rock  has  decomposed  and  left  the 
bed  of  iron  ore  —  mostly  limonite  —  in  its  place.  This  is  the  fact  in 
the  region  of  Lower  Silurian  schists  of  the  Green  Mountains,  as  first 
explained  by  Percival,  and  of  their  continuation  in  New  Jersey,  Penn 
sylvania,  Virginia,  Tennessee,  Georgia  and  Alabama.  The  lamina 
tion  of  the  schist  may  be  sometimes  detected  in  the  ore  bed,  when  its 
minerals  have  disappeared.  In  one  of  the  mines  of  Richmond,  Mass. 
(the  Leete  ore -bed),  it  is  apparent  that  the  source  of  the  iron  was 
mainly  a  ferriferous  carbonate.  A  high  limestone  ledge  stands  just 
along-side  of  the  mine,  to  the  north  ;  and,  within  the  deep  and  large 
excavation,  in  the  midst  of  the  ore,  there  are  some  few  beds  of  very 
compact  gray  carbonate  of  iron  still  remaining,  which  are  conformable 
or  nearly  so  in  dip  with  those  of  the  limestone  ledge  a  hundred  yards 
off.  The  rock  from  which  the  limonite  originated  was  probably,  there 
fore,  this  carbonate  ;  possibly,  portions  of  it  that  were  less  compact  or 
more  permeable  to  moisture. 

The  iron  of  exposed  rocks  undergoing  decomposition  is  very  com 
monly  washed  out  of  them  into  low  places  or  marshes,  and  there  de 
posited,  making  beds  of  cellular  limonite,  called  "  bog  iron  ore."  Such 
beds  often  contain  nuts  and  leaves,  petrified  by  the  oxyd  of  iron.  The 
iron,  when  carried  by  the  waters,  is  in  solution  as  bicarbonate,  or  com 
bined  with  organic  acids  derived  from  the  soil.  The  change  to  limonite 
takes  place  where  the  waters  have  a  chance  to  stand  and  evaporate. 
In  this  way,  vast  beds  of  ore  have  been  made,  even  those  of  Archaean 
time  (p.  153).  The  beds  made  in  marshes  are  in  general  less  pure  than 


WATER  AS  A  CHEMICAL  AGENT.  695 

those  formed  in  place,  because  a  marsh  gathers  much  dead  animal  matter, 
and  therefore  the  ore  usually  contains  phosphates  (p.  59).  Even  much 
of  the  Archaean  ore  contains  phosphate  of  lime  (apatite)  in  visible  grains. 

The  oxydation  of  iron  has  also  taken  place  without  any  attending 
destruction  of  rocks.  In  the  Marquette  iron  region,  and  others,  there 
are  imbedded  octahedrons  of  iron  ore,  which  are  now  hematite  Fe2O3, 
or,  what  is  the  same,  FeOf,  but  which  were  originally  magnetite,  FeO*, 
as  is  proved  by  their  having  the  crystalline  form  of  magnetite,  instead 
of  that  of  hematite.  They  show  that  the  great  bed  of  ore,  of  which 
they  are  a  part,  has  been  in  some  way  oxydized  (receiving  in  it  a  sixth 
more  of  oxygen).  This  was  probably  done  through  the  aid  of  the 
moisture  penetrating  the  whole,  when  at  a  high  temperature.  Igneous 
rocks  usually  contain  magnetite  rather  than  hematite. 

Consolidation  of  rocks  is  another  effect,  in  some  cases,  of  the  pro 
duction  of  iron  ore.  Limonite  becomes  distributed  among  pebbles,  and 
thereby  makes  an  ironstone  conglomerate. 

The  waters,  filtering  through  soil  and  gravel,  often  take  up  enough  oxyd  of  iron  to 
cement  a  bed  of  pebbles  lying,  at  a  lower  level,  on  another  layer  sufficiently  close  in  tex 
ture  to  hold  the  water  and  give  the  iron  a  chance  to  deposit;  and  this  is  one  way  in 
which  what  is  called  hard-pan  is  sometimes  made.  The  underlying  impervious  bed  is 
not  absolutely  necessary  to  the  result,  although  promoting  it.  The  pebbles  wet  with  the 
ferruginous  waters,  when  they  dry,  in  times  of  drought,  take  a  deposit  of  iron ;  and 
this  process  may  end  in  complete  consolidation. 

When  a  low  degree  of  heat  is  concerned  in  the  consolidation  of  beds  of  sand,  contain 
ing  iron-bearing  minerals  in  grains,  the  red  oxyd  of  iron  is  usually  produced,  reddening 
the  rock,  and  acting  also  in  some  degree  as  a  cement  for  the  sand;  the  same  heat,  how 
ever,  often  leads  to  the  production  of  a  solution  of  silica,  which  aids  in  the  consolidation. 

The  fumes  of  chlorid  of  iron  from  a  volcanic  fumarole,  in  contact  with  water  in  vapor, 
give  up  the  chlorine  to  the  hydrogen  of  the  vapor  (making  hydrochloric  acid,),  and  the 
iron  to  the  oxygen  of  the  same,  making  oxyd  of  iron,  or  hematite.  In  this  way,  crystal 
lized  hematite  is  sometimes  formed  in  scorias  about  a  fumarole.  But  according  to  Pal- 
mieri,  this  is  not  the  only  or  common  way.  Iron  exists  in  the  liquid  lava,  in  the  state 
of  magnetite ;  and  the  oxydation  of  magnetite  may  be  the  more  common  method. 

4.  Through    Decomposition    of   Feldspars.  —  Feldspars    change    to 
kaolin  (the  clay  o*f  which  porcelain  is  made),  on  decomposition,  losing 
the  alkalies  and  part  of  the  silica,  and  taking  in  water ;  so  that  feld 
spar,  consisting  of  one  part  atomically  of  alkali,  one  part  of  alumina, 
and  three  to  six  parts  of  silica,  becomes  reduced  to  one  of  alumina,  two 
of  silica,  and  two  of  water  (or  kaolin).     Thus  the  large  beds  of  kaolin 
have  been  made,  and  larger  beds  of  clay  slate  free  from  alkalies. 

5.  Through  the  Action  of  Sulphuric  Acid.  —  Limestone  (carbonate 
of  lime)  is  changed  to  sulphate  of  lime  by  sulphuric  acid ;  and  thus 
beds  of  gypsum  and  anhydrite  have  been  formed.     The  sulphuric  acid 
may  come  directly  from  the  decomposition  of  sulphids  ;  or  from  the 
oxydation  of  sulphid  of  hydrogen  or  of  sulphurous  acid,  in  volcanic 
regions.     Alumstone   (sulphate  of   alumina)   and    alum  efflorescences 
(sulphates  of  alumina  and  the  alkalies,  or  magnesia,  or  iron)  are  often 


696  DYNAMICAL   GEOLOGY. 

produced  when  alumina  is   present.     Different  sulphates  of  iron,  or 
vitriols,  and  some  related  products  are  other  results. 

6.  By  Deoxydation.  —  Organic  matters,  owing  to  their  tendency  to 
oxydation,  may  take  oxygen  from  sesquioxyds,  arid  make  protoxyds  of 
them  ;  so  that  carbonic  acid,  if  at  hand,  can  combine  with  the  iron,  and 
form  carbonate  or  bicarbonate  ;  and  organic  acids,  as  Hunt  has  urged, 
may  form    soluble  organic   compounds.     In    the    decomposition  of  a 
rock  containing  feldspars,  in  which  iron  is  present,  the  clay,  when  first 
made,   is    usually  colored  ;   but  after  the  bed  of  clay  has   thickened 
to  a  few  inches  or  feet,  it  is  often  found  that  the  oxyd  of  iron  has  all 
been  washed  out,  leaving  it  nearly  or  quite   white.     This  is   accom 
plished  by  the  process  of  deoxydation  just  mentioned.     By  means  of 
it  also,  large  beds  of  carbonate  of  iron  have  sometimes  been  formed. 

In  a  similar  way,  sulphates  have  been  reduced  to  sulphids.  In  the 
black  marsh-mud  deposit  of  the  Quaternary  of  Louisiana,  there  is 
some  pyrite,  derived  through  the  deoxydizing  process  of  organic 
matters.  (Hilgard.) 

7.  Through  the  Evaporation  of  Sea-water,  and  attendant  Chemical 
Changes.  —  The  ocean  is  a  mineral  spring  that  dates  from  the  period 
in  the  earth's  history  when  the  vapors  first  settled  on  the  cooling  crust. 
All  the  materials  that  were  at  all  soluble,  and  that  the  conflict  of  hot 
rocks  and  hot  waters  could  have  then  made,  were  at  first  present  in 
it.     An  excess  of  phosphates  and  of  carbonate  of  lime  continued  to 
characterize  it  after  the  Paleozoic  era  had  begun,  as  is  learned  from 
the  abundance  of  Lingulce  and  other  phosphatic  shells  (pages  59,  593), 
and  the  profusion  of  other  shells,  and  of  corals.     At  present,  and  since 
Paleozoic  time  began,   the   only  chemical  deposits   abundantly  made 
from  the  waters,  in  confined  basins  where  evaporation  was  possible, 
appear  to  have  been  gypsum  and  common  salt.     But,  with  these,  some 
magnesian  minerals   have  been  produced,  and  also  some  deposits  of 
borates.     Salt  deposits  are  now  in  progress,  in   confined   salt-water 
basins,  along-side  of  low  seashores. 

The  production  of  magnesian  carbonate  of  lime  (dolomite)  has  been  attributed  to  the 
reaction  of  the  magnesian  salts  of  the  ocean's  waters,  in  evaporating  basins,  on  the  cal 
careous  material  of  the  bottom.  The  magnesia  can  have  come  only  very  sparingly  from 
corals,  shells,  or  other  calcareous  relics,  animal  or  vegetable,  and  must,  therefore, 
have  been  introduced  from  outside.  As  the  dolomites  are  of  all  ages,  include  the 
majority  of  the  earth's  limestones,  and  have  often  a  wide  continental  extent,  no  mag 
nesian  mineral  springs  can  be  adequate  for  their  production,  excepting  the  great  ocean 
itself.  The  chemistry  of  the  process  is  not  yet  fully  understood. 

In  the  preceding  pages  on  water  as  a  chemical  agent,  only  the 
more  prominent  and  obvious  of  the  results  have  been  considered.  All 
the  ingredients  of  mineral  springs  have  done  work,  in  the  way  both  of 
destruction  and  of  construction.  A  full  discussion  of  the  effects  be 
longs  only  to  a  treatise  on  chemical  geology. 


HEAT.  697 


V.    HEAT. 

The  effects  of  heat  here  considered  are  those  affecting  the  rock-ma 
terial  of  the  globe,  exclusive  of  the  comprehensive  changes  resulting 
from  the  earth's  gradual  refrigeration.  They  include  (1)  -expansion  and 
contraction  ;  (2)  fusion,  solidification,  and  attending  igneous  phe 
nomena  ;  (3)  metamorphism  and  vein-making,  besides  chemical  deposi 
tions  and  changes.  After  some  observations  on  (1)  the  Sources  of 
Heat,  these  subjects  are  considered  under  the  following  heads  :  (2)  Ex 
pansion  and  Contraction  ;  (o)  Igneous  Action  and  Results ;  (4)  Meta- 
morphjsm  ;  (5)  Mineral  Veins. 

1.  SOURCES  OF  HEAT. 

The  Earth  has  three  prominent  sources  of  heat:  (1)  The  Sun; 
(2)  Chemical  and  mechanical  action  ;  (;>)  The  igneous  condition  of  the 
Earth's  interior. 

1.  The  Sim.  —  The  heat  of  the  earth's  surface  derived  from  the  sun 
has  depended  on  (1)  the  condition  of  the  sun,  and  (2)  the  density  of 
the  earth's  atmosphere.  The  atmosphere  absorbs  and  retains  heat, 
and  is  thus  like  a  blanket  about  the  sphere.  Moreover,  the  heat  it 
takes  varies  with  its  density.  Hence,  the  ancient  globe  had  through 
its  atmosphere  more  warmth  than  the  modern,  the  atmosphere  having 
then  been  denser  than  now,  through  the  presence  of  more  carbonic  acid 
and  more  moisture  ;  and,  for  the  same  reason,  elevated  regions  have 
less  warmth  than  lower  ones.  Some  facts  with  regard  to  the  local 
distribution  of  heat  over  the  earth  are  stated  on  pages  41  to  44. 

As  the  Sun,  like  other  heated  spheres,  has  been  losing  heat  through 
all  time,  the  earth  receives  less  now  than  in  Archcean  time.  But  it  is 
not  probable  that  the  diminution  since  the  commencement  of  the 
Paleozoic  has  produced  any  appreciable  change  on  the  climate  of  the 
globe. 

The  amount  of  heat  received  from  the  sun  varies  not  only  with  the 
seasons,  but  also  with  the  variations  in  the  eccentricity  of  the  earth's 
orbit. 

The  eccentricity  passed  one  of  its  maxima,  according  to  Stockwell's  calculations,1 
about  100,000  years  since';  another,  higher,  200,000  years;  another,  not  so  high,  300,- 
000  years;  a  rather  low  minimum,  410,000  years;  a  low  maximum,  475,000  years;  a 
very  low  minimum,  520,000  years;  a  maximum,  570,000  years;  two  maxima,  the  second 
750,000  years;  a  very  low  minimum,  800,000  years;  an  extreme  maximum,  850,000 
years;  another  very  low  minimum,  900,000  years;  a  high  maximum,  950,000  years,  and 
so  on.  In  future  time,  there  will  be  a  very  low  minimum,  24,000  years  on ;  a  low  max 
imum,  150,000  years;  another  low  maximum,  250,000  years;  a  very  low  minimum, 
300,000  years;  a  low  maximum,  400,000  years:  a  very  high  maximum,  515,000  years; 


Am.  Jour.  ScL,  II.  xlvi.  1808. 


698  DYNAMICAL    GEOLOGY. 

a  minimum,  560,000  years;  an  extreme  maximum, 610, 000  years,  and  soon.   The  points 
of  maxima  and  minima  are  repeated  approximately  at  intervals  of  1,450,000  years. 

At  a  time  of  maximum  eccentricity,  while  almost  precisely  the  same 
amount  of  heat,  as  now,  would  reach  the  earth,  it  would  be  differently 
distributed  through  the  seasons.  If,  during  an  era  of  great  eccentri 
city,  the  winter  of  the  northern  hemisphere  occurs  in  perihelion  and 
the  summer  in  aphelion,  the  winters  will  be  mild  and  the  summers 
cool  ;  and  the  reverse  will  be  true  for  the  same  era  in  the  southern 
hemisphere,  the  winter  there  occurring  in  aphelion,  and  cold,  and  the 
summer  in  perihelion,  and  hot.  Geological  effects,  from  this  condition, 
would  be  manifested  in  one  hemisphere,  according  to  Croll,  in  the 
snows  of  winter  continuing  long  into  the  summer,  or  through  it,  and 
even,  as  he  argues,  in  bringing  on  the  conditions  of  a  glacial  era. 
But,  while  this  was  the  condition  in  one  hemisphere,  the  other  would 
have  an  equable  climate.  Croli  states  that  the  glaciated  hemisphere 
would  be  that  which  had  the  cold  winter  ;  while  J.  J.  Murray  holds  l 
that  it  would  be  the  one  that  had  the  cold  summer.  Professor  H.  A. 
Newton  (to  whom  the  author  has  submitted  the  subject)  believes  it 
very  questionable  whether  the  differences  of  eccentricity,  and  the  con 
sequent  differences  of  summer  and  winter  temperatures,  are  capable 
of  producing  so  great  a  result  in  either  direction. 

2.  Chemical  mid  Mechanical  Action.  —  Heat  is  evolved  by  chemical 
changes  in  which  there  is  condensation,  as  in  liquids  becoming  solids, 
or  gases,  liquids,  etc.  ;  often  an  effect  of  the  natural  decomposition  of 
minerals,  or  of  vegetable  or  animal  matter. 

Mechanical  action,  as  the  beating  of  waves  on  a  coast,  the  falling  of 
water  in  cascades  or  rain,  the  shakings  of  earthquakes,  sliding  of  rocks, 
motion  of  the  atmosphere  in  winds,  produces  heat,  whenever  the  action 
meets  with  resistance,  on  the  principle  that  motion  corresponds  to  an 
amount  of  heat,  or  that  heat  is  transformed  motion.  The  heat  thus 
resulting  is,  however,  of  very  little  geological  importance.  But  the 
motion  attending  uplifting,  plicating,  shoving,  along  fractures,  and  crush 
ing  of  rocks,  is,  as  demonstrated  by  Mallet,  an  efficient  and  wide-reach 
ing  source  of  heat  and  of  geological  work  :  for  heat  thus  originated 

*  o  O  C5 

among  the  earth's  strata  has  been  an  important  means  of  consolida 
tion,  metamorphism,  and  probably  even  of  fusion. 

Mallet  demonstrates,  by  manv  careful  experiments,  that  the  crushing  of  a  cubic  foot 
of  syenyte  or  granyte  produces  119  to  213^  degrees  Fahrenheit;  of  two  slates,  132-85 
and  144-29  degrees;  of  three  sandstones,  32-84,  4779,  86-13  degrees;  of  two  compact 
limestones,  20-98,  26.28  degrees;  of  Devonshire  marble,  114-68  degrees.  He  obtained 
for  the  speciiic  heats  of  the  same  rocks,  the  syenytes  and  granyte.*,  0-181  to  0-196;  slates, 
0-201,  0-218;  sandstones,  0-238,  0-233,  0-215;"  limestone,  0'245,  0'265;  marble,  0  203.2 

1  Quarterly  Journal  of  the  Geological  Society,  xxv.  350,  1869. 

2  Mallet  on  Volcanic  Energy,  Trans.  Roy.  Soc.,  1872. 


HEAT.  699 

Mallet,  from  this  and  other  data,  calculates,  that  7,200  cubic  miles  of 
crushed  rock  would  cause  heat  enough  to  make  all  the  volcanic  moun 
tains  of  the  globe  ;  and,  as  the  ejections  of  the  volcanoes  have  been 
going  forward  through  a  very  long  period,  the  action  would  require 
but  an  infinitesimal  amount  of  annual  crushing,  —  not  over  O'GOG  of  a 
cubic  mile.  Whether  Mallet's  conclusion,  "•  that  the  crushing  of  the 
earth's  solid  crust  affords  a  supply  of  energy  sufficient  to  account  for 
terrestrial  volcanicity,"  is  correct  or  not,  the  fact  is  well  established, 
that  motion  in  the  earth's  rocks  has  been  a  powerful  source  of  heat. 

3.  Internal  Neat.  —  The  proofs  of  the  existence  of  a  source  of  heat 
within  the  earth  are  the  following :  — 

1.  The  spheroidal  form  of  the  earth  (p.  9),  this  being  evidence  that 
the  earth  was  originally  fluid. 

2.  Borings  for  Artesian  wells  and  shafts  in  mines  have  afforded  a 
means  of  taking  the  temperature  of  the  earth  at  different  depths ;  and 
it  has  been  uniformly  found  that,  after  passing  the  limit  of  surface- 
action,  the  heat  increases.     The  ordinary  rate   is  1°  F.  for  50  or  60 
feet  of  descent.     At  the  Artesian  well  of  Grenelle,  a  temperature  of 
85°  F.  was  obtained  at  2,000  feet,  equivalent  to  1°  F.  for  every  60  feet 
of  descent.     In  Westphalia,  at  Neusalzwerk,  in  a  well  2,200  feet  deep? 
the  temperature  at  the  bottom  was  91°  F.,  or  1°  F.  for  50  feet  of  de 
scent.     At  Pregny,  near  Geneva,  a  depth  of  680  feet  gave  63°  F.    At 
Yakutsk,  Siberia,  Magnus  found  a  gain  of  15°  F.  in  descending  407 
feet,  equal  to  1°  F.  for  27  feet.     The  variations  are  considerable  ;  but 
still  the  facts  authorize  the  ratio  above  given. 

It  has  been  proposed  to  make  a  tropical  climate  in  the  Garden  of 
Plants,  by  taking  the  heat  from  the  earth's  interior.  Arago  and  Wal- 
ferdin  have  estimated  that,  at  a  depth  of  3,000  feet,  the  water  would 
have  a  temperature  of  200°  F.,  "  sufficient  not  only  to  cheer  the  tropical 
birds  and  monkeys  of  the  Zoological  Gardens,  and  the  hot-houses  and 
green-houses  of  the  establishment,  but  to  give  warm  baths  to  the  in 
habitants  of  Paris." 

The  rate  1°  F.  for  fifty  feet  of  descent,  in  the  latitude  of  New  York, 
would  give  heat  enough  to  boil  water,  at  a  depth  of  8,100  feet;  and 
3,000°  F.,  the  fusing-point  of  iron,  at  a  depth  of  about  twenty-eight 
miles.  As  the  ratio,  however,  cannot  be  an  arithmetical  one,  because 
of  both  the  greater  conductivity  of  the  earth  below  (owing  to  greater 
density)  and  the  increased  pressure,  the  depth  of  fusion  exceeds  this 
amount ;  but  how  much,  has  not  yet  been  determined. 

The  amount  of  heat  now  lost  by  the  earth,  as  a  consequence  of 
cooling,  is,  according  to  Thomson,  such  as  would  melt  annually  a  com 
plete  covering  of  ice,  -0085  millimeters  thick,  to  water  at  32°  F.,  or 
bring  777  cubic  miles  of  ice  to  the  same  state. 


700  DYNAMICAL   GEOLOGY. 

3.  The  wide  distribution  of  volcanoes  over  the  globe  affords  evi 
dence  of  internal  heat.  Volcanoes,  extinct  or  active,  border  the  Pa 
cific,  from  Fuegia  to  Alaska  ;  through  the  Aleutian  Archipelago  to 
Asia ;  down  the  Asiatic  coast,  through  Kamtchatka,  Japan,  and  the 
Philippines,  to  New  Guinea,  New  Hebrides,  and  New  Zealand  ;  and 
they  constitute  half  of  the  islands  of  this  ocean,  two  of  which,  in  Ha 
waii,  are  nearly  14,000  feet  high.  This  volcanic  region  is  equal  to  a 
whole  hemisphere,  and  is  therefore  evidence  of  a  wide  distribution  of 
interior  heat.  Volcanoes  occur  also  through  Java  and  Sumatra  ;  in 
central  Asia,  in  the  Thian-Shan  Mountains ;  about  the  Mediterranean 
and  Red  Seas  ;  in  wrestern  Asia,  and  southern,  central,  and  southwest 
ern  Europe ;  in  Iceland,  and  in  the  West  Indies. 

The  ejection  of  melted  rock  through  fissures  has  taken  place  over 
all  the  continents:  in  Nova  Scotia,  Canada,  New  England,  New  Jer- 

& 

sey,  and  the  States  south,  the  region  of  Lake  Superior,  the  Rocky 
Mountains,  and  western  America ;  in  Ireland,  Scotland,  and  various 
parts  of  Europe ;  and  so  over  much  of  the  globe. 

If  all  volcanic  heat  is  a  consequence  of  movements  in  the  earth's 
crust  (p.  699),  the  evidence  from  volcanoes  proves  nothing  with  re 
gard  to  independent  subterranean  sources.  But  that  this  is  not  so  is 
apparently  proved  by  facts  connected  with  the  earth's  movements, 
stated  on  page  735  ;  and  consequently  igneous  eruptions  must  for  the 
most  part  have  come  from  great  fire-seas,  that  had  their  origin  in  the 
earth's  original  liquidity. 

2.  EXPANSION  AND  CONTRACTION. 

1.  In  Solids:  the  Heat  from  an  External  Source.  —  The  sun  is  pro 
ducing  somewhere,  at  all  times,  alternations  of  temperature,  and  there 
by  change  of  size  and  position ;  and  the  same  effect  comes  from 
changes  of  temperature,  whatever  the  source.  The  cause  is  universal 
in  its  action. 

Colonel  Totten,  of  the  United  States  Engineer  Department,  having  observed  that  the 
stones  of  the  coping  of  a  wall  became  loosened  from  some  cause,  undertook,  in  1830  to 
1833,  by  a  series  of  experiments,  to  ascertain  the  effects  of  the  daily  and  annual  change 
of  temperature.  He  found  that  an  inch  of  fine-grained  granyte  (obtained  from  a  bowl 
der  at  the  head  of  Buzzard's  Bay)  expands,  in  inches,  for  an  increment  of  1°  F. 
•000004825:  of  white  granular  limestone  (from  Sing  Sing,  thirty  miles  north  of  Xew 
York),  -000005668;  of  red  sandstone  (from  Portland,  Conn.),  -000009532.  These  num 
bers  become,  for  an  increase  of  1°  F.  in  100  feet  of  the  granyte,  -00579  in.;  the  marble, 
•00680  in.;  the  sandstone,  '01144  in.;  and  for  1°  C.,  respectively,  -01042  in.,  -01224  in., 
•02059  in. 

Bunker  Hill  Monument,  a  hollow  obelisk,  two  hundred  and  twenty-one  feet  high  and 
thirty  feet  square  at  base  (made  of  granyte  blocks),  swings  to  one  side  and  the  other, 
with  the  progress  of  the  sun  during  a  sunny  day  —  a  pendulum  suspended  from  the 
centre  of  the  top  describing  an  irregular  ellipse  nearly  half  an  inch  in  its  greatest 
diameter  (Horsford). 


VOLCANOES.  701 

Such  a  cause,  working  day  after  clay  about  rocky  peaks  and  preci 
pices,  causing  each  day  some  displacement,  may  end  in  degradations 
of  geological  importance.  Besides  shifting  the  positions  of  masses  of 
rock,  it  causes  expansion  and  contraction  of  thin  portions  of  the  exte 
rior  of  rocks,  and  in  some  kinds  leads  to  a  peeling  off  of  thin  layers, 
as  observed  by  Shaler,  or  to  the  opening  of  delicate  fractures  that 
give  access  to  air  and  moisture  for  chemical  work. 

Among  the  Thimble  Islands,  off  the  shores  of  Stony  Creek,  Con 
necticut,  the  walls  of  granite  or  granitoid  gneiss  facing  the  water,  in 
some  of  the  islands,  are  peeling  off  in  great  laminre,  a  third  to  a  half 
inch  thick,  without  any  apparent  decomposition,  or  even  a  dimming  of 
the  lustre  of  the  feldspar  or  mica  ;  and  it  may  be  owing  to  the  heat  of 
the  day's  sun,  and  the  chilling  by  the  waters  when  the  tide  is  in.  Over 
the  rocky  surface  of  countries  within  the  glacial  latitudes  of  the  Glacial 
period,  the  scratches  left  by  the  glacier  are  generally,  when  first  un 
covered,  as  fresh  and  sharp-edged  as  when  they  were  made.  But,  if 
the  surface  be  open  to  the  sun's  heat  and  light,  and  the  rains  and  frosts, 
for  a  dozen  years,  far  the  larger  part  of  the  markings  disappear  ;  and 
alternate  heating  and  cooling  is  an  important  means  of  this  oblitera 
tion  of  the  old  markings. 

The  sun's  heat  also  produces  cracks  by  drying.  Mud-cracks  (p. 
84)  are  an  example.  Such  cracks  in  rocks  are  recognized  by  their 
being  very  shallow  ;  yet,  in  the  deep  soil  of  some  prairies,  they  extend 
down  two  or  three  yards. 

2.  In  Solids:  the  Heat  from  a  Subterranean  Source.  —  From  Totten's 
experiments  as  data,  Lyell   has  calculated  that  a  mass  of  sandstone,  a 
mile   thick,  raised  in  temperature  200°  F.,  would   have  its  upper  sur 
face  elevated   ten   feet ;  and   that  a  portion   of  the   earth's  crust,  fifty 
miles  thick,  raised  600°  F.  to  800°  F.,  might  produce  an  elevation  of 
1,000  to  1,500  feet.     Cooling  again,  would  reverse  the  result. 

In  the  cooling  of  a  rock  that  has  been  in  fusion,  the  contraction 
usually  produces  fractures  at  right  angles  to  the  cooling  surfaces.  In 
this  way,  in  connection  with  a  concretionary  tendency  in  the  process 
of  solidification,  basaltic  columns  are  produced  (pp.  87,112).  The 
cooled  mass,  when  in  contact  with  the  adjoining  rock,  is  often  much 
fractured  in  an  irregular  way,  besides  having  a  finer  grain  than  else 
where,  in  consequence  of  rapid  cooling.  Basaltic  columns  are  some 
times  curved,  when  the  cooling  surfaces  are  not  parallel.  Sands  tones 
and  shales,  subjected  to  a  heating  and  drying,  from  contact  with  melted 
rock,  are  often  fractured  in  columnar  forms. 

3.  Expansion  and  Contraction  attending  Solidification  and  Fusion. — 
I^xperiments  on  the  contraction  attending  solidification  of  rock  mate 
rial  have    been   made   by  Bischof,  St.  Claire  Deville,   Delesse,  and 


702  DYNAMICAL    GEOLOGY. 

Mallet ;  and  the  results  of  the  three  investigators  last  mentioned 
nearly  agree.  In  solidification,  the  glass  state  is  a  consequence  of 
rapid  cooling,  and  the  stone  state,  of  slow  ;  and,  consequently,  glass 
will  become  stone,  if  melted  and  very  slowly  cooled. 

In  passing  from  the  liquid  to  the  glass  state,  in  the  case  of  plate 
glass,  at  the  Thames  Glass  Works,  the  cubic  contraction  was  1'59  per 
cent,  —  100  parts,  by  weight,  becoming  98-41  (Mallet).  In  passing 
from  the  glass  to  the  stone  state,  according  to  Delesse,  granite  de 
creases  in  density  9  to  1 1  per  cent. ;  syeny te,  8  to  9  ;  diory  te,  6  to  8 ; 
doleryte  and  melaphyre,  5  to  7 ;  basalt  and  trachyte,  3  to  5  per  cent.1 
The  whole  increase  of  density  for  doleryte,  in  passing  from  the  liquid 
to  the  stone  state,  would  be  near  8  per  cent.,  which  is  equivalent  to  a 
change  of  volume  from  100  to  92  per  cent. 

3.  IGNEOUS  ACTION  AND  KESULTS. 
1.  VOLCANOES. 

The  facts  relating  to  volcanoes  are  here  presented  under  the  follow 
ing  heads :  (1)  General  nature  of  volcanoes,  and  their  geographical 
distribution ;  (2)  Kinds  of  volcanic  cones ;  (3)  Volcanic  action  ;  (4) 
Origin  of  the  forms  of  volcanic  cones ;  (5)  Subordinate  volcanic 
phenomena;  (6)  Source  of  volcanoes. 

1.  General  Nature  of  Volcanoes,  and  their  Geographical 
Distribution. 

1.  Volcanoes.  —  Volcanoes  are  mountains  or  hills,  of  a  more  or 
less  conical  shape,  in  a  state  of  igneous  action,  and  consequently 
emitting  vapors  and,  occasionally,  melted  rock,  or  lava,  with  showers 
of  fragments,  or  cinders,  from  a  central  opening,  called  the  crater.  They 
are  conduits  of  fire,  opening  outward  from  within  or  beneath  the 
earth's  crust.  An  extinct  volcano  is  a  volcanic  mountain  that  has 
ceased  to  be  active,  —  the  body,  with  the  fire  out. 

The  lavas  flow  out  either  over  the  edge,  or  lip,  of  the  crater,  or, 
more  commonly,  through  fissures  in  the  sides,  or  about  the  base  of 
the  mountain.  The  cinders  are  thrown  upward  from  the  vent,  or 
crater,  to  a  great  height,  as  a  jet  of  sparks  or  fiery  masses,  and  fall 
around  in  cooled  particles  or  fragments,  which  are  simply  granulated 
lava :  they  may  build  up  a  conical  elevation  around  the  vent,  or  be 
carried  to  a  distance  by  the  winds. 

When  rain  or  moisture  from  any  source  descends  with  the  cinders, 
the  mass  forms  tufa,  —  a  kind  of  volcanic  sandstone,  being  stratified, 

i  Mallet,  on  Volcanic  Energy,  Traits.  Roy.  Soc.,  1872;  Delesse,  Bull.  Soc,  Geol.  de 
France,  II.  iv.  1380,  1847. 


VOLCANOES.  703 

granular  in  texture,  not  very  firm,  and  usually  of  a  gray,  yellowish- 
brown,  or  brownish  color. 

2.  Geographical  Distribution.  —  Volcanoes  occur  (1)  over  the  bor 
der-regions  of  the  continents,  —  that  is,  the  regions  between  the 
oceans  and  the  summit  of  the  border-range  of  mountains,  as  between 
the  Pacific  and  the  eastern  limit  of  the  summits  of  the  Rocky 
Mountains  ;  (2)  in  the  continental  islands,  or  those  near  sea-coasts  ; 
(3)  in  oceanic  islands,  nearly  all  of  which,  excepting  a  few  of  very 
large  size  and  the  coral  islands,  are  throughout  volcanic,  —  and  the 
coral  islands  have  probably  a  volcanic  basis.  (4)  Volcanoes  are 
mostly  confined  to  the  borders  of  the  larger  ocean,  the  Pacific,  and 
to  the  seas  separating  the  northern  from  the  southern  continents, 
namely,  the  West  Indies,  between  North  and  South  America,  —  the 
Mediterranean,  between  Europe  and  Africa,  —  the  Red  Sea,  between 
Asia  and  Africa,  —  the  East  Indies,  between  Asia  and  Australia. 
There  are  but  few  about  the  Atlantic,  excepting  those  of  the  islands  ; 
and  over  the  interior  of  continents,  remote  from  the  regions  men 
tioned,  they  are  almost  unknown. 

(5.)   Volcanoes  are  very  commonly  in  linear  series  or  groups. 

1.  Borders  of  the  Pacific. — The  Pacific  is  almost  completely  belted  with  volcanic 
mountains.     They  occur  in  Fuegia,  the  southern  extremity  of  the  Andes;  in  Patagonia; 
thirty-two  in  Chili,  — that  of  Aconcagua,  23,000  feet  high;  seven  or  eight  in  Bolivia 
and  southern  Peru,  —  Arequipa,  18,877  feet;  nineteen  or  twenty  about  Quito,  nearly 
all  over  14,000  feet,  and  among  them  Cotopaxi.  19,660  feet  in  altitude  (bv  barometer, 
Dr.   Reiss,  in  1873);  in  Central  America,  there  are  thirty-nine;  in   Mexico,  seven  of 
large  size,  with  others  smaller;  in  California,  Oregon,  and  northwest  America,  twelve, 
making  a  lofty  series  of  snowy  summits,  11.000  to  14,000  feet  high,  —  St.  Helen's,  in 
Oregon,  probably  12,600  feet;  Mount  Hood,  11,225;  Mount   Shasta,  14,440.     In  the 
Aleutian  Islands,  which  form  a  curve  like  a  festoon,  across  the  Northern  Pacific,  there 
are  twenty-one  islands  with  volcanoes;  in  Kamtchatka,  fifteen  to  twenty;  in  the  Kuriles, 
thirteen;  in  the  Japan  group,  twenty-four,  some  10,000  feet  high;  in   the  Philippines, 
fifteen  to  twenty;  several  along  the  north  coast   of  New  Guinea;  a   number  in  New 
Zealand;  in  the  Antarctic,  on  the  parallel  of  76°  5',  and -near  the  meridian  of  168°  E., 
Mounts  Erebus  and  Terror,  12,400  and  10.900  feet  high,  both  in  full  action  when  seen 
by  Ross  in  1841;  and,  more  to  the  east,  south  of  Cape  Horn,  Deception  Island,  and 
Bridgman's. 

2.  Over  the  Pacific.  —  At  the  Hawaian   Islands,  there  are  remains  of  ten  or  more 
volcanic  mountains;  and  two  on  Hawaii  are  now  active,  —  Mount  Loa,   13,760  feet 
high,  and  Mount  Hualalai,  about  10,000  feet;  while  Mount  Kea,  on  the  same  island, 
13,950  feet  high,  has  not  been  very  long  extinct. 

There  are  other  volcanic  mountains  at  the  Society  group,  Marquesas,  Navigator, 
Friendly  Islands,  Feejees,  Santa  Cruz  group,  New  Hebrides,  Ladrones;  among  which, 
Tauna  and  Ambrym  in  the  New  Hebrides,  Tafoa  and  Amargura  in  the  Friendly  group, 
Tinakoro  in  the  Santa  Cruz  group,  and  two  or  three  in  the  Ladrones,  are  in  action. 

3.  Over  the  seas  that  divide  the  northern  and  southern  continents  from  one  another, 
and    the  ret/ions  in   their  vicinity.  —  (a.)  The  West  Indies,    where    ten    islands   are 
eminently  volcanic,      (b.)  The  Mediterranean  and  its  borders,   as   in   Sicily  and  the 
islands  north;  Vesuvius,   and  other  parts  of  Italy;  Spain,   central  France,  Germany 
etc.,  in  Europe;  the  Grecian  Archipelago,  which  contains  five  volcanic  islands,  —  San- 
toriu,  Milo,  Cimolos,  Polenos,  and  Mmyros ;  iu  Asia  Minor,  where  are  the  Catacecau- 


704  DYNAMICAL    GEOLOGY. 

mene  and  other  volcanic  regions;  and,  more  to  the  eastward,  toward  the  Caspian, 
Mount  Ararat,  16,950  feet  high;  Little  Ararat,  12,800  feet;  Demavend,  on  the  south 
shore  of  the  Caspian,  20,000  feet.  (c. )  The  Red  Sea,  along  its  southern  borders,  where 
there  are  a  number  of  lofty  volcanic  summits,  (d.)  The  East  Indies,  where  there  are 
two  hundred  or  more  volcanoes,  of  which  there  are  nearly  tifty  in  Java  alone,  according 
to  Dr.  Junghuhn,  and  twenty-eight  out  of  the  fifty  now  active;  nearly  as  many  in 
Sumatra;  one  hundred  and  nine  in  the  small  islands  near  Borneo;  a  number  in  the 
Philippines,  etc. 

4.  In  the  Indian  Ocean.  —  A  few  in  Madagascar;  also  the  Isle  of  Bourbon,  Mauritius, 
and  the  Comoro  Islands,  and,  to  the  south,  Kerguelen  Land,  etc. 

5.  On  the  Atlantic  Borders.  —  Only  in  the  Bight  of  Benin,  on  the  African  coast,  where 
one  in  the  Cameroons  Mountains  is  said  to  be  14,000  feet  high ;  and  the  neighboring 
islands,  from  Fernando  Po  to  Annabon. 

6.  In  the  Atlantic  Occ-'in.  — St.  Helena,  the  Cape  Verdes,  Canaries,  Madeira,  Azores, 
and  Iceland.     All  the  islands  of  the  deep  part  of  the  ocean  (that  is,  not  on  the  European 
or  American  borders)  are  volcanic. 

7.  Over  the  Interior  of  the  Continents.  —  In  America,  North  and  South,  there  are  none 
east  of  the  Rocky  Mountains  and  Andes;  in  North  America,  there  are  extinct  cones  at 
the  summit  of  the  Rocky  Mountain  chain,  about  the  head- waters  of  the  Yellowstone, 
but  none  east  of  its  crest  range.     In  Africa,  none  are  known.     In  Asia,  there  is  a  small 
volcanic  region  in  the  Thian-Shan  Mountains,  at  Pe-schan  and  Turfan,  besides  hot 
springs  near  Alak-tu-kul,  and  some  other  spots  in  that  vicinity.     In  Australia,  none 
are  known  over  the  interior,  the  few  observed  being  situated  near  its  southern  border. 

2.  Kinds  of  Volcanic  Cones. 

As  the  volcanic  mountain  is  made  from  its  own  ejections,  it  may 
consist  either  (1)  of  lava  alons ;  (2)  of  tufa  alone;  (3)  of  cinders 
alone  ;  (4)  of  combinations  of  lavas  with  either  cinders  or  tufas,  or 
with  both.  The  last  is  the  more  common  kind. 

1.  Lava-cones.  —  Lavas,  when  quite  liquid,  flow  off  naturally  at  a 
small  angle.  The  average  slope  of  lava-cones  is,  therefore,  very  gen 
tle,  —  usually  between  three  and  eight  degrees. 

The  great  volcanoes  of  Hawaii  (Sandwich  or  Ilawaian  Islands), 
Mount  Loa  and  Mount  Kea,  shown  in  the  map  (Fig.  1109),  and  sec 
tions  of  which  are  given  in  Figure  1108,  are  mainly  lava-cones  ;  and 

Fig.  1108. 


B  — 

A,  B,  B,  C,  profile  of  Hawaii,  as  seen  from  the  east.v  ird  ;  L   Mount  Loa  ;  K,  Mount  Kea 

the  general  slope  is  six  to  eight  degrees.  (These  two  figures  are  parts 
of  one  profile  view  of  the  island,  the  two  joining  at  B.)  JEtna  has  a 
similar  low  inclination.  A  horizontal  section  of  Mount  Loa,  1,800 
feet  below  its  top,  would  be  nearly  twenty  miles  broad. 


VOLCANOES. 


705 


In  true  lava-cones,  like  Mount  Loa,  the  crater  is  generally  a  pit- 
crater,  —  a  great  depressed  area  in  the  surface  of  the  mountain,  like  a 

Fit;.  1109. 


Map  of  part  of  Hawaii. 

pit  or  quarry-hole  in  a  plain,  as  in  the  summit-crater  of  Mount  Loa 
and  in  Kilauea,  the  latter  4,000  feet  above  the  sea.     A  larger  bird's-eye 


Crater  of  Kilauea,  in  1840 :  a,  large  boiling  lake  of  lava ;  at  o  and  near  e,  sulphur-banks  ;  r,  an 
adjoining  small  crater  ;  p,  neck  between  Kilauea  and  the  crater  r. 

view  of  Kilauea  (with  an  adjoining  small  crater,  r)  is  shown  in  Fig. 
1110,  and  a  vertical  transverse  section  of  the  same,  more  enlarged,  in 
Fig.  1111.  The  pits  have  precipitous  walls  of  stratified  rocks;  for 
the  lavas  are  in  layers,  and  the  layers  are  nearly  horizontal. 

At  Mount  Loa,  the  summit-crater  is  13,000  feet  in  its  longer  diameter,  and  780  feet 
deep.     Kilauea  is  16,000  feet  in  its  greatest  length,  seven  and  one  half  miles  in  circuit, 
nearly  four  square  miles  in  area,  and  600  feet  deep.    After  its  last  great  eruption,  of  1840, 
45 


T06 


DYNAMICAL    GEOLOGY. 


the  pit  at  centre  was  1,000  feet  deep,  with  a  shelf  around  of  about  600  feet,  a  condition 
represented  in  Fig.  1111.  The  crater  is  as  much  open  to  the  day  as  a  city  of  two  miles 
square  would  be,  within  an  encircling  wall  of  six  hundred  feet  (the  present  depth);  and 
the  pools  of  boiling  lavas  and  vapors  (one  of  which  is  at  a,  Fig.  1110)  may  be  as  leis 
urely  surveyed  from  the  brink  as  if  the  objects  were  gardens  and  cathedrals. 

Fig.  1111. 


Vertical  section  of  crater  of  Kilauea,  1840. 

2.  Tufa-cones.  —  Flowing  mud  from  a  boiling  basin,  or  cinders  wet 
with  water  and  steam,  will  take  a  larger  angle  of  flow  than  lavas  ; 
and  tufa-cones,  therefore,  have  commonly  an  angle  of  between  fifteen 
and  thirty  degrees.  The  layers  usually  slope  inward  toward  the  bot 
tom  of  the  crater  (Fig.  1112),  as  well  as  outward  down  the  sides. 
Fig.  1112.  Fig.  1113. 


Section  of  a  tufa-cone. 


Assumption  Island,  one  of  the  Ladroues. 

The  tufa  has  a  brownish-yellow  color,  owing  to  the  action  of  the  steam 
or  hot  water  on  the  cinders,  peroxydizing  part  of  the  iron  in  the  min 
erals  (pyroxene  mainly)  of  the  lavas,  and  making  a  hydrous  peroxyd. 
The  crater  is  generally  saucer-shaped.  A  tufa-cone  on  Oahu  (called 
Diamond  Hill)  has  a  height  of  one  thousand  feet.  Such  cones  are 
among  the  results  of  lateral  eruptions  about  great  volcanoes  near  the 
sea. 

3.  Cinder-cones.  —  Falling  cinders  may  make  a  declivity  of  about 
forty  degrees.     The  eruption  of  cinders,  therefore,  produces  a  crater 
with  a  narrow  throat,  a  narrow  rim  above,  steep  sides,  the  slope  thirty- 
five  to  forty  degrees   (Fig.  1113).     If  the  volcano  is   in  brisk  action, 
the  space  within  the  crater  is  dark  with  the   rising  vapors  ;  and   the 
explosions  attending  the  ejection  of  cinders  occur  usually  at  short  in 
tervals. 

The  cone  is  at  first  nearly  black  or  brownish-black:  but,  if  not  soon  covered  with 
vegetation,  it  often  becomes,  through  atmospheric  agencies,  of  a  red  color,  from  the 
peroxydation  of  the  protoxyd  of  iron  in  the  lava:  the  perox}rd  of  iron  formed  differs 
from  that  of  the  tufa-cone  in  not  containing  water,  and  hence  the  difference  of  color. 
The  growth  of  vegetation  tends  to  change  back  the  red  color  to  brownish-black,  since 
the  carbon  deoxydizes  the  peroxyd,  making  protoxyd  and  carbonic  acid. 

4.  Mixed  Cones.  —  The   cones    which,    like  Vesuvius,    are   formed 
partly  of  lava  and  partly  of  cinders  or  tufa,  may  have  any  angle  of 
slope,  up  to  thirty-five  degrees.     They  may  be  lava  below,  and  termi- 


VOLCANOES.  707 

nate  in  a  lofty  cone  of  cinders,  of  forty  degrees.  The  crater  may  be 
nearly  like  that  of  the  cinder-cone,  —  a  deep  cavity,  with  the  walls 
thin,  compared  with  those  of  the  simple  lava-cone.  There  is  no  fixed 
order  in  the  alternations  of  lavas  and  cinder  or  tufa  layers  ;  the  lavas 
are  apt  to  prevail  most  in  the  early  stages  of  a  volcano. 

3.  Volcanic  Action. 

The  agents  concerned  in  volcanoes  are  (1)  lava,  and  (2)  over 
heated  steam  and  atmospheric  air,  with  vapors  of  sulphur  and  some 
other  gases. 

The  phenomena  are  (1)  Rising  and  projectile  effects,  from  escaping 
vapors ;  (2)  Movements  of  the  lavas  in  the  crater  ;  (3)  Eruptions. 

The  facts  presented  in  illustration  of  this  subject  are  taken  mainly  from  the  volcanoes 
of  Kilauea  and  Vesuvius,  both  of  which  have  been  visited  by  the  author. 

1.  Agents. 

1.  Kinds  of  Volcanic  Rocks,  or  Lavas.  —  The  fused  rock-material  is 
called  lava.     When  solidified,  it  is  lava  still,  and  is  often  so  termed, 
whatever  its  texture  ;  but  in  general  the  name  is  restricted  to  those 
volcanic  rocks  which  are  more  or  less  cellular.     The  cellules  are  usu 
ally  ragged,   and   not   smooth   and   almond-shaped   like  those  of  an 
amygdaloid.    The  solid  kinds,  with  rarely  a  cellule  or  with  none  at  all, 
come  under  the  general  designation   of  volcanic  rocks.     A  very  light 
cellular  lava  is  a  scoria,  or  volcanic  slag,  or  is  said  to  be  scoriaceous. 

The  principal  kinds  of  volcanic  rocks  and  lavas  have  been  described  on  pp.  76-79,  to 
which  reference  may  here  be  made.  The  most  common  are  doleryte,  which  takes  on  the 
form  of  lava,  and  is  then  often  called  basalt;  peridotyte,  or  a  doleryte  or  basalt  contain 
ing  chrysolite  ;  trachyte  and  phonolyte.  The  rock  of  Vesuvius  is  amphiyenyte,  it  contain 
ing  the  white  mineral  leucite  (or  amphigene)  disseminated  through  it;  that  of  Mount 
Loa  is  mostly  of  the  first  three  of  the  kinds  just  mentioned.  But,  about  some  parts, 
and  even  at  the  summit,  of  Mount  Loa,  there  is  phonolyte,  —  a  compact  light  colored 
feM  spathic  rock  without  cellules.  It  is  not  an  uncommon  fact,  that,  while  the  ordinary 
rocks  of  the  exterior  of  a  volcanic  mountain  are  the  heavy  cellular  dolerytes  or  basalt 
or  peridotyte,  those  of  the  interior  (a*  best  seen  when  the  mountain-mass  is  intersected 
by  profound  gorges)  are  of  these  compact  feldspathic  kinds,  having  no  resemblance  to 
ordinary  lavas. 

2.  Liquidity  of  Lava.  —  The    liquid   lava  flows  usually  with  nearly 
the  mobility  of  melted  iron  or  glass.     The  whole  of  the  flowing  mass 
does  not,  however,  appear  to  be  properly  in  a  liquid  or  melted  condi 
tion  ;  a   portion,  in   unfused  grains,  is   suspended  in  a  fused  portion. 
As  the  heat  just  below  the  surface  has  the  intensity  of  what  is  called 
white  heat,   any   part    of  the   rock-material  which  is  fusible  at    this 
temperature,  or,  rather,  which  is  not  consolidated  at  this  temperature 
(for  the  material  has  come  from  the   depths  below,  where  the  heat  is 
much  greater,  it  increasing  with  the  depth  or  pressure),  will  be  in  a 


708  DYNAMICAL   GEOLOGY. 

melted  state.  In  the  crater  of  Kilauea,  the  liquid  lava  cools  at  sur 
face  into  a  scoriaceous  glass ;  and  this  glass  was,  beyond  doubt,  in 
fusion,  like  the  glass  of  a  glass-furnace,  —  though  perhaps  less  per 
fectly  so,  as  stony  unfused  grains  may  be  disseminated  through  it.  Be 
low  the  surface,  six  inches  more  or  less,  the  consolidated  lava  has  the 
aspect  of  a  cellular  rock ;  but  even  glass  takes  a  stone-like  texture,  if 
very  slowly  cooled,  and  would  do  so  all  the  more  readily  if  it  contained 
a  large  amount  of  umnelted  grains  of  any  stony  material. 

At  Kilauea,  the  liquidity  is  so  complete  that  jets,  but  a  quarter  of  an  inch  through, 
are  sometimes  tossed  up  from  a  tiny  vent,  and,  as  they  fall  back  on  one  another,  make 
a  column  of  hardened  tears  of  lava.  Again,  the  winds  draw  out  the  glass  of  the  lava- 
jets,  in  the  boiling  pools,  into  fine  threads,  by  carrying  off  small  fragments,  and  thus 
make  what  is  called  Pele's  hair:  the  crater  being  the  residence,  in  native  mythology,  of 
the  goddess  Peld. 

The  mobility  is  also  very  largely  promoted  by  the  vapors  rising  in 
the  lava,  especially  the  overheated  steam.  Scrope  considers  this  its 
sole  cause. 

3.  Vapors  or  Gases.  —  Besides  air,  steam  (vapor  of  water),  and 
sulphurous  vapors  (either  sulphurous  acid  or  sulphur),  there  are  some 
times  (1)  Carbonic  acid  yas,  derived  from  limestone,  and  perhaps 
from  other  sources  below  ;  (2)  Chlorhydric  acid  yas,  derived  from  sea- 
water,  but  probably  not  exclusively. 

But  these  two  gases,  along  with  nitrogen  and  sulphuretted  hydrogen,  are  mostly  em 
anations  from  fumaroles,  —  vents  of  hot  air,  steam,  or  sulphurous  fumes,  in  the  neigh 
borhood  of  a  volcano,  —  rather  than  from  the  liquid  lava.  Aqueous  vapor  exceeds 
vastly  in  amount  all  other  vapors,  and,  at  Vesuvius,  is  the  first  that  issues  from  newly 
opened  fumaroles ;  afterward  follow  in  some  cases  carbonic  acid,  generally  hydrochloric 
acid,  sulphurous  acid,  and  also  common  salt,  with  often  oxyds  or  chlorids  of  copper, 
lead,  etc.  The  hydrochloric  acid  changes  the  oxyds  to  chlorids,  and  thus  the  chlorids 
originate;  and  sulphurous  acid  is  the  means  of  changing  them  to  sulphates. 

These  facts  appear  to  show  that  sea-water  gains  access  to  the  lavas.  The  steam 
comes  mainly  from  superficial  wraters. 

2.    Volcanic  Phenomena. 

1.  Rising  and  Projectile  Effects  of  escaping  Vapors.  —  The  water 
and  other  vaporizable  substances  within  the  lava  are  under  a  pressure 
of  about  125  pounds  to  a  square  inch,  for  every  100  feet  of  depth. 
Owing  to  the  heat  and  their  consequent  expansion,  they  slowly  rise  in 
the  heavy,  viscid  liquid  ;  as  they  rise,  they  keep  expanding,  until, 
nearing  the  surface,  they  begin  to  take  the  form  of  vapors,  and  finally 
break  through. 

The  bubble  or  vapor  in  boiling  water  has  projectile  force  enough, 
as  it  breaks  at  the  surface,  to  throw  up  water  in  jets  to  a  height  of  two 
or  three  inches.  In  lavas  which  have  the  freest  liquidity,  as  those  of 
Kilauea,  the  jets  are  thirty  to  forty  feet  high.  Consequently,  a  surface 


VOLCANOES.  709 

of  liquid  lava,  as  in  the  lakes  of  lava  in  Kilanea,  is  covered  through 
out  with  jets,  like  a  vat  of  boiling  water;  and  there  is  only  a  muttering 
noise  from  the  action.  It  looks  like  ordinary  ebullition,  only  the  jets 
are  jets  of  fiery  liquid  rock.  They  rise  vertically,  and  fall  back  into 
the  pool,  or  on  its  sides,  before  they  have  cooled.  A  lake  one  thousand 
feet  in  diameter  (at  a,  Fig.  1110)  was  thus  in  brilliant  play  over  its 
whole  surface,  when  visited  by  the  author  in  1840 ;  and  in  more  act 
ive  times  a  large  part  of  the  area  at  bottom  has  been  in  this  boiling 
state. 

If  the  lavas  be  less  liquid,  the  vapors  are  kept  from  escaping,  by  the 
resistance,  until  they  have  collected  in  far  larger  bubbles;  and, when 
such  bubbles  burst,  the  projectile  force  may  be  enormous :  it  carries 
the  fragments  far  aloft,  to  descend  in  a  shower  of  cinders  of  great 
extent. 

Such  bubbles,  rising  and  bursting,  were  seen  by  Spallanzani  in  the  crater  of  Strom- 
boli,  a  high  cinder-cone  in  the  Mediterranean,  north  of  Sicily.  In  times  of  moderate 
action,  at  Vesuvius,  the  outbursts  of  cinders  occur  every  three  to  ten  minutes;  but,  in 
a  period  of  eruption,  they  are  almost  incessant.  According  to  Sir  Win.  Hamilton,  the 
cinders  rose  to  a  height  of  10,000  feet,  at  the  eruption  of  1779,  —  a  height  indicating  a 
vast  projectile  force.  Occasionally,  masses  of  lava  are  thrown  up,  which  descend  like 
huge  cannon-balls,  having  been  rounded  by  the  rotation  before  they  had  cooled,  and 
rendered  compact  externally,  while  usually  cellular  within.  Such  masses  are  called 
volcanic  bombs.  The}'  may  have  lenticular  as  well  as  spheroidal  shapes.  The  centre  is 
in  some  an  aggregation  of  chrysolite,  in  others  of  older  pieces  of  lava,  or  other  mineral 
matter,  that  was  not  in  a  state  of  fusion.  They  are  sometimes  twelve  or  fifteen  feet 
in  diameter,  and  when  so  are  very  slow  in  cooling. 

2.  Movements  of  the  Lavas  in  the  Crater.  —  (a.)  Upward  Move 
ment.  —  As  the  vaporizable  substances  (water,  sulphur,  etc.)  and  at 
mospheric  air  expand,  while  rising  in  the  volcanic  vent,  they  displace 
correspondingly  the  lava,  and  so  cause  a  general  expansion  of  the 
mass.  This  alone  is  sufficient  to  produce  a  rise  of  the  lava  in  a  con 
duit. 

The  water  is  mainly  from  the  rains  which  fall  over  the  volcanic  re 
gion.  They  descend  toward  the  vent,  and,  as  they  approach  the  lava 
conduit,  are  prevented  from  being  driven  back  by  the  pressure  of  the 
waters  above:  thus  they  pass  into  the  lavas  and  become  the  great 
source  of  their  activity.  In  a  similar  mariner,  the  salt  waters  of  the 
ocean  will  find  their  way  to  the  lavas,  provided  there  are  no  fresh 
waters  pressing  seaward  to  prevent  it. 

When  the  boiling  of  a  viscid  fluid  in  a  tube  causes  its  upper  surface  to  ascend,  be 
cause  the  liquid  at  top  becomes  inflated  or  frothy  with  vapor,  it  exemplifies,  as  Prevost 
long  since  remarked,  the  same  principle,  although  the  degree  of  inflation  very  far  ex 
ceeds  that  in  a  dense  lava.  The  fact  of  a  rising  in  the  volcano  from  this  cause  is 
beyond  question. 

This  rising  becomes  apparent  in  overflowings  from  the  pools  of  the 


710  DYNAMICAL    GEOLOGY. 

crater,  over  its  bottom,  in  streams  which  cool  and  become  solid  lava. 
Whether  the  whole  rising  is  due  to  this  cause  is  not  ascertained.  The 
risings  and  overflowings  are  repeated  from  time  to  time,  until  the  ma 
terial  within  the  crater  has  reached  a  height  and  an  intensity  of  action 
that  lead  to  an  eruption. 

At  Kilauea  (the  bottom  of  which,  when  at  its  lowest  mark,  is  3,000  feet  above  the 
sea),  the  conduit  of  liquid  lava,  below  the  crater,  is  3,000  feet  long,  to  the  sea-level; 
and  it  may  extend  many  miles,  or  perhaps  scores  of  miles,  below  this.  Nineteen  miles 
would  correspond  to  about  100,000  feet.  A  rise  of  the  lavas  within  the  crater,  for  400 
to  500  feet,  in  the  manner  above  explained,  is  all  that,  in  three  cases  of  eruption  at  Ki 
lauea,  preceded  the  outbreak.  Five  hundred  feet  in  100,000  is  an  average  expansion  of 
onlv  a  half  of  one  per  cent.  But  it  is  probable  that  the  vapors  which  produce  this 
result  are  comparatively  superficial;  they  may  be  from  the  fresh  waters  of  the  sur 
rounding  region,  or  from  those  of  the  ocean  adjoining. 

The  increase  of  activity,  as  the  lavas  rise  in  a  crater,  has  two  obvi 
ous  causes:  (1)  the  temperature  of  the  lavas  increases  with  the  pres 
sure;  and.  consequently,  a  rise  of  100  feet  would  have  increased  very 
much  the  temperature  at  the  bottom  of  that  100  feet,  and  so  on  for 
greater  depths  ;  (2)  the  rise  exposes  a  higher  column  of  liquid  lava 
above  to  the  action  of  external  waters. 

(&.)  Circulating  Movement.  —  In  the  lava-conduit,  the  greatest  heat 
is  along  the  centre,  most  remote  from  the  cold  sides.  Hence,  as  in 
any  cauldron,  the  ascent  from  inflation  by  rising  vapors  would  be 
greatest  at  the  centre ;  there  would  therefore  be  at  the  surface  a  flow 
from  the  centre  to  the  sides,  and  a  system  of  circulation.  This  was 
exhibited  on  a  grand  scale  at  Kilauea,  in  1840,  where  the  liquid  lava 
in  the  great  lake  (1,000  feet  across,  a,  Fig.  1110,  p.  705)  seemed  like 
a-  river  that  came  to  the  surface  for  a  moment  and  then  disappeared. 

The  area  of  greatest  heat  was  near  the  northeast  side  of  the  lake ; 
and  the  stream  seemed  to  flow  to  the  southwest. 

3.  Eruptions.  —  (a.)  General  Facts.  —  The  lavas  within  the  crater 
reach  such  a  height,  and  the  activity  of  ttfe  vapors,  from  one  cause  or 
another,  becomes  so  great  that  an  eruption  takes  place,  either  over  the 
brim  of  the  crater  or  through  the  fractured  mountain,  and  generally 
the  latter.  The  lavas  flow  off  to  a  distance  sometimes  of  sixty  miles 
or  more. 

The  outflow  of  lavas  is  attended,  in  most  volcanoes,  as  at  Vesuvius, 
with  the  ejection  of  cinders  from  the  wider  parts  of  fissures ;  and  they 
often  continue  to  be  thrown  out,  long  after  the  flow  has  ceased.  They 
thus  build  up  a  cinder-cone  immediately  around  the  open  vent. 

Most  of  the  small  cones  about  volcanic  mountains  —  called  often  parasitic  cones  —  are 
formed  in  this  manner  about  a  point  in  some  opened  fissure  from  which  lavas  were 
ejected.  Cinder  and  vapor  eruptions  are  the  last  effects  of  the  subsiding  fires  of  a  vol 
cano.  Mt.  Kea  is  an  example  of  a  mountain-cone  which  finished  its  career  as  an  erup 
tive  volcano  by  the  formation  of  a  number  of  cinder-cones  at  summit.  Their  height  is 


VOLCANOES.  711 

300  to  500  feet.  In  other  cases,  the  central  vent  continues  to  eject  cinders  for  a  long 
period;  and  the  mountain  becomes  high  and  steep. 

Where  the  liquid  rock  flows  from  an  open  vent  or  pool,  like  those  of  Kilauea,  the  cooled 
lava  has  a  surface-crust,  four  to  six  inches  thick,  of  glassy  scoria.  The  process  of  boil 
ing  covers  the  lavas  in  the  pools  with  a  scum,  as  it  does  molasses;  and  this  scoria  is  the 
hardened  scum  or  froth.  Below  this  scoriaceous  surface,  the  lava  is  solid  rock,  often 
containing  only  a  few  ragged  cellules. 

When  the  outflow  takes  place  from  fissures,  through  which  the  lavas  come  up  with 
out  having  undergone  any  boiling,  the  stream  is  often  solid  lava  throughout,  without 
any  scoria;  the  surface  is  hard  and  compact,  but  looks  ropy,  owing  to  the  marks  of 
flowing. 

Whenever  the  stream  of  lava  stops  on  its  course,  it  rapidly  hardens,  over  its  surface. 
If  it  is  then  made  to  move  again,  from  another  accession  of  lavas,  the  hardened  crust 
breaks  up  like  ice  on  a  pond,  but  makes  black  and  rough  cakes  and  blocks,  100  to 
10,000  cubic  feet  in  size,  which  lie  piled  together  over  acres  or  square  miles.  Such 
masses  are  sometimes  called  clinkers.  A  large  part  of  the  island  of  Hawaii  is  covered 
by  the  bare  lava-streams,  —  some  with  twisted,  ropy  markings  over  the  surface,  drawn 
out  as  the  sluggish  liquid  flowed  along;  others,  great  clinker-jiclds,  horrid  exhibitions 
of  utter  desolation. 

The  streams  of  lava  over  the  land  often  rise  into  great  protuberances,  many  yards 
across,  with  oven-shaped  cavities  within,  formed  by  waters  beneath,  that  were  evapo 
rated  by  the  heat  while  the  flow  was  in  progress. 

In  a  submarine  eruption,  or  wherever  the  lavas  enter  the  sea,  an  upper  portion  of  the 
outflow,  in  contact  with  the  water,  is  shivered  to  fragments ;  if  in  deep  water,  the  frag 
ments  are  deposited  and  make  a  stratum  of  tufa,  sometimes  taking  a  conical  form ;  if  at 
the  water's  edge,  they  rise  in  a  shower  of  water  and  cinders,  and  fall  around,  making  a 
tufa-cone  over  the  opened  vent,  besides  spreading  far  and  wide  over  the  adjoining 
region;  or  they  make  a  permanent  boiling  basin,  which  also  is  the  centre  of  a  tufa-cone. 
This  latter  kind  of  tufa-cone  has  a  saucer-shaped  crater  and  the  inward  and  outward 
slopes  of  the  layers  represented  in  Fig.  1112;  while  the  preceding  may  fail  mostly  of 
the  inward  slope. 

(&.)  Forces  causing  Eruptions  of  Lava.  —  A.  Hydrostatic  Pressure 
in  the  Lava  against  the  Sides  of  the  Mountain.  —  An  increase  of  500 
feet  in  the  depth  of  the  lavas  is  an  increase  of  625  Ibs.  of  pressure  to 
the  square  inch.  Such  a  pressure  tends  to  produce  fractures  for  the 
escape  of  the  lavas. 

B.  Pressure  of  Vapors.  —  Vapors  rising  out  of  the  lavas  into  any 
confined  space  may  bring  pressure  to  bear  against  the  sides  of  the 
mountain ;  and,  if  suddenly  evolved,  this  effect  may  cause  fracture. 

Water  may  come  in  contact  with  hot  lavas,  and  enter  the  spheroidal 
state  (the  state  in  which  a  drop  of  water  is  when  it  dances  about  on  a 
red-hot  stove)  ;  and  when  so,  it  will  suddenly  and  explosively  pass  into 
a  state  of  vapor  on  cooling.  This  is  supposed  to  be  one  cause  of  ex 
plosion  in  steam-boilers ;  and,  with  the  apparatus  of  a  volcanic  moun 
tain,  the  results  may  rend  the  mountain.  In  this  way,  and  also  through 
the  more  quiet  evolution  of  vapors,  earthquakes  sometimes  result. 

C.  Lateral  Pressure  in  the  Earth's  Crust,  resulting  from  Contrac 
tion. —  This  cause  has  produced  subsidences  of  the  crust,  in  the  earth's 
history ;  and  such  subsidences  must  have  been  attended  by  movements 
in  the  underlying  liquid  rock.     This  cause  must  have  acted  when  the 


712 


DYNAMICAL    GEOLOGY. 


great  fissures  were  made  by  lateral  pressure,  in  which  volcanoes  have 
originated ;  but  facts  seem  to  show  that  it  is  not  concerned  in  ordinary 
volcanic  movements  or  eruptions. 

The  action  alone  of  pressure,  in  the  column  of  lava,  is  quiet ;  of 
vapors  gradually  evolved,  quiet ;  of  vapors  suddenly  evolved,  either 
directly  or  through  the  spheroidal  state,  violent,  and  attended  with 
earthquakes. 

Fig.  1114. 


Tufa-hills,  Xanawale. 

Three  eruptions  of  Kilauea  were  consequent  upon  the  rise  of  the  lavas  to  a  height  of 
400  or  500  feet  in  the  crater,  and  were  attended  with  no  violence.  When  ready  for 
eruption,  there  was  active  ebullition  in  most  parts  of  the  immense  crater,  and  occasional 
detonations  were  heard ;  but  there  was  no  subterranean  shaking. 

The  eruption  in  1840  was  without  earthquake ;  and  the  first  sign  of  the  outbreak  waa 

Fig.  1115. 


ISLAND  OF  HAWAII.  —  L,  Mount  Loa ;  K,  Mount  Kea  ;  H,  Mount  Hualalai ;  P,  Kilauea  or  Lua-Pele  y 
1,  Eruption  of  1843  ;  2,  of  1852 ;  3,  of  1855  ;  4,  of  1859  :  a,  Waimea ;  6,  Kawaihae  ;  c,  Wainanalii ; 
d,  Kailua ;  e,  Kealakekua  ;  /,  Kaulanamauna  ;  g,  Kailiki :  h,  Waiohinu  ;  i ,  Honuapo  ;  ;,  Kapoho; 
k,  Nanawale;  /,  Waipio ;  m,  first  appearance  of  eruption  of  1868;  n,  Kahuku.  The  courses  of 
the  currents,!,  2,  3,  and  5,  are  from  a  map  by  T.  Coan,  and  4,  from  one  by  A.  F.  Judd. 

a  fire  in  the  woods.     The  lava  broke  out  through  a  rent  in  the  sides  of  the  mountain, 
about  six  miles  from  Kilauea,  and  appeared  for  a  short  distance  at  the  surface  (A,  J3,  C, 


VOLCANOES.  T13 

Fig.  1109,  p.  705);  then,  for  seven  miles,  there  were  a  few  little  patches  of  lava,  and 
some  steaming  fissures.  Finally,  27  miles  from  Kilauea,  12  from  the  sea,  and  1,250 
feet  above  tide-level,  an  outflow  began  from  fissures,  and  continued  on  to  the  sea  at 
Nanawale;  and  three  tufa-cones  (Fig.  1114)  were  thrown  up  over  points  in  these  fis 
sures  on  the  sea-shore.  It  was  a  tapping  of  the  mountain  and  letting  out  of  the  lavas; 
and  contemporaneously  they  fell  400  feet  within  the  crater,  —  topp',  Fig.  1111,  which 
plain  then  became  the  bottom  of  the  lower  pit. 

The  same  quiet  has  generally  attended  the  eruptions  of  the  summit-crater  of  Mount 
Loa.  The  courses  of  some  eruptions  are  shown  on  the  accompanying  map. 

In  January,  1843,  an  outflow  began,  through  fissures  13,000  feet  above  the  sea  (No.  1, 
Fig.  1115),  and  continued  on  northward  and  westward  for  twenty-five  or  thirty  miles. 
It  broke  out  in  silence,  though  one  of  the  grandest  eruptions  on  record,  and  finished  its 
work  without  an  earthquake. 

In  Februarv,  1852,  a  bright  light  at  the  summit  announced  another  eruption  (No.  2, 
Fig.  1115):  after  three  days,  it  was  continued  by  means  of  a  second  outbreak,  4,000  feet 
lower,  or  10,000  above  the  sea,  which  also  was  a  quiet  one.  At  this  second  opening,  as 
described  by  T.  Coan,  there  was  a  fountain  of  fiery  lavas,  1,000  feet  broad,  playing  to 
a  height  at  times  of  700  feet,  with  indescribable  grandeur  and  brilliancy.  There  were 
rumbling  and  muttering  from  the  plunging  flood,  and  explosions,  but  no  earthquakes. 
Mr.  Coan  attributed  the  fountain  to  the  hydrostatic  pressure  of  the  column  of  lava 
above. 

In  August,  1855,  another  great  eruption  began  (No.  3,  Fig.  1115),  without  noise  or 
shakings,  at  an  elevation  of  12,000  feet;  and  for  a  year  and  a  half  the  flood  continued: 
the  whole  length  of  the  stream  was  sixty  miles. 

In  January,  1859,  there  was  still  another  eruption  (No.  4,  Fig.  1115).  It  made  its 
first  appearance  near  the  summit,  in  the  same  quiet  manner  as  the  preceding,  Kilauea 
remaining  undisturbed.  About  1,500  feet  above  the  sea,  on  the  northwest  side  of  the 
mountain,  there  was  a  larger  opening,  where  the  lavas  were  thrown  up,  "like  the 
•waters  of  a  geyser,"  to  a  great  height.  The  stream  here  became  wider,  subdivided 
into  three  or  more  lines,  and  continued  on  toward  the  base  of  Mount  Hualalai;  from 
this  point  it  bent  northward,  and  then  northwestward  again,  and  finally  entered  the  sea 
on  the  western  coast,  after  a  course  of  over  fifty  miles. 

There  were  thus  three  great  eruptions  from  the  summit,  with  intervals  of  only  three 
years  and  a  half,  and  four  within  sixteen  years. 

On  the  30th  of  December,  1865,  there  was  again  action  at  the  summit,  but  no  out 
break.  Finally,  in  March  and  April,  1868,  a  fifth  great  eruption  occurred,  in  which, 
contrary  to  all  known  precedent,  there  were  violent  earthquakes;  and,  besides,  Kilauea 
took  part,  and  probably  furnished  a  portion  of  the  lavas.  On  the  28th  of  March,  steam 
and  light  shot  up  from  fissures  on  the  southwest  side  of  the  summit  (at  m,  Fig.  1115), 
which  were  threats  of  an  eruption.  The  light  disappeared  the  same  day,  but  earthquakes 
follow.ed  which  shook  violently  the  southern  half  of  the  island,  and  opened  many  deep 
rents.  April  2nd,  after  a  quaking  that  was  "  absolutely  terrific,"  exceeding  all  that 
had  preceded  it,  great  fissures  opened,  at  Kahuku,  in  southwestern  Hawaii  (at  n  on  the 
map),  from  which  floods  of  lava  commenced  flowing  to  the  sea.  As  late  as  April  10th, 
there  were,  near  Kahuku,  four  fountains  of  lava  playing  to  a  height  varying  from  500 
to  1,000  feet.  Kilauea,  although  twenty-six  miles  from  the  place  of  outflow,  and  on 
another  side  of  Mount  Loa,  was  simultaneously  emptied ;  its  bottom  sinking  300  to  400 
feet,  as  after  the  eruption  of  1840.  This  emptying  of  the  Kilauea  crater  was  probably 
due,  not  to  its  own  eruption,  but  to  the  rendings  of  the  mountain  consequent  on  the 
eruption  of  the  central  vent  of  Mount  Loa;  for  only  the  lofty  column  of  lava  supplying 
the  latter  could  have  produced  the  fountains  at  Kahuku.  After  such  events,  it  is  not 
incredible  that  Kilauea  itself  should  have  been  begun  in  a  rending  of  Mount  Loa,  accom 
pany  ing  some  early  eruption. 

In  the  eruptions  of  Kilauea,  —  one  of  the  largest  of  volcanic  craters,  —  there  is  evi 
dence  only  of  the  action  of  hydrostatic  pressure  and  of  vapors  quietly  evolved,  as  the 
causes  of  the  outbreak.  The  fountain  had  a  head  of  lavas  3,000  to  4,000  feet  high; 


714  DYNAMICAL    GEOLOGY. 

and  3,000  feet  of  lavas  correspond  to  3,750  pounds  of  pressure  to  the  square  inch.  In 
the  eruptions  from  the  summit-crater  of  Mount  Loa,  the  fountain-head  is  10,000  to 
13,000  feet  above  the  sea;  and  the  first  three  of  the  above-mentioned  eruptions  may  also 
have  been  mainly  a  result  of  hydrostatic  pressure.  Previous  to  the  last,  there  had  been 
a  season  of  long-continued  rains;  and  the  Avaters  thus  furnished  to  the  island,  sinking 
down  to  the  seat  of  the  fires,  may  have  been,  as  Mr.  Coan  observes,  one  occasion  of  the 
violence  of  the  eruption. 

In  the  eruptions  of  Vesuvius,  there  are  usually  earthquakes  of  more  or  less  power, 
lofty  ejections  of  cinders  and  dark  vapors,  a  breaking  of  the  mountain's  summit  on  one 
side  or  the  other,  or  fissures  opened  in  the  sides  below.  In  these  violent  ejections,  there 
may  be  proof  of  a  sudden  evolution  of  vapors.  But  pressure  also  acts  as  at  Mount  Loa ; 
for  the  volcano,  during  the  year  or  more  preceding,  had  become  charged  nearly  to  its 
brim,  ready  for  the  outbreak. 

(c.)  Eruptions  mostly  through  Fissures.  —  Most  eruptions  take  place 
through  fissures  in  the  sides  of  the  mountain,  and  not  by  overflows 
of  the  crater.  The  fissures  may  come  to  the  surface  only  at  intervals, 
so  as  to  appear  like  an  interrupted  series  of  rents,  although  continuous 
deep  below ;  and  they  may  underlie  the  erupted  lavas  as  far  as  the 
flow  extends,  although  nothing  appears  to  indicate  it,  owing  to  their 
being  concealed  from  view  by  the  lavas.  But  frequently  small  cones 
form  over  the  wider  parts  of  the  rent,  and  stand  along  the  lava-field, 
marking  the  courses  of  the  fissures. 

This  method  of  eruption  through  fissures  makes  dikes  (p.  112)  in 
the  mountain  ;  and  all  volcanic  mountains,  when  the  interior  is  ex 
posed  by  gorges,  contain  dikes  in  great  numbers.  After  the  mending 
of  the  fracture  by  a  filling  of  solid  lava,  the  mountain  is  stronger 
than  before. 

(d.)  Eruptions  Periodical.  —  Three  eruptions  occurred  at  Kilauea 
at  intervals  of  eight  to  nine  years,  this  being  the  length  of  time  re 
quired  to  fill  the  crater  up  to  the  point  of  outbreak,  or  four  to  five 
hundred  feet.  The  action  was  regular  in  its  period,  or  a  result  of  a 
systematic  series  of  changes,  and  not  paroxysmal.  The  crater  again 
filled  to  within  500  feet  of  the  top,  or  half  its  depth,  in  eight  years 
after  1840.  But,  for  some  reason,  another  great  eruption  did  not  take 
place  until  April,  1868.  There  may  have  been  a  submarine  eruption 
in  the  interval. 

Even  in  the  case  of  Vesuvius,  —  the  other  type  of  volcanoes,  —  the 
history  may  be  similarly  progressive,  although  the  violent  activity 
excited  usually  ends  in  a  kind  of  paroxysmal  eruption.  There  are, 
however,  so  many  causes  of  irregularity  that  the  periodicity,  if  exist 
ing,  would  be  distinguishable  only  after  a  long  period  of  observation. 

(e.)  Difference  in  Eruptions  due  to  Liquidity  of  Lavas.  —  At  Mount 
Loa,  the  absence  of  cinders  and  the  low  lava-jets  prove  remarkable 
liquidity  in  the  lavas  at  all  times.  At  Vesuvius,  the  great  abundance 
of  ciuder-eruptious  proves,  on  the  contrary,  that  the  lavas  are  very 


VOLCANOES.  715 

viscid.  In  cases  like  the  latter,  the  escape  of  vapors  would  be  more 
likely  to  be  repressed  until  violent  paroxysmal  effects  became  a  con 
sequence  of  the  accumulation  ;  and  this  may  be  one  reason  of  the 
earthquakes  attending  the  eruptions  of  such  volcanoes. 

4.  Origin  of  the  Forms  of  Volcanic  Cones. 

The  general  form  cf  the  growing  mountain  has  been  stated  to  de 
pend  on  the  nature  of  the  material  ejected,  whether  lava,  tufa,  or 
cinders,  or  combinations  of  these.  But  there  are  modifications  arising 
from  other  causes.  The  principal  one  is  the  following :  — 

The  angle  of  declivity  in  a  growing  cone  depends  on  the  part  of  the 
cone  from  which  the  eruptions  take  place.  Overflows  at  top,  if  de 
scending  but  part  of  the  way  to  the  base,  increase  the  height  and 
steepness  ;  but,  descending  all  the  way  to  the  base,  they  add  to  the 
magnitude  of  the  cone  without  varying  the  general  slope.  In  fissure- 
eruptions,  fissures  at  the  summit  widen  the  top  and  increase  the  slope, 
for  it  is  like  driving  in  a  wedge  ;  but  fissures  and  outflow  about  the 
base  spread  the  base  and  diminish  the  average  slope  :  the  southeastern 
slope  of  Mount  Loa  spreads  out  for  a  score  of  miles,  at  an  angle  of 
one  to  three  degrees,  owing  to  this  flattening  process.  The  slope, 
then,  of  a  cone  depends  on  the  concomitant  action  of  the  force  causing 
eruption  (this  force  fracturing  the  cone,  and  sometimes  increasing, 
sometimes  diminishing,  its  slope),  with  the  ejection  of  lava  or  other 
material  over  the  sides. 

The  slope  of  flowing  lava,  while  generally  small  and  producing  cones  of  small  angle, 
may  still  be  of  almost  any  angle.  It  forms  continuous  streams  of  $0°;  and  even  verti 
cal  cascades  of  solid  lava  occur  about  Mount  Loa  and  other  volcanoes.  As  Provost 
observed,  flowing  lava,  like  flowing  beeswax,  if  stream  follow  stream  rather  rapidly, 
and  not  too  copiously,  so  that  one  becomes  melted  to  another,  may  make  layers  of  great 
thickness,  having  a  large  angle  of  inclination.  Hence,  Avhile  the  average  angle  of  a 
lava-cone  is  small,  because  lavas  when  in  a  very  large  outflow  spread  rapidly  and  easily, 
there  are  many  regions  of  much  steeper  angle,  over  its  declivities.  The  author  observed 
a  stream  descending  into  the  ci'ater  of  Kilauea,  at  an  angle  of  30°.  It  was,  however, 
hollow,  the  interior  having  run  out  after  the  crust  had  formed.  Mr.  Coan  mentions  the 
frequent  occurrence  of  slopes  of  15°  to  20°  and  more,  along  the  stream  formed  at  the 
eruption  of  Mount  Loa  in  1855. 

The  outflow  of  lavas  from  a  vent  is  an  undermining  process ;  and  the  region  about  the 
crater  sometimes  subsides  as  a  consequence  of  it.  There  are  many  fractures  and  a  large 
depressed  border,  around  Kilauea,  produced  by  this  means. 

The  violence  attending  eruptions,  at  times,  opens  widely  the  mountain,  and  makes  deep 
gorges,  that  become  filled  by  lavas.  Maui,  one  of  the  Sandwich  Islands,  has  a  volcanic 
mountain  10,000  feet  high,  a  crater  like  Kilauea,  at  summit,  2,000  feet  deep,  and  two 
deep  valleys  with  precipitous  sides  leading  down  to  the  coast,  one  northward  and  the 
other  eastward,  where  the  lavas  flowed  off  at  the  last  eruption.  It  seems  as  if  a  quarter 
of  the  island  had  been  started  from  its  foundations.  Oahu  consists  of  parts  of  two 
volcanic  mountains.  The  one  of  them  which  is  most  entire  is  only  a  remnant  of  the 
old  cone, — about  one-third:  a  precipice  twenty  miles  long  and  one  to  two  thousand 
feet  high,  the  course  of  a  great  fracture,  is  a  grand  feature  of  northern  Oahu.  As  there 


716  DYNAMICAL   GEOLOGY. 

are  small  cones  over  the  very  region  where  the  large  part  of  the  cone  has  sunk,  the 
fracture  must  have  occurred  before  the  volcano  was  extinct. 

Mount  Somma  is  part  of  an  outer  wall  to  Vesuvius;  and  it  is  supposed,  with  good 
reason,  that  the  fracture  of  the  mountain  at  an  eruption  reduced  the  mountain  to  its 
present  size. 

The  Val  del  Bove  is  a  gorge  or  valley,  with  precipitous  sides,  1,000  to  3,000  feet  high, 
in  the  upper  slopes  of  Mount  Etna.  Fresh-looking  lavas  cover  the  bottom;  and  dikes 
intersect  the  sides.  It  has  been  regarded  as  the  result  of  subsidence.  It  is  probable,  as 
suggested  by  the  author  in  his  Keport  on  Volcanoes,  that  at  its  head  was  once  a  crater, 
like  Kilauea  or  the  summit-crater  of  Maui.  The  conditions  within  and  about  the  great 
depression  accord  with  this  view. 

2.  NON-VOLCANIC  IGNEOUS  ERUPTIONS. 

Non-volcanic  igneous  eruptions  are  those  that  take  place  through 
fissures,  in  regions  remote  from  volcanoes.  The  modes  of  eruption  are 
not  essentially  different  from  those  of  true  volcanic  regions.  The 
cooled  rock  occupying  the  fissure  is  called  a  dike  ;  and  the  dikes  vary- 
in  width,  from  a  fraction  of  a  foot  to  many  yards  or  even  rods.  Some 
of  the  characteristics  of  non-volcanic  igneous  rocks  and  dikes  are 
mentioned  on  pages  107  and  112. 

These  eruptions  have  occurred  on  various  parts  of  all  the  continents, 
but  especially  along  their  mountainous  border-regions.  Examples  in 
New  P^ngland,  and  along  other  portions  of  the  Atlantic  Border  of 
North  America,  have  been  mentioned  (p.  418),  and  others  in  the  Lake 
Superior  region  (p.  185).  But,  over  the  larger  part  of  the  Mississippi 
basin,  they  are  wanting.  They  abound  in  many  parts  of  Europe,  the 
larger  part  of  which  is  the  mountain-border  region  of  the  east  side 
of  the  North  Atlantic.  They  are  very  numerous  in  western  Great 
Britain,  especially  in  Cornwall,  Wales,  and  portions  of  Scotland  and 
Ireland.  Fingal's  Cave  and  the  Giants'  Causeway  are  noted  ex 
amples. 

The  fissures  for  the  ejections  were  formed  by  a  fracturing  of  the 
earth's  crust,  down  to  a  region  of  liquid  rock.  They  have  thus  the 
same  origin  as  volcanoes,  —  but  with  this  difference  :  that  the  fissures 
were  not  so  large  as  to  remain  open  vents. 

The  columnar  form  which  the  rocks  often  assume  —  not  unfrequent 
in  volcanic  regions  —  is  well  illustrated  in  the  accompanying  sketch 
(Fig.  1116)  of  a  scene  in  New  South  Wales. 

The  rocks  include  nearly  all  the  igneous  rocks  mentioned  on  pages 
76-79,  except  the  scoriaceous  and  glassy  kinds  ;  and  even  the  latter 

O  J 

occur  at  times,  in  forms  like  the  mineral  tachylite.  The  heavy  basic 
rocks,  doleryte  and  peridotyte,  and  the  lighter  feldspathic  or  acidic 
kinds,  trachyte  and  others  allied,  are  the  most  common.  They  are 
sometimes  cellular,  owing  to  inflations  by  steam  or  other  vapors  ;  but 
the  cellules  have  generally  a  smooth  or  even  surface  within,  and  are 


IGNEOUS   ERUPTIONS. 


717 


not  ragged  like  those  of  lavas,  —  a  fact  due  to  their  having  been  under 
pressure  when  formed.     When  cellular,  the  rock  is  said  to  be  amygda- 

Fig.  1116. 


Basaltic  columns,  coast  of  Illawarra,  New  South  Wales. 

loidal ;  it  is  often  called  an  amygdaloid  (from  amygdalum,  an  almond], 
in  allusion  to  the  fact  that  the  cellules  or  little  cavities  are  filled 
through  subsequent  infiltration,  and  the  filling,  like  the  cavity,  is  often 
almond-shaped. 

The  manner  of  filling  these  cavities,  and  the  nature  of  the  materials, 
are  explained  on  page  734.  Amygdaloidal  varieties  of  dolerytic  rocks 
usually  contain  considerable  moisture,  and  often  also  disseminated 
chlorite.  They  thus  show  that  they  were  subjected  to  a  free  supply 
of  moisture,  from  a  subterranean  source,  when  in  process  of  eruption ; 
and  this  fact  accounts  for  the  existence  of  the  cellules. 

These  igneous  rocks  sometimes  form  layers,  interstratified  with  ordi 
nary  sandstones  or  other  sedimentary  rock,  and  even  uncompacted 
sand  and  gravel ;  they  having  fiowed  out  over  a  region,  it  may  be  for 
hundreds  of  miles,  covering  up  the  strata  previously  laid  down,  and 
then  becoming  the  basis  for  new  deposits  of  sand  or  mud.  They  thus 
lie  between  beds,  in  all  the  geological  formations.  Examples  of  Ameri 
can  Lower  Silurian  rocks  of  the  kind  are  described  on  page  185.  In 
the  British  Lower  Silurian,  in  Wales,  they  occur  among  both  the  Llan- 
deilo  and  Bala  formations.  The  Triassic  or  Jurassic  trap,  on  the  At 
lantic  Border  of  North  America,  affords  another  example,  as  described 
on  page  418 ;  but  the  beds  here  have  come  up  through  sandstone  rocks, 
without  extensive  overflows.  The  Cretaceous  era,  and  still  more  the 
Tertiary  and  Quaternary,  were  remarkable  for  the  extent  of  the  erup 
tions  over  the  western  slope  of  the  Rocky  Mountains  (p.  524),  and 
also  in  Britain  (p.  525)  and  many  parts  of  Europe,  and  on  other  conti 
nents. 

The   following    sketch,  from    Hayden's    Report    for    1873,    repre- 


718 


DYNAMICAL    GEOLOGY. 


sents  "  Gothic  Mountain,"  in  Colorado,  in  which  a  mountain  mass  of 
trachyte  rests  on  a  base  of  Cretaceous  rocks.  In  this  nearly  horizon 
tally  stratified  base,  near  the  top,  there  is  an  independent  dike  of 
the  same  rock,  which  was'  probably  produced  cotemporaneously  with 
the  outflow  making  the  mountain.  The  mountain  is  nearly  2,000 
feet  in  height  above  the  Cretaceous  base,  and  12,465  feet  high  above 
the  sea-level.  The  rock  is  trachyte,  —  a  porphyritic  variety,  —  and, 
like  that  of  many  trachytic  eruptions,  is  destitute,  according  to  Hay- 
den,  of  bedding  or  evidences  of  separate  lava  flows. 

Fig.  1117. 


m^:..  I 


Gothic  Mouutain,  Colorado.     A  trachytic  mass  overlying  Cretaceous  rocks. 

These  eruptions  through  fractures  are  sometimes  accompanied  by 
deposits  of  tufa,  made  of  the  lava  that  was  shivered  to  powder  by  the 
cold  waters  which  the  melted  rock  came  in  contact  with. 

Large  outflows  of  steam  have  frequently  attended  the  outbursts, 
which  has  penetrated  the  adjoining  rocks,  making  portions  of  them 
to  look  like  scoria,  and  as  described  on  page  419,  often  forming  new 
minerals  in  the  walls  of  the  dikes,  or  wherever  the  heat  reached. 

3.  SUBORDINATE  IGNEOUS  PHENOMENA. 

1.  Solfataras.  —  Solfataras  are  areas  where  sulphur-vapors  escape, 
and  sulphur-incrustations  form.  They  occur  away  from  intense  vol 
canic  action,  where  sulphur  vapors  and  steam  rise  slowly.  Incrusta 
tions  of  alum  are  common  in  such  places,  arising  from  the  action  of 
sulphuric  acid  on  the  alumina  and  alkali  of  the  lavas.  A  decom 
position  of  the  lavas  is  another  consequence  ;  it  often  results  in  pro 
ducing  gypsum  (or  sulphate  of  lime),  through  the  action  of  the 
sulphuric  acid  on  the  lime  of  the  feldspar  or  pyroxene;  also  opal, 


HOT    SPRINGS   AND    GEYSERS. 


719 


or  quartz,  or  siliceous  earth,  from  the  silica  set  free.  Carbonic  acid 
is  sometimes  given  out  in  such  places,  when  there  is  limestone  below 
to  be  decomposed,  —  some  acid  (either  sulphuric  acid  or  silica  in 
solution)  setting  free  the  carbonic  acid,  by  combining  with  the  lime. 

2.  Hot  springs.  —  Hot  springs  are  common  in  volcanic  regions. 
The  waters  may  be  either  essentially  pure,  or  strong  mineral  solutions. 

In  many  cases,  the  hot  waters  hold  silica  in  solution,  whose  depo 
sition,  over  the  region  around,  makes  irregular  accumulations  of  9, 
coarse  opal,  or  rarely  of  quartz,  often  in  the  form  of  low  cones  or 
rims  about  basins,  and  sometimes  in  irregular  massive  inclosures. 
Occasionally,  the  waters  are  calcareous,  instead  of  siliceous,  and  make 
calcareous  basins  or  cones.  The  waters  get  their  silica  from  the 
rock  adjoining,  and  mostly  from  its  feldspar,  this  mineral  containing, 
besides  silica,  the  alkalies  that  are  needed  to  aid  in  dissolving  it. 
The  lime  come>  from  limestones,  as  already  explained. 

Iceland  has  long  been  noted  for  its  geysers  ;  but  it  is  far  out 
stripped  by  the  region  of  the  Yellowstone  Park,  explored  ami  mapped 
by  the  expeditions  under  the  charge  of  Dr.  F.  V.  Hayden.  This 
locality  is  situated  about  the  head-waters  of  the  Yellowstone  and 
Madison,  two  tributaries  of  the  Missouri,  and  of  the  Snake  River,  a 
tributary  of  the  Columbia,  at  heights  of  6,500  to  8,000  feet  above  the 
sea-level.  The  geysers,  which  are  mostly  about  the  Fire-Hole  Fork 
of  the  Madison,  and  near  Shoshone  Lake  at  the  head  of  Lake  Fork  of 
the  Snake,  are  exceedingly  numerous,  and  play  at  all  heights,  up  to  200 
feet,  or  more ;  and,  besides,  there  are  multitudes  of  hot  springs  of 
various  temperatures,  the  most  of  them  between  160°  and  200°  F.,  the 
boiling-point  of  the  region  being  198°  to  199°  F.  All  together,  the 
number  of  hot  vents  in  this  region  cannot  be  less  than  10,000.  But 
the  region  is  far  from  fully  explored  ;  and  the  geyser-areas  east  and 
southeast  of  Yellowstone  Lake,  recently  reported,  may  double  this 
number. 

Figs.  1118-1120. 


GEYSER-COXES.  —  Fig.  1118,  Giant  Geyser;  1119,  Liberty  Cap  ;  1120,  Beehive  Geyser. 

The  hot  waters  of  the  Fire-hole  Fork  of  the  Madison  and  of  the  Shoshone  Lake  region 
are  siliceous,  while  those  of  Gardiner's  River,  a  tributary  of  the  Yellowstone,  are 
calcareous.  Some  of  the  forms  of  the  geyser-cones  are  shown  in  the  accompanying 
tigures.  Fig.  1118  represents  the  cone  of  the  "  Giant"  Geyser,  in  the  Tipper  Geyser 
Basin  of  the  Fire-hole;  it  is  about  ten  feet  high  and  twenty -four  feet  in  diameter  at 


720 


DYNAMICAL   GEOLOGY. 


base,  and  has  one  side  partly  broken  down  and  bent  inward.  It  throws  out,  at  long 
intervals,  a  jet  ninety  to  two  hundred  feet  in  height.  The  "  Beehive  "  geyser-cone 
(Fig.  1120),  of  the  same  region,  is  small,  being  but  three  feet  high  and  five  in  diameter 

Fig.  1121. 


Beehive  Geyser  in  action. 

at  base;  but  its  jet,  shown  in  Fig.  1121,  as  it  appears  when  in  full  play,  from  an  excel 
lent  drawing  by  Mr.  Holmes,  is  one  of  the  highest,  it  exceeding  two  hundred  feet.  It 
plays  about  once  a  day.  Fig.  1119  represents  the  "Liberty  Cap,"  one  of  the  cal 
careous  geyser-cones  of  the  Gardiner  River  region,  now  extinct;  it  has  a  height  of  fifty 
feet,  and  a  diameter  at  base  of  twenty  feet.  "  Old  Faithful "  is  one  of  the  largest  of 
the  Madison  River  geysers;  it  has  a  low  and  broad  irregular  cone,  and  throws  up  its 


HOT   SPRINGS   AND    GEYSERS.  721 

great  jet  to  a  height  of  one  hundred  and  thirty  feet,  once  in  about  sixty  five  minutes, 
the  remarkable  regularity  of  its  action  having  suggested  the  name  it  bears.  The 
"Giantess  "  is  another  of  the  large  geysers  of  the  Fire-hole;  the  basin  has  a  breadth 
of  twenty-three  and  a  half  by  thirty-two  and  a  half  feet,  and  holds  sixty-three  feet  in 
depth  of  water,  and  at  intervals  throws  the  whole  to  a  height  of  sixty  feet.  Another, 
the  "Architectural"  geyser,  is  actually,  when  in  action,  a  combination  of  jets  of  all 
sizes  and  angles  of  inclination,  each  having  some  independence  in  its  movements,  but 
all  working  together,  and  hence  producing  a  marvellous  effect  from  the  ever-changing 
views. 

Frank  H.  Bradle>-,  of  the  expedition  under  F.  V.  Hayden,  in  1872,  observes  that, 
while  standing  on  the  mound  of  "Fountain  "  geyser,  whose  pool  was  overflowing,  and 
watching  a  steam-jet  of  a  hundred  yards  away,  the  jets  suddenly  ceased,  and  "Foun 
tain  "  commenced,  throwing  up  a  jet,  ten  feet  in  diameter,  to  varying  heights,  from 
five  to  forty  feet.  In  thirty  minutes,  "  Fountain  "  stopped  suddenly,  and  immediately 
the  steam-jet  began  again ;  in  twenty  minutes  more,  the  jet  again  stopped,  and  at  once 
a  small  pool,  a  few  yards  from  "  Fountain,"  which  was  empty  when  that  was  playing, 
but  had  become  partly  rilled  from  its  overflow,  began  to  boil  and  throAV  up  water 
to  a  height  of  five  or  ten  feet,  and  continued  this  for  half  an  hour;  as  it  moderated, 
the  steam-jet  opened  anew,  but  ceased  when  the  boiling  became  more  violent.  The 
facts  prove  a  sympathy  between  different  vents;  and  the  same  was  illustrated  in  other 
parts  of  the  region. 

Bradley  also  states  that,  during  the  eruption  of  some  of  the  larger  geysers,  there 
are  pulsating  sounds  or  thumps,  in  the  depths  of  the  geyser  conduit,  which  have  no 
parallel  movement  in  the  jet;  and  that,  in  an  eruption  of  the  "Giantess,"  there  were 
seventy-three  of  these  pulsations  a  minute;  and  in  that  of  "  Grand  "  geyser,  at  first 
seventy-two  or  seventy-three,  but  in  the  course  of  twenty  minutes  they  decreased  to 
seventy,  and  became  gradually  fainter 

These  and  other  geysers,  and  additional  hot-spring  phenomena,  are  described  in  the 
Reports  of  the  expedition  under  Hayden,  for  the  years  1871  and  1872. 

The  siliceous  geyser-cones  are  all  beautiful  concretionary  work ;  and  the  beauty  of 
form  and  texture  and  pearly  lustre  is  often  greatly  enhanced  by  the  delicate  shades 
of  pink,  buff,  yellow,  and  other  tints,  mingled  with  white,  over  their  surfaces. 
Pebbles,  in  the  bottom  of  the  small  basins  formed  about  the  cones,  are  commonly  con 
cretions  of  the  opal,  like  the  rosettes  of  the  bottom  and  sides. 

In  the  eruption  of  a  geyser,  the  jet  is  first  water;  then  much  steam  with  the  water; 
and,  at  last,  mostly  or  wholly  steam,  the  water  having  been  all  thrown  out;  and, when 
the  water  partly  falls  or  runs  back  into  the  basin,  the  eruption  is  sometimes  renewed 
successively,  before  finally  stopping. 

The  action  of  geysers  is  owing  (1)  to  the  access  of  subterranean 
waters  to  hot  rocks,  producing  steam,  which  seeks  exit  by  conduits 
upward  ;  (2)  to  cooler  superficial  waters  descending  those  conduits  to 
where  the  steam  prevents  farther  descent,  and  gradually  accumulating, 
until  the  conduit  is  filled  to  the  top ;  (3)  to  the  heating  up  of  these 
upper  waters,  by  the  steam  from  below,  to  near  the  boiling  point ; 
when  (4)  the  lower  portion  of  these  upper  waters  becomes  converted 
into  steam,  and  the  jet  of  water  or  eruption  ensues.,  This  is  nearly 
the  explanation  given  by  Bunsen.  The  deposit  of  silica  in  the  throat 
of  the  conduit,  after  an  eruption,  tends  to  diminish  its  size,  and  some 
times  closes  it  completely,  so  that  the  waters  are  obliged  to  open  a 
new  vent. 

Hot  springs  also  occur  at  many  other  points  in,  and  west  of,  the 
Rocky  Mountains.  There  is  a  region  of  springs  of  hot  water  and 

46 


722  DYNAMICAL   GEOLOGY. 

steam  in  California,  north  of  San  Francisco,  in  Geyser  Canon,  a 
branch  from  Pluton  Canon.  The  waters  have  a  temperature,  accord 
ing  to  Whitney,  of  206°  to  207°;  and  deposits  of  sulphur  are  formed 
from  them.  Near  Clear  Lake,  there  is  a  "  Borax  lake,"  holding  borax 
in  solution,  and  having  a  deposit  of  it,  over  its  bottom  ;  and,  as  Whit 
ney  observes,  it  is  evidence  of  the  action  of  hot  waters  in  former 
times.  Boracic  acid  is  held  in  solution  in  the  hot  waters  of  the 
Tuscan  lagoons.  Other  beds  of  borates  occur  in  southern  Oregon, 
near  the  sea,  and  in  Nevada  and  Arizona. 

3.  Structure  of  Rocks  produced  by  Cooling The  sketch  on 

page  717  illustrates  the  columnar  structure  common  in  many  kinds  of 
igneous  rocks.  It  results  from  contraction  on  cooling  and  concretion 
ary  solidification  (pp.  86,  87).  By  the  same  means,  a  rock  often  be 
comes  irregularly  cracked,  or  regularly  jointed.  Moreover,  an  argil 
laceous  rock,  or  even  a  sandstone,  in  the  vicinity  of  a  dike  of  igneous 
rock,  is  often  columnar,  in  consequence  of  cooling  after  having  been 
heated  up  by  the  rock  of  the  dike  at  the  time  of  its  ejection.  A  good 
exhibition  of  columnar  sandstone  occurs  near  a  trap  dike  at  New  Ha 
ven,  Conn.  The  columnar  structure  is  always  at  right  angles  to  the 
cooling  surfaces,  as  stated  on  page  421. 

The  outer  part  of  a  dike,  where  it  adjoined  the  enclosing  rock,  is 
often  much  cracked,  and  also  of  very  much  finer  texture  than  the  in 
terior,  because  it  was  most  rapidly  cooled ;  and  obsidian,  or  volcanic 
glass,  is  an  extreme  effect  of  rapid  cooling  (p.  702). 

4.    SOURCES  OF  IGNEOUS  ERUPTIONS. 

1.  The  Earth's  interior  Fire-seas.  — The  existence  of  a  liquid  layer, 
or  of  great  fire-seas,  beneath  the  crust,  being  a  fact,  volcanoes  are  nat 
urally  regarded  as  outlets  to  the  surface  for  the  liquid  rock.  The  great 
extent  of  the  lines  of  volcanoes  about  the  globe  (p.  703),  and  also  of 
the  regions  of  igneous  eruption  in  all  ages,  to  the  present  time,  shows 
that  the  interior  fire-seas  have  been  and  still  are  large.  Over  a  range 
of  country  1,000  miles  long,  from  Nova  Scotia  to  South  Carolina,  the 
eruptions  at  the  close  of  the  Triassico-Jurassic  era  were  all  dolerytic 
(p.  78),  proving  the  oneness  of  the  sea  of  fire  at  that  time  beneath 
the  Atlantic  Border.  Far  greater  eruptions  took  place  in  the  Tertiary 
and  early  Quaternary  eras,  over  the  Pacific  slope  of  North  America. 

But,  supposing  a  great  fire-sea,  or  a  general  liquid  layer  to  be  the  primary  source 
of  volcanic  action,  it  does  not  follow  that  a  connection  with  the  same  is  now  retained. 
After  the  eruption  from  a  fracture  had  continued  for  a  while,  the  connection  may  have 
become  cut  off  by  cooling,  so  as  afterward  to  extend  onlv  to  a  subordinate  reservoir  of 
liquid  rock.  When  several  volcanoes  have  been  opened  on  a  single  profound  fracture, 
they  may  afterward  have  become  wholly  disconnected  from  one  another,  and  also  from 
the  earth's  interior.  Kilauea,  on  the  flanks  of  Mount  Loa,  is  one  of  the  largest  volcanic 


SOURCES   OF   IGNEOUS    ERUPTIONS.  723 

craters  on  the  globe;  and  yet  eruptions  occur  at  the  summit  of  the  same  mountain, 
10,UOO  feet  above  the  level  of  Kilauea,  and  so  extensive  that  the  lavas  flow  off  for  twenty- 
five  to  fifty  miles,  without  any  sign  of  sympathy  in  the  lower  crater.  If  the  two  are  con 
nected,  the  siphon,  in  such  a  case,  has  the  liquid  10,000  feet  higher  in  one  leg  than  in 
the  other. 

Connection  without  sympathy  is  possible  only  on  two  suppositions:  (1)  that  the 
junction  of  the  two  conduits  is  at  such  a  depth  that  10,000  feet  is  but  a  small  fraction 
of  the  whole  length,  and  the  additional  pressure  is  more  than  counterbalanced  by  the 
friction  along  the  conduits;  or  (2)  that,  if  the  lavas  rise  in  consequence  of  an  inflating 
process,  the  difference  of  length  may  not  imply  a  corresponding  difference  of  pressure. 

Even  about  Kilauea  itself,  eruptions  sometimes  take  place  through  the  upper  walls  of 
the  crater  to  the  surface  (as  at  P,  Fig.  1109),  when  the  lavas  are  boiling  freely  in  the 
bottom  of  the  crater,  undisturbed  by  the  ejection. 

While  the  linear  arrangement  of  the  volcanic  mountains  of  a  group  is  evidence  that 
they  all  originated  in  one  grand  breaking  of  the  earth's  crust,  the  several  volcanoes  in 
a  line  may  not  stand  over  one  prolonged  fracture,  but  over  a  series  having  a  common 
direction,  in  the  manner  illustrated  by  the  figures  on  page  19.  This  was,  beyond  ques 
tion,  the  mode  of  origin  of  the  Hawaian  Islands. 

The  islands  of  Oahu  and  Maui  (see  Fig.  24,  p.  31)  consist  each  of  two  great  volcanic 
mountains,  united  at  base,  and  Hawaii  of  three  mountains.  In  the  case  of  both  Oahu 
and  Maui,  the  northwestern  of  the  two  volcanoes  became  extinct  long  before  the  south 
eastern,  —  as  is  apparent  in  the  profound  valleys  of  denudation  that  intersect  its  slopes 
and  almost  obliterate  its  original  features;  while  the  lavas  and  parasitic  cones  of  the  Lit 
ter  look  fresh  and  recent.  In  HaAvaii,  also,  Mount  Kea,  the  northern  volcano,  is  the 
extinct  one.  Again,  in  the  whole  Hawaian  group,  the  only  active  volcanoes  are  in  the 
southeastern  island,  Hawaii,  while  the  north w e stern  island,  Kauai,  shows  in  its  features 
that  its  extinction  was  among  the  earliest,  if  not  the  very  earliest,  of  the  whole  number. 
It  appears,  therefore,  that  each,  Oahu  and  Maui,  stands  over  a  fissure  which  was  largest 
toioard  the  southeast,  since  the  fires  of  the  southeast  extremity  of  each  were  last  ex 
tinguished;  that  Hawaii  had  a  similar  origin,  but  with  probably  a  second  more  western 
fissure  as  the  origin  of  the  volcano  of  Hualalai;  and  that  the  whole  Hawaian  group 
originated  in  a  series  of  fractures,  which  increased  in  extent  from  the  nortlnvest  to  the 
southeast;  for  Maui  continued  in  eruption  long  after  Oahu  (a  more  western  island  in 
the  group);  and  Hawaii,  the  southeasternmost,  is  the  only  island  now  active,  and  the 
one  that  through  its  prolonged  activity  has  attained  the  greatest  height  above  the  sea. 

These  facts  illustrate  a  general  principle,  with  regard  to  the  fractures  of  the  earth's 
crust,  as  well  as  the  origin  of  volcanic  groups. 

2.  Motion  transformed  into  Heat.  —  Mallet,  as  stated  on  page  698, 
has  shown  that  the  motion  in  the  earth's  crust,  or  its  rocks,  attending 
mountain-making,  is  sufficient  to  generate  great  heat,  and  regards  it  as 
sufficient  to  produce  fusion,  and  to  originate  and  sustain  the  volcanoes 
of  the  globe.  Many  trachytic  rocks  have  nearly  the  constitution  of 
granyte  and  gneiss  ;  and  they  may  hence  have  come  from  such  a 
fusion.  But  the  fact  that  eruptions  of  one  epoch,  along  a  country  a 
thousand  miles  or  more  in  range  (as  over  the  1,000  miles  along  the 
Atlantic  Border  of  North  America,  from  Nova  Scotia  to  South  Caro 
lina,  in  the  Triassico-Jurassic  era),  have  ejected  the  same  kind  of 
dolerytic  rock,  shows  that  the  material  of  the  fire-seas  beneath  was  of 
very  uniform  composition  ;  and  this  uniformity  could  not  have  come 
from  the  fusion  of  the  diversified  sedimentary  or  metamorphic  rocks  of 
the  region,  or  of  its  depths  ;  and,  besides,  scarcely  any  of  these  rocks 


724  DYNAMICAL    GEOLOGY. 

would  have  made  doleryte,  when  fused.  If  then  a  liquid  dolerytic 
fire-sea  has,  for  such  a  range  of  eruptions,  been  made  by  the  transform 
ation  of  motion  into  heat,  the  material  fused  must  have  been  the  un 
derlying  first-formed  crust  of  the  globe; and  this  must  then  be  doleryte 
in  constitution.  On  this  point  see,  further,  page  735. 

4.  METAMORPHISM. 

1.  General  Characteristics. 

The  process  of  metamorphism  is  a  process  of  change  in  texture  and 
often  in  mineral  constitution,  such  as  has  occurred  among  many  of  the 
strata  of  the  globe,  after  their  original  deposition.  The  term  is  ap 
plied  especially  when  the  changes  have  affected  great  series  of  strata, 
producing,  as  an  extreme  result,  a  crystallization  of  the  rocks,  and  as 
a  more  moderate  effect,  simple  consolidation,  and  where  it  is  evident 
that  some  degree  of  heat  above  the  ordinary  atmospheric  temperature 
has  been  concerned. 

Cases  of  local  alteration  of  structure  and  crystallization  are  common,  modifying  the 
composition  of  isolated  crystals  or  masses.  But  such  changes  come  mostly  under  the 
term  pseudomorphism  (from  x//ev8rfc,  false,  and  M°P</»?,  form).  If,  however,  as  is  not 
unusual,  they  occur  over  considerable  areas,  or  near  dikes  or  veins,  and  are  not  due 
simply  to  ordinary  mineral  solutions  infiltrating  through  a  rock  or  seam,  or  to  some 
similar  local  action,  but  to  a  wider  cause,  analogous  to  that  crystallizing  the  meta_ 
morphic  rocks,  and  requiring  some  elevation  of  temperature,  they  are  then  examples  of 
true  metamorphism.  Still,  it  is  often  difficult  to  draw  the  line  between  the  two  series. 

Examples  of  metamorphic  rocks  in  part  fossiliferous,  are  mentioned  on  pages  237,  256, 
432.  The  famous  Carrara  marble  is  an  altered  Jurassic  limestone,  underlaid  by  talcose 
and  mica  schist  and  gneiss.  Extensive  strata  of  limestone,  gneiss,  and  mica  schist 
in  the  Green  Mountains  are  Lower  Silurian,  and  others  in  the  Connecticut  Valley  are 
Lower  or  Upper  Helderberg  (p.  256)-  The  gold-bearing  slates  of  the  Sierra  Nevada 
are  Triassic  or  Jurassic,  as  proved  by  the  presence  of  fossils  in  some  cases.  In  the 
Vosges,  corals  are  said  to  occur  in  a  hornblendic  rock,  changed,  without  a  change  of 
form,  to  hornblende,  garnet,  and  axinite. 

The  various  kinds  of  metamorphic  rods  have  been  described  on 
pages  66—74 ;  and  examples  of  the  results  on  a  large  scale  have  been 
presented  in  the  case  of  rocks  of  the  Archaean  age  on  pages  151—156, 
and  of  those  of  the  Paleozoic  ages  on  pages  214,  400.  The  pages  re 
ferred  to  are  a  proper  introduction  to  the  review  of  the  subject,  and 
the  additional  explanations  which  are  here  given. 

2.  Effects  of  Metamorphism. 

The  principal  effects  of  metamorphism  upon  rocks  are  the  follow 
ing:  (1)  Consolidation;  (2)  Loss  of  water  or  other  vaporizable  in 
gredients  ;  (3)  Change  of  color  ;  (4)  Obliteration  of  fossils  ;  (5)  Crys 
tallization,  with  or  without  a  change  of  constitution. 


METAMORPHISM.  725 

1.  Consolidation.  —  Ordinary  atmospheric  or  subterranean  waters, 
however  prolonged  their  action,  do  not  necessarily  produce  solidifica 
tion.     The  soft  sandstones  of  all  ages,  from  the  Potsdam  to  the  inco 
herent  beds  of  the    Quarternary,  are   evidence   on   this   point.     It  is 
probable  that  deposits  have  existed  to  an  immense  extent  in  past  time, 
that  failed  to  be  consolidated,  and  consequently  were  washed  away  in 
the  course  of  subsequent  changes. 

But  while  there  are  many  fragile  Potsdam  sandstones,  there  arc 
others,  as  those  of  eastern  New  York  and  Vermont,  that  have  been 
hardened,  through  the  metamorphic  process,  into  quartzytes  and  quartz- 
ose  gneisses,  and  deposits  of  sand  and  pebbles  of  various  other  ages 
that  are  refractory  sandstones  and  grits.  That  the  consolidation  took 
place  through  the  metamorphic  process,  is  often  evident  from  their 
position  within,  or  on  the  outskirts  of,  regions  of  other  metamorphic 
rocks.  In  the  same  way,  fragile  absorbent  argillaceous  shales  have 
been  hardened  into  firm  non-absorbent  slates. 

At  the  Geyser  region  of  Yellowstone  Park,  according  to  F.  H.  Bradley,  the  sand-beds 
of  a  terrace  on  Shoshone  Lake,  over  a  hundred  feet  high,  have  been  firmly  consolidated, 
so  as  to  look  like  quartzyte;  and  this  was  done  by  the  hot  siliceous  waters,  when  the 
waters  of  the  lake  stood  at  a  higher  level. 

2.  Loss  of  Water  or  other    Vaporizable  Ingredients.  —  The  water 
contained  in  the  original  material  of  a  rock  is  sometimes  wholly,  and 
sometimes  but  partly,  expelled.    The  volatile  ingredients  of  bituminous 
coal  have  been  partly  or  wholly  driven  off  by  the  process,  and  anthra 
cite  and  semi-bituminous  coal  formed  (p.  400). 

Carbonic  Acid  is  expelled  from  carbonate  of  lime,  or  limestone,  as 
is  well  known,  in  a  heated  lime-kiln.  But,  in  the  metamorphism  of 
limestone,  it  is  retained.  It  has  been  shown  by  experiment  that  the 
carbonic  acid  is  not  given  out,  if  the  material  is  under  heavy  pressure. 
If  this  be  true  of  carbonic  acid,  it  will  be  so  also  of  other  ingredients 
less  easily  expelled. 

3.  Change  of  Color.  —  Compact  limestones  are  usually  of  grayish, 
yellowish,  brownish,  and  blackish  colors.     From  the  metamorphic  pro 
cess  they  may  come  out  white.     The  original  color,  in  these  limestones, 
and  also  argillaceous  beds,  is  often  due  to  carbon,  from  ancient  plants 
or  animal  matters  ;  and,  when  so,  this  carbon  is  removed  and  the  rock 
blanched  by  the  metamorphism.     When  oxyd  of  iron  in  any  form  is 
present,  the  blanching  does  not  take  place  unless  the  oxyd  is  thrown 
into  some  new  state  of  combination,  in  the  crystallizing  process.    When 
there  is  only  a  partial  metamorphism,  and  the  heat  is  considerable,  its 
presence  generally  causes  a  change  of  color  to  red. 

4.  Obliteration  of  Fossils.  —  Rocks  that  have  been  subjected  to  the 
metamorphic  process  have  usually  lost  all  their  original  fossils.    Where 


726  DYNAMICAL    GEOLOGY. 

the  metamorphism  is  partial,  the  fossils  may  in  part  remain,  only  ob 
scured.  A  Devonian  coral  limestone,  near  Lake  Memphremagog,  and 
at  Littleton,  New  Hampshire,  contains  some  nearly  perfect  corals ;  but 
most  of  them  are  much  flattened  and  indefinite  in  outline,  and  others 
are  only  patches  of  white  crystalline  carbonate  of  lime  in  a  bluish- 
gray  limestone  rock,  which  is  itself  hardly  at  all  crystallized. 

The  crystallization,  in  some  cases,  involves  no  change  of  composi 
tion.  This  is  the  fact  with  most  limestone ;  the  ordinary  compact 
rock  may  be  simply  changed  by  the  process  to  a  crystalline-granular 
condition,  and  bleached  in  color.  Argillaceous  shales  are  changed  to 
mica  schists,  and  argillaceous  sandstones  to  gneiss  or  granite.  But, 
while  the  alteration  in  texture  is  very  great,  the  clays  or  argillaceous 
deposits  very  often,  as  stated  on  page  649,  contain  the  minerals  of  the 
latter,  even  in  the  requisite  proportions,  so  that  metamorphism  is  only 
a  change  in  crystalline  condition. 

But  in  other  cases  the  constitution  of  the  original  bed  is  altered, 
new  mineral  species  being  formed.  Even  in  the  case  of  limestone,  the 
impurities  are  turned  into  crystalline  minerals  of  different  kinds,  such 
as  garnet,  idocrase,  pyroxene,  scapolite,  mica,  sphene,  chondrodite,  apatite, 
etc. 

The  crystallization  which  is  produced  by  the  process  is  of  all 
grades,  from  mere  solidification  of  a  bed  of  shale  or  sandstone,  to  the 
formation  of  a  perfect  granite. 

3.  Origin  of  Metamorphic  changes. 

Promoting  Cause.  —  One  great  promoter  of  metamorphic  changes 
is  subterranean  heat,  acting  in  conjunction  with  moisture,  and  usually, 
if  not  always,  under  pressure. 

The  heat  requisite  for  metamorphism  is  less  than  that  of  fusion  ;  for 
the  evidence  is  decisive  that,  although  the  rocks  may  be  so  far  softened 
as  to  have  some  degree  of  plasticity,  this  is  unusual ;  and  for  the  most 
part  a  comparatively  low  temperature  is  all  that  was  required.  It  is 
probable  that  the  results  have  generally  taken  place  between  300°  and 
1,200°  F. ;  but  it  was  heat  in  slow  and  prolonged  action,  operating 
through  a  period  that  is  long  even  according  to  geological  measure. 
A  low  temperature,  acting  gradually,  during  an  indefinite  age  —  such  as 
Geology  proves  to  have  been  required  for  many  of  the  great  changes 
in  the  earth's  history  —  would  produce  results  that  could  not  be  other 
wise  brought  about,  even  by  greater  heat. 

The  lower  limit  of  temperature  is  sometimes  placed  much  below  300°  F. ;  and  for  con 
solidation  it  may  be  rightly  so.  But  there  is  definite  evidence  that  it  has  exceeded  this, 
in  the  majority  of  cases.  In  the  great  faults  of  the  Appalachians,  10,000  feet,  or  more, 
in  extent,  Lower  Silurian  limestones  are  brought  up  to  view,  containing  their  fossils, 


METAMORPHISM.  727 

and  not  metamorphic ;  and  in  Nova  Scotia  the  coal  formation,  though  15,000  feet  thick, 
is  not  metamorphic  at  base.  Taking  the  increase  of  temperature  in  the  earth's  crust  at 
1°  F.  for  sixty  feet  of  descent,  10,000  feet  of  depth  would  give  220°  F.  as  the  tempera 
ture  of  the  limestone  before  the  faulting,  and  15,000  feet,  314°  F.  But  1°  F.  per  sixty 
feet  of  descent  is  the  present  rate,  and  must  be  far  short  of  that  at  the  close  of  the 
Carboniferous  age,  when  the  earth's  crust  was  so  easily  flexed,  and  metamorphism  took 
place  on  so  grand  a  scale;  and  hence  the  limestone  must  have  been  subjected  to  a  heat 
far  above  220°  F.,  if  at  a  depth  of  10,000  feet. 

Moisture  is  essential,  because  dry  rock  is  a  non-conductor  of  heat 
(as  well  shown  in  the  case  of  a  common  fire-brick),  and  also  because 
of  its  chemical  powers  when  heated.  Rocks  usually  contain  some 
moisture  ;  and,  when  moist,  heat  goes  rapidly  through  them. 

The  pressure  may  have  been  that  of  either  superincumbent  waters 
or  of  overlying  rocks.  A  little  thickness  of  the  latter  would  give  all 
the  pressure  that  was  in  any  case  essential. 

The  evidence  that  heat  has  been  a  promoting  cause  is  as  follows  :  — 

1.  The  effects  are  analogous  to  those  which  heat  is  known  to  produce. 
—  Water,  though  a  weak  chemical  agent  when  cold,  if  heated,  has  in 
creased  solvent  and  decomposing  powers,  and  increased  efficiency  in 
promoting  chemical  changes.  As  stated  on  page  719,  it  becomes 
siliceous  ;  and,  at  high  temperatures,  it  is  an  exceedingly  powerful  agent 
as  a  destroyer  of  cohesion,  a  solvent,  and  a  promoter  of  decompositions 
preparatory  to  recompositions,  as  Daubree  and  others  have  shown. 
The  moisture  disseminated  through  rocks,  and  distributed  among  them, 
wrould  be  for  the  most  part,  if  not  everywhere,  in  a  superheated  con 
dition.  When  moisture  is  diffused  through  a  rock  containing  feld- 
spathic  ingredients,  the  siliceous  solution  is  alike  diffused,  and  is  in  a 
state  to  promote  combinations,  and,  wherever  the  conditions  are  favor 
able,  may  aid  in  the  formation  anew  of  feldspar  and  other  silicates. 

Crystallizations  of  epidote,  tourmaline,  garnet,  chlorite,  and  hematite  have  been 
formed  in  the  sandstones  adjoining  the  trap  dikes  intersecting  the  Triassico-Jurassic 
red  sandstones  of  the  Atlantic  Border  of  North  America,  through  the  heat  which  the 
trap  had  when  ejected.  These  are  examples  of  local  metamorphism;  but  still  they  are 
good  illustrations  of  the  changes  in  regional  metamorphism. 

A  trap  dike  intersecting  the  clayey  layers,  sandstones,  and  coal  beds  of  the  island  of 
Nobby,  New  South  Wales,  has  baked  the  clavey  layers  to  a  flint-like  rock,  to  a  distance 
of  tAvo  hundred  yards  from  the  dike,  the  whole  length  of  the  island:  the  baking  effect 
must  have  continued  much  farther,  —  though  the  direct  evidence  is  cut  off  by  the 
river. 

Daubrt'e,  besides  decomposing  various  silicates  by  means  of  superheated  steam,  has 
made,  in  this  way,  quart/  crystals,  feldspar,  pyroxene,  and  mica,  the  crystallization 
taking  place  btloio  the  point  of  fusion. 

Through  the  diffusion  of  superheated  steam  at  a  high  temperature, 
the  rocks  may  have  been  rendered  even  plastic;  and,  in  this  condition, 
limestone  might  have  been  pressed  into  fissures  in  adjoining  rocks,  so 
as  to  make  a  kind  of  injected  vein.  The  preservation  in  nearly  all 


728  DYNAMICAL   GEOLOGY. 

cases  of  the  original  planes  of  lamination  is  evidence  that  this  plastic 
or  semi-fused  state  was  not  common  in  metamorphic  operations.  It 
was  one  of  the  conditions  requisite  for  the  formation  of  granite,  —  a 
non-schistose  rock  ;  and  the  transitions  from  gneiss  to  granite,  which 
are  by  imperceptible  gradations,  indicate  different  degrees  of  this  plastic 
state. 

There  may  seem  to  be  some  difficulty  in  accounting  for  metamor 
phic  results,  on  the  ground  of  the  diversity  of  mineral  species  that  are 
produced.  But,  in  the  first  place,  the  elements  constituting  these 
species  are  few  in  number,  —  silica,  alumina,  potash,  soda,  lime,  mag 
nesia,  and  the  oxyds  of  iron  being  all  that  are  necessary  for  the  great 
majority  of  them.  In  the  second  place,  as  just  stated,  the  material  of 
sedimentary  strata  is,  to  a  large  extent,  nothing  but  pulverized  meta 
morphic  rocks,  so  that  the  metamorphism  is  often  only  a  new  crystalli 
zation  of  the  minerals  already  present.  In  the  third  place,  the  organic 
remains,  out  of  which  many  rocks  have  been  largely  made,  even  the 
arenaceous  and  argillaceous,  have  contributed  a  variety  of  ingredients, 
besides  carbonate  of  lime,  —  the  most  important  of  which  are  phos 
phoric  acid  and  fluorine. 

The  following  table  presents  a  general  view  of  the  composition  of  the  more  common 
rock-making  materials,  showing  their  close  similarity.  These  species  are  briefly  de 
scribed  on  pages  52-58.  The  names  mica  and  feldspar  each  include  several  species:  — 

Silica Quartz. 

Silica  +  magnesia  and  water Talc. 

Silica  -|-  magnesia  and  water  ........  Serpentine. 

Silica  -f  magnesia  +  lime  or  protoxyd  of  iron Pyroxene. 

Silica  +  magnesia  +  lime  or  protoxyd  of  iron         ....  Hornblende. 

Silica  +  magnesia  +  alumina  and  protoxyd  of  iron  ....  Chlorite. 

Silica  +  alumina Andalusite. 

Silica  +  alumina Cyanite. 

Silica  -f  alumina  +  fluorine Topaz. 

Silica  +  alumina  +  ox\  ds  of  iron       .......  Staurolite. 

Silica  +  jilumina  +  oxyds  of  iron  +  potash  or  magnesia        .         .  Mica. 

Silica  +  alumina  +  lime  and  soda Scapolite. 

Silica  -f  alumina  +  lime,  magnesia,  iron,  or  manganese          .         .  Garnet. 

Silica  +  alumina  -f  oxyd  of  iron         .......  Epidote. 

Silica  +  alumina  +  potash,  soda,  or  lime         .....  Feldspar. 

Silica  +  alumina  +  alkali,  magnesia,  and  boracic  acid       .         .         .  Tourmaline. 

The  presence  of  phosphoric  acid,  from  organic  remains,  determines  often  the  formation 
in  metamorphic  limestones,  and  even  sometimes  in  granites,  of  crystals  of  apatite 
(phosphate  of  lime);  and  the  presence  of  fluorine  may  promote  the  crystallization  of 
chondrodite,  topaz  and  some  other  species.  When  the  alkalies  are  absent  from  a  clay 
or  shale,  metamorphism,  as  Hunt  has  stated,  cannot  produce  feldspar,  but  may  fill  the 
slate  with  staurolite,  andalusite,  cyanite,  or  other  non-alkaline  minerals. 

Again,  all  heated  subterranean  waters  would  become  mineral  waters, 
and  would  serve  to  carry  the  material  they  held  in  solution  wherever 
they  might  have  access.  In  addition,  the  ocean  is  a  mineral  source 


METAMORPHISM.  729 

as  wide  as  the  world,  furnished  abundantly  with  soda  and  magnesia, 
and  in  smaller  proportions  with  boracic  acid  and  many  other  ingre 
dients. 

2.  The  effects  on  the  same  sedimentary  rock  have  varied  with  the  de 
gree  of  heat  and  pressure,  and  the  amount  of  moisture.  —  Granite   and 
gneiss  are  examples  of  different  results  in  consequence  of  difference  in 
heat  and  pressure.     The  differences  between  mica  schist,  mica  slate, 
hydromica   slate,  clay  slate,  appear  to  have  arisen  largely  from  the 
differences  of  temperature  attending  metamorphism  ;  for,  in  going  west, 
in  Berkshire  County,  Mass.,  the  same  formation,  overlying  the  Stock- 
bridge  limestone,  passes  through  these  gradations.    The  stratum  which 
is  chlorite  rock  in   one  part  of  a  region  of  metamorphism  is  horn 
blende  rock  in  another. 

An  example  of  the  effect  of  pressure  is  afforded  by  granular  lime 
stone,  or  marble.  It  is  usually  the  firmest,  and  least  divided  by  frac 
tures  or  planes  of  bedding,  and  hence  best  for  architectural  purposes, 
when  its  bedding  is  nearly  vertical  in  position  ;  for,  in  that  case,  it  has 
been  subjected  to  the  greatest  pressure,  and  the  original  bedding  has 
disappeared  through  a  soldering  together  of  the  whole. 

3.  The  attending  circumstances  were  favorable  for  the  production 
of  subterranean  heat.  —  The  rocks,  during  a  period  of  metamorphism, 
are  undergoing  extensive  displacements  and  foldings,  profound  fractur- 
ings  and  faultings,  as  illustrated  in  the  examples  which  have  been  de 
scribed.     Metamorphic  rocks   are  always  displaced  and  folded  rocks, 
and  never  for  any  considerable  distance  horizontal.     Where  the  fold 
ings  are  most  numerous  and  abrupt,  reducing  the  strata  to  a  system 
of  parallel  dips,  by  the  pressing  of  fold  upon  fold,  there,  as  remarked 
by  the  Professors  Rogers,  the  metamorphism  is  most  complete.     In 
the  case  of  mineral  coal,  the  bitumen  is  more  completely  expelled,  the 
greater  the  disturbance  of  the  strata ;  and,  in  the  metamorphic  region 
of  Rhode  Island,  the  coal  has  been  changed  even  to  graphite,  by  the 
heat  (p.  400).     Now,  if  the  transformation  of  this  motion  into  heat  can 
produce  fusion  and  volcanoes,  as  Mallet  has  explained,  it  is  certainly 
sufficient  for  the  feebler  work  of  metamorphism.     It  is  then  true,  as 
Wurtz  was  first  to  announce,  that  the  heat  of  metamorphism  was  made, 
in  the  very  rocks  that  were  altered,  by  the  movements  to  which  they 
were  subjected. 

The  thermal  springs  of  Virginia  are  regarded  by  the  Professors 
Rogers  as  owing  their  heat  to  the  same  cause  which  produced  the  con 
solidation  and  metamorphism  in  the  Appalachian  region  ;  and  they 
instance,  as  evidence  of  this,  the  fact  that  the  localities  where  they 
occur  are  generally  situated  over  the  axis  of  some  fold  in  the  Appa 
lachian  strata. 


730  DYNAMICAL    GEOLOGY. 

Herschel  brought  forward  the  argument  that,  since  there  is  an  increase  of  tempera 
ture  for  every  sixty  feet  of  descent  in  the  earth's  crust,  if  strata  should  accumulate 
over  a  region  in  the  sea  to  a  depth  of  10,000  feet,  the  heat  would  rise  accordingly  into 
the  stratified  mass;  and,  as  the  same  temperature  as  before  would  exist  at  a  depth  of 
sixty  feet,  there  would  be  accordingly  in  the  lower  part  of  the  mass  the  same  elevated 
temperature  that  existed  10,000  feet  below  the  former  surface  — this  being  a  means  of 
raising  heat  from  below  without  disturbance,  and  a  degree  of  heat  that  in  some  circum 
stances  might  be  sufficient  for  metamorphism.  But,  if  metamorphism  had  actually 
taken  place  in  this  way,  we  should  expect  to  find  sections  showing  horizontal  or  slightly- 
disturbed  metamorphic  beds,  and  a  gradual  transition  through  a  series  of  such  beds  to 
an  absence  of  metamorphism;  but  this  has  nowhere  been  observed.  The  great  Appa 
lachian  faults  and  the  Nova  Scotia  coal-series  are  direct  testimony  against  the  theory. 
(Am.  Jour.  Sci.,  III.  vi.  13.) 

4.  Metamorphism  in  some  cases  obliterates  differences  in  rocks,  and 
in  others  intensijies  them,  (a.)  Differences  obliterated.  —  A  coarse 
conglomerate  and  a  granitic  sandstone  associated  with,  it  may  have 
come  from  the  wear  of  the  same  granitic  rocks,  and  hence  may,  by 
metamorphism,  be  made  into  a  uniform  bed  of  granite.  It  is  possi 
ble,  also,  that  the  same  identical  granite  might  come  from  an  argilla 
ceous  deposit  or  shale,  since  such  a  shale  may  consist  of  the  same  gra 
nitic  ingredients  in  a  finer  state  of  division. 

In  the  volcanic  regions  of  South  America  and  Mexico,  the  partial  metamorphism  of 
volcanic  tufas  (both  sandstones  and  conglomerates)  has  produced  red  rocks  spotted  with 
crvstals  of  feldspar,  which  are  so  like  red  porphyry  that  they  have  been  mistaken  for  it 
by  good  geologists.  They  often  show  their  pebbles  only  on  worn  surfaces. 

(b.)  Differences  intensified.  —  On  the  other  hand,  layers  of  argilla 
ceous  sandstone,  differing  but  little  in  color  or  texture,  may  be  pro 
foundly  different  after  metamorphism,  one  becoming  in  the  change  a 
whitish  gneiss,  another  a  dark-gray  mica  schist,  another  hornblende 
rock  or  schist,  another  chlorite  slate,  etc.,  these  differences  depending 
on  the  presence  or  absence  of  oxyd  of  iron,  feldspar,  and  one  or  two 
other  ingredients  which  do  not  make  much  impression  upon  the  ap 
pearance  of  the  unaltered  material,  and  on  the  amount  of  heat  and 
moisture  concerned. 

A  purely  siliceous  sandstone,  and  one  a  little  argillaceous,  are  looked  upon  as  essen 
tially  the  same  rock;  and, in  the  study  of  sedimentary  formations,  the  difference  would 
hardly  attract  attention.  But,  after  subjection  to  the  metamorphic  process,  the  purely 
siliceous  sandstone  comes  out  quartzyte,  while  the  argillaceous  may  be  either  gneiss 
or  quartzytic  mica  schist,  or  hydromica  slate,  or  chlorite  slate,  or  hornblende  schist, 
rocks  very  unlike  quartzyte.  Grave  errors  are  often  committed  in  consequence  of  not 
appreciating  this  class  of  facts. 

4.  Metamorphism  of  Metamorphic  Recks. 

Metamorphic  rocks  are  not  proof  against  further  metamorphism. 

Among  the  Archaean  rocks  of  northern  New  York  (in  Fowler,  De  Kalb,  Edwards, 
Russel,  Gouverneur,  Canton,  and  Hermon,  St.  Lawrence  County),  there  are  extensive 
beds  of  a  kind  of  soapstone  (called  rensselaerite)  which  has  in  places  the  cleavage  of 


MINERAL    VEINS.  731 

pyroxene,  showing  an  alteration  of  pyroxenic  arid  perhaps  other  rocks  into  soapstone, 
bv  some  magnesian  process;  and  the  serpentine  of  the  region  may  be  of  the  same 
period  of  rnetamorphic  change.  Examples  of  the  change  of  crystals  and  rocks  to 
soapstone  or  serpentine,  occur  in  the  metamorphic  regions  of  New  Jersey  and  Pennsyl 
vania;  and  they  are  common  in  other  countries.  Again,  at  Diana  and  other  places  in 
Lewis  County,  N.  Y.,  there  are  beds  of  a  soft  compact  rock,  which  is  sometimes  worked 
into  inkstands,  and  resembles  the  agalmatolite  of  China;  and,  at  one  locality,  crystals  of 
nephelite  have  been  altered  to  this  agalmatolite.  These  cases  of  the  metamorphism  of 
metamorphic  Archaean  rocks  may  have  taken  place  during  the  epoch  of  metamorphism 
after  the  Lower  Silurian,  when  the  rocks  of  the  Green  Mountains  were  to  so  large  an 
extent  crystallized. 

Sec,  further,  on  the  history  of  this  branch  of  science  and  its  processes,  a  Memoir  by 
Daubri'e,  translated  from  the  French  by  T.  Egleston,  and  published  in  the  Smithsonian 
Annual  Report  (8vo)  for  1861. 

5.  FORMATION  OF  VEINS. 

1.  Veins.  —  The  general  forms  of  veins  are  described  and  illustrated 
on  pages  108-114.     They  occupy  either  fissures  or  spaces  opened  be 
tween  the  layers  of  upturned  or  folded  beds.     Fissures  01  opened  spaces 
may  result  from  any  movement  of  the  rocks,  however  slight,  or  from 
whatever  cause.    Veins  abound  in  all  disturbed  and  metamorphic  beds. 
They  may  have  great  depth,  extending  through  a  series  of  formations, 
or  be  confined  to  particular  strata.     Where  a  disturbance  is  in  pro 
gress,  the  different  kinds  of  rock  will  necessarily  be  fractured  differ 
ently,  according  to  their  nature.     Those  that  are  unyielding  or  fragile 
may  be  broken  into  numberless  fragments,  arid  these  fragments  widely 
displaced :  so  that,  when  the  opened  spaces  or  fissures  are  filled,  the 
rock  will  be  reticulated  with  irregular  and  seemingly  faulted  veins. 

The  forming  of  veins  by  the  opening  of  the  layers  or  laminre  has 
taken  place  especially  in  slate-rocks  :  auriferous  quartz  veins  have  to 
a  great  extent  thus  originated. 

2.  Methods  of  Filling  Veins.  —  There    are    three   ways   of   filling 
veins:   (1)  by  injection  from  below;   (2)  by  infiltration  from  above; 
(3)  by  infiltration  from  the  rocks  either  side  of  the  vein,  or  from  those 
bounding  it  along  some  portion  of  its  course.     Under  the  second  and 
third  methods,   heat   is    not    absolutely  necessary,   though    generally 
required. 

First  Method.  —  The  first  method  —  that  by  which  trap  dikes  were 
formed  —  is  not  the  common  one.  There  are  cases,  like  that  of  the 
Lake  Superior  region  (p.  185),  where  metals  or  metallic  ores  are 
directly  associated  with  injected  dikes.  But  it  is  always  a  question,  in 
such  a  case,  whether  the  metallic  ingredient  was  derived  from  the 
same  deep  igneous  source  with  the  melted  rock  of  the  dike,  or  whether 
it  was  received  from  the  rocks  of  the  deeper  walls  of  the  fissure  during 
the  progress  of  its  ejection.  The  vapors  or  mineral  solutions  pro 
duced  at  such  a  time  often  penetrate  the  rock  adjoining  the  veins, 


732  DYNAMICAL    GEOLOGY. 

sometimes  to  considerable  distances,  either  diffusing  ores  through  them, 
or  filling  cracks  or  long  fissures. 

Second  Method.  —  The  second  method  is  exemplified  only  in  super 
ficial  veins,  seams,  or  cavities.  Carbonate  of  lime  is  often  thus  de 
posited  in  seams  or  open  cavities. 

Third  Method.  —  The  third  method  is  that  by  which  the  great  ma 
jority  of  the  veins  in  metamorphic  rocks,  whether  simply  stony  or 
metalliferous,  were  produced.  The  nature  of  the  minerals  constituting 
veins,  their  associations,  and  the  banded  structure  often  characterizing 
them,  are  opposed  to  their  formation  by  injection.  Examples  of  the 
banded  structure  are  represented  in  Figs.  132,  133,  p.  112.  Such  a 
banded  arrangement  could  have  resulted  only  from  a  lateral  filling  of 
the  vein,  by  slow  and  successive  supplies  of  material. 

The  fissures  occupied  by  veins  are  simply  cavities  penetrating  the 
rocks  more  or  less  deeply,  sometimes  down  to  regions  of  great  heat, 
but  not  to  those  of  fused  rock.  During  the  metamorphic  changes, 
such  cavities,  as  soon  as  formed,  would  begin  to  receive  mineral  solu 
tions  or  vapors  from  the  rocks  adjoining.  The  rocks  may  contain  suf 
ficient  moisture  to  carry  on  this  system  of  infiltration,  if  there  were 
no  other  source  ;  and  this  moisture,  and  any  vapors  present,  would 
move  toward  the  open  spaces.  The  mineral  matters  thus  carried  to 
the  fissure  would  there  become  concreted,  and  commence  the  formation 
of  the  vein. 

These  materials  from  the  adjoining  rock  may  be  taken  directly  from 
it  by  simple  solution,  or  be  derived  by  a  decomposition  of  some  of  its 
constituents.  And,  when  transferred  to  a  vein,  they  may  be  concreted, 
unchanged,  or  enter  into  new  compositions,  through  the  mutual  action 
of  the  several  ingredients  there  collected. 

The  veins  in  semi-crystalline  slates  are  mostly  of  quartz,  because 
silica  is  readily  taken  up  by  heated  waters  from  siliceous  minerals,  and 
is  everywhere  abundant.  Many  are  of  carbonate  of  lime,  and  for  a 
similar  reason.  The  solutions  of  carbonate  of  lime  may  enter  from 
above  ;  but  the  supply  has  usually  been  derived  from  the  materials  of 
the  adjoining  rock,  through  the  process  of  infiltration. 

The  veins  in  granitic  rocks  must  have  often  been  formed  at  the  high 
temperature  required  for  the  metamorphism  of  granite ;  and  the  ma 
terial  constituting  them  is  therefore  often  the  same  essentially  as  that 
of  the  granite,  only  in  a  coarser  state  of  crystallization. 

In  the  infiltrating  process,  materials  that  are  scattered  very  widely 
and  only  in  minute  quantities,  through  the  adjoining  rocks,  are  gathered 
gradually  into  these  open  cavities.  The  crystallizing  of  the  material 
held  in  solution  robs  the  moisture  of  its  mineral  portion,  and  will  lead 
to  a  constant  re-supply  of  it  from  the  rock  around,  so  long  as  the 


MINERAL   VEINS.  733 

material  lasts,  or  the  conditions  favoring  its  being  taken  up  are  con 
tinued.  Thus  veins  become  filled  with  crystals  of  various  minerals 
and  with  ores  that  are  not  visible  in  the  rock  outside  of  them. 

The  minerals  through  any  particular  portions  of  a  vein  are  not 
necessarily  derived  from  the  rock  adjoining  that  portion.  The  granitic 
or  other  material  derived  from  its  deeper  part  may  rise  and  occupy  the 
vein  where  it  intersects  slate-rocks. 

With  this  mode  of  filling,  when  the  process  is  very  slow,  the  outer 
layers,  or  those  lying  against  the  inclosing  walls,  will  be  first  formed, 
and  then  another  layer  inside  of  this,  and  so  on,  until  the  whole,  to 
the  centre,  is  occupied.  By  such  means,  the  banded  structure  is  pro 
duced.  Owing  to  the  varying  circumstances,  during  the  slow  filling 
of  a  vein,  —  the  work  sometimes  evidently  of  a  long  period,  —  the 
infiltrating  material  varies  in  kind  ;  and  hence  comes  the  variation  in 
the  minerals  constituting  the  successive  layers.  Some  of  the  layers, 
especially  the  metallic,  may  be  formed  from  vapors  or  solutions  rising 
from  a  deeper  source  than  the  range  of  level  along  which  they  occur. 

If  the  process  of  filling  were  rapid,  the  vein  would  fail  of  this 
division  into  layers.  The  adjoining  rock  is  often  cotemporaneously 
altered. 

Certain  veins  in  crystalline  rocks,  which  blend  on  either  side  with  the  rock  adjoining, 
are  sometimes  called  seyreyated  vtins.  They  are  supposed  to  have  been  formed  by  a 
segregating  process,  or  a  crystallization  out  of  the  rock  in  which  they  occur,  the  direc 
tion  of  the  plane  of  the  vein  being  determined,  not  by  the  previous  existence  of  a  fis- 
sure,  but  by  magnetic  currents  through  the  rock,  or  other  less  intelligible  cause.  No 
facts  authorize  us  to  infer  that  magnetic  currents  have  the  power  here  attributed  to 
them.  Such  a  blending  of  a  vein  with  the  walls  is  a  natural  result,  when  its  formation 
in  a  fissure  takes  place  at  a  high  temperature  during  the  metamorphism  or  crystalliza 
tion  of  the  containing  rock. 

3.  Alterations  of  Veins.  —  Veins  do  not  always  retain  their  original 
constitution  ;  and  those  that  are  metalliferous  are  especially  liable  to 
alteration.  There  are  often  lines  of  small  cavities  through  the  middle 
of  a  vein,  or  along  its  sides,  or  in  both  ;  and,  when  the  rocks  in  which 
they  occur  are  raised  above  the  level  of  the  ocean,  the  atmospheric 
waters  find  access  as  they  become  subterranean,  and  constantly  trickle 
through  them.  These  waters  decompose  some  species  readily  (pyrite, 
etc.),  and  take  the  new  ingredients  (sulphate  of  iron,  etc.)  into  solu 
tion.  Feldspathic  minerals  may  be  decomposed,  an^d  the  waters  thereby 
become  siliceous  and  alkaline.  Also,  in  one  way  or  another,  they  may 
become  carbonated.  Thus  armed,  the  waters  go  on  making  various 
changes  in  the  ores  and  minerals  of  the  vein,  altering  chalcopyrite 
(sulphid  of  copper  and  iron)  to  copper-glance  or  erubescite  (sulphids 
of  copper),  or  to  malachite  (carbonate  of  copper),  or  changing  in  a 
similar  manner  ores  of  silver  or  lead,  etc.  In  some  parts,  the  arrange- 


734  DYNAMICAL    GEOLOGY. 

merits  may  be  such  as  to  produce  a  galvanic  effect,  further  promoting 
decompositions  and  recompositions.  When  the  solutions  differ,  after 
intervals  of  time,  there  will  be  a  succession  in  the  changes  ;  and  layers 
of  different  species  may  be  formed. 

Thus,  a  layer  of  quartz  may  be  succeeded  by  one  of  fluorite,  or  of  zinc  blende,  or  of 
calcite,  or  of  quartz  again,  etc.  In  the  course  of  the  changes,  a  layer  of  cubes  of  fluo- 
rite,  underlying  one  of  quartz,  may  be  entirely  dissolved  away,  and  the  cubical  cavi- 
ries  filled  up  by  another  species,  as  blende,  etc. 

The  rock  of  the  walls  (especially  of  the  lower  wall,  where  the  vein  is  inclined),  when 
not  united  firmly  to  the  vein,  often  undergoes  deep  alteration,  and  may  become  pene 
trated  by  ores'  from  the  vein  itself,  carried  in  by  infiltrating  solutions.  These  altera 
tions  are  most  extensive  in  the  upper  part  of  veins,  where  it  often  happens  that  the 
metals  are  removed  by  infiltrating  waters;  excepting  for  the  most  part  the  iron,  which  is 
left  in  the  state  of  red  oxyd,  giving  its  color  to  the  earthy  mass  at  the  top  of  the  vein 
(called  then  the  iron  hat).  Hence  the  occurrence  of  a  line  of  red  earth  in  the  soil  may 
be  an  indication  of  a  vein  of  ore  beneath. 

Gold-bearing  quartz  veins  generally  lose  the  pyrite,  and  perhaps  other  ores  which 
they  contain,  and  thus  become  cavernous  to  a  considerable  depth.  To  this  distance, 
they  are  mined  with  comparative  ease;  but,  beyond,  they  are  extremely  hard  and  much 
more  difficult  to  work. 

4.  Veins  of  Different  Ages.  —  In  the  progress  of  the  uplifting  and 
folding  of  a  region  undergoing  metamorphism,  fissures  formed  at  one 
time  and  filled  would  be  liable  to  be  broken  by  cross-fissures  at  some 
subsequent  time  in  the  epoch  (perhaps  a  following  day,  week,  or  year), 
and  these,  again,  by  others.  Thus,  a  succession  of  veins  faulting  one 
another  might  be  formed  during  one  epoch  of  disturbance  ;  and  they 
might  differ  in  constitution  as  the  bands  in  a  banded  vein  differ. 

Again,  veins  may  be  intersected  and  faulted,  by  fissures  formed 
during  subsequent  epochs  of  disturbance. 

It  is  evident,  therefore,  that  a  vein  which  faults  another  does  not 
necessarily  belong  to  a  later  independent  epoch.  When  actually  later 
in  epoch,  it  will  usually  appear  in  a  different  distribution  of  the  new 
veins  over  a  wide  region  of  country,  and  in  their  direction,  and  their 
wholly  distinct  mineral  composition. 

5.  Filling  of  Amyydaloidul  Cavities.  —  The  cavities  in  a  lava  or  igneous  rock,  such  as 
are  formed  by  expanding  vapors  while  the  rock  is  liquid,  differ  from  veins  in  size,  but 
not  essentially  in  the  method  by  which  they  are  filled  with  minerals.  In  amygdaloids, 
these  minerals  are  usually  chlorite,  quartz,  prehnite,  datolite,  analcite,  or  some  of  the 
zeolites,  or  calcite;  and  in  each  cavity  they  often  are  in  successive  layers,  analogous  to 
the  layers  of  a  banded  vein.  They  are  introduced  by  infiltrating  waters,  which  derive 
the  ingredients  mainly  from  the  inclosing  rock,  through  the  decomposition  of  some  of 
its  minerals.  Quartz  (glassy  quartz,  chalcedony,  agate,  carnelian,  etc.)  and  calcite  are 
the  most  common  of  these  minerals,  just  as  they  are  in  veins.  Most  of  the  species  in 
amvgdaloidal  cavities  are  hydrous,  —  showing  that  they  were  formed  at  a  much  lower 
temperature  than  the  materials  of  a  grany tic  vein ;  and  some  of  them  may  perhaps  be 
formed  even  at  the  ordinary  temperature. 

At  Plombieres  in  France,  the  cement  and  brick  of  walls,  of  Roman  origin,  have  he- 
come  penetrated  in  places  with  zeolites,  through  the  action  of  the  water  of  a  warm 
mineral  spring  having  a  temperature  of  140°  to  160°  F.  (Daubree.) 


KESULTS    OF    THE   EARTH'S    CONTRACTION.  735 

THE    EARTH  A  COOLING    GLOBE:   ITS    CON 
SEQUENCES. 

As  the  globe  has  cooled  from  fusion,  it  has  been  through  all  time  a 
contracting  globe ;  and  this  contraction  of  the  crust  has  been  the  chief 
agency  in  determining  the  evolution  of  the  earth's  surface-features, 
and  the  successive  phases  in  its  long  history. 

I.    GENERAL   CONSIDERATIONS. 

1.  Seat  of  the  Organizing  Agency  of  Contraction.  —  It  is  stated  on 
page  146,  that  solidification  probably  began,  as  suggested  by  Hopkins, 
at  the  earth's  centre,  and  as  a  consequence  of  pressure  ;    that  the    tem 
perature  of  the  globe  in  which  pressure  would  produce  this  result  was 
reached  long  before  a  crust  began  to  form  from  external  cooling  ;  and 
that,  when  the  crust  had  formed,  the  globe  consisted  of  (1)  a  solid  nu 
cleus,  which  had  solidified  from  the  centre  outward  ;   (2)  a  crust,  which 
had  solidified  from  the  surface  inward  ;  and  (3)  a  layer  of  plastic  rock 
between  the  two,  which,  through  continued  cooling,  would  tend  to  be 
come  united  ultimately  with  the  latter.     The  earth's  crust  could  not 
have  undergone   flexures,  unless   it  were  lying  upon  a  bed  of  liquid 
rock,  that  could  yield  before  it;  and,  if  the  globe  is  now  essentially 
solid  throughout  its  mass,  there  must  have  been  in  past  time, at  least, 
a  more  or  less   complete   layer   of  plastic  rock-material,  such   as   this 
view  of    Hopkins    supposes.      The    subsidences  and   elevations   have 
affected  areas  of  vast  extent  at  once ;  arid  even  in  the  Quaternary,  or 
Quaternary  and  Tertiary,  occurred  the  coral-island  subsidence  in  the 
Pacific,  whicli  moved  the  bottom  of  the  ocean  for  a  breadth  of  5,000 
miles.     The  fire-seas  beneath  the  crust  must  hence  have  been  of  great 
extent. 

In  accordance  with  the  above,  the  organizing  agency  of  contraction 
was  confined  mainly  to  the  crust,  of  which  the  supercrust  is  an 
upper  transformed  portion  (p.  147)  ;  and  there  was  enough  of  plastic 
rock  beneath  this  crust  to  have  allowed  of  all  the  bendings  the  crust 
has  experienced. 

2.  The  Force  resulting  from  Contraction.  — The  crust  which  should 
form  over  a  melted  sphere,  as  it  cooled,  would  have  the  size  the  sphere 
had  at  the  time.     As  it  thickened  downward,  by  the  continued  cooling, 
the  added  portions  would  contract,  since  the  density  of  the  solidified 
rock  is  at  least  eight  per  cent,  greater  than  that  of  the  liquid,  and  this 
would  occasion  lateral  pressure  throughout  the  crust,  which  would  in 
crease  as  the  cooling  and  thickening  continued.     A  yielding  some 
where  would  finally  become  an  inevitable  result. 


736  DYNAMICAL   GEOLOGY. 

The  effect,  in  a  melted  spheroid,  of  cooling  more  rapidly  at  the  sur 
face  than  within,  is  illustrated  in  glass  in  a  Prince  Rupert's  drop. 
The  pressure  of  particle  against  particle  over  the  whole  exterior  is  so 
great,  from  the  interior  contraction,  that  the  removal  of  a  portion  of 
the  surface-layer  by  a  slight  scratcli  of  a  file  destroys  the  equilibrium, 
and  causes  it  to  break  instantly,  and  almost  explosively,  to  fragments. 
Another  familiar  example  of  contraction  beneath  an  exterior  coat  is 
seen  in  a  drying  apple.  The  exterior,  in  this  case  flexible,  gradually 
becomes  wrinkled,  from  the  diminution  of  size  within ;  and  the  wrink 
ling  covers  the  whole  surface  alike,  unless  some  part  be  protected  by 
resin  or  otherwise,  —  in  which  case  the  largest  wrinkles  would  be  those 
about  the  border  of  the  protected  portion. 

3.  Constitution  of  the  Earth's  liquid  Exterior,  and  of  the  cooled 
Crust  made  from  it.  —  The  nature  of  the  first-formed  crust,  or  of  the 
liquid  material  of  which  it  was  made  by  cooling,  may  be  inferred  (1) 
from  the  materials  which  have  come  up  through  tappings  of  the  inte 
rior,  that  is,  igneous  rocks ;  and  (2)  from  the  nature  of  the  earliest 
rocks  of  the  supercrust,  the  Archaean. 

Igneous  rocks  show,  by  the  fact  that  four-fifths  consist  of  the  lime- 
feldspar,  labradorite,  and  the  iron-bearing  silicates,  augite,  hornblende 
and  chrysolite,  together  with  magnetite  (the  iron  oxyd  Fe3O4),  the  con 
stituents  of  doleryte,  that  four-fifths  of  the  true  crust  are  probably 
dolerytic,  or  basic,  and  iron-bearing ;  while  the  remainder  of  the  igne 
ous  rocks  —  the  feldspathic  kinds,  related  to  trachytes  —  evince  that 
it  has  its  regions  of  potash  and  soda  feldspars  (orthoclase  and  oligo- 
clase),  nearly  free  from  iron-bearing  minerals.  The  former  kinds  have 
mostly  a  specific  gravity  of  2-9  to  3-2,  and  the  latter  of  2-5  to  2-75, 
and  hence  the  mean  specific  gravity  of  the  true  crust  is  probably 
about  2-9. 

Among  Archaean  rocks,  hypersthenyte  has  nearly  the  constitution 
of  doleryte ;  other  kinds,  containing  chrysolite,  are  closely  related  to 
the  dolerytic  rock,  peridotyte ;  diabase  has  the  composition  of  a  chlo- 
ritic  doleryte  ;  so  that  these  first  deposits  over  the  crust,  made  from  its 
detritus,  suggest  the  same  conclusion  as  the  igneous  rocks.  Moreover, 
iron-bearing  Archaean  rocks  greatly  exceed  in  amount  all  others  ;  and 
the  iron-ore  beds  of  the  Archaean  are  vastly  larger  than  any  of  later 
time,  —  some  exceeding  a  hundred  feet  in  thickness.  Hence,  unlike 
human  history,  the  earth's  iron-age  was  its  earliest. 

The  distribution  of  the  dolerytic,  or  basic,  and  the  trachytic,  or  acidic,  portions  of  the 
crust  was  probably  determined  by  the  general  currents  over  the  sphere  when  it  was 
liquid,  and  also  by  local  movements  dependent  on  special  centres  of  igneous  activity. 
This  cause  would  naturally  have  led  to  a  more  or  less  perfect  separation  of  the  less  fusi 
ble  and  liyhter  feldspathic  portion  from  the  rest.  Daubre"e  has  inferred  the  occurrence 
of  a  large  proportion  of  chrysolite  in  the  true  crust,  from  its  prevalence  in  meteorites. 


KESULTS   OF   THE   EARTH'S   CONTRACTION.  737 

(On  this  and  related  subjects,  see  Daubrce,  Exp.  Synth,  relatives  aux  Meteorites, 
Comptes  Rendus,  Ixii.,  1866,  and  Smithson.  Ann.  Rep.  for  the  year  1868.) 

That  the  dolerytic  or  basic  rocks  should  have  been  the  most  abundant,  in  the  earth's 
liquid  interior,  is  indicated,  as  Hunt  has  observed,  by  the  fact  that  nearly  all  the  lime 
of  limestones  must  then  have  been  in  the  condition  of  silicates,  making,  probably,  the 
feldspar,  labradorite,  and  forming,  with  iron  and  the  magnesia  now  in  magnesian  lime 
stones,  atigite,  hornblende,  or  chrysolite. 

The  rock  of  the  true  crust  must  be  coarsely  crystalline,  and,  in  this  respect,  unlike 
ordinarv  doleryte ;  for  a  coarsely  crystalline  structure  is  a  necessary  consequence  of 
extremely  slow  cooling.  Which  of  the  two  minerals,  augite  and  hornblende  (essentially 
alike  in  constitution,  but  unlike  in  crystallization),  would  have  been  formed,  there  are 
not  yet  facts  to  decide. 

4.  Constitution  of  the  Earth's  Nucleus.  —  The  large  proportion  of 
oxyd  of  iron,  in  igneous  rocks  and  the  Archaean  terranes,  suggests  that 
the  increase  of  density  in  the  earth  toward  the  centre,  shown  to  exist 
by  its  specific  gravity,  5-5  to  6,  may  be  due,  so  far  as  it  is  not  owing 
to  increased  density  below  from   pressure,  to  the  presence  of  iron, 
either  pure  or  in  combination.     All  our  platinum  and  gold  come  from 
the  supercrust  and  its  infiltration-veins,  and  hence  were  derived  from 
the  outer  part  of  the  true  crust.     They  probably  reached  this  exterior 
position,  through  combinations  under  the  extreme  heat ;  and  most  that 
existed  in  the  sphere  may  have  thus  escaped.     If  iron  be  the  chief 
material  of  the  nucleus,  and  the  specific  gravity  be  mainly  due  to  it, 
supposing  no  increase  of  density  below,  the  mass  of  the  globe  should 
be  two-thirds  iron,  and  this  would  bring  the  iron  to  within  500  miles 
of  the  outer  surface,  so  that  the   nucleus,  in  such   a  case,  might  be 
nearly  all  iron.     The  iron  meteorites  which  have  reached  the  earth, 
appear  to  favor  the  above  view. 

5.  Cleavage  Structure  in  the  Earth's  Crust.  —  The  prevalent  north 
east  and  northwest  courses  of  trends,  the  curves  in  the  lines  varying 
the  direction  from  these  courses,  and   the  dependence  of  the  outlines 
and   feature-lines    of  the  continents    and  oceanic    lands    upon    these 
courses   (p.  29),  are  the  profoundest  evidence  of  unity  of  development 
in  the  earth.     Such  lines   of  uplift  are   lines  of  fracture,  or  lines  of 
weakest    cohesion ;   and    therefore,   like    the    courses    of   cleavage  in 
crystals,   they  show  by  their  prevalence  some   traces  of  a  cleavage- 
structure  in  the  earth,  —  in  other  words,  a  tendency  to  break  in  two 
transverse  directions  rather  than  others. 

Such  a  cleavage-structure  would  follow  from  the  mode  of  origin  of 
the  earth's  crust.  The  crust  has  thickened  by  cooling,  until  now 
scores  of  miles  through  ;  and  very  much  as  ice  thickens,  —  by  additions 
to  its  lower  surface.  Ice  takes  on  a  columnar  structure,  perpendicular 
to  the  surface,  in  the  process,  so  as  often  to  break  into  columns,  on 
slow  melting.  The  earth's  crust  contains  as  its  principal  ingredient 
one  or  more  kinds  of  feldspar,  all  cleavable  minerals  ;  and,  as  crystals, 
47  * 


738  DYNAMICAL   GEOLOGY. 

on  slow  solidification,  often  take  a  parallel  position,  so  it  might  have 
been  in  the  cooling  crust.  This  appears  the  more  probable,  when  it 
is  considered  with  what  extreme  slowness  the  thickening  of  the  crust 
has  gone  on,  and  the  immeasurable  length  of  time  it  has  occupied. 

6.  Formation  of  Continents  and  Oceanic  Basins.  —  The  earth's  crust 
rises  over  large  areas  into  plateaus  or  continents,  leaving,  between,  a 
depressed  area,  of  much  larger  extent,  occupied  by  the  ocean  ;  and 
the  depression  has  rather  abrupt  sides  against  the  plateaus  (p.  11). 
These  plateaus  show  by  their  position — -thus  sustaining  the  infer 
ences  from  geological  history  (p.  1 60)  —  that  they  were  the  parts  of 
the  crust  which  first  stiffened,  in  the  gradual  cooling  of  the  exterior, 
and  that  the  oceanic  basins  are  due  to  a  subsequent  consolidation  of 
the  areas  they  occupy,  the  attending  contraction  carrying  them  below 
the  level  of  the  previously  solidified  continental  areas. 

The  crust  over  the  first  solidifying  areas,  — now  the  continents,  —  after  attaining  a 
thickness  that  would  enable  it  to  overcome,  by  its  gravity,  the  cohesion  in  the  liquid 
rock  beneath,  would  have  sunk  in  masses,  and  then  have  been  remelted  by  the  heat 
beneath;  and  this  remclting  would  have  cooled  somewhat  the  liquid  layer.  So,  this 
process  of  crusting  and  sinking,with  an  overflow  from  either  side,  remelting  and  cool 
ing,  would  have  gone  forward  until  the  masses  could  sink  without  much  remelting, 
to  bring  up  at  the  level  where  the  density  of  the  liquid  layer  was  that  of  the  solid 
rock,  if  this  liquid  layer  had  not  become  so  stiffly  viscid  by  the  cooling  as  to  offer  too 
great  resistance  to  their  reaching  quite  to  this  level.  The  sinking  rock-masses  may 
have  had  their  density  somewhat  increased,  by  the  pressure  to  which  they  were  sub 
jected  on  descending;  but,  whatever  density  they  acquired,  this  density  would  deter 
mine  the  limit  to  which,  setting  aside  resistance  from  viscidity,  —  they  would  have 
sunk.  It  may  be  that  portions  went  down  until  they  came  in  contact  with  the  nucleal 
solid  mass.  As  the  crust  sank,  the  liquid  material  adjoining  would  have  continued  to 
flow  over  the  solidifying  area,  and  to  add  to  the  solidifying  material. 

Finally,  a  layer  of  crust-rock,  miles  in  thickness,  would  have  been  made,  over  the 
great  continental  areas.  Throughout  the  other  portions  of  the  sphere,  the  surface, 
whether  all  liquid  or  in  incipient  solidification,  would  have  had  the  level  of  that  of 
the  continental  areas.  For  the  sake  of  the  illustration,  suppose  them  to  have  been  all 
liquid,  and  the  continental  crust  twelve  miles  thick,  and  the  oceanic  areas  to  go 
through  the  same  process  of  solidification  as  had  been  completed  over  the  continental 
areas;  when,  finally,  the  material  of  the  oceanic  regions  had  solidified  down  to  the 
same  plane  with  that  of  the  continental,  that  is,  to  the  twelve-mile  limit,  the  oceanic 
crust  thus  formed  would  have  become  depressed  in  the  consolidation  (on  the  ratio  of 
8  per  cent,  less  volume  for  the  solid  than  for  the  liquid),  5,000  feet;  or,  if  the  layer 
consolidated  were  thirty-six  miles  thick,  15,000  feet;  that  is,  supposing  the  continental 
part  to  have  undergone  no  contraction  during  the  time.  As  such  contraction  would 
have  been  in  progress,  from  the  continued  cooling,  the  above  5,000  feet  is  not  the  actual 
depth  which  the  basin  would,  under  the  supposed  circumstances,  have  acquired;  and 
yet,  since  the  change  of  volume  in  the  cooling  of  solid  rock  is  small,  it  is  not  very  wide 
from  the  fact. 

The  case  here  supposed  is  partly  hypothetical,  because  the  condition,  over  the 
oceanic  areas,  when  the  solidified  crust  of  the  continental  areas  was  completed,  may 
have  been  that  of  incipient  solidification,  so  that  some  of  the  contraction  had  already 
taken  place.  Butr  apart  from  this,  it  represents  the  steps  in  the  process,  and  illustrates 
how  it  is  that  great  depressed  areas  would  have  been  an  inevitable  result,  and  why 
they  should  have  had  comparatively  abrupt  sides,  or  a  basin-like  character.  The 


RESULTS    OF   THE   EARTH'S    CONTRACTION.  739 

present  mean  depth  of  the  oceanic  areas  below  the  mean  level  of  the  continental 
plateaus  is  probably  about  10,000  feet.  The  thickness  of  the  layer  of  liquid  rock 
required  to  make  a  depression  of  10,000  feet,  by  its  consolidation,  would  be  about  thirty- 
eight  and  a  quarter  miles.  But,  as  contraction  has  gone  on  through  time,  over  both 
continental  and  oceanic  areas,  this  is  the  mean  excess  of  depression  for  the  oceanic 
area.  What  part  of  this  excess  existed  when  the  oceanic  depression  was  first  made, 
there  are  no  facts  for  satisfactorih-  deciding.  If  the  coral-island  subsidence  was  due 
in  anv  considerable  part  to  radial  contraction,  beneath  the  central  Pacific  crust  itself, 
it  is  probable  that  the  excess  has  increased,  even  in  Cenozoic  time. 

The  cooling  of  one  part  of  the  crust  before  the  rest  mu*t  have  been  a  consequence 
of  there  being  less  vivid  heat  and  violent  action  in  the  liquid  rock  of  that  part;  and 
this  may  have  been  connected  with  the  exterior  of  the  solid  nucleus,  in  that  part,  being 
nearer  than  elsewhere  to  the  outer  surface  of  the  sphere,  that  is,  to  there  being  less 
depth  of  liquid  rock  over  it  to  cool. 

7.  Results  of  Contraction.  —  The  differences  of  level  thus  early 
developed  in  the  surface  of  the  sphere  had  a  controlling  effect  over 
all  the  subsequent  results  of  contraction.  These  results  include.  — 

1.  Flexures  of  the  crust  and  its  strata,  fractures,  earthquakes. 

2.  The  evolution  of  the  earth's  fundamental  features. 

3.  Changes  in  climate. 

And,  incidental  to  these,  there  were  igneous  eruptions  along  frac 
tures,  consolidation  of  rocks,  metamorphism  of  strata,  making  of 
mineral  veins,  destructions  of  life,  and  other  progressing  changes  in 
the  earth's  physical  condition. 

II.  FLEXURES  OF  THE  CRUST,  AND  OF  STRATA,  FRACTURES, 
EARTHQUAKES. 

1.  FLEXURES,  FRACTURES. 

The  sudden  production  of  vapors  beneath  a  portion  of  the  earth's 
crust  is  referred  to,  on  a  preceding  page,  as  a  possible  cause  of  local 
changes  of  level  in  volcanic  regions.  It  is  often  regarded  as  a  means 
of  making  mountains  and  raising  continents.  But  mountain-chains 
are  heavy,  and  continents  very  heavy ;  and  such  vapors,  if  formed, 
could  at  the  most  only  shake  the  rocky  crust.  Mountain-chains  and 
continents  could  not  be  sustained  long  on  a  bed  of  vapors ;  for  perma 
nent  elevation,  there  must  be  some  mode  of  holding  them  up  after  the 
uplift.  Moreover,  there  is  no  reason  to  believe  in  the  existence  of 
cavities  beneath,  such  as  would  be  required  for  the  spread  of  the 
vapors. 

Flexures  of  the  Crust  and  of  Strata.  —  Lateral  pressure,  from  con 
traction,  is  a  force  of  indefinite  power,  fully  adequate  for  all  the  moun 
tain-making  which  has  taken  place.  It  acts  horizontally,  or  very 
nearly  so,  and  therefore  in  a  direction  to  produce  the  flexures  of  the 
rocks  involved  in  the  making  of  mountains.  Its  first  effect  is  to  cause 
great  upward  and  downward  bendings  in  the  crust,  —  geanticlinals  and 


740  DYNAMICAL   GEOLOGY. 

geosynclinals,1  —  besides  flexures,  fractures,  and  displacements  of  the 
overlying  strata,  and  great  fractures,  sbovings,  and  crushings,  where 


bending  has  reached  its  limit. 


1122. 


Upturned  stiata  of  the  west  slope  of  the  Elk  Mountains,  Colorado.    The  light-shaded  stratum,  Tri- 
as.sico- Jurassic  ;  that  to  the  right  of  it,  Carboniferous  ;  that  to  the  lefr,  Cretaceous. 

Some  of  the  kinds  of  flexures  have  been  described  on  pages  93,  94,  and  views  are 
given  of  examples  from  the  Green  Mountains  on  page  213,  and  from  the  Appalachians 
on  page  396.  Another  sketch  is  here  introduced,  from  the  Elk  Mountains,  in  Western 
Colorado,  where  the  hills  are  free  from  vegetation,  and  show  their  rocks  at  surface,  so 
that  the  bendings  may  be  easily  followed.  It  represents  Cretaceous,  Jurassico-Triassic, 
and  Cnrboniferous  strata,  and  shows  that,  through  a  twist  in  the  upturning,  the  Creta 
ceous,  which  is  the  overlying  rock  in  the  back  part  of  the  scene  (to  the  left),  is  really  the 
underlving  in  the  front  part,  and  the.  Carboniferous  the  upper  part,  the  pressure  having 
so  pushed  forward  the  mass  that  the  order  of  superposition  is  the  reverse  of  the  order 
of  age,  and  the  Carboniferous  beds  of  the  front  ridge  incline  45°  beyond  the  vertical. 
The  flexures  and  upturning  took  place  after  the  Lignitic  period  of  the  Tertiary;  and 
several  of  the  summits,  as  measured  in  1873  by  Gardner,  are  12,000  to  14,000  feet  in 
height.  The  facts  and  view  are  from  Hay  den  &  Gardner's  Report  for  1873. 

Geological  history  is  full  of  such  examples  and  of  many  of  greater 
complexity.  No  material  is  so  solid  that,  when  in  broad  tabular  masses, 
it  will  not  become  flexed,  by  lateral  pressure  very  gradually  applied. 
By  "very  gradually"  should  be  understood  movement  by  the  foot  or 
so  a  century,  or  that  degree  of  extreme  slowness  which  has  so  often 
been  exemplified  in  geological  history,  and  which  is  the  most  common 
of  nature's  methods  of  progress.  The  rock  or  other  solid,  though  ap 
parently  inflexible,  will  undergo,  under  such  conditions,  a  molecular 
movement,  adapting  it  to  its  new  condition.  Even  brittle  ice,  as 
stated  on  p.  681,  becomes  flexed  by  its  own  weight,  if  a  slab  be  sup 
ported  only  by  its  ends.  If  ice  covered  a  lake  to  a  thickness  of  a 
score  or  more  feet,  and  a  slowly-accumulating  pressure  to  a  sufficient 
amount  could  be  brought  to  bear  against  one  side  of  it,  the  ice  might 
be  plicated  over  its  surface,  as  boldly  and  numerously  as  the  formations 
of  the  Appalachians. 

Fractures,  Joints.  —  Fractures  are,  however,  a  natural  result  of  the 

1  The  prefix  in  these  words  is  from  the  Greek  for  earth ;  the  bendings  are  bendiugs, 
not  of  strata  or  formations,  but  of  the  earth's  crust  covered  with  its  strata,  folded  or  not 
folded. 


EARTHQUAKES.  741 

strain  attending  the  bending,  especially  along  the  axes  of  folds ;  and, 
under  this  strain,  those  of  an  anticlinal  axis  should  open  upward,  and 
those  of  a  synclinal  downward,  as  is  the  usual  fact.  In  some  cases, 
where  the  rocks  were  stiff,  they  have  been  broken  into  numberless 
masses,  which,  under  the  pressure,  have  slid  among  one  another,  in  a 
very  promiscuous  way.  Ordinary  faults  are  nothing  but  the  dropping 
of  the  rock  on  one  side  of  a  fracture  by  gravity,  or  else  a  pushing  of 
it  up  or  down  sidewise,  or  in  some  cases  horizontally,  along  a  plane  of 
fracture,  by  the  pressure  which  caused  the  breaking. 

The  cause  appealed  to,  moreover,  is  precisely  that  demanded,  to  ac 
count  for  the  great  systems  of  fractures  in  rocks,  called  joints,  and  the 
lamination  of  slate  transverse  to  the  bedding  (p.  89)  ;  for  these  depend 
on  the  working  of  lateral  pressure  with  extreme  slowness  through  long 
periods  of  time.  The  joints  are  parallel  to  some  axis  of  upheaval.  The 
pressure  which  turns  an  argillaceous  rock  into  a  roofing  slate,  places 
all  flattened  particles  in  positions  tranverse  to  the  force,  and  flattens 
out  all  compressible  grains  and  air-bubbles  ;  and  thus  lamination  at 
right  angles  to  the  pressure  is  a  necessary  result.  Sand-beds  under 
the  same  circumstances  may  have  all  their  bedding  obliterated,  through 
the  shaking  they  experience,  and  become  jointed  instead,  as  illustrated 
on  page  89.  Slaty  cleavage  has  been  produced  by  Tyndall  in  wax, 
as  well  as  clay,  by  simple  pressure,  and  the  laminated  structure  of 
glacial  ice  (p.  682)  has  been  explained  by  him  in  the  same  way. 

2.  EARTHQUAKES. 

1.  General  Characteristics. — Earthquakes  are  vibrations  of  the 
earth's  crust.  The  vibrations,  begun  at  a  line  of  fracture,  or  by  a  sud 
den  movement  or  shock  of  whatever  kind,  are  conveyed  in  the  rocky 
crust,  just  as  the  sound  of  a  scratch  at  one  end  of  a  log  is  propagated 
to  the  other.  An  abrupt  fracture  of  the  crust,  along  a  line  where  the 
force  from  lateral  pressure  has  long  been  increasing,  may  send  a  vibra 
tion  through  a  hemisphere,  which  will  move  on  almost  regardless  of 
the  mountains  on  the  surface. 

An  earthquake  is  either  (1)  a  simple  vibratory  movement,  from  a 
slight  yielding  to  a  strain  or  pressure  or  other  cause,  without  any  per 
manent  displacement  of  the  rocks  ;  or  (2)  a  vibration,  consequent  on  a 
permanent  displacement  or  change  of  level.  The  latter  is  far  the 
most  violent,  as  the  simple  impulse  of  vibration  has  an  additional  on 
ward  progression,  equivalent  to  the  uplift  or  displacement. 

Besides  these  wave-movements  in  the  rocks,  there  is  also,  in  most 
cases,  the  very  rapid  wave  which  gives  sound  to  the  ear.  The  sound 
wave  may  be  felt  before  the  translation-wave,  and  may  travel  farther. 
At  the  shock  of  St.  Vincent,  in  1812,  sounds  like  thunder  were  heard 


742  DYNAMICAL    GEOLOGY. 

over  several  thousand  square  miles  in  the  Caraccas,  on  the  plains  of 
Calaboso,  and  on  the  banks  of  the  Rio  Apure.  At  the  Lima  earth 
quake,  in  1746,  a  subterranean  noise,  like  a  thunder-clap,  was  heard  at 
Truxillo,  where  the  earthquake  did  not  reach.  The  rate  of  progress 
will  vary  with  the  elasticity  of  the  rock,  and  somewhat,  also,  with  the 
elevations  over  the  surface. 

Regular  progression  may  be  a  usual  fact,  although  not  generally 
observed.  Henry  D.  Rogers  has  shown  that  an  earthquake,  on  the 
4th  of  January,  1843,  traversed  the  United  States  from  its  north 
western  military  posts,  beyond  the  Mississippi,  to  Georgia  and  South 
Carolina,  along  an  east-southeast  course,  Natchez  lying  on  the  south 
ern  border,  and  Iowa  about  the  northern.  The  rate  of  travel  ascer 
tained  was  thirty-two  to  thirty -four  miles  a  minute. 

Phenomena  attending  Earthquakes.  —  (1)  Fractures  of  the  earth, 
sometimes  of  great  extent ;  (2)  subsidences  or  elevations  of  extended 
regions,  and  draining  of  lakes  ;  (3)  displacements  of  loose  rocks,  and, 
where  a  mass  overlies  another,  and  is  not  attached  to  it  by  its  precise 
centre,  a  partial  revolution,  resulting  from  an  onward  impulse  ;  (4) 
destruction  of  life  in  the  sea,  on  the  same  principle  that  a  blow  on  the 
ice  of  a  pond  will  stun  or  kill  the  fish  in  the  waters  beneath ;  (5) 
production  of  forced  waves  in  the  ocean  ;  (6)  destruction  of  life  on 
the  land.  Destructions  of  cities  and  of  human  life  have  been  too 
often  recounted  to  need  special  illustration  in  this  place. 

The  elevations  that  take  place  are  sometimes  spoken  of  as  effects 
of  an  earthquake,  although  not  properly  so.  Vibration  may  be  at 
tended  by  fractures  and  uplifts ;  but  these  effects  result  from  the  cause 
that  produces  the  shaking. 

Some  of  the  elevations  and  subsidences  that  have  attended  earth 
quakes  are  mentioned  on  page  585. 

Earthquake  oceanic  waves  have  been  alluded  to  on  page  662.  One 
or  two  additional  examples  of  their  effects  may  here  be  added.  In 
1755,  accompanying  the  Lisbon  earthquake,  the  sea  came  in,  in  a  wave 
forty  feet  high  along  the  Tagus,  sixty  at  Cadiz,  eighteen  on  the  shores 
of  Madeira,  eight  to  ten  on  the  coast  of  Cornwall.  One  in  1746,  on 
the  coast  of  Peru,  deluged  the  sea-port  Callao,  and  the  city  of  Lima 
seven  miles  from  the  coast,  sunk  twenty-three  vessels,  and  carried  a 
frigate  several  miles  inland.  Two  hundred  shocks  were  experienced 
in  twenty-four  hours.  The  ocean  twice  retreated,  to  rush  in  a  lofty 
wave  over  the  land.  The  shock  to  a  vessel  from  an  earthquake  wave 
is  like  that  from  a  heavy  blow  or  from  striking  a  rock. 

As  announced  by  A.  D.  Bache,  the  oceanic  waves,  produced  by  the 
great  earthquake  at  Simoda  (Japan)  in  1854,  crossed  the  Pacific,  and 
were  registered,  as  to  their  number,  intervals,  and  forms,  on  the  self- 


EARTHQUAKES.  743 

registering  tide-guages  of  the  Coast  Survey,  along  the  coast  of  Oregon 
and  California  ;  and,  from  the  data  thus  afforded,  he  was  enabled  to 
calculate  the  mean  depth  of  the  intervening  ocean,  stated  on  page  12. 

3.  Cause  of  Earthquakes.  —  (1.)  The  chief  cause  is  the  lateral  pres 
sure  in  the  earth's  crust,  or  conditions  produced  by  it.  Fractures, 
crushings,  shovings,  and  minor  displacements  of  the  crust,  or  of  its 
overlying  strata,  have  made  the  greater  earthquakes  of  the  past ;  arid 
the  same  cause  is  probably  the  chief  source  of  modern  earthquakes. 
The  rocks  have  been  everywhere  left  in  a  state  of  strain,  in  conse 
quence  of  the  upliftings  and  foldings  to  which  they  have  been  sub 
jected  ;  and  any  yielding,  however  slight,  is  necessarily  attended  by 
an  earthquake  shock.  Professor  W.  H.  Niles  states  that,  at  a  quarry 
of  gneiss  near  Monson,  Mass.,  bendings,  sudden  fractures,  and  expan 
sions  of  the  rock  take  place ;  masses,  before  their  ends  are  detached, 
become  bent  upward  at  middle,  and  one  mass,  three  hundred  and  fifty- 
four  feet  long,  eleven  wide,  and  three  thick,  was  an  inch  and  a  half 
longer  after  it  was  detached  than  before ;  showing  a  strain  which  was 
greatest  in  a  direction  transverse  to  the  strike.  This  may  be  an  ex 
ample,  on  a  small  scale,  of  the  strain  that  pervades  the  whole  crust. 

All  are  familiar  with  the  cracking  sounds  occurring  at  intervals  in 
a  board  floor  of  a  house,  and  arising  from  change  of  temperature, 
especially  in  a  room  in  winter  that  is  heated  only  during  the  day  ;  and 
with  the  more  common  sounds  of  similar  character  from  the  jointed 
metallic  pipe  of  a  stove  or  furnace,  given  out  after  a  fire  is  first  made, 
or  during  its  decline.  In  each  case,  there  is  a  strain  or  tension  ac 
cumulating  for  a  while  from  contraction  or  expansion,  which  relieves 
itself,  finally,  by  a  movement  or  slip  at  some  point,  though  too  slight 
a  one  to  be  perceived  ;  and  the  action  and  effects  are  quite  analogous 
to  those  connected  with  the  lighter  kind  of  earthquakes. 

There  are  other  causes  for  local  shakings,  among  which  are  —  the 
subterranean  undermining  of  strata ;  the  sudden  evolution  of  vapors 
about  volcanoes  ;  and  local  changes  of  temperature  in  the  crust. 

Tidal  waves  in  the  internal  igneous  material  of  the  globe  have  been  considered  a 
chief  cause  of  earthquakes.  Investigations  carried  out  by  Alexis  Perrey,  of  Dijon,  France, 
have  seemed  to  indicate  that  there  is  a  periodicity  in  earthquakes,  synchronous  with 
that  in  the  tides  of  the  ocean,  —  the  greatest  number  occurring  at  the  season  of  the 
syzygies,  in  each  lunar  month.  But,  if  the  earth  is  not  mostly  liquid  within,  some 
other  explanation  of  the  facts,  so  laboriously  worked  out  by  Professor  Perrey,  will  have 
to  be  found. 

The  earth's  contraction  from  cooling  is  thus  at  the  foundation  of  its 
profoundest  movements.  But  all  these  movements  were  only  steps  in 
the  grand  system  of  evolution  which  was  in  progress. 


744  DYNAMICAL    GEOLOGY. 

III.    EVOLUTION  OF  THE  EARTH'S  FUNDAMENTAL  FEATURES. 
1.    FACTS  TO  BE  EXPLAINED. 

The  principal  facts  in  the  earth's  system  of  features,  to  be  explained 
by  the  lateral  pressure  referred  to,  are  the  following :  — 

1.  The  continents  have  mountains  along  their  borders,  while  the  in 
terior  is  in  general  relatively  low  ;  and  these  border  mountain-regions 
often  include  two  or  more  parallel  ranges  or  chains,  elevated  at  differ 
ent  epochs. 

2.  When  there  are  one  or  more  ranges  along  a  border  in  addition 
to  the  main  chain,  they  are  almost  always  situated  on  the  seaward 
side  of  the  main  chain. 

3.  The  highest  mountain-border  faces  the  largest  ocean,  and  con 
versely. 

4.  The  volcanoes  of  the  continental  areas  are  mostly  confined  to 
the  sea-borders,  or  the  oceanic   slope  of  the  border  mountain -chains, 
not  because  of  the  vicinity  of  salt  water,  but  because  these  were  the 
regions  of  greatest  disturbance  and  fractures  through  lateral  pressure. 

5.  Nearly  all  of  the  volcanoes  of  a  continent  are  on  that  border 
which  faces  the  largest  ocean :  the  Pacific  is  consequently  girt  with 
volcanoes. 

G.  The  strata  of  the  continental  borders,  especially  over  the  sea 
ward  slope  of  the  border-chain,  are  for  the  most  part  plicated  on  a 
grand  scale,  while  those  of  the  interior  are  relatively  but  little  dis 
turbed. 

7.  The  folds  in  the  Appalachians  and  in  other  border- regions  are 
not  usually  symmetrical  folds,  but  have  one  slope  much  steeper  than 
the  other. 

8.  The  successive  changes  of  level  on  coasts,  even  from  Archaean 
time  to  the  Tertiary,  have  been  in  general  along  lines  parallel  to  the 
border  mountain-chains ;  as   those  of  the  eastern  United   States,  par 
allel  to  the  Appalachians,  and  those  of  the  Pacific  side,  so  far  as  now 
appears,  parallel  to  the  Rocky  Mountains. 

9.  The  successive  mountain-ranges  made  over  the  same  part  of  a 
border-region  are  generally  parallel  to  one  another :  e.  #.,  the  course 
of  the  Triassico- Jurassic  uplifts  and  trap  hills  is  parallel  throughout  to 
the  Appalachian  chain,  —  the  New  England  part  of  each  having  a 
north-by-east  course,  and  parallel  also  to  the  Archaean  range  of  the 
Adirondacks  ;  the  Pennsylvania  part,  an  east-northeast ;  the  Virginia 
and  North  Carolina  part,  a  northeast.     The   same  general   truth  is 
exemplified  elsewhere  in  North  America. 

10.  The  features  of  the  North  American  continent  were  to  a  great 


EVOLUTION  OF  THE  EARTH'S  FEATURES.         745 

extent  defined  in  pre-Silurian  time  (p.  160),  the  course  of  the  Archaean, 
from  the  Great  Lakes  to  Labrador,  being  that  of  the  Appalachians, 
and  various  ridges  in  the  Rocky  Mountains  foreshado  wings  of  this 
great  chain,  and  so  on  in  many  lines  over  the  continental  surface  ; 
and  thus  its  adult  characteristics  were  as  plainly  manifested  in  its  be 
ginnings  as  are  those  of  a  vertebrate  in  a  half- developed  embryo. 

11.  The  prevalent  courses  of  coast-lines,  mountain-chains,  and  groups 
of  islands  over  the  globe  are  two,  —  one  from  about  northeast-by-east 
to  southwest-by-west,  and  the  other  from  about  northwest-by-north  to 
southeast-by-south  (p.  29). 

12.  In  the  courses  of  the  earth's  outlines,  while  there  are  two  prev 
alent  trends,  there  are  very  commonly  curves  :  in  some  cases  a  gradual 
curve,  as  from  E.  N.  E.  to  N.  N.  E.,  as  in  the  great  central  chain  of 
the  Pacific ;  or  from  N.  W.  to  W.,  and  then  to  N.  N.  W.,  as  in  the 
line  from  New  Zealand  to  Malacca  (p.  33) ;  in  others,  a  series  of  sev 
eral  curves,  as  in  the  island-ranges   off  the  Asiatic  coast  (p.  35),  and 
also  on  the  east  coast  of  North  America. 

13.  The  earth  toward  or  about  the  equatorial  regions  is  belted  with 
oceanic  waters  separating  its  northern  and  southern  continents,  pass 
ing  through  the  East  Indies,  Red  Sea,  Mediterranean,  and  West  In 
dies  ;  and  this  region  is  remarkable  for  its  volcanoes  (p.  703). 

The  preceding  are  some  of  the  characteristics  of  the  globe,  which 
exhibit  the  system  that  pervades  its  physiognomy,  and  illustrate  the 
manner  in  which  this  system  was  educed.  They  correspond  in  com 
prehensiveness  and  grandeur  with  the  agency  appealed  to  for  their  ex 
planation. 

2.    DEVELOPMENT  OF  THE  EARTH'S  SYSTEM  OF  FEATURES. 

1.  Action  of  the  Pressure  against  the  Continental  Borders.  —  The 
positions  of  the  great  mountain-chains  along  the  borders  of  the  con 
tinents,  and  of  uplifts,  fractures,  plications,  volcanoes,  metamorphism, 
chiefly  on  the  seaward  slope  of  the  chains,  prove  that,  while  the  force 
from  contraction  was  a   universal   force  over  the  sphere,  the  lateral 
pressure  was  vastly  more  effective  in  a  direction  from  the  ocean  than 
in  the  reverse  direction.     Now  this  landward  action  of  the  force  is  a 
necessary  consequence  of  the  fact  that  the  crust  over  the  oceanic  areas 
was  and  is  depressed  below  the  level  of  the  continental,  so  that  the 
lateral  pressure  from  its  direction  would  have   had  the  advantage  of 
leverage  beneath  the  Continental  crust,  or,  rather,  would  have  acted 
obliquely  upward  against  it. 

2.  Pressure  against  the  Continental  Borders  greatest  on  the  sides  of 
the  largest  oceans.  —  The  fact  that  the  largest  and  loftiest  mountain 
chains,  greatest  volcanoes,  and  other  results  of  uplifting  and  disruptive 


746  DYNAMICAL   GEOLOGY. 

force,  characterize  the  borders  of  the  greatest  oceans,  shows  that  the 
lateral  pressure  from  the  direction  of  the  oceans  was  approximately 
proportional  to  the  extent  of  the  oceanic  basins. 

3.  Comprehensiveness  of  the  action  of  Lateral  Pressure.  —  The  uni 
versality  of  the  great  movements  resulting  from  the  earth's  cooling 
and  contraction  is  manifested,  not  only  in  the  relations  existing  be 
tween  the  continental  features  and  the  positions  of  the  oceanic  basins, 
but  also  in  the  fact  that  cotemporaneous,  parallel  movements  have  taken 
place  in  the  continents  on  the  opposite  sides  of  the  same  ocean,  and  in 
some  cases  in  all  continents  together.  Thus,  the  Trenton  period  in 
the  Lower  Silurian  was  a  period  of  extensive  submergence,  both  in 
North  America  and  in  Europe ;  so  also  was  the  Niagara  period,  in  the 
Upper  Silurian  ;  and  the  Subcarboniferous  period.  Again,  the  period 
of  the  Coal-measures  was  one  of  general  emergence,  over  both  conti 
nents,  but  of  small  emergence,  with  very  long  intervals  without,  or 
with  scarcely  any,  change  of  level,  sufficient  for  the  making  of  great 
beds  of  vegetable  debris.  The  Triassic  was  an  era  of  salt-marsh  and 
estuary  formations,  containing  few  fossils,  both  in  Europe  and  Amer 
ica,  facts  showing  again  a  like  condition  on  both  sides  of  the  ocean. 
On  the  contrary,  the  Jurassic  was,  in  America  and  Europe,  a  period 
of  more  submergence  than  the  Triassic.  The  great  era  of  mountain- 
making,  which  commenced  in  the  early  Tertiary,  and  continued  to  its 
end,  was  a  mountain-making  era  for  all  continents  alike  ;  in  Asia  and 
South  America,  as  well  as  Europe  and  North  America,  mountain 
ranges  were  raised  over  10,000  feet. 

Again,  the  destruction  of  species  following  the  close  of  the  Per 
mian  was  as  complete  in  America  as  in  Europe  ;  and  that  closing  the 
Cretaceous  was  scarcely  less  universal.  The  upward,  downward,  and 
again  upward  movements  of  the  crust  in  the  Quaternary  age,  corre 
sponding  to  the  Glacial,  Champlain,  and  Recent  periods,  affected  the 
higher  latitudes  of  the  northern  hemisphere,  on  all  its  sides  ;  and  it  is 
probable  that  these  movements  of  the  northern  hemisphere  were 
attended  by  parallel  movements  in  the  southern. 

Again,  along  the  Atlantic  Border  of  North  America,  the  mountain 
ranges  made  at  different  times  have  on  any  part  the  same  course  (p. 
393);  and  so  also,  along  the  Pacific  Border:  indicating  that  the  all- 
pervading  force  was  in  each  place  at  its  old  work,  through  all  the  suc 
cessive  ages,  with  but  small  modifications  from  the  changed  conditions. 

The  force  has  thus  acted  as  if  one  in  origin  and  nature,  and  mani 
fested  at  all  times  the  fact  that  one  single  system  of  evolution  was  in 
progress. 

3.  Influence  of  the  Cleavage  Structure  of  the  Globe  on  the  developments 
in  progress.  —  While  the  relative  positions  of  the  continental  plateaus 


EVOLUTION   OF    THE    EARTH'S    FEATURES.  747 

and  oceanic  basins  have  influenced  the  general  direction  of  the  action 
of  lateral  pressure,  the  cleavage  structure,  or  the  existence  of  direc 
tions  of  weakest  cohesion,  appears  to  have  in  part  controlled  the 
courses  of  fractures  and  uplifts,  somewhat  as  the  warp  and  woof  in  a 
piece  of  cloth  fix  the  courses  of  rents,  while  the  direction  of  the  force 
applied  determines  the  positions  and  extent  of  the  rents.  Force  ex 
erted  at  right  angles  to  the  lines  of  structure,  and  equal  along  the 
line,  would  produce  a  straight  series  of  rents  or  uplifts  (Figs.  11,  12, 
p.  19).  If  not  equal  along  a  given  line,  the  series  of  rents  made, 
taken  together,  might  be  oblique  or  else  curving  (Figs.  13,  14,  15). 
If  the  tension  were  oblique  to  the  structure-courses,  the  series  of  rents 
would  be  an  oblique  series,  and,  as  above,  either  straight  or  curved. 
Hence,  curves  are  necessarily  in  the  system. 

We  observe  now  that  the  North  Atlantic  follows  one  of  the  cleav 
age-courses,  and  the  Pacific  another  (page  35).  North  America  is 
bounded  by  the  two,  and  hence  its  triangular  form.  The  coincidence 
between  the  trend  of  the  Pacific  (northwest  and  southeast),  the  mean 
trend  of  the  Pacific  islands  (p.  33),  and  the  axis  of  the  coral-island 
subsidence  (p.  583),  shows  that  the  ocean  in  its  movements  has  been 
one  great  area  of  oscillation.  The  central  curving  range,  five  thousand 
five  hundred  miles  long,  lies  on  the  southern  side  of  the  axis  of  this 
great  approximately-elliptical  area. 

The  double  or  triple  system  of  curves  around  Australia,  from  New 
Hebrides,  or  perhaps  northern  New  Zealand,  to  New  Guinea  and 
Timor,  are  such  as  might  arise  from  pressure  acting  against  that  stable 
continental  area  of  Australia  ;  for  they  are  concentric  with  it ;  and 
the  branch  of  the  central  Pacific  chain,  leading  off  westward  through 
the  Carolines,  has  been  shown,  on  page  34,  to  conform  to  this  Aus 
tralian  system.  The  rising  curve  from  Java,  through  Sumatra,  sug 
gests  that  here  pressure  acts  from  the  direction  of  the  Indian  Ocean 
as  well  as  the  Pacific  ;  and  this  is  further  confirmed  by  the  fact  that 
the  deep-water  channel,  separating  the  Australian  seas  from  the  Asi 
atic,  passes  just  north  of  New  Guinea  and  Celebes,  and  south  of  Java. 

The  East  Indian  Archipelago  lies  between  the  North  Pacific  and 
the  Indian  Ocean  ;  and  the  two,  along  with  the  reacting  stable  conti 
nental  areas,  have  together  modelled  out  the  group.  The  West  Indian 
Archipelago  has  a  similar  position  between  the  North  Atlantic  and 
the  South  Pacific,  and  hence  the  resemblances  to  the  East  Indian, 
pointed  out  on  pages  35,  36. 

The  curves  along  eastern  Asia,  in  the  islands  and  continental  moun 
tain-ranges  (page  35),  seem  to  show  that  the  pressure  from  the  direc 
tion  of  the  Pacific,  which  produced  the  curves,  was  unequal  along  dif 
ferent  parallel  lines.  The  courses  and  positions  of  the  groups  of 


748  DYNAMICAL   GEOLOGY. 

Pacific  islands  prove  that  the  bottom  has  its  ranges  of  southeast  and 
northwest  elevations  and  depressions,  crossing  the  ocean  ;  and  this 
would  occasion  the  unequal  tension  required. 

Between  the  directions  of  the  structure-lines  and  the  directions  of 
the  acting  force,  as  determined  by  the  oceanic  and  continental  areas, 
the  origin  of  the  prevalent  trends  and  of  their  frequent  curving  courses 
may  therefore  be  explained. 

4.  America  simple  in  evolution,  because  of  its  situation  between  the 
great  oceans.  —  From  the  above,  we  perceive  why  it  is  that  North 
America  should  illustrate  most  simply  and  perfectly  the  laws  of  the 
earth's  genesis.  Unlike  the  other  continents,  it  is  bounded  on  all 
sides  by  oceanic  basins  ;  on  one  side,  the  North  Atlantic  with  a  north 
east  trend,  on  the  other,  the  greater  Pacific  with  a  northwest  trend. 
The  conditions  under  which  the  lateral  pressure  acted  were  therefore 
the  simplest  possible  ;  and  the  evolution  was  therefore  regular  as  well 
as  systematic.  Europe  has  Africa  on  the  south,  and  Asia  on  the  east ; 
and  hence  the  complexity  in  its  feature  lines.  .  Yet,  even  amid  that 
complexity,  results  according  with  the  general  principles  here  ex 
plained  may  be  made  out. 

3.  SPECIAL  DEVELOPMENT  OF  MOUNTAIN  CHAINS. 

1.  A  Geosynclinal,  or  downward  bend  of  the  Crust,  the  frst  step 
in  ordinary  Mountain-making.  —  In  the  making  of  the  Appalachians, 
there  was  first,  under  the  lateral  pressure,  a  slowly  progressing  sub 
sidence  ;  it  began  in,  or  before,  the  Primordial  period,  the  com 
mencing  era  of  the  Silurian,  and  continued  in  progress  until  the 
Carboniferous  age  closed.  As  the  trough  deepened,  deposits  of  sedi 
ment,  and  sometimes  of  limestone,  were  made,  that  kept  the  surface 
of  the  region  near  the  water  level ;  and,  when  the  trough  reached 
its  maximum,  there  were  40,000  feet  in  thickness  of  stratified  rock 
in  it  (p.  380),  and  this,  therefore,  was  the  depth  of  the  trough.  The 
Green  Mountains  began  in  a  similar  subsidence,  and  at  the  same 
time ;  and  the  trough  was  kept  full  with  deposits  as  it  progressed  ; 
but  it  reached  its  maximum,  or  the  era  of  catastrophe,  at  the  close  of 
the  Lower  Silurian.  Such  facts  are  in  the  history  of  many,  if  not  all, 
mountains. 

The  bearing  of  the  great  subsidence  of  the  Appalachian  region  during  the  Paleozoic, 
under  the  action  of  lateral  pressure,  and  of  the  consequent  formation  there  of  a  very 
thick  accumulation  of  sedimentary  beds,  on  the  origin  of  the  mountain-range,  was 
dwelt  upon  by  the  author,  in  an  address  before  the  American  Association  in  1856.  (Am. 
Jour.  Sci.,  II.  xxii.  1856.) 

In  1859,  the  general  statement  was  made  by  Hall  (Report  on  the  Palaeontology  of 
New  York.  vol.  3,  Introduction),  that  the  formation  of  all  mountains  commenced  with 
a  slowly  progressing  subsidence  of  the  region,  and,  panpassu,  a  thick  accumulation  of 


EVOLUTION  OF  THE  EARTH'S  FEATURES.  —  MOUNTAIN-MAKING.      749 

sedimentary  beds  in  the  trough,  the  Appalachians  being  referred  to  as  an  example. 
But  he  made  the  subsidence  a  consequence  of  the  sedimentary  accumulation,  and  not 
the  accumulation  a  consequence  of  the  subsidence,  throwing  aside  lateral  pressure  al 
together.  The  earth's  crust  would  have  had  to  yield  like  a  film  of  rubber,  to  have 
sunk  a  foot  for  every  added  foot  of  accumulations  over  its  surface;  and  mountains 
would  have  had  no  standing-place. 

2.  The  bottom  of  the  Geosynclinal  weakened  by  the  Heat  rising  into 
it  from  below.  —  As   planes   of  equal  temperature  within   the  earth 
have  a  nearly  uniform  distance  from  the  surface,  the  accumulation  of 
sedimentary  beds  in  the   sinking  trough  would  occasion,  as  Herschel 
long  since  urged,  the  corresponding  rising  of  heat  from  below,  so  that, 
with   40,000  feet   of   such   accumulations,  a  given    isothermal    plane 
would  have  been  raised  40,000  feet.     Under  such  an  accession  of  heat, 
the  bottom  of  the  trough  would  be  greatly  weakened,  if  not  partly 
melted  off.     If  the  lower  surface  of  the  crust  had  dipped  down  this 
much  into  the  plastic  layer  that  was  beneath  it,  it  would  have  been 
actually  melted  off. 

3.  The  Heat  in  the  lower  part  of  the  trough  increased  by  the  Trans 
formation  of  Motion  into  Heat  — The  heat  from  the  transformation 
of  the  motion  of  the  crust  would  have  been  of  feeble  amount,  if  the 
motion  were  extremely  slow  and  regular.     But,  with  fractures,  shov- 
ings,  and  crushing  accompanying  it,  the  heat  from  the  rise  of  the  iso- 
geothermal  would  have  been  much  reenforced. 

4.  The  weakened  trough  yields  before  the  Pressure.  —  The  lateral 
pressure,  acting  against  a  trough  thus  weakened,  would  end,  as  Hunt 
has  observed,  in  causing  a  collapse,  that  is,  a  catastrophic   break  of 
the  trough  below,  and  a  pressing  together  of  the  stratified  beds  within 
it.     And  with  this  break  the  shaping  of  the  mountain  would  begin. 

5.  Character   of  the  Mountain  thus  made.  —  Under    such  circum 
stances,    the    stratified   rocks    would    be    folded,    profoundly    broken, 
shoved  along  fractures,  and  pressed  into  a  narrower  space  than  they 
occupied  before ;  and  thus  they  would   become  raised,  as  argued  by 
Le  Conte,  above  their  former   level,  so  that  a   mountain -range  would 
be   the  result,  even  without  any  actual  uplift   of  the  crust  beneath. 
The  crust  beneath  was  that  of  the  geosynclinal ;  and  lateral  pressure, 
however  powerful,  could  not  possibly   have  raised  at  the   time   the 
downward  flexed  crust. 

6.  The  finished  Mountain  Range  a  Synclinorium.  —  Such  a  moun 
tain-range,  begun   in  a  geosynclinal,  and  ending  in   a   catastrophe  of 
displacement  and  upturning,  is,  as  named  by  the  author,  a  synclinorium, 
it  owing  its  origin  to   the  progress  of  a  geosynclinal.      (The  word  is 
from  the  Greek  for  synclinal,  and  opos,  mountain.)     Although  at  first 
consisting  of  a  series  of  parallel  folds  of  strata,  with   the  anticlinals 
greatly  broken,  —  the  anticlinals,  perhaps  two,  or  three,  or  more  miles 


750  DYNAMICAL    GEOLOGY. 

in  height,  —  a  denudation,  after  pursuing  its  work  for  a  while,  would 
reduce  it  to  a  group  of  synclinal  ridges.  The  fractured  anticlinals 
are  easily  worn  away ;  while  the  synclinals  have  the  elements  of 
greater  permanence,  in  being  much  less  broken  above,  and  in  having 
their  rocks  folded  and  pressed  together,  if  a  close  synclinal,  and  thus 
made  firmer  and  more  durable,  even  if  not  also  crystallized  by  meta- 
morphism.  The  synclinals  of  greatest  breadth  and  depth,  other  things 
being  equal,  will  become  ultimately  the  highest  of  the  mountain 
ridges,  because  more  material  is  embraced  in  them.  In  the  Taconic 
Mountains,  on  the  western  border  of  Massachusetts,  Mount  Washing 
ton  (including  Mount  Everett)  and  Graylock  are  the  high  peaks,  for 
the  reason  just  explained.  Other  portions  of  the  Taconic  range  are 
made  of  narrower  portions  of  the  synclinal,  and  are  less  elevated, 
(p.  213.) 

7.  A  Mountain  Chain  may  comprise  Synclinoria  of  different  ages. 
—  The  Appalachian  chain  consists  of  (1)  mountains  of  Archaean  rocks, 
that  were  made  in  pre-Silurian  time  ;   (2)  the  Green  Mountains,  that 
date  from  the  close  of  the  Lower  Silurian  ;  and   (3)  the  Alleghanies, 
that  were  formed  at  the  close  of  the  Carboniferous  age.     The  Green 
Mountains  began  in  the  same  great  geosynclinal  with  the  Alleghanies  ; 
but  that  northern  part  of  it  reached  its  completion   and  catastrophe 
long  before  the  Alleghany  part,  probably  because   so  near  the  Adi 
rondack  border  of  the  stable   part  of  the   continent.     It  is  probable 
that  the  Archaean  portion   of  the  Appalachian  chain,  which  includes 
the  Blue  Ridge,  the  New  Jersey  Highlands,  continued  in  Dutchess 
County,  N.   Y.,   and  the  Adirondacks,  corresponds   to  another  older 
synclinorium.     Thus   a  mountain   chain    may  comprise  several    syn- 
clinoria  made  at  widely  different  epochs. 

The  several  areas  of  the  Triassico-Jurassic  sandstone  (p.  403)  were 
areas  of  subsidence  or  sinking  troughs,  and  of  sedimentary  accumu 
lations  in  progress  in  each  trough  ;  and  the  geosynclinal,  in  each  case, 
ended  in  catastrophe,  as  exhibited  in  upturned  or  displaced  rocks,  and 
in  many  lines  of  great  fractures,  giving  exit  to  igneous  rocks.  The 
progress  was  like  that  in  the  case  of  a  synclinorium,  although  no 
true  mountain-chain  was  made. 

8.  Metamorphism  and  other  attendant  Effects.  —  The  heat,  developed 
through   the   transformation  of  the  motion,  in   the  making  of  a  range 
by  great  flexures  and  fractures,  would  produce  all  the  consolidation 
and  crystallization  of  the  beds  which  has  been,  in  any  case,  observed ; 
and  would  cause,  as  lighter  effects,  the  change  of  brown  oxyds  of  iron 
to  red  oxyd,  thereby  reddening  sandstones  and  clays  ;  or  make  other 
decompositions  in   which   red  oxyd   of  iron   is  developed ;  and,   as  a 
lighter  effect,  debitumiuize  mineral  coal,  and  evolve  mineral  oil  from 


EVOLUTION  OF  THE  EARTH'S  FEATURES.  — MOUNTAIN-MAKING.      751 

black  hydrocarbon  shales  (like  the  Black  shale  of  the  Hamilton),  to 
be  condensed  in  cavities  in  overlying  strata.  The  heat  engendered, 
and  causing  the  metamorphism,  may  be  so  great  as  to  reduce  the  rock 
subjected  to  it  to  a  plastic  condition,  and  make  granite,  or  some 
other  granite -like  rock  ;  in  which  case,  granite  may  be  made  to  fill 
opened  fissures,  like  a  true  igneous  rock,  or  to  constitute  the  core  of 
a  long  mountain  range,  like  that  of  the  Sierra  Nevada. 

9.  The  region  of  a  Synclinorium  becomes  added  to  the  stable  part 
of  the  Continent.  —  The  region  that  had  been   long  undergoing  sub 
sidence   becomes,  after  the  upturning  and  consolidation,  stiff,  unyield 
ing,  and  stable  ;  and  the  locus  of  the  next  progressing  geosynclinal 
on  the  same   continental  border  will  be  situated   to  one  or  the  other 
side  of  it.     After  the  Alleghany  range  was  made,  there  was,  in  the 
next,  or  Triassic  period,  a  new  trough,  or  rather  a  series  of  them,  more 
to  the  eastward,  in  which  the  Triassico-Jurassic  beds  were  laid  down. 

On  the  Pacific  Border,  there  were  geosynclinals  in  progress,  from 
the  early  Paleozoic,  onward,  in  the  regions  of  the  Sierra  Nevada,  the 
Humboldt  Mountains  over  the  Great  Basin,  and  the  Wahsatch  just 
east  of  the  Great  Salt  Lake ;  and,  after  the  Jurassic  period,  the  catas 
trophes  occurred  in  which  these  great  mountain  ranges,  or  synclirioria, 
were  made.  Next^  there  were  two  geosynclinals  in  progress  during 
the  Cretaceous  period,  outside  of  these,  one  east  of  the  Wahsatch,  and 
the  other  in  California,  west  of  the  Sierra  Nevada  ;  and,  in  the  early 
Tertiary,  both  of  these  ended  in  synclinoria.  Next,  these  regions 
having  thus  become  part  of  the  stable  land,  two  other  geosynclinals, 
some  thousands  of  feet  in  depth,  were  in  progress,  one  farther  west  in 
California,  and  the  other  farther  east  in  Wyoming,  Colorado,  etc. 
They  continued  sinking  until  the  close  of  the  Miocene  Tertiary,  when 
that  on  the  west  ended  in  mountain -making,  adding  ridges,  2,000  to 
3,000  feet  in  height,  to  the  Coast  range ;  and  that  on  the  east  experi 
enced  some  small  displacements.  There  were  hence  two  parallel 
series,  cotemporaneous  in  steps  of  progress,  on  opposite  borders  of 
the  Great  Basin,  a  coast-series,  and  a  mountain-series,  each  having  its 
highest  member  toward  the  basin  ;  the  coast-series  the  grandest  in  its 
three  parts,  and  leaving  evidences  of  the  profoundest  disturbance,  and 
the  greatest  amount  of  metamorphism.  The  Wahsatch  range  is  nearly 
as  high  as  the  Sierra ;  but  probably  a  fourth  of  its  height  is  due  to 
the  final  elevation  of  the  Rocky  Mountain  region. 

10.  Geanticlinals  as  well  as   Geosynclinals  concerned  in  Mountain- 
making.  —  In  the  movements  of  the  earth's  crust,  there  would  neces 
sarily  be  upward  as  well  as  downward  flexures  —  that  is,  geanticlinals 
as  well  as  geosynclinals.     The  Appalachians,  as  explained  above,  may, 
when  first  made,  have  stood  up  in  lofty  ridges,  without  having  under- 


752  DYNAMICAL    GEOLOGY. 

gone  any  uplifting  from  force  below.  But,  however  this  may  be,  the 
region  actually  experienced  elevation  before  the  Triassic  period  opened, 
as  is  proved  by  the  position  of  the  Triassic  beds ;  and  this  took  place 
through  a  gentle  upward  bending  of  the  crust,  such  a  bending  becom 
ing  possible  after  (although  not  before)  the  region  of  the  Appalachi 
ans  had  become  a  portion  of  the  stable  part  of  the  continent. 

The  Rocky  Mountains  in  the  Cretaceous  era  were  10,000  feet  be 
low  their  present  level,  the  sea  covering  them.  They  were  raised  as 
a  whole,  during  the  Tertiary,  through  a  low  geanticlinal.  The  last 
bendings  were  more  local  than  the  preceding,  because  the  crust  had 
become  stiffened  by  its  plicated  and  solidified,  and  partly  crystallized, 
coatings,  as  well  as  by  thickening  beneath  ;  and,  therefore,  while  the 
Tertiary  movements  were  in  progress,  the  part  of  the  force  not  ex 
pended  in  producing  them  carried  forward  an  upward  bend,  or  geanti- 
clinal,  of  the  vast  Rocky  Mountain  region  as  a  whole. 

11.  Anticlinoria  of  the  Atlantic  Border  of  North  America.  —  An 
upward  bend  of  the  crust,  or  geanticlinal,  is  of  itself  an  elevation  ;  and 
such  an  elevation  is  an  anticlinorium.    The  Cincinnati  uplift,  described 
on  page  217,  is  an  anticlinorium,  made,  parallel  with  the  Appalachians, 
after  the  Lower  Silurian  era,  cotemporarieously  with  the  making  of 
the  Green  Mountains. 

While  the  geosynclinal  preparatory  for  the  making  of  the  Appala 
chians,  and  those  for  the  Triassico-Jurassic  formations,  were  going  for 
ward,  through  Paleozoic  and  Mesozoic  time,  there  was,  along  the  At 
lantic  Border,  near  or  outside  of  the  present  coast-line,  a  geanticlinal 
in  progress,  or  sea-border  anticlinorium.  It  was  the  first  effect  of  the 
pressure  from  the  ocean-ward  ;  and  the  geosynclinal  was  the  second. 

Proofs  of  this  are  found  (1)  in  the  necessity  that  one  movement  should  have  taken 
place  as  a  counterpart  to  the  other,  since  the  depression  of  a  geosynclinal  thousands  of 
feet  would  push  out  from  beneath  it  an  equivalent  mass  of  plastic  rock;  and  this  would 
involve  a  bulging  on  one  side  or  the  other;  (2)  in  the  fact  that  obliquely-upward  pressure 
from  the  ocean-ward,  however  slight  the  obliquity,  would  first  have  made  an  upward 
bend,  and  beyond  this  the  downward  bend;  and  (3)  in  the  character  of  the  remains  of 
marine  life,  or  else  its  absence,  in  the  sea-border  rocks,  through  a  large  part  of  Paleozoic 
and  Mesozoic  time,  showing  that  a  barrier  of  some  kind  existed  along  the  sea  border. 

The  facts  from  the  fossils  are  these:  While,  in  the  early  part  of  the  Lower  Silurian, 
the  species  of  the  eastern  border  are  like  those  of  Europe  in  some  points,  this  is  not  so 
in  the  long  Trenton  period,  so  that  the  barrier  must  then  have  existed  (page  250).  In 
the  Carboniferous  rocks  of  eastern  Pennsylvania,  there  are  almost  no  marine  fossils; 
and  again,  in  the  following  Triassic  and  Jurassic  eras,  none  at  all.  It  was  not  until  the 
Cretaceous  period  that  the  coast  was  open  to  the  ocean,  through  a  disappearance  of  the 
geanticlinal  barrier.  The  Cretaceous  rocks  abound  in  marine  fossils. 

Anticlinoria  appear  generally  to  have  faded  out,  as  gravity  was  against  their  perma 
nence;  and  that  in  the  region  of  Cincinnati,  extending  southwestward  to  Tennessee,  i 
one  of  the  few  permanent  ones. 

1 2.  Geanticlinal  Effects  over  the  Continents,  yreatest  and  most  per 
manent,  and   Geosynclinal  least    so,  in  the   Tertiary  and   Quaternary 


MOUNTAIN-MAKING.  753 

.  —  After  the  crust  had  become  thickened,  by  the  earth's  internal 
cooling,  through  the  ages,  and  had  been  stiffened  also  by  the  plication 
and  solidification,  and  partly  the  crystallization,  of  the  strata  of  the 
supercrust,  geosynclinals  became  less  a  possibility,  and  therefore  of 
diminished  extent;  and  consequently  the  chief  movement  caused  by 
the  ever-continuing  lateral  pressure  was  an  upward  one.  Hence  it  is 
that  the  mountain -chains  received  their  great  height  so  largely  in  the 
Tertiary ;  and  hence,  also,  the  vastness  of  the  areas  over  the  earth's  sur 
face  that  were  affected  by  single  movements,  such  as  the  high-latitude 
movements  of  the  Quaternary.  There  was,  also,  a  downward  bending 
over  those  higher  latitudes,  in  the  Quaternary,  and  another  in  the  warm 
parts  of  the  oceans  —  the  coral-island  subsidence.  But  these  bear  the 
character  of  the  times,  in  the  extent  of  surface  involved,  and  are  wholly 
unlike  the  mountain-making  geosynclinals  of  earlier  time.  It  is  prob 
able  that  the  Pacific  coral-island  subsidence,  or  geosynclinal,  was  the 
counterpart  of  the  geanticlinals  over  the  continents  of  the  later  Ter 
tiary  arid  Quaternary. 

13.  Fractures  and  Outflows  of  Igneous  Rocks  become  numerous, 
after  the  Crust  has  become  too  much  stiffened  to  bend  easily.  • —  Great 
floods  of  doleryte  and  trachyte  were  poured  out  over  the  Rocky 
Mountain  slope,  after  the  close  of  the  Cretaceous  period.  The  pre 
vious  plications  and  solidifications  of  the  strata  involved  in  the  making 
of  the  various  ranges  of  mountains  —  the  Sierra  Nevada  and  the  Coast 
ranges  on  the  west,  and  the  Wahsatch  and  Cretaceous  mountains  on 
the  east  —  had  left  the  crust  firm  and  unyielding  ;  and,  being  too  stiff 
to  bend,  it  broke,  and  out  leaped  the  fiery  floods.  It  had  broken 
at  times  before ;  but  at  this  time  the  fractures  became  much  more 
numerous,  and  the  floods  of  rock  more  extensive.  Moreover,  from 
this  era  appears  to  date  the  opening  of  the  great  volcanoes  of.  the 
Shasta  range.  In  fact,  the  greater  part  of  the  volcanic  eruptions  of 
the  world  are  probably  of  Tertiary  and  later  origin. 

Fractures  giving  outlet  to  igneous  eruptions  have  probably  been,  in 
all  cases,  consequences  either  (1)  of  catastrophe  in  a  geosynclinal,  as 
in  the  Triassico-Jurassic  areas  of  the  Atlantic  Border,  or  (2)  catas 
trophe  in  a  geanticlinal,  when  the  crust  was  too  stiff  for  geosynclinal 
headings,  as  over  the  Pacific  slope  of  the  Rocky  Mountains  ;  and  the 
latter  became  far  the  most  common,  in  the  later  part  of  geological  time. 

The  principles  in  the  earth's  evolution  above  presented,  have  been 
elucidated,  for  the  reason  stated  on  page  737,  by  reference  mainly  to 
facts  from  North  America.  If  true  for  that  continent,  the  same  must 
be  law  for  all  continents.1 

1  For  a  fuller  discussion  of  the  subject  here  briefly  presented,  see  a  memoir  in  the 
American  Journal  of  Science  for  June,  July,  August,  and  September,  1873,  vols.  v. 
and  vi. 

48 


754  DYNAMICAL   GEOLOGY. 

(14.)  Mountain-making  slow  work.  —  To  obtain  an  adequate  idea 
of  the  way  in  which  lateral  pressure  has  worked,  it  is  necessary  to 
remember  that  mountain -elevation  has  taken  place  after  immensely 
long  periods  of  quiet  and  gentle  oscillations.  After  the  beginning  of 
the  Primordial,  the  first  period  of  disturbance  in  North  America,  of 
special  note,  was  that  at  the  close  of  the  Lower  Silurian,  in  which  the 
Green  Mountains  were  finished ;  and  if  time,  from  the  beginning  of  the 
Silurian  to  the  present,  included  only  forty-eight  millions  of  years 
(p.  591),  the  interval,  between  the  beginning  of  the  Primordial  and 
the  uplifts  and  metamorphism  of  the  Green  Mountains,  was  at  least 
twenty  millions  of  years.  The  next  epoch  of  mountain -making  on 
the  Atlantic  Border  was  after  the  Devonian  in  Nova  Scotia  and  New 
Brunswick ;  on  the  above  basis,  it  occurred  thirty  millions  of  years 
from  the  beginning  of  the  Primordial.  The  next  epoch  of  disturb 
ance  was  that  at  the  close  of  the  Carboniferous  era,  in  which  the  Al- 
leghanies  were  folded  up  ;  by  the  above  estimate  of  the  length  of 
time,  thirty-six  millions  of  years  after  the  commencement  of  the  Silu 
rian  ;  so  that  the  Alleghanies  were  at  least  36,000,000  of  years  in 
making,  the  preparatory  subsidence  having  begun  as  early  as  the  be 
ginning  of  the  Silurian.  The  next  on  the  Atlantic  Border  was  that 
of  the  displacements  of  the  Triassico-Jurassic  Sandstone,  and  the 
accompanying  igneous  ejections,  which  occurred  before  the  Cretaceous 
era  —  at  least  five  millions  of  years,  on  the  above  estimate  of  the 
length  of  time,  after  the  Appalachian  revolution.  Thus  the  lateral 
pressure  resulting  from  the  earth's  contraction  required  an  exceedingly 
long  time,  in  order  to  accumulate  force  sufficient  to  produce  a  general 
yielding  and  plication  or  displacement  of  the  beds,  and  start  off  a  new 
range  of  prominent  elevations  over  the  earth's  crust. 

IV.    CHANGES  IN  CLIMATE. 

As  the  cooling  of  the  earth  from  fusion  went  forward,  the  earth's 
outer  temperature  finally  became  climatal ;  and  although  at  first  ex 
cessive  in  its  heat,  with  the  thickening  of  the  crust  there  was  slow 
amelioration,  until  a  genial  climate  finally  pervaded  the  surface,  when 
life  took  its  place  in  the  waters.  Cooling  has  ever  since  gone  forward  ; 
but  it  is  supposed  that,  amid  the  other  causes  of  change,  the  heat  of 
the  earth's  interior  has  long,  perhaps  since  the  Silurian  age  began, 
produced  little  impression  on  the  temperature  of  the  air  and  waters. 

Yet,  while  the  direct  action  of  the  earth's  refrigeration  may,  for 
some  ages  past,  have  had  small  effect  on  climate,  the  indirect  effects, 
or  those  proceeding  from  changes  of  level  in  the  land,  increase  in  its 
extent  and  height,  and  the  variations  in  its  distribution  about  the 
sphere,  have  had,  as  Lyell  has  shown,  vast  effect  on  the  climatal  phases 


CHANGES   IN   CLIMATE.  755 

of  the  globe.  The  Lyellian  principle  here  appealed  to,  is  thus  briefly 
expressed  on  page  43.  Absence  of  land,  and  especially  of  high  land, 
from  the  higher  latitudes,  is  equivalent  to  absence  of  a  source  of  extreme 
cold ;  and  absence  of  continental  lands  from  tropical  latitudes,  that  of 
extreme  heat ;  and  therefore,  if  the  land  existed  only  over  temperate 
latitudes,  it  would  have  but  a  small  range  in  its  temperature,  and  be 
neither  very  warm  nor  very  cold.  The  sinking  of  all  lands  would 
diminish  greatly  both  extremes,  and  perhaps  give  the  whole  globe 
nearly  the  present  mean  temperature,  60°. 

In  conjunction  with  these  differences  in  the  distribution  of  land, 
there  have  been  differences  in  the  courses  of  ocean-currents  ;  and  these 
have  probably  more  than  quadrupled  the  effect  from  variation  alone  in 
amount  and  position  of  land-surface. 

In  the  northern  hemisphere,  each  ocean  has  its  great  tropical  cur 
rent,  and  its  much  smaller  polar  current.  The  polar  current  is  much 
the  smaller,  because  a  large  part  of  the  tropical  waters  make  their 
circuit  without  going  into  the  Arctic  regions ;  and  this  must  have  been 
the  case  in  all  time,  for  it  would  still  be  true  if  the  earth  were  all 
water,  and  of  like  depth  throughout,  since  the  cold  Arctic  areas  are 
even  now  small,  compared  with  the  rest  of  the  surface  of  the  globe. 
Changes  in  the  direction  of  flow  of  the  Gulf  Stream  in  the  Atlantic, 
and  of  the  Japan  Stream  in  the  Pacific,  must  hence,  as  all  admit,  have 
made  wide  diversities  of  climate  over  the  earth.  Croll  has  stated  that 
the  Gulf  Stream,  according  to  his  calculations  (based  on  the  estimate 
that  the  stream  in  the  Florida  Straits  averages  fifty  miles  in  breadth, 
and  1,000  feet  in  depth,  is  four  miles  an  hour  in  velocity,  and  65°  F.  in 
temperature,  and  that,  in  its  course  northward,  it  cools  down  to  at 
least  40°  F.),  conveys  from  the  Gulf  5,578,680,000,000  cubic  feet  of 
water  per  hour  ;  and  consequently  that  the  total  quantity  of  heat  trans 
ferred  from  the  equatorial  regions  per  day  by  the  stream  amounts  to 
154,959,300,000,000,000,000  foot-pounds.1  Reducing  this  one-half,  to 
accord  with  Mr.  Findlay's  estimate,  the  stoppage  of  the  Gulf  Stream,  as 
he  says,  would  still  deprive  the  Atlantic  of  77,479,650,000,000,000,000 
foot-pounds  of  energy  in  the  form  of  heat  per  day,  a  quantity  equal 
to  one  fourth  of  all  the  heat  received  from  the  sun  by  that  area. 

Speculations  as  to  the  way  to  divert  the  Gulf  Stream  from  the 
North  Atlantic,  in  order  to  account  for  a  cold  era  like  the  Glacial,  are 
alluded  to  on  page  541.  It  is  probable  that  the  changes  it  has  effected 
have  been  brought  about,  not  by  a  diversion  of  the  current  from  the 
ocean,  and  its  restoration  to  it  again,  but  by  variations  in  the  amount 
and  height  of  Arctic  lands,  in  one  case  closing,  and  the  other  opening 
the  Arctic  regions  to  the  tropical  stream  ;  and  the  same  for  the  Pacific 

il.  Mat/.,  February,  1867:  Am.  Jour.  Sd.,  ii.  v.,  118. 


756  DYNAMICAL   GEOLOGY. 

current.  Sinking  the  land  about  Behring  Straits,  so  as  to  let  the 
Japan  current  flow  freely  into,  and  distribute  itself  along  with  the 
Gulf  Stream  through  the  Arctic,  would,  as  F.  H.  Bradley  has  sug 
gested,  especially  if  the  Arctic  lands  were  low,  make  all  the  warm 
temperature  there  that  the  forest  vegetation  of  the  Miocene  might 
have  demanded.  And  it  is  probable  that  the  closing  of  the  same  polar 
region  to  both  of  these  tropical  flows  would  aid  much  toward  produ 
cing,  as  stated  on  page  541,  the  Arctic  climate  of  the  Glacial  period. 

Again,  if  ever  the  region  of  the  Red  Sea  and  Mediterranean  gave 
free  passage  to  the  current  of  the  Indian  Ocean,  this  would  have  had  a 
warming  effect  over  all  Europe,  and  even  in  the  Arctic  regions.  On 
the  contrary,  if  southern  South  America,  up  to  latitude  30°,  were 
deeply  submerged,  it  would  give  passage  into  the  Atlantic  of  the  great 
frigid  current  that  now  carries  cold  along  the  west  coast  of  South 
America  to  the  Galapagos,  under  the  equator,  and  the  whole  Atlantic, 
north  and  south,  and  the  neighboring  continents,  would  feel  its  chilling 
influence,  As  to  the  sinking  of  the  Isthmus  of  Darien,  it  is  not 
probable  that  it  has  been  deeply  enough  submerged,  at  any  time  since 
the  Paleozoic,  to  affect  appreciably  the  flow  of  the  Gulf  Stream  in 
the  Atlantic,  or  of  the  Antarctic  current  of  the  Pacific. 

VII.  PROGRESS  IN  ACCORDANCE  WITH  THE  UNI 
VERSAL  LAW  OF  DEVELOPMENT. 

The  general  law  at  the  basis  of  all  development  is  strikingly  ex 
hibited  in  the  earth's  physical  progress,  as  has  been  well  shown  by 
Guyot.  The  law  is  simply  this  :  Unity  evolving  multiplicity  of  parts, 
through  successive  iridividualizations,  proceeding  from  the  more  funda 
mental  onward. 

The  earth  in  igneous  fusion  had  no  more  distinction  of  parts  than  a 
germ.  Afterward,  the  continents,  while  still  beneath  the  waters,  began 
to  take  shape.  Then,  as  the  seas  deepened,  the  first  dry  land  ap 
peared,  low,  barren,  and  lifeless.  Under  slow  intestine  movements, 
and  the  concurrent  action  of  the  enveloping  waters,  the  dry  land  ex 
panded,  strata  formed  ;  and,  as  these  processes  went  on,  mountains  by 
degrees  rose,  each  in  its  appointed  place.  Finally,  in  the  last  stage 
of  the  development,  the  Alps,  Pyrenees,  and  other  heights  received 
their  majestic  dimensions  ;  and  the  continents  were  finished  to  their 
very  borders. 

Again,  as  to  the  history  of  fresh  waters.  The  first  waters  were  all 
salt,  and  the  oceans  one,  the  waters  sweeping  around  the  sphere  in  an 
almost  unbroken  tide.  Fresh  waters  left  their  mark  only  in  a  rain 
drop  impression.  Then  the  rising  lands  commenced  to  mark  out  the 


CONCLUSION.  757 

great  seas  ;  and  the  incipient  continents  were  at  times  spread  with 
fresh-water  marshes,  into  which  rills  were  flowing  from  the  slopes 
around.  As  the  mountains  enlarged,  the  rills  changed  to  rivers,  till 
at  last  the  rivers  also  were  of  majestic  extent ;  and  the  continents 
were  throughout  covered  with  streams  at  work,  channelling  mountains, 
spreading  out  plains,  opening  lines  of  communication,  and  distributing 
fertility  everywhere. 

Again,  the  first  climates  were  all  tropical.  But,  when  mountains 
and  streams  were  attaining  their  growth,  a  diversity  of  climate  (essen 
tial  to  the  full  strength  of  the  latter)  was  gradually  evolved,  until 
winter  had  settled  about  the  poles  as  well  as  the  earth's  loftier  sum 
mits,  leaving  only  a  limited  zone  —  and  that  with  many  variations  — 
to  perpetual  summer. 

The  organic  history  of  the  earth,  from  its  primal  simplicity  to  the 
final  diversity,  has  been  shown  to  exemplify  in  many  ways  the  same 
great  principle. 

Thus  the  earth's  features  and  functions  were  successively  individ 
ualized, —  first  the  more  fundamental  qualities  being  evolved,  and 
finally  those  myriad  details  in  which  its  special  characteristics,  its  mag 
nificent  perfection,  and  its  great  purpose  of  existence  and  fitness  for 
duty,  largely  consist. 

CONCLUSION.  —  The  causes  of  the  earth's  movements  which  have 
been  considered  appear  to  explain  the  evolution  of  the  prominent 
features  of  the  globe  ;  and  the  special  history  made  out  for  North 
America  may  be  safely  regarded  as  an  example  of  what  will  hereafter 
be  accomplished  for  all  the  continents. 

But  Geology,  while  reaching  so  deeply  into  the  origin  of  things, 
leaves  wholly  unexplained  the  creation  of  matter,  life,  and  spirit,  and 
that  spiritual  element  which  pervades  the  whole  history  like  a  proph 
ecy,  becoming  more  and  more  clearly  pronounced  with  the  progressing 
ages,  and  having  its  consummation  and  fulfillment  in  Man.  It  gives 
no  cause  for  the  arrangement  of  the  continents  together  in  one  hemi 
sphere  (p.  10),  and  mainly  in  the  same  temperate  zone,  or  their  situa 
tion  about  the  narrow  Atlantic,  with  the  barrier-mountains  in  the 
remote  west  of  America  and  in  the  remote  east  of  Europe  and  Asia, 
thus  gathering  the  civilized  world  into  one  vast  arena  (p.  29)  ;  it  does 
not  account  for  the  oceans  having,  in  extent  and  depth,  that  exact 
relation  to  the  land  which,  under  all  the  changes,  allowed  of  submer 
gence  and  emergence  through  small  oscillations  of  the  crust,  and  hence 
permitted  the  spreading  out  of  sandstones  and  shales  by  the  waves 
and  currents,  the  building  up  of  limestones  through  animal  life,  and 
the  accumulation  of  coal-beds  through  the  growth  of  plants,  —  and 


758  DYNAMICAL   GEOLOGY. 

all  in  numberless  alternations  ;  nor  for  the  various  adaptations  of  the 
system  of  plants  and  animals  to  the  wants  of  the  last  species  in  that 
system.  Through  the  whole  history  of  the  globe,  there  was  a  shaping, 
provisioning,  and  exalting  of  the  earth,  with  reference  to  a  being  of 
mind,  to  be  sustained,  educated,  exalted.  This  is  the  spiritual  element 
in  geological  history,  for  which,  attraction,  water,  and  fire  have  no  ex 
planation. 

VIII.   EFFECTS    REFERRED    TO    THEIR   CAUSES.     RE 
CAPITULATION. 

Iii  many  cases,  the  same  effect  —  the  formation  of  valleys,  for  ex 
ample  —  has  come  from  different  causes ;  and  the  subject  is  therefore 
discussed  in  different  places,  in  the  course  of  the  preceding  pages  on 
Dynamical  Geology.  In  this  chapter,  the  pages  are  mentioned  where 
each  topic  is  considered ;  and  under  some  subjects  additional  explana 
tions  are  introduced. 

I.  FRAGMENTAL  MATERIAL  OR  DEPOSITS. 

1.  Sources  of  Band,  Gravel,  Stones. 

A.  Mechanical.  —  1.  From  erosion  by  water,  pp.  648,  667. 

2.  From  erosion  by  means  of  winds,  p.  632. 

3.  From  the  abrasion  of  rocks  or  stones  moved  by  ice,  pp.  538,  684. 

4.  From  the  abrasion  of  opposite  walls  of  fractures. 

5.  Through  the  freezing  in  the  crevices  of  rocks,  a  very  efficient  agency  in  regions 
of  cold  winters,  p.  674. 

6.  Through  the  divellent  action  of  the  growth  of  vegetation  in  crevices  or  fissures — 
a  work  in  which  all  kinds  of  plants  serve,  from  Lichens  and  microscopic  fresh-water 
Algae  to  great  trees,  and  which  produces  vast  results,  p.  607. 

7.  Through  the  mutual  attrition  of  rocks  or  stones  in  a  slide,  p.  655. 

8.  Through  ordinary  changes  of  temperature,  expanding  and  contracting  the  super 
ficial  portion  of  a  rock,  p.  701. 

9.  Through  the  explosion  of  bubbles  of  lava  in  a  volcano,  producing  volcanic  cinders, 
and  the  material  of  tufas,  p.  709. 

10.  Through  the  tearing  action  of  the  ice  of  the  under  part  of  a  glacier,  p.  538. 

B.  Chemical.     (1)  Through  the  chemical  alteration  or  decomposition  of  one  of  the 
essential  or  adventitious  constituents  of  rocks,  p.  688. 

(2.)  Through  the  action  of  acid  or  alkaline  solutions  from  some  external  source, 
p.  689. 

2.  Rounding  of  Stones,  Making  Bowlders.  —  (1.)  Through  the  attrition 
caused  by  moving  waters,  air,  or  ice. 

2.  Through  the  loosening  of  surface-grains  or  outer  layers  in  succession,  by  ordinary 
alternations  of  surface  temperature,  the  action  from  two  directions  at  the  edges,  and 
from  three  at  the  angles,  ultimately  producing  curved  surfaces,  p.  701. 

3.  By  decomposition  at  the  surface — a  cause,  that,  like  the  last,  removes  the  edges 
and  angles  most  rapidly,  p.  87. 

4.  By  revolution  in  the  air,  on  ejection  to  a  considerable  height  from  the  throat  of  a 
volcano,  producing  what  are  called  volcanic  bombs,  p.  709. 

3.  Assorting  of  Fragmental  Material.  —  (l.)  By  variations  in  the  rate  of 
flow  of  waters,  p.  650. 


EFFECTS  REFERRED  TO  THEIR  CAUSES.          759 

2.  Through  the  unequal  wear  of  harder  and  softer  grains,   under  the  action  of  the 
waves  or  running  water,  the  softer  being  worn  first  and  drifted  off,  and  so  leaving  the 
harder  behind,  as  in  the  making  of  a  sand-beach,  p.  670. 

3.  By  the  action  of  the  winds. 

4.  Transportation  of  Fragmental  Material.  —  l.  By  fresh  or  salt  water, 
pp.  647,  666. 

2.  By  ordinary  floating  ice,  icebergs,  or  glaciers,  pp.  538,  683,  686. 

3.  By  the  winds,  pp.  631,  632. 

4.  By  means  of  migrating  animals,  p.  607. 

5.  By  the  help  of  floating  logs  or  living  plants,  p.  607. 

5.  Deposition  and  Arrangement  in  Beds  of  Fragmental  Material. 
—  1.  By  winds,  p.  631. 

2.  By  fresh  waters  in  their  ordinary  condition,  or  during  occasional  or  annual  floods, 
pp.  650,  651. 

3.  By  fresh  waters  in  a  prolonged  flood,  producing  till,  p.  546. 

4.  By  a  plunging  flow  of  waters,  pp.  546,  671. 

5.  By  marine  waters,  p.  668. 

6.  By  glaciers  or  icebergs,  p.  666,  684. 

6.  Organic   Contributions   to    Fragmental  and  other  Deposits. — 

1.  Of  a  Calcareous  nature,  pp.  59,  60,  135,  615. 

2.  Of  a  Siliceous  nature,  pp.  59,  60,  135. 

3.  Of  Excrementitious  origin,  or  phosphatic,  pp.  59,  60,  613. 

4.  Of  Carbonaceous  character,  pp.  60,  61,  612,  616. 

7.  Colors  of  Fragmental  Deposits,  Limestone  included. — i.  Brown 
ish-yellow  to  brown  colors  due  to  limonite,  the  hydrous  oxyd  of  iron,  Fe203+  l^HO.     (1.) 
The  limonite  derived  directly  from  the  oxydation  attending  the  disintegration  by  which 
the  sands  were  made,  the  sands  having  not  been  subjected  afterward  to  washing  on  a 
seashore,  which  removes  such  iron-oxyd. 

(2.)  The  limonite  that  which  is  deposited  in  a  low  wet  region,  where  the  fragmental 
deposit  was  in  process  of  accumulation ;  not  a  possible  result  in  an  open  estuary  or  on  an 
open  coast,  p.  694. 

(3.)  The  limonite  produced  by  the  action  of  ordinary  waters  on  a  deposit,  pervious  to 
water,  containing  an  iron-bearing  mineral,  p.  694. 

2.  Brownish-yellow  or  brown  color,  due  to  the  hydrous  iron-silicate,  palagonite.     This 
mineral  is  formed  when  a  bed  of  volcanic  cinders  or  granulated  volcanic  rock  is  sub 
jected  to  the  action  of  warm  waters,  the  pyroxene  of  the  material  being  altered,  bv 
losing  part  of  its  silica,  having  its  iron  changed  to  the  sesquioxyd  state,  and  taking  in 
water. 

3.  Green,  Brownisk-yreen,  or  Olive-green  color,  due  to  the  hydrous  iron-silicate,  (jlau- 
conite.  —  The  silica  in  glauconite,  the  green  mineral  giving  the  color  to  the  yreen-sand 
of  the  Cretaceous  and  other  formations,  is  supposed  to  come  from  the  siliceous  secretions 
of  minute  Sponges  in  the  cellules  of  Rhizopods,  etc. ;  but  the  process  of  formation  is 
not  understood. 

4.  Red  color,  due  to  red  oxyd  of  iron,  Fe2O3. — (1)  From  the   heating  of  beds  con 
taining  limonite  as  the  coloring  material,  limonite  becoming  the  red  oxyd  when  heated, 
p.  750. 

(2.)  From  the  oxydation  of  the  iron  of  an  iron-bearing  mineral  through  the  action  of 
moisture  and  heat,  p.  695. 

(3.)  The  same  as  (2),  at  the  ordinary  temperature  in  dry  warm  regions. 

5.  Black  and  Brownish-black  colors.  —  (1.)  From  the  presence  of  carbonaceous  sub 
stances,  derived  from  vegetable  or  animal  matters;  in  which  case  the  rock  will  burn 
white. 

(2.)  From  the  presence  of  an  oxyd  of  iron;  in  which  case  the  rock  will  burn  red. 
(3.)  From  the  presence  of  an  oxyd  of  manganese;  in  which  case  the  rock  will  remain 
black  or  bluish-black,  on  heating. 


760  DYNAMICAL   GEOLOGY. 

6.  Mottled  Coloring. — 1.  Rocks  colored  red  or  brownish-red,  with  oxyd  of  iron,  be 
come  mottled,  through  the  deoxydation   of  the  iron,  by  means  of  waters  containing 
organic  matters:  the  waters  often  pass  through  loose  sandy  beds  without  altering  them, 
and  then  reach  a  clayey  layer  where  they  spread  and  make  the  changes,  p.  695. 

7.  External  color's  due  to  vegetation.  —  Minute  black,  brownish-black,  and  greenish- 
gray  lichens  give  an  external  coloring  to  rocks,  which  is  often  mistaken  for  their  true 
colors.     Outcrops  of  Granular  limestone,  a  white  rock,  are  usually  quite  black,  from 
the  species  with  which  they  are  overgrown.     Larger  lichens  sometimes  spread  over  the 
surfaces  of  rocks,  and  give  them  a  mottled  aspect. 

NOTE.  —  The  above  observations  on  the  colors  of  fragmental  rocks  apply  to  the 
decomposed  crusts  of  crystalline  rocks,  and  to  some  extent  to  the  crystalline  rocks 
themselves.  Red,  as  a  color  of  rocks,  always  comes  from  traces  of  the  red  oxyd  of 
iron;  green  is  usually  owing  to  disseminated  chlorite,  but  sometimes  to  serpentine, 
pyroxene,  or  hornblende ;  and  black  and  greenish-black  to  iron-bearing  varieties  of 
hornblende,  pyroxene,  or  mica. 

Granular  limestone  or  marble  has  often  been  mottled  and  veined  through  an  extensive 
fracturing,  and  then  a  displacement  of  the  pieces,  and  the  subsequent  filling  of  the 
intervals  between  the  pieces  with  a  deposit  of  white  or  colored  carbonate  of  lime. 
Another  style  of  mottling  or  clouding  in  marble  is  due  to  the  distribution  of  impurities, 
the  impurities  of  the  original  limestone  having  received  a  crystallized  condition  and 
agreeable  colors  (being  converted  into  crystalline  minerals),  during  the  metamorphism 
of  the  rock. 

9.  Consolidation  of  Fragmental  Deposits. 

1.  Through  siliceous  solutions,  pp.  693,  725. 

2.  Through  calcareous  solutions,  p.  692. 

3.  Through  the  production  of  an  oxyd  or  silicate  of  iron,  by  one  of  the  methods 
mentioned  under  section  7.     See  also  p.  695. 

4.  Through  infiltration  of  phosphates  into  calcareous  beds,  from  overlying  guano. 

5.  By  pressure  of  superincumbent  beds,  which  alone  is  ineffectual  in  the  case   of 
sand-beds,  but  may  produce  some  effect  with  clayey  deposits. 

6.  Through  metamorphism,  p.  724. 

II.  CRYSTALLINE  TEXTURE  OF  ROCKS. 

1.  Through  metamorphism,  pp  63,  724. 

2.  On  cooling,  from  more  or  less  perfect  fusion,  p.  63. 

3.  On  depositions  from  solution,  p.  63.     (In  the  case  of  the  opal  depositions  from  hot 
springs,  p.  719,  it  is  questioned  whether  there  is  a  crystalline  texture.) 

4.  On  passing  to  the  solid  state,  at  the  time  when  made  by  chemical  means,  as  in  the 
case  of  beds  of  gypsum,  made  from  action  of  sulphuric  acid  on  limestone,  p.  234. 

III.  FRACTURES. 

1.  By  lateral  pressure —  1.  The  lateral  pressure  resulting  from  the  contrac 
tion  of  the  crust  on  cooling,  pp.  735,  739. 

2.  The  lateral  pressure  produced  by  change  of  temperature  in  rocks,  p.  700. 

2.  By  contraction.  —  1-  Through  cooling,  producing  sometimes  a  columnar 
structure,  pp.  112,  701. 

2.  Bv  drying,  producing  sometimes  columnar  fractures,  pp.  84,  701. 

3.  By   means   of  foreign   substances  in  crevices    or  openings.  — 

1.  The  growth  of  vegetation,  p.  607. 

2.  Water  freezing,  p.  674. 

3.  Chemical  change  in  the  crevice,  developing  an  oxyd  of  iron  or  some  other  mineral, 
and  so  prying  open  and  deepening  it. 

4.  The  ice  of  the  bottom  of  a  moving  glacier,  p.  538. 


EFFECTS  REFERRED  TO  THEIR  CAUSES.         761 

4.  By  the  action  of  gravity.  —  Takes  place  after  an  undermining,  or  a  loosen 
ing  in  some  way,  pp.  645,  654,  655,  713. 

5.  By  vapors  suddenly  developed,  p.  711. 

IV.  FLEXURES.  « 

1.  By  lateral  pressure.  —  1'  The  lateral  pressure  from  the  earth's  contraction 
on  cooling,  pp.  736,  738. 

2.  The  lateral  pressure  from  the  expansion  of  rocks  by  heat. 

3.  The  lateral  pressure  due  to  the  action  of  gravity,  p.  655. 

2.  Through  the  conditions  of  cooling.  —  Want  of  parallelism  in  the  op 
posite  cooling  surfaces  of  cooled  rock,  making  curved  columns  in  some  igneous  rocks, 
p.  701. 

3.  By  gravity.  —  Acting  on  a  mass  supported  only  at  the  edges,  p.  681. 

V.  VEINS. 

Pages  108  to  114,  731  to  734. 

VI.  ELEVATIONS.     MOUNTAINS. 

1.  By  Lateral  Pressure.  —  1-  The  lateral  pressure  from  the  Earth's  contraction 
on  cooling,  producing  geanticlinals  and  geosynclinals,  pp.  739,  748. 

2.  The  same,  producing  a  synclinorium  or  an  anticlinorium,  pp.  749,  751. 

3.  The  same,  resulting  in  fractures  and  monoclinal  uplifts. 

4.  The  lateral  pressure,  produced  by  expansion  from  heat,  received  from  a  region  of 
liquid  rock  or  otherwise. 

2.  By  circumdenudation.  — Produced  by  denudation  over  a  region  of  nearly 
horizontal  rocks,  p.  645. 

3.  Apparent  elevation  due  to  a  sinking  of  the  Water-level.  —  1.  In 
consequence  of  a  sinking  of  the  ocean's  bottom. 

2.  In  consequence  of  the  abstraction  of  water  in  the  making  of  rocks,  p.  657. 

3.  In  consequence  of  the  abstraction  of  water  to  make  ice  over  the  land,  as  in  the 
Glacial  period. 

VII.  SUBSIDENCES. 

1  and  2.  As  under  VI. 

3.  By  contraction  beneath  from  cooling,  p.  701. 

4.  By  undermining,  through  subterranean  streams,  p.  654. 

5.  By  undermining,  through  volcanic  action,  p.  715. 

6.  Through  contraction  from  the  drying  of  an  underlying  bed,  as,  when  a  portion  of 
a  marsh  is  drained,  the  surface  of  that  part  sinks  below  the  rest. 

VIII.  VALLEYS. 

1.  By  Erosion.  —  1.  Through  fresh-water  streams,  this  is  the  great  source  of  the 
valleys  and  gorges  in  mountainous  regions:    sometimes,  though  seldom,  the  direction 
is  predetermined  by  fractures,  p.  638. 

2.  Through  marine  currents  and  waves,   removing  dikes   that  intersect  coast  rocks, 
or  portions  of  yielding  rock  ;  a  process  which  produces  small  cuts  or  excavations,  but 
not  true  valleys,  p.  672. 

3.  Through  the   action   of  glaciers,  either  by  the   tearing  action  of  the  ice,  where 
descending  at  bottom  into  cavities  in  the  rocks,  or  by  abrasion  carried  on  by  means  of 
the  stones  in  the  bottom  and  sides  of  the  glaciers,  p.  539. 

2.  By  movements  of  the  Earth's  crust.  —  1.  Producing  parallel  ranges  of 
mountains  (synclinoria,  or  anticlinoria,  or  both),  of  which  the  "  Mississippi  valley  " 
is  an  example,  pp.  23,  740. 

2.  Producing  a  geosynclinal,  p.  740;  but  the  progressing  geosynclinal  usually  be 
comes  filled  with  sediment  as  it  forms,  and  hence  does  not  appear  as  a  valley-depression. 


762  DYNAMICAL    GEOLOGY. 

3.  Producing  flexures  of  strata  (as  in  a  synclinorium),  and  thereby  making  proper 
synclinal  valleys  ;  but  such  valleys  are  generally  obliterated  afterward  by  denuda 
tion,  pp.  749,  750. 

4.  Producing  monoclinal  uplifts,  and  consequently  intervening  depressions. 

5.  Producing  widely  opened  fractures  (a  rare  occurrence.) 

IX.  LAKE  BASINS. 

1.  Through  glacial  action,  the  glacier  ploughing  deep  where  the  rocks  are  soft,  and  so 
making  a  deep  depression,  and  then  ceasing  the  excavation  where  there  is  a  change 
to  a  hard  rock,  p.  539. 

2.  Through  a  dam  thrown  across  a  valley,  by  (1)  a  moraine  from  a  glacier,  p.  686; 
(2)  a  slide  of  gravel,  or  avalanche  ;  (3)  a  flow  of  lava;  or  (4),  of  a  temporary  charac 
ter,  through  damming  by  a  glacier. 

3.  Through  a  dam  or  dike  of  sand  or  gravel  made  along  a  seashore,  by  the  waves 
and  tidal  currents,  shutting  off  a  region  of  water  from  connection  with  the  sea,  which 
may  finally  become  fresh,  if  it  receives  the  drainage  of  the  back  country. 

4.  Through  uplifts  of  mountains  surrounding  intervales  or  low  plains,  for  which 
subsequent  erosion  provides  no  complete  drainage. 

5.  Through  the  elevation  of  a  country  producing  level  regions,  over  which  depres 
sions  remain  without  a  drainage  channel,  because  the  waters  are  too  sluggish  in  move 
ment  for  much  erosion,  as  about  the  headwaters  of  the  Mississippi. 

6.  Through  the  undermining  of  the  surface  deposits  of  a  country  by  the  action  of 
water. 

7.  Through  the  ejection  of  lavas  from  a  volcano,  leaving,  when  the  volcano  becomes 
extinct,  a  crater  as  a  basin-like  depression. 

8.  Through  the  contraction  of  the  rocks  beneath  a  region,  in  consequence  of  cooling, 
causing  a  depression  of  the  surface. 

X.  MARKINGS  ON  ROCKS. 

1.  Scratches.  —  1.  By  the  movement  of  glaciers,  pp.  538,  684;   or  of  icebergs,  p. 
686 ;  or  of  any  floating  ice,  carrying  stones  at  bottom. 

2.  By  the  mutual  friction  of  the  opposite  walls  of  a  fissure,  at  the  time  of  the  making 
of  the  fissure  (the  usual  way),  or  afterward,  p.  90. 

3.  By  the  sliding  of  beds  on  one  another,  either  as  a  consequence  of  gravity,  p.  655, 
or  of  lateral  pressure,  p.  90 

4.  By  the  drifting  of  sands  by  winds,  pp.  91,  632. 

5.  Through  the  rapid  transportation  of  stones  by  water. 

6.  By  land  slides. 

2.  Of  organic  origin,  as  footprints,  etc. 

2.  Other  markings.  —  1.  Ripple-marks,  rill-marks,  rain-drop  impressions,  p.  84. 

XL  IGNKOUS  ACTION.     EARTHQUAKES. 
Pages,  702,  741. 

XII.  CHANGE  OF  TEMPERATURE.     SOURCES  OF  HEAT. 

1.  Transformation  of   motion  into  heat.  —  1.  By  movements  in  strata  ; 
probably  the  principal  source  in  metamorphism,  p.  698. 

2.  By  means  of  movements  in  water  or  air,  as  in  the  breaking  of  waves  on  a  rocky 
coast;  very  feeble  in  its  action,   if  at  all  appreciable,  unless  in  warming  slightly  the 
atmosphere. 

2.  The  Earth's  interior  heat.  —  1.  Through  escape  outward  from  the  earth's 

interior,  p.  699. 

1.  Through  convection  upward  into  strata,  or  "a  rise  of  the  isogeothermals,"  in 
consequence  of  the  accumulation  of  sedimentary  beds  at  surface,  p.  730. 


EFFECTS  REFERRED  TO  THEIR  CAUSES.         763 

3.  Through  convection  from  masses  or  dikes  of  fused  rock  into  the  adjoining  rocks. 

3.  Chemical  change,  p.  698. 

4.  The  Sun,  p.  697. 

XIII.  SECULAR  VARIATIONS  IN  CLIMATE. 

1.  Through  change  in  amount  of  heat  given  out  by  the  sun,  p.  697. 

2.  Through  the  escape  outward  of  the  earth's  interior  heat,  p.  699. 

3.  Through  a  secular  change  in  the  density  of  the  atmosphere,  that  is  in  the  amount 
of  carbonic  acid,  moisture,  etc.,  p.  697. 

4.  Through  changes  in  the  amount,  position,  and  height  of  lands  over  the  earth, 
pp.  44,  541. 

5.  Through  changes  in  the  courses  of  oceanic  currents,  pp.  541,  755. 

6.  Through  variations  in  the  eccentricity  of  the  earth's  orbit,  p.  697. 

XIV.  ORIGIN  OK  CONTINENTS  AND  OCEANIC  BASINS. 

Page  738. 

XV.  EXTINCTION  OF  SPECIES. 

The  ordinary  effects  of  nearly  all  the  following  causes  of  extinction  are  simply 
destruction  of  life.    But  they  may  also  occasion  extinction  of  species. 

I.  Catastrojjhic  Causes,  not  Climatal. 

1.  Through  the  emergence  of  a  region, with  its  aquatic  life. 

2.  Through  the  submergence  of  a  region, with  its  terrestrial  life. 

3.  Through  a  change  in  the  level  of  wave  action,  or  in  the  relations  of  a  sea  to 
currents,  these  bearing  detritus  or  not. 

4.  Through  a  change  of  salt-water  seas  or  lagoons  to  fresh-water,  and  the  reverse, 
p.  610. 

5.  Through  the  partial  or  complete  evaporation  of  salt-water  seas  or  lagoons. 

6.  Through  earthquake-waves. 

7.  Through  the  heating  of  the  ocean's  waters  by  means  of  extensive  igneous  erup 
tions,  or  through  the  flooding  the  land  by  such  eruptions;  effectual  for  volcanic  islands, 
but  hardly  for  wide  continental  or  oceanic  areas. 

II.   CHmatal  Causes. 

8.  Through  the  change  of  level  of  an  emerged  region,  changing  its  climate  as  to  its 
range  of  temperature,  moisture,  etc.,  or  as  to  the  excesses  of  that  range. 

9.  Through  the  change  of  level  of  a  submerged  oceanic  region,  changing  thereby 
its  relations  to  warm  and  cold  oceanic  currents. 

10.  Through  changes  of  level  in  the  land,  giving  a  changed  direction  to  the  cold  or 
warm  oceanic  currents,  and  affecting  thus  oceanic  temperature,  and  also  the  temper 
ature  of  atmospheric  currents. 

11.  Through  terrestial  or  cosmical  changes,  occasioning  an  era  of  great  cold  for  a 
hemisphere,  or  for  both  hemispheres,  thereby  giving  greater  cold  to  oceanic  as  well 
as  to  atmospheric  currents,  p.  488. 

11.  Through  climatal  excesses  as  to  heat  and  cold,  moisture  and  drought,  such  as 
occur,  under  unchanged  conditions  of  level,  once  or  so  in  a  century. 

13.  Through  the  gradual  change  of  climate  over  the  globe,  consequent  on  the  earth's 
secular  refrigeration. 

III.   Causes  of  Extinction  depending  on  the  Mutual  Relations  of  Species. 

14.  Through  a  loss  of  the  proper  food,  occasioned  by  destructions  of  species,  accord 
ing  to  any  of  the  above  or  other  methods. 


764  DYNAMICAL    GEOLOGY. 

15.  Through  the  excessive  multiplication  of  the  natural  enemies  of  the  individuals 
of  any  species. 

16.  Through  the  excessive  multiplication  of  individuals  of  a  species,  so  that  food  fails 
and  famine  ensues. 

These  and  other  related  causes  have  been  ably  discussed  by  Darwin. 

IV.  Causes  of  Extinction  depending  on  the  Successional  Relations  of  Species. 

17.  Through  whatever  means  —  the  above  or  others  —  that  may  have  sufficed,  with 
the  lapse  of  time,  to  produce  changes  in  the  specific  characters  of  species  :  in  other 
words,  through  progress  in  the  evolution  —  however  carried  forward  —  of  the  systems 
of  life. 


COSMOGONY. 

THE  science  of  cosmogony  treats  of  the  history  of  creation. 

Geology  comprises  that  later  portion  of  the  history  which  is  within 
the  range  of  direct  investigation,  beginning  with  the  rock-covered 
globe,  and  gathering  only  a  few  hints  as  to  a  previous  state  of  igneous 
fluidity. 

Through  Astronomy,  our  knowledge  of  this  earlier  state  becomes 
less  doubtful,  and  we  even  discover  evidence  of  a  period  still  more  re 
mote.  Ascertaining  thence  that  the  sun  of  our  system  is  in  intense 
ignition,  that  the  moon,  the  earth's  satellite,  was  once  a  globe  of  fire, 
but  is  now  cooled  and  covered  with  extinct  craters,  and  that  space  is 
filled  with  burning  suns,  —  and  learning  also  from  physical  science 
that  all  heated  bodies  in  space  must  have  been  losing  heat  through 
past  time,  the  smallest  most  rapidly,  —  we  safely  conclude  that  the 
earth  has  passed  through  a  stage  of  igneous  fluidity. 

Again,  as  to  the  remoter  period  :  the  forms  of  the  nebulae  and  of 
other  starry  systems  in  the  heavens,  and  the  relations  which  subsist 
between  the  spheres  in  our  own  system,  have  been  found  to  be  such  as 
would  have  resulted  if  the  whole  universe  had  been  evolved  from  an 
original  nebula,  or  gaseous  fluid.  It  is  not  necessary  for  the  strength 
of  this  argument  that  any  portion  of  the  primal  nebula  should  exist 
now,  at  this  late  period  in  the  history  of  the  universe  :  it  is  only  what 
might  have  been  expected,  that  the  so-called  nebulas  of  the  present 
heavens  should  be  turning  out  to  be  clusters  of  stars.  If,  then,  this 
nebular  theory  be  true,  the  universe  has  been  developed  from  a  primal 
unit ;  and  the  earth  is  one  of  the  individual  orbs  produced  in  the 
course  of  its  evolution.  The  history  of  the  universe  is  in  kind  like 
that  which  has  been  deciphered  with  regard  to  the  earth  :  it  only  car 
ries  the  action  of  physical  forces,  under  a  sustaining  and  directing 
hand,  farther  back  in  time. 

The  science  of  Chemistry  also  is  aiding  in  the  study  of  the  earth's 
earliest  development,  and  is  preparing  itself  to  write  a  history  of  the 
various  changes  which  should  have  taken  place  among  the  elements, 
from  the  first  commencement  of  combination  to  the  formation  of  the 
solid  crust  of  our  globe. 

It  is  not  proposed  to  enter  in  this  place  into  either  chemical  or  as- 


766  COSMOGONY. 

tronomical  details,  but,  assuming  the  nebular  theory  to  be  true,  briefly 
to  mention  the  great  stages  of  progress  in  the  history  of  the  earth,  or 
those  successive  periods  in  time,  which  stand  out  prominently  through 
the  exhibition  of  some  new  idea  in  the  grand  system  of  progress.  The 
views  here  offered,  and  the  following  on  the  cosmogony  of  the  Bible, 
are  essentially  those  brought  out  by  Professor  Guyot,  in  his  lectures. 

Stages  of  Progress.  —  These  stages  of  progress  are  the  following :  — 

(1.)  The  BEGINNING  OF  ACTIVITY  IN  MATTER.  —  In  such  a  be 
ginning,  the  activity  would  show  itself  instantly,  by  a  manifestation  of 
light,  since  light  is  a  resultant  of  molecular  activity.  A  flash  of  light 
through  the  universe  would  therefore  be  the  first  announcement  of  the 
work  begun. 

(2.)  The  development  of  the  EARTH.  —  A  dividing  and  subdividing 
of  the  original  fluid,  carried  forward,  would  ultimately  have  evolved 
systems  of  various  grades,  and  ultimately  the  orbs  of  space,  among 
these  the  earth,  an  igneous  sphere  enveloped  in  vapors. 

(3.)  The  production  of  the  EARTH'S  PHYSICAL  FEATURES,  by  the 
outlining  of  the  continents  and  oceans.  The  condensible  vapors  would 
have  gradually  settled  upon  the  earth,  as  cooling  progressed. 

(4.)  The  introduction  of  LIFE,  —  in  the  first  existence  of  the  lowest 
of  plants,  and  of  Protozoans  among  animals.  In  these  simplest  forms 
of  living  beings,  the  systems  of  structure  characterizing  the  Animal 
kingdom,  the  Radiate,  Molluscan,  Articulate,  and  Vertebrate,  are  not 
clearly  pronounced. 

(5.)  The  display  of  the  SYSTEMS  in  the  Kingdoms  of  Life,  —  the  ex 
hibition  of  the  four  grand  types  under  the  Animal  kingdom,  being  the 
predominant  idea  in  this  phase  of  progress. 

(6.)  The  introduction  of  the  highest  class  of  Vertebrates,  —  that  of 
MAMMALS,  the  class  to  which  MAN  belongs,  —  eminent  above  all  other 
Vertebrates  for  a  quality  prophetic  of  a  high  moral  purpose,  —  that  of 
suckling  their  young. 

(7.)  The  introduction  of  MAN,  —  the  first  being  gifted  with  moral 
qualities  and  high  reason,  and  one  in  whom  the  unity  of  nature  has  its 
full  expression. 

There  is  another  great  event  in  the  Earth's  history  which  has  not 
yet  been  mentioned,  because  of  the  uncertainty  with  regard  to  its  ex 
act  place  among  the  others.  The  event  referred  to  is  the  first  shin 
ing  of  the  sun  upon  the  earth,  after  the  vapors,  which  till  then  had 
shrouded  the  sphere,  were  mostly  condensed.  This  must  have  pre 
ceded  the  introduction  of  the  Animal  system,  since  the  sun  is  the  grand 
source  of  activity  throughout  nature  on  the  earth,  and  is  essential  to 
the  existence  of  life,  excepting  its  lower  forms.  In  the  history  of  the 
globe,  which  has  been  given  on  page  146,  it  has  been  shown  that  the 


COSMOGONY.  767 

outlining  of  the  continents  was  one  of  the  earliest  events,  dating  even 
from  Archaean  time ;  and  it  is  probable,  from  the  facts  stated,  that  it 
preceded  that  clearing  of  the  atmosphere  which  opened  the  sky  to  the 
earth.  This  would  place  the  event  between  numbers  3  and  5,  and,  as 
the  sun's  light  was  not  essential  to  the  earliest  of  organisms,  probably 
after  number  4. 

The  order,  in  the  history,  will  then  be  — 

(1.)  Activity  begun,  —  light  an  immediate  result. 

(2.)   The  earth  made  an  independent  sphere. 

(3.)  Outlining  of  the  land  and  water,  determining  the  earth's  gen 
eral  configuration. 

(4.)  The  idea  of  life  expressed  in  the  lowest  plants,  and  afterward, 
if  not  cotemporaneously,  in  the  lowest  or  systemless  animals,  the  Pro 
tozoans. 

(5.)  The  energizing  light  of  the  sun  shining  on  the  earth,  —  an 
essential  preliminary  to  the  display  of  the  systems  of  life. 

(6.)  Introduction  of  the  systems  of  life. 

(7.)  Introduction  of  Mammals,  —  the  highest  of  Vertebrates,  —  the 
class  afterward  to  be  dignified  by  including  a  being  of  moral  and  in 
tellectual  nature. 

(8.)  Introduction  of  Man. 

Cosmogony  of  the  Bible.  —  There  is  one  ancient  document  on  cos 
mogony  —  that  of  the  opening  page  of  the  Bible  —  which  is  not  only 
admired  for  its  sublimity,  but  is  very  generally  believed  to  be  of  divine 
origin,  and  which,  therefore,  demands  at  least  a  brief  consideration  in 
this  place. 

In  the  first  place,  it  may  be  observed  that  this  document,  if  true,  is 
of  divine  origin.  For  no  human  mind  was  witness  of  the  events  ;  arid 
no  such  mind  in  the  early  age  of  the  world,  unless  gifted  with  super 
human  intelligence,  could  have  contrived  such  a  scheme,  —  would  have 
placed  the  creation  of  the  sun,  the  source  of  light  to  the  earth,  so 
long  after  the  creation  of  light,  even  on  the  fourth  day,  and,  what  is 
equally  singular,  between  the  creation  of  plants  and  that  of  animals, 
when  so  important  to  both ;  and  none  could  have  reached  to  the  depths 
of  philosophy  exhibited  in  the  whole  plan. 

Again,  If  divine,  the  account  must  bear  marks  of  human  imperfection, 
since  it  was  communicated  through  Man.  Ideas  suggested  to  a  human 
mind  by  the  Deity  would  take  shape  in  that  mind  according  to  its 
range  of  knowledge,  modes  of  thought,  and  use  of  language,  unless  it 
were  at  the  same  time  supernaturally  gifted  with  the  profound  knowl 
edge  and  wisdom  adequate  to  their  conception  ;  and  even  then  they 
could  not  be  intelligibly  expressed,  for  want  of  words  to  represent 
them. 


768  COSMOGONY. 

The  central  thought  of  each  step  in  the  Scripture  cosmogony  —  for 
example,  Light ;  the  Dividing  of  the  fluid  earth  from  the  fluid  around 
it,  individualizing  the  earth ;  the  Arrangement  of  its  land  and  water ; 
Vegetation  ;  and  so  on  —  is  brought  out  in  the  simple  and  natural 
style  of  a  sublime  intellect,  wise  for  its  times,  but  unversed  in  the 
depths  of  science  which  the  future  was  to  reveal.  The  idea  of  vege 
tation  to  such  a  one  would  be  vegetation  as  he  knew  it ;  and  so  it  is 
described.  The  idea  of  dividing  the  earth  from  the  fluid  around  it 
would  take  the  form  of  a  dividing  from  the  fluid  above,  in  the  imper 
fect  conceptions  of  a  mind  unacquainted  with  the  earth's  sphericity 
and  the  true  nature  of  the  firmament,  —  especially  as  the  event  was 
beyond  the  reach  of  all  ordinary  thought. 

Objections  are  often  made  to  the  word  "  day,"  — as  if  its  use  limited  the  time  of  each 
of  the  six  periods  to  a  day  of  twenty-four  hours.  But,  in  the  course  of  the  document, 
this  word  "  day  "  has  various  significations,  and,  among  them,  all  that  are  common  to 
it  in  ordinary  language.  These  are  —  (1)  The  light,  —  "God  called  the  light,  day," 
v.  5;  (2)  the  "  evening  and  the  morning  "  before  the  appearance  of  the  sun;  (3)  the 
"  evening  and  the  morning  "  after  the  appearance  of  the  sun;  (4)  the  hours  of  light  in 
the  twenty -four  hours  (as  well  as  the  whole  twenty -four  hours),  in  verse  14;  and  (5)  in 
the  following  chapter,  at  the  commencement  of  another  record  of  creation,  the  whole 
period  of  creation  is  called  "a  day."  The  proper  meaning  of  "evening  and  morning," 
in  a  history  of  creation,  is  beginning  and  completion;  and,  in  this  sense,  darkness  before 
light  is  but  a  common  metaphor. 

A  Deity  working  in  creation,  like  a  day-laborer,  by  earth-days  of  twenty-four  hours, 
resting  at  night,  is  a  belittling  conception,  and  one  probably  never  in  the  mind  of  the 
sacred  penman.  In  the  plan  of  an  infinite  God,  centuries  are  required  for  the  maturing 
of  some  of  the  plants  with  which  the  earth  is  adorned. 

The  order  of  events  in  the  Scripture  cosmogony  corresponds  essen 
tially  with  that  which  has  been  given.  There  was  first  a  void  and 
formless  earth  :  this  was  literally  true  of  the  "  heavens  and  the  earth," 
if  they  were  in  the  condition  of  a  gaseous  fluid.  The  succession  is  as 
follows :  — 

(1.)   Light. 

(2.)  The  dividing  of  the  waters  below  from  the  waters  above  the 
earth  (the  word  translated  waters  may  mean  fluid). 

(3.)  The  dividing  of  the  land  and  water  on  the  earth. 

(4.)  Vegetation ;  which  Moses,  appreciating  the  philosophical  char 
acteristic  of  the  new  creation,  distinguishing  it  from  previous  inorganic 
substances,  defines  as  that  "  which  has  seed  in  itself." 

(5.)  The  sun,  moon,  and  stars. 

(6.)  The  lower  animals,  those  that  swarm  in  the  waters,  and  the 
creeping  and  flying  species  of  the  land. 

(7.)   Beasts  of  prey  (" creeping  "  here  meaning  "prowling"). 

(8.)   Man. 

In  this  succession,  we  observe  not  merely  an  order  of  events,  like 
that  deduced  from  science :  there  is  a  system  in  the  arrangement,  and 


COSMOGONY.  769 

a  far- reaching  prophecy,  to  which  philosophy  could  not  have  attained, 
however  instructed. 

The  account  recognizes  in  creation  two  great  eras,  each  of  three 
days,  —  an  Inorganic  and  an  Organic. 

Each  of  these  eras  opens  with  the  appearance  of  light:  the  first, 
lio-ht  cosmical ;  the  second,  light  from  the  sun,  for  the  special  uses  of 
the  earth. 

Each  era  ends  in  a  "  day  "  of  two  great  works.  —  the  two  shown  to 
be  distinct,  by  being  severally  pronounced  "good."  On  the  third 
"  day,"  that  closing  the  Inorganic  era,  there  was  first  the  dividing  of 
the  land  from  the  waters,  and  afterward  the  creation  of  vegetation,  or 
the  institution  of  a  kingdom  of  life,  —  a  work  widely  diverse  from  all 
preceding  it  in  the  era.  So,  on  the  sixth  "  day,"  terminating  the  Or 
ganic  era,  there  was  first  the  creation  of  Mammals,  and  then  a  second 
far  greater  work,  totally  new  in  its  grandest  element,  the  creation  of 
Man. 

The  arrangement  is,  then,  as  follows  :  — 

1.    The  Inorganic  Era. 

1st  Day.  —  LIGHT  cosmical. 

2d  Day.  —  The  earth  divided  from  the  fluid  around  it,  or  individ 
ualized. 

o,   pv       (  1.  Outlining  of  the  land  and  water. 

(2.   Creation  of  vegetation. 

2.    The  Organic  Era. 

4th  Day.  —  LIGHT  from  the  sun. 
5th  Day.  —  Creation  of  the  lower  orders  of  animals, 
fifl    D         -1^'  Creation  °f  Mammals. 
1  2.   Creation  of  Man. 

In  addition,  the  last  day  of  each  era  included  one  work  typical  of 
the  era,  and  another  related  to  it  in  essential  points,  but  also  prophetic 
of  the  future.  Vegetation,  while,  for  physical  reasons,  a  part  of  the 
creation  of  the  third  day,  was  also  prophetic  of  the  future  Organic 
era,  in  which  the  progress  of  life  was  the  grand  characteristic.  The 
record  thus  accords  with  the  fundamental  principle  in  history  that  the 
characteristic  of  an  age  has  its  beginnings  within  the  age  preceding. 
So,  again,  Man,  while  like  other  Mammals  in  structure,  even  to  the 
homologies  of  every  bone  and  muscle,  was  endowed  with  a  spiritual 
nature,  which  looked  forward  to  another  era,  that  of  spiritual  exist 
ence.  The  seventh  "  day,"  the  day  of  rest  from  the  work  of  creation, 
is  Man's  period  of  preparation  for  that  new  existence  ;  and  it  is  to 
49 


770  COSMOGONY. 

promote  mis  special  end  that  —  in  strict  parallelism  —  the  Sabbath 
follows  man's  six  days  of  work. 

The  record  in  the  Bible  is,  therefore,  profoundly  philosophical  in 
the  scheme  of  creation  which  it  presents.  It  is  both  true  and  divine. 
It  is  a  declaration  of  authorship,  both  of  Creation  and  the  Bible,  on 
the  first  page  of  the  sacred  volume. 

There  can  be  no  real  conflict  between  the  two  Books  of  the  GREAT 
AUTHOR.  Both  are  revelations  made  by  Him  to  Man,  —  the  earlier 
telling  of  God-made  harmonies,  coming  up  from  the  deep  past,  and 
rising  to  their  height  when  Man  appeared,  the  later  teaching  Man's 
relations  to  his  Maker,  and  speaking  of  loftier  harmonies  in  the  eter 
nal  future. 


APPENDIX. 


A.  —  Suggestions  for  the  Working  Geologist. 

1.  Diagrams  of  Sections.  —  With  uniformity  among  geologists  in  the  mode  of  repre 
senting  the  several  kinds  of  rocks  in  diagrams  of  sections,  it  would  not  be  necessary  with 
each  such  section  to  explain  that  this  part  stands  for  sandstone,  that  for  limestone,  and 
so  on.    The  particular  modes  exemplified  in  the  section  on  page  102  have  the  advantage 
of  being  simple  and  self-explaining.      They  consist  in  representing  limestone   by  a 
blocked  surface,  as  opposite  Trenton  or  Lower  Helderberg,  in  the  section  referred  to; 
shale,  by  fine  lining  parallel  with  the  bedding,  as  opposite  Utica  and  Cincinnati;  sand 
stone  of  different  degrees  of  fineness,  by  dots  of  different  degrees  of  coarseness ;  laminated 
or  shaly  sandstone,  by  cut  lines  or  a  combination  of  short  lines  and  dots,  as  opposite  Sa- 
lina  and  Hamilton ;  conglomerate,  by  very  coarse  or  open  dots,  as  opposite  Millstone-grit. 
Also,  for  a  schist  (as  mica  schist  or  gneiss),  in  the  manner  illustrated  on  page  213. 

2.  Tilted  or  Plicated  Rods.  —  In  studying  a  region  of  tilted  rocks  with  clinometer  in 
hand,  first,  after  finding,  over  the  upturned  edges,  a  place  Avhere  the  edges  are  quite  hori 
zontal,  or  marking  carefully  on  the  tilted  surface  a  horizontal  line,  take  the  strike ; 
then,  the  amount  of  dip,  noting  also  its  general  direction  (its  precise  direction  being  at 
right  angles  to  the  strike).    From  the  note-book,  put  the  observation  on  a  map  by  means 
of  a  symbol  shaped  like  a  letter  T)  the  top  having  the  direction  of  the  strike,  and  the 
stem  that  of  the  dip,  the  length  of  the  stem  being  shortened  as  the  dip  increases.     Mul 
tiply  the  observations  until  the  map  is  covered  with  T's.     Their  positions  on  the  map 
will  indicate  all  anticlinals  and  synclinals,  the  meeting  of  two,  thus  H  )-,  indicating  the 

former,  and  thus  I 1,  the  latter.     Where  the  strata  are  vertical,  the  T  would  become 

a  straight  line;  and,  where  horizontal,  a  cross  thus,  +.    The  angle  of  strike  and  dip  can 
be  written  with  each  T  on  the  map,  in  very  fine  letters. 

In  all  cases,  especially  those  of  high  dip  (40°  and  upward),  wherever  faults  or  folds 
are  a  possibility,  question  their  existence  until  their  absence  is  fully  proved,  or  the  con 
trary ;  and,  when  proof  cannot  be  obtained,  doubt.  Be  careful  not  to  let  local  flexures 
obscure  the  truth  with  regard  to  the  general  folds  of  the  region.  Note,  also,  that,  where 
the  dip  is  small,  the  variations  in  the  strike  are  often  great;  and  that  a  careful  compar 
ison  of  all  the  results  over  a  wide  range  of  country,  and  of  the  bendings  indicated,  may 
be  necessary,  to  ascertain  the  true  direction  of  the  axis  of  elevation. 

It  is,  moreover,  important  to  have  in  view,  in  the  study  of  plicated  regions,  that  the 
beds  were  once  horizontal,  and  have  been  warped  out  of  horizontality  by  lateral  pres 
sure  ;  and  that,  therefore,  the  warpings  or  flexures,  although  obscured  by  faults,  must 
be  compatible  with  one  another. 

Xote,  also,  that  limestone  is  as  solid  when  first  made  and  consolidated,  as  at  any  time 
afterward,  as  exemplified  by  the  coral  limestone  of  Coral  Islands;  and  that  thick  strata 
of  limestone — the  thickness  a  thousand  feet  or  more  —  are  very  resistant  to  flexure 
before  lateral  pressure,  while  shales  may  bend  and  fold  easily. 

Xote  further,  that  the  mountain  ridges  of  a  region  are  more  probably  synclinals  than 
anticlinals,  the  rocks  of  an  anticlinal  breaking  and  yielding  easily  to  denudation,  while 
those  of  a  synclinal  are  pressed  and  compacted  together,  and  put  in  a  condition  to  resist 
denudation. 


772  APPENDIX. 

3.  Unconformability.  —  Never  confound  the  unconformity  that  is  connected  with  a 
fault  with  true  unconformability,  due  to  unconformable  superposition.     The  different, 
and  differently-dipping,  rocks  on  the  opposite  sides  of  a  fault  of  a  thousand  feet  or 
more  may  belong  to  the  same  period. 

Never  assert  with  positiveness  that  unconformability  exists,  unless  the  fact  is  dis 
tinctly  visible  in  an  actual  section  showing  the  contact  of  beds  of  unlike  dip;  for  the 
unlike  dip  in  different  rocks,  if  observed  at  points  only  a  hundred  feet  apart,  may  be 
owing  to  a  bend  in  one  or  the  other  stratum  in  that  interval,  or  to  displacement. 

Observe  the  distinction  between  overlap  (p.  101),  and  unconformability  due  to  deposi 
tion  on  upturned  strata. 

4.  Metamorphic  JRocks.  —  Study  regions  of  metamorphic  or  granitoid  rocks  in  pre 
cisely  the  same  manner  as  those  of  ordinary  stratified  rocks,  whether  they  be  Archaean 
or  of  later  origin,  making  no  use  of  lithology  except  in  order  to  follow  a  series  of 
rocks  from  mile  to  mile  over  a  country,  and  always  relying  implicitly  on  stratigraphy. 
Remember  also  that  a  layer  of  quartzite  may  be  gneiss  or  mica  schist  a  few  rods  off; 
and  that  the  same  crystalline  rocks,  with  a  rare  exception,  may  belong  to  formations  of 
very  various  geological  ages. 

As  to  granyte,  syr-nyte,  and  dioryte,  leave  to  the  infancy  of  geology  the  notion  that 
they  are  primitive  rocks,  and  make  their  age,  in  each  case,  a  question  to  be  solved  by 
careful  stratigraphical  investigation.  In  connection  with  the  investigation  the  following 
questions  are  to  be  answered:  Is  the  rock  eruptive  granyte,  syenyte,  or  dioryte?  Is  the 
rock  a  vein  formation  ?  Or,  is  the  rock  part  of  the  metamorphic  series  of  a  region,  as 
proved  by  its  mode  of  association  with  metamorphic  rocks,  and  its  gradation  into  gneiss- 
oid  granyte  and  gneiss,  or  into  any  other  schistose  crystalline  rock  ?  a  fact  with  much 
the  larger  part  of  the  granyte,  syenyte,  and  dioryte  of  the  world.  The  kinds  of  crys 
talline  rocks  that  are  most  characteristic  of  the  Archaean  terranes  are  mentioned  on 
page  151. 

B.  —  Catalogue  of  American  Localities  of  Fossils. 

The  following  catalogue  contains  some  of  the  more  important  of  American  localities 
of  fossils,  and  is  intended  for  the  convenience  especially  of  the  student-collector. 

LOCALITIES  OF  FOSSILS. 

Acadian  Group.  — Coldbrook,  Ratcliffe's  Millstream,  St.  John,  N.  B. ;  Long  Arm  of 
Canada  Bay,  Newfoundland. 

Potsdam  Group.  —  Swanton,  Yt.;  Braintree,  Mass. ;  Keeseville  (at  "  High  Bridge  "), 
Alexandria,  Troy,  N.  Y. ;  Chiques  Ridge,  Pa. ;  Falls  of  St.  Croix.  Osceola  Mills,  Trem- 
paleau,  Wisconsin;  Lansing,  Iowa;  St.  Ann's,  Isle  Perrot,  C.  W. ;  near  Beauharnois 
on  Lake  St.  Louis,  C.  E. 

Calciferous.  —  Mingan  Islands,  St.  Timothy,  and  near  Beauharnois,  C.  E.;  Grand 
Trunk  Railway  between  Brockville  and  Prescott,  St.  Ann's,  Isle  Perrot,  C.  W. ;  Am 
sterdam,  Fort  Plain,  Canajoharie,  Chazy,  Lafargeville,  Ogdensburg,  N.  Y. 

Quebec  Group. — Mingan  Islands,  Point  Levi,  Philipsburg,  and  near  Beauharnois, 
C.  E. ;  Point  Rich,  Cow  Head,  Newfoundland;  cuts  in  Black  Oak  Ridge  and  Copper 
Ridge,  Knoxville  and  Ohio  Railroad,  Tenn.;  Malade  City,  Idaho. 

Chazy  Limestone. — Chazy,  Galway,  Westport,  N.  Y. ;  one  to  three  miles  north  of 
"the  Mountain,"  Island  of  Montreal,  C.  E. ;  St.  Joseph's  Island,  Sault  Ste.  Marie,  C. 
W.;  Knoxville,  Lenoir's,  Bull's  Gap,  Kingsport,  Tenn. 

Bird's-eye  Limestone. — Amsterdam,  Little  Falls,  Fort  Plain,  Adams,  Watertown, 
N.  Y. 

Black  River  Limestone.  —  Watertown,  N.  Y. ;  Ottawa.  C.  W. ;  Island  of  Montreal,  and 
near  Quebec,  C.  E. 

Trenton  Limestone.  —  Adams,  Watertown,  Boonville,  Turin,  Jacksonburg,  Little 
Falls,  Lowville,  Middleville,  Fort  Plain,  Trenton  Falls,  N.  Y. ;  Pine  Grove,  Aaronsburg, 
Potter's  Fort,  Milligan's  Cove,  Pa.;  Highgate  Springs,  Vt. ;  Montmorency  Falls  and 


APPENDIX.  773 

Beauport  Quarries  neai1  Quebec,  Island  of  Montreal  (quarries  north  of  the  city),  C.  E. ; 
Ottawa,  Belleville,  Trenton  (G.  T.  R.  R.,  west  of  Kingston),  C.  W. ;  Copper  Bay,  Mich.; 
Elkader  Mills,  Turkey  River,  Dubuque,  Iowa;  Falls  of  St.  Anthony,  St.  Paul,  Mineral 
Point,  Cassville,  Beloit,  Quimby's  Mills  near  Benton,  Wis. ;  Warren,  Rockton,  Wins- 
low,  Dixon,  Freeport,  Cedarville,  Savanna,  Rockford,  Illinois;  Murfreesborough,  Colum 
bia,  Lebanon,  Tenn. 

Utica  Slate.  —  Turin,  Martinsburg,  Lorraine,  Worth,  Utica,  Cold  Spring,  Oxtungo 
and  Osquago  Creeks  near  Fort  Plain,  Mohawk,  Rouse's  Point,  N  Y.;  Rideau  River 
along  railroad  at  Ottawa,  bed  of  river  two  miles  above,  C.  W. 

Hudson  Eiver  Group,  — Pulaski,  Rome,  Lorraine,  Boonville,  N.  Y.  —  Penn's  Valley, 
Milligan's  Cove,  Pa.  —  Oxford,  Cincinnati,  Lebanon,  O.  —  Madison,  Richmond,  Ind. — 
Anticosti,  opposite  Three  Rivers,  C.  E.  — Weston  on  the  Humber  River,  nine  miles  west 
of  Toronto,  C.  W.  — Little  Makoqueta  River,  Iowa.  — Savannah,  Green  Bay,  Wis.  — 
Thebes,  Alexander  County;  Savanna,  Carroll  County;  Scales'  Mound,  Jo  Daviess 
County;  Oswego,  Yorkville,  Kendall  County;  Naperville,  Du page  County ;  Wilming 
ton,  Will  County,  111. — Cape  Girardeau,  Mo. — Drummond's  Island,  Mich. — Nash 
ville,  Columbia,  Knoxville,  Tenn. 

Medina  Sandstone.  —  Lockport,  Lewiston,  Medina,  Rochester,  N.  Y. ;  Long  Narrows 
below  Lewistown,  Pa. ;  Duiulas,  C.  W. 

Clinton  Group.  —  Lewiston,  Lockport,  Reynolds'  Basin,  Brockport,  Rochester,  Wol- 
cott.  New  Hartford,  N.  Y. ;  Thorold  on  Welland  Canal,  Hamilton,  Ancaster,  Dundas, 
C.  W. ;  Hanover,  Ind. 

Niagara. — Lewiston,  Lockport,  Gosport,  Rochester,  Wolcott,  N.  Y. ;  Thorold,  Ham 
ilton,  Ancaster,  C.  W. ;  Anticosti,  C.  E.;  Arisaig,  Nova  Scotia;  Racine,  Waukesha, 
Wis.;  Sterling,  Grafton,  Savanna,  Chicago,  Joliet,  111.;  Marblehead  on  Drummond's 
Island,  Michigan;  Springtield,  Cedarville,  Ohio;  Delphi,  Waldron,  Jeffersonville, 
Madison,  Ind.;  Louisville,  Ky. ;  the  "glades"  of  West  Tennessee.  (Coralline  Lime 
stone.  —  Schoharie,  N.  Y.) 

OnondcHja  Salt  Group.  —  Buffalo,  Williamsville,  Waterville,  Jerusalem  Hill  (Herki- 
mer  County),  N.  Y.;  Gait,  Guelph  (G.  T.  R.  R.),  C.  W. 

Lower  Helderberg  Limestones.  —  Dry  Hill,  Jerusalem  Hill  (Herkimer  County), 
Sharon,  East  Cobleskill,  Judd's  Falls,  Cherry  Valley,  Carlisle,  Schoharie,  Clarksville, 
Athens,  N.  Y. ;  Pembroke,  Parlin  Pond,  Me. ;  Gaspe,  C.  E. :  Arisaig,  East  River, 
Nova  Scotia;  Peach  Point,  opposite  Gibraltar,  Ohio;  Thebes,  Devil's  Backbone,  111.; 
Bailey's  Landing,  Mo.;  "  glades  "  of  Wayne  and  Hardin  Counties,  Tenn. 

Orixkany  Sandstone.  —  Oriskany,  Vienna,  Carlisle,  Schoharie,  Pucker  Street,  Cat- 
skill  Mountains,  N.  Y. ;  Cumberland,  Md.;  Moorestown  and  Frankstown,  Pa.;  Bald 
Bluffs,  Jackson  County,  111.,  four  miles  S.  W.  of  St.  Mary's,  Ste.  Genevieve  County,  Mo. 

Cauda-yalli  Grit.  —  Schoharie  (Fucoides  Cauda-galli),  N.  Y. 

Schoharie  Grit.  —  Schoharie,  Cherry  Valley,  N.  Y.         • 

Upper  Helderberg  Limestones.  —  Black  Rock,  Buffalo,  Williamsville,  Lancaster, 
Clarence  Hollow,  Stafford,  Le  Roy,  Caledonia,  Mendon,  Auburn,  Onondaga,  Cass 
ville,  Babcock's  Hill,  Schoharie,  Cherry  Valley,  Clarksville,  N.  Y.;  Port  Colborne, 
and  near  Cayuga,  C.  W. ;  Columbus,  Delaware,  White  Sulphur  Springs,  Sandusky, 
Ohio;  Mackinac,  Little  Traverse  Bay,  Dundee,  Monguagon,  Mich.;  North  Vernon, 
Charlestown,  Kent,  Hanover,  Jeffersonville,  Ind.;  Louisville,  Ky. 

Marcellus  Shales. — Lake  Erie  shore,  ten  miles  S.  of  Buffalo,  Lancaster.  Alden, 
Avon,  Leroy,  Marcellus,  Manlius,  Cherry  Valley,  N.  Y. 

Hamilton  Group. — Lake  Erie  shore,  Eighteen  Mile  Creek,  Hamburg,  Alden, 
Darien,  York,  Moscow,  East  Bethany,  Bloomfield,  Bristol,  Seneca  Lake,  Cayuga  Lake, 
Skaneateles  Lake,  Moravia,  Pompey,  Cazenovia,  Delphi,  Bridgewater,  Richland, 
Cherry  Valley,  Seward,  Westford,  Milford,  Portlandville,  N.  Y.;  Widder  Station 
(G.  T.  R.  R.),  near  Port  Sarnia,  C.  W. ;  New  Buffalo,  Independence,  Rockford,  Iowa; 
Devil's  Bake  Oven,  Jackson  County,  Moline,  Rock  Island,  111.;  Grand  Tower,  Mo.; 
Thunder  Bay,  Little  Traverse  Bay,  Mich. ;  Nictaux,  Bear  River,  Moose  River,  Nova 
Scotia. 


774  APPENDIX. 

Genesee  Slate. —Banks  of  Seneca  and  Cayuga  Lakes,  Lodi  Falls,  Mount  Morris, 
two  miles  south  of  Big  Stream  Point,  Yates  County,  N.  Y. 

Portage  Group. —Eighteen  Mile  Creek  on  Lake  Erie  Shore,  Chautauqua  Lake,  Gene- 
see  River  at  Portage,  Flint  Creek,  Cashaqua  Creek,  Nunda,  Seneca  and  Cayuga  Lakes, 
N.  Y. ;  Delaware,  Ohio;  Kockford,  North  Vernon,  Ind.;  Danville,  Ky. 

Chemung   Group.  —  Rockville,    Philipsburg,    Jasper,    Greene,    Chemung   Narrows, 
Troopsville,  Elmira,  Ithaca,  AYaverly,  Hector,  Entield,  Franklin,  N.  Y.;  Gaspe,  C.  E. 
Cat  skill  Group. — Fossils  rare.  —  Richmond's  quarry  above   Mount  Upton  on  the 
Unadilla,  Oneonta,  Oxford,  Steuben  County,  south  of  the  Canisteo,  N.  Y. 

Subcarboniferous.  — Burlington,  Keokuk,  Columbus,  Iowa;  Quincy,  Warsav,  Alton, 
Kaskaskia,  Chester,  111.;  Crawfordsville,  Greencastle,  Bloomington,  Spergen  Hill', 
New  Providence.  Ind.;  Hannibal,  St.  Genevieve,  St.  Louis,  Mo.;  Willow  Creek,  Battle 
Creek,  Marshal,  Moscow,  Jonesville,  Holland,  Grand  Rapids,  Mich.;  Mauch  Chunk, 
Pa.;  Newtonville,  Ohio;  Ice's  Ferry,  on  Cheat  River,  Monongalia  Countv,  W.  Va,; 
Red  Sulphur  Springs,  Pittsburg  Landing,  White's  Creek  Springs,  Waynesvifle,  Cowan, 
Tenn. ;  Big  Bear  and  Little  Bear  Creeks,  Big  Crippled  Deer  Creek,  Miss. ;  Clarksville, 
Huntsville,  Ala. ;  Windsor,  Horton,  Nova  Scotia. 

Carboniferous.  —  South  Joggins,  Pictou,  Sydney,  Nova  Scotia.  —  Wilkesbarre, 
Shamokin,  Tamaqua,  Pottsville,  Minersville,  Tremont,  Greensburg,  Carbondale,  Port 
Carbon,  Lehigh,  Trevorton,  Johnstown,  Pittsburg,  Pa.  —  Pomeroy,  Marietta,  Zanesville, 
Cuyahoga  Falls,  Athens,  Yellow  Creek,  Ohio.  —  Charlestown,  Clarksburg,  Kanawha, 
Salines,  Wheeling,  W.  Ya.  —  Saline  Company's  Mines,  Gallatin  County;  Carlinville, 
Hodges  Creek,  Macoupin  County;  Colchester,  McDonough  County;  Duquoin,  Perrv 
County;  Murphysborough,  Jackson  County;  Lasalle;  Morris,  Mazon  and  Waupecan 
Creeks,  Grundy  County;  Danville,  Pettys'  Ford,  Vermilion  County;  Paris,  Edgar 
County ;  Springfield,  111.  —  Perrysville,  Eugene,  Newport,  Horseshoe  of  Little  Vermil- 
lion,  Vermillion  County;  Durkee's  Ferry,  near  Terre  Haute,  Vigo  County;  Lodi, 
Parke  County;  Merom,  Sullivan  County,  Ind. — BelFs,  Casey's  and  Union  Mines, 
Crittenden  County;  Hawesville  and  Lewisport,  Hancock  County;  Breckenridge, 
Giger's  Hill,  Mulford's  Mines,  and  Thompson's  Mine,  Union  County;  Providence  and 
Madisonville,  Hopkins  County;  Bonharbour,  Daviess  County,  Ky.  — Muscatine,  Alpine 
Dam,  Iowa.  —  Leavenworth,  Indian  Creek,  Grasshopper  Creek,  Juniata,  Manhattan, 
Kansas.  —  Rockwood,  Emory  Mines,  Coal  Creek,  Carey ville,  Tenn.  —  Tuscaloosa,  Ala. 
Trinssic.  —  Southbury,  Middlefield,  Portland,  Conn.;  Turner's  Falls,  Sunderland, 
Mass. ;  Phoenixville,  Pa. ;  Richmond,  Va.;  Deep  River  and  Dan  River  Coal-fields,  N.  C. 
Cretaceous.  —  Upper  Freehold,  Middletown,  Marlborough,  Blue  Ball,  Monmouth 
County,  Pemberton,  Vincenton,  Burlington  County,  Blackwoodtown,  Camden  County, 
Mullica  Hill,  Gloucester  County,  Woodstown,  Mannington,  Salem  County,  New  Egypt, 
Ocean  County,  N.  J.  —  Warren's  Mill,  Itawamba  County,  Tishomingo  Creek,  R.  R. 
cuts,  Hare's  Mill,  Carrollsvilk,  Tishomingo  County,  Plymouth  Bluff,  Lowndes  County. 
Cha walla  Station  (M.  &  C.  R.  R.),  Ripley,  Tippah  County,  Xoxubee,  Macon,  Noxubee 
County,  Kemper,  Pontotoc  and  Chickasaw  Counties,  Miss. —Finch's  Ferry,  Prairie 
Bluff,  on  Alabama  River;  Choctaw  Bluff,  on  Black  Warrior  River;  Greene, "Marengo, 
and  Lowndes  Counties,  Ala.  —Fox  Hills,  Sage  Creek,  Long  Lake,  Great  Bend,  Chey 
enne  River,  etc.,  Nebraska.  —  Fort  Harker,  Fort  Hayes,  Fort  Wallace,  Kansas. —Fort 
Lyon,  Santa  Ft5,  New  Mexico. 

Eocene.  —  Every  where  in  Tippah  County;  Yockeney  River;  New  Prospect  P.  0., 
Winston  County;  Marion,  Lauderdale  County;  Enterprise,  Clarke  County:  Jackson; 
Satartia,  Yazoo  County;  Homewood,  Scott  County;  Chickasawhay  River,  Clarke 
County;  Winchester,  Red  Bluff  Station,  Wayne  County;  Yicksburg,  Amsterdam, 
Brownsville,  Warren  County;  Brandon,  Byram  Station/ Rankin  County;  Paulding. 
Jasper  County,  Miss.  — Claiborne,  Monroe  County,  St.  Stephen's,  Washington  County, 
Ala.  —  Charleston,  S.  C.  —  Tampa  Bay,  Florida.  —  Fort  Washington,  Fort  Marlborough, 
Piscataway,  Md.  —  Marlbourne,  Ya.  —  Brandon,  Yt.  —  In  New  Jersey,  at  Fanningdale, 
Squankum  and  Shark  River,  Monmouth  Co.  —  Green  River,  Fort  Bridges,  Wyoming. 
—  Canada  de  las  Uvas,  Cal. 


APPENDIX.  775 

Miocene.  —  Gay  Head,  Martha's  Vineyard,  Mass.;  Shiloh,  Jericho,  Cumberland 
County,  and  Deal,  Monmouth  Co.,  N.  J.;  St.  Mary's,  Easton,  Md. ;  Yorktown,  Suffolk, 
Sinithrield,  Richmond,  Petei'sburg,  Va. ;  Astoria,  Willamette  Valley,  John  Day  Valley, 
Oregon ;  San  Pablo  Bay,  Ocoya  Creek,  San  Diego,  Monterey,  San  Joaquin  and  Tulare 
Valleys,  Cal. ;  White  River,  Upper  Missouri  Region;  Crow  Creek,  Colorado. 

Pliocene. — Ashley  and  Santee  Rivers,  S.  C.;  Platte  and  Niobrara  Rivers,  Upper 
Missouri;  John  Day  Valley,  Oregon;  Sinker  Creek,  Idaho;  Alameda  County,  Cal. 

C.  —  Brief  Synopsis  of  this  Manual. 

This  synopsis  is  intended  to  serve  as  a  basis  for  a  short  course  of  instruction,  such 
as  may  be  desired  in  Institutions  not  strictly  scientific. 

I.  INTRODUCTION.  —  PHYSIOGRAPHIC  GEOLOGY.  —  Page  1.  Distinctions  between  a 
plant  or  animal  and  a  crystal,  or  organic  and   inorganic  individuals.  —  1,  2.  In  what 
respects  the  earth    is   an    individuality. —2.  Of  what   Geology  treats.  —  Id.  Physiog 
raphy.  —  The  Earth  in    its  relations  to  Man.  —  3.  Proof  of  oneness  of    law  through 
space.  —  4.  Aim  of  Geology.  —  5.  Instruction   from    fossils  and   strata.  —  6.  Existing 
forces  and  the  ancient  identical.  —  7.  Subdivisions  of  Geology.  —  9,  10.  Form  of  the 
earth.  — 10.  Relative  extent  of  land  and  water.  —  The  land  in  one  hemisphere.  —  11. 
General   arrangement   of    the   oceans,   and   continents.  —  Contrast    in    extent   of    the 
Atlantic  and  Pacific  oceans  and  Occidental  and  Oriental  continents.  —  Oceanic  depres 
sion:    its   true  outline.  — 12.  Depth   and  character  of   the  Oceanic   depression.  —  13. 
Distribution  of  the  continental  areas.  —  14.  Oceanic   islands  in  ranges.  — Mean  eleva 
tion  of  the  land.  — 15,  16.  Subdivisions  of  the  surface  of  continents,  with  examples  of 
each.  —  1G,    17.    Average   slope    of    Rocky   Mountains.  — 19.    Composite    nature   of 
Mountain-chains,  and  variations   in   the  positions  of  the  ridges  along  their  courses.  — 
21.  Examples  of  plateaus. — 22.  General  character  of  River-systems. — River-systems 
of  North  America.  —  Positions  of  Lakes. 

II.  PHYSIOGRAPHIC  GEOLOGY,  continued.  —  Page  23.  First  law  with  regard  to  the 
reliefs  of  continents;  Second  law  id.  —  23,  24.  How  exemplified  in  North  America.  — 
24,    25.  Id.    in    South  America. —25,   20.  Id.    in  Europe  and   Asia.  —  27,  28.  Id.   in 
Africa. —  28.  Id.    in  Australia.  —  29.  What   is   a  Continent?  —  29.  First  and  second 
principles,  with  regard  to  the  systems  of  courses  of  the  earth's  features;  third  prin 
ciple;  fourth  an&ffth.  —  29,  30.  Examples  in  the  Pacific  of  the  Northwesterly  system 
of  trends. — 31,    32.  Examples  of  the  Northeasterly  system.  —  32,33.  Characteristics 
and  extent  of  the  Polynesian  Chain.  —  33.  Id.  of  the  Australasian  Chain.  — 34.   Id.  of 
the  New  Zealand  Chain.  —  35.  Trends  <>f  the  Pacific  and  Atlantic  oceans.  —  Curves  on 
the  const  of  Asia. —  36.  Examples  of  the  systems  of  trends  in  North  America.  —  37. 
Id.  in  Asia  and  Europe. 

III.  PHYSIOGRAPHIC  GEOLOGY,   continued. — Page  38.    Main  facts  in   the   system 
of   oceanic    movements. — 39.    Explanation    of    the    courses.  —  40.    Examples   in    the 
Atlantic  and  Pacific.  —  40,  41.  Effect  of   Oceanic  currents  on   the  isothermal   lines  of 
the  tropics  (Physiographic  Chart).  —  42.   Uses  of  the  subject  of  oceanic  temperature 
to   the  Geologist.  —  43.  General  system  of   Atmospheric  currents.  —  Effects  of  land 
and  water  on  climate.  —44.  Effect  of  varying  the  distribution  of  land  over  the  globe. 

—  44,  45.  Laws  governing  the  distribution  of  forest-regions,  prairies,  and  deserts.  — 45. 
Examples  in  America.  — Cause  of  individual  characteristics  of  continents. 

IV.  LITHOLOGICAL   GEOLOGY.  —Page  47.    Subjects  treated  of  under  Lithological 
Geology. — A    rock. — Organic    constituents.  —  48.    Mineral     constituents.  —  Diverse 
qualities   of  the  elements   of  organic   and  inorganic  nature. — 49.  Characteristic   ele 
ments;    Oxygen. —  Special    importance    of    Silicon. — 50.    Aluminum;    Magnesium; 
Calcium.  —  51.  Potassium  and  Sodium;  Iron;  Carbon.  —52,  53.  Characters  of  Quartz. 

—  53.    Feldspar.  — Mica.  —  54.    Hornblende.  —  55.    Pyroxene;     Talc;     Serpentine; 
Chlorite;  Calcite;  Dolomite.  —  56.  Gypsum.  —  59.  Some  of  the  materials  of  organic 
origin.  —  62.  Changes  in  fossils. 

V.  LITHOLOGICAL    GEOLOGY,   Continued.  —  Page   62.    Definitions    of    fragmental, 
sedimentary,   stratified,   fossiliferous   rocks. — 62,  63.  Of  crystalline   rocks. — 63.  Ig- 


776  APPENDIX. 

neous  rocks;  metamorphic  rocks.  —  64.  Porphyritic  rocks  — 65.  Conglomerate;  Sand 
stone;  Shale. —  66.  Tufa;  Alluvium.  — 67.  Granyte.  —  68.  Gneiss;  Mica  schist. —69. 
Argillyte;  Syenyte.  —  70.  Hornblendic  or  Syenytic  gneiss.  —  72.  Protogine;  Talcose 
slate;  Chlorite  slate.  — 73.  Serpentine;  Ophiolyte;  Quartzyte.  —  74.  Limestone,  massive; 
Magnesian,  or  Dolomyte.  —  75.  Hydraulic;  Oolitic  or  oolyte;  Chalk;  Granular  lime 
stone;  Gypsum. — 76.  Igneous  rocks:  feldspathic  series;  hornblende  and  pyroxene  series. 

VI.  LITHOLOGICAL   GEOLOGY,  continued.  —  Page   79.    Stratified    rocks;    the   three 
conditions. — 79-81.    Stratification. — 81.    A    layer;    stratum;    formation;    terrane. — 
Origin  of  strata.  —  82.  Massive  structure;  shaly;  laminated:  compound  structures. — 
83.    Ebb-and  flow   structure;    flow-and-plunge    structure;    sand-drift    structure.  —  84. 
Ripple-marks;  rill-marks;  mud-cracks;    rain-prints. — 85.  Concretiona^   structure. — 
88.  Jointed  structure ;  joints. — 89.  Slat}' structure. — 90.  Scratches,  etc.,  on  rocks. 

VII.  LITHOLOGICAL  GEOLOGY,  continued.  —Page  91.  Natural  positions  of  strata.  — 
92.  Consequent  principle  in  Geology.  —  92.  93.  Dislocations,  faults.  —  93.  Folds  or  flex 
ures. —  94.   Outcrop;  dip;  strike.  —  95.  Anticlinal;  synclinal;  clinometer. — 96.  Faults. 

—  96-98.  Results  of  denudation  in  obscuring  the  order  of  Stratification. — 99.  Calcu 
lating  thickness  of  strata.  —  100.  Conformable;  unconformable  strata.  —  101.  Time  of 
upturning,  how  determined ;  overlap;  true  order  of  arrangement  of  Strata. — 101,  102. 
Difficulties  in  the  way  of  determining  the  order  of  arrangement.  —102,  103.  Determina 
tion  by  order  of  superposition;  precautions.  —  104.  Second  means  of  determination.— 
104,  105.     Third  method;  principles  on  which  the  value  of  fossils  depends,  and  the 
uncertainties  connected  with  the  method.  —  107.  Unstratified  rocks:  examples.  —  108- 
111.  General  nature  of  Veins.  —  111,  112.  Dikes.  —  112.  Simple  and  banded  Veins.  — 
113.  False  Veins. 

VIII.  LIFE.  —  Page  114.  Characteristics  of  a  living  being.  — 115.  The  first  distinc 
tion  between  a  Plant  and  an  Animal;  the  second;  the  third;  the  fourth;  the  fifth.  — 
116.  The  sixth;  the  seventh.  —  The  Sub-kingdoms  of  Animals.  —  Protozoans.  —  117. 
Characteristics  of  Radiates,  and  examples.  — 118.  Id.  of  Mollusks.  — 118,  119.  Id.  of 
Articulates.  — 120.  Id.  of  Vertebrates.  —  Recapitulation.  — 121.  Characteristics  of  Mam 
mals,  and  examples. —  Id.  of  Birds.  —  Id.  of  Reptiles,  and  the  two  subdivisions.  —  Id. 
of  Fishes.  —  Names  of  Classes  of  Articulates.  — Characteristics  of  Insects,  and  exam 
ples.  —  Id.  of  Spiders.  —  Id.  of  Myriapods.  —  Id.  of  Crustaceans.  —  122.  Id.  of  Worms. 

—  The  three  Orders  of  Crustaceans,  and  their  distinctions.  —  122,  123.  Trilobites. 

IX.  LIFE,  continued.  —  Pages  123,  124.  The  three  subdivisions  of  Mollusks ;    their 
characteristics,  with  examples.  — 124.    Subdivisions   of   Ordinary  Mollusks,  with  ex 
amples. — 124,  125.  Peculiarities  of  Cephalopods. — 125.  Peculiarities  of  the  two  groups 
of  Cephalates.  — Name  of  the  group  of  Acephals,  and  peculiarities.  — 126.  Ascidians.  — 
The  two  groups  of  Brachiate  Mollusks ;  distinctions  between  Brachiopods  and  Conchi- 
fers,  or  the  ordinary  Bivalves.  —  127.  Peculiarities  of  Bryozoans.  —  The  three  Classes 
of  Radiates.  —  Characteristics  of  Echinoderms. — Id.  of  Acalephs. — Id.  of  Polyps. — 
128.  Distinctions  of  Crinoids  and  other  Echinoderms. — 128,  129.   Distinctions  of  the 
three  groups  of  Crinoids.  — 129,  130.  Coral-making  Acalephs.  — 130.  The  two  Orders 
of  Polyps;  formation  of  Coral.  —  131.    Characteristics  of  Rhizopods. —  132.    Id.   of 
Sponges. 

X.  LIFE,  continued.  —  Page  133.  Cryptogams:  Thallogens,  with  examples,  Anogens, 
Acrogens;   the  three  grand  divisions  of  Acrogens.  — The  second  grand  division  of 
plants.  — 133,  134   Characteristics  of  Gymnosperms,  with  examples.  — The  subdivisions 
of  Gymnosperms.  —  Id.  of  Angiosperms,  with  examples. — Id.  of  Endogens.  —  Dico 
tyledons;  Monocotyledons.  — 134,  135.  Alga?;  Fucoids. —Kinds  of  Algae  having  cal 
careous  secretions;  kinds  having  siliceous  secretions;  Desmids. 

HISTORICAL  GEOLOGY.  —  Pages  136,  137.  Three  principles  characterizing  subdi 
visions  in  all  history,  whether  the  limits  of  an  Age  are  marked  or  not  in  the  rocks.  — 
137.  Fourth  principle.  — 138.  Fifth  principle.  —  Sixth  principle;  use  of  the  word  equiv 
alent.  —  139.  The  Ages.—  140.  The  five  higher  divisions  of  Time,  and  the  ages  they 
correspond  to.  —  141.  Basis  of  the  subdivisions  into  Periods  and  Epochs.  —  145.  Thick 
ness  of  the  stratified  rocks.  —  145,  146.  Subdivisions  of  North  America  into  independent 
regions  of  progress. 


APPENDIX.  777 

X.  ARCHAEAN  TIME.  —Pages  146,  147.     The  early  Azoic  part;  its  three  earlier  eras. 

—  147.  Extent  of  the  Archaean  rocks.  — 148.  Its  fourth  era.  —  148-150.  Distribution  in 
North  America.  —  151.  The  two  periods.  —  Kinds  of  rocks;  prevalence  of  iron-ore. — 
152.  Graphite.  — 152-154.  Arrangement  of  the  rocks.  — 154.  Their  original  condition. 
— 155.  Disturbances  and  foldings.  — 156.  Proof  that  there  were  long  ages  of  quiet  in 
the  course  of  Archaean  Time.  — Alterations  or  metamorphism  of  the  rocks;  examples.  — 
157.  Life  in  the  Archaean.  —  Evidences  as  to  plants.  —  158.  Evidences  as  to  animals. 
— 159.  Huronian  Period ;  the  rocks  so-called.  —  160.  Relations  of  the  North  American 
Archfeari  areas  to  the  present  continent.  — 161.  Source  of  the  material  of  later  f rag- 
mental  rocks.  —  Characteristics  of  the  earliest  life. 

XII.  PALEOZOIC   TIME,  SILUKIAN  AGE.  —  Page  162.  First  of  the  Paleozoic  Ages; 
origin  of  the  term  Silurian;  subdivision  of  the  Silurian  into  two  parts.  — 163.  Names 
of  the  three  Periods  in  the  American  Lower  Silurian,  beginning  with  the  earliest.  — 
164.  Id.  in  the  Upper  Silurian.     PRIMORDIAL  PERIOD.  — 166.  The  two  Epochs  of  the 
Period.  —  166,   167.    General  distribution  of   the  rocks  in  America.  — 167.   Kinds  of 
rocks.  — 168.  Markings  in  the  rocks.  — 169.  General  fact  with  regard  to  the  life. — 
Kinds  of  plants.  — The  Sub-kingdoms  of  animals  represented.  — The  kinds  of  Radiates. 

—  Id.  of  Mollusks.  —  170.  Id.  of  Articulates.  —  173,  174.  The  earliest  Mollusks. —  174. 
The  earliest  Articulates.  — 175.  Graptolites.  —  176.  Footprints. —  179.  Primordial  rocks  of 
Great  Britain.  —  180,   181.  North  American  Geography.  —  181.  Climate.     Extermina 
tion  of  life. —  182,  183.  Disturbances  during  the  Primordial. 

XIII.  LOWER  SILURIAN  —  CANADIAN  PERIOD.  —  Page  182.  Epochs.  — Rocks.  — 185. 

—  Igneous  rocks  of  the  Lake  Superior  region.  — 185,  186.  Copper  mines.  — 186.  Gen 
eral  fact  respecting  the  life. — 187.  The  kinds  representative  of  the  several  sub-king 
doms  of  animal  life,  Protozoans,  Radiates,  Mollusks,  Articulates;  the  most  common  of 
Mollusks.  —  188.  Trilobites.  —  192.  European  rocks.  — 192, 193.  General  characteristics 
of  the  Period.  — 193.  Origin  of  the  limestones. 

XIV.  LOWER  SILURIAN.  —  Page  194.  The  third  Period  in  the  Silurian  Age.  —  Its 
Epochs.  —  General  character  of  the  Trenton  rocks,  and  their  distribution. — 194,  195. 
Rocks  of  the  Utica  and  Cincinnati  epochs.  — 198.  Kinds  of  plants.  —  The  prevailing 
kinds  of   animal  life.  — 199.  New  Radiates.  —  The  most  abundant  of  Mollusks ;    the 
kinds  associated  with  these. — 200,  201.  Kinds  of  Cephalopoda,  and  the  character  of 
their  shells.  —  202.  The  most  common  of  Articulates.  —  206.  Rocks  in  Great  Britain. — 
208.  Evidence  as  to  the  Geography  of  America.  —  209.  Climate.  —  Exterminations  of 
life. 

XV.  LOWER  SILURIAN.  —  Page.  210.  General  facts  respecting  the  Lower  Silurian.  — 
The  Eastern-border  region  in  American  geological  history.  — 210,  211.  Diversity  between 
the  Appalachian  and  Interior  regions  as  to  the  kinds  and  thickness  of  rocks.  —  211. 
Evidence  as  to  subsidences  through  the  Lower  Silurian  over  the  Appalachian  region.  — 
General  quiet  of  the  Lower  Silurian  era. 

DISTURBANCES  AT  THE  CLOSE  OF  THE  LOWER  SILURIAN.  —  Page  212.  Region  of 
principal  disturbance,  and  the  evidence. — 214.  Change  in  the  texture  of  the  rocks. — 
Displacements.  — 215.  Evidence  as  to  the  time  of  the  epoch  of  disturbance.  — 215,  216. 
Other  effects  of  the  disturbance.  — 216.  Characteristics  of  the  force  engaged.  —  216,  217. 
Contrast  in  the  condition  of  the  region  of  the  Stt  Lawrence  Gulf. — 217.  Cincinnati 
uplift.  —  218.  Events  in  Europe. 

XVI.  UPPER  SILURIAN. — Page  218.   General  characteristics  of  the  Upper  Silurian. 

—  Periods  of  the  Upper  Silurian.  —  Fourth  Period  of  the  Silurian,  or  first  of  the  Upper 
Silurian.  —  Epochs.  —  Kinds  of  rock,  of  the  Medina  and  Clinton  epochs.  —  219.  Rocks 
of  the  Niagara  epoch,  and  their  distribution;  thickness  at  Niagara  Falls. — 222.  Evi 
dence  from  structural  peculiarities.  —  223.  Plants. — Common  kinds   of  animal  life. — 
The  Sub-kingdoms    represented. — 230.    Facts  with  regard   to   the   Geography   of    the 
Niagara  Period.  —  1st;  2d;  3d;  4th;  5th;  6th.  —  230,  231.  Conclusions  as  to  geograph 
ical  changes  —  232.  Condition,  at  the  same  time,  of  the  region  of  the  St.  Lawrence  Gulf. 
Geographical  condition  of  Europe  and  Arctic  America. 

XVII.  UPPER  SILURIAN,  continued.—  Page  232.  Second  Period  of  the  Upper  Silurian. 


778  APPENDIX. 

—  232,  233.  Kinds  and  distribution  of  rocks.  —  234.  Important  minerals.  —  Mode  of  oc 
currence  of  the  gypsum,  and  its  origin.  —  Mode  of  occurrence  of  salt.  — 235.  Absence  of 
fossils.  —  Geography  and  origin  of  the  salt  in  the  beds.  — 236.  Third  Period  of  the  Upper 
Silurian. —  Kinds  and  distribution  of  rocks,  contrasting  the  Interior  and  Appalachian 
regions.  —  237.  Hocks  in  the  Connecticut  valley. — 238.  Abundance  of  life.  —  Promi 
nent  kinds  of  animal  life.  — 24'.'.   Geography;  contrast  with  the  Salina  Period. 

XVIII.  UPPEK  SILUKIAN.  — Page  241.  Fourth  Period  of  the  Upper  Silurian.  —  Kinds 
of  rocks  and  their  distribution.  —  242.  Plants.  —  242,  243.  Common  animal  fossils.  — 
243,  244.  Geographical  facts  connected  with  the  Oriskany  Period. 

Page  244.   Distribution  of  the  foreign  Upper  Silurian  formation.  —  245.  Plants.  — 
Invertebrates.  —  Vertebrates. — 249.  General  characteristics  of  the  Upper  Silurian  era. 

—  250.  The  Eastern-border  region. — 250,  251.  Conditions  of  the  North  American  Con 
tinent.  —  252.  New  feature  among  plants.  —  General  fact  with  regard  to  the  animal  life. 

—  253.  Climate. 

XIX.  DEVONIAN  AGE.  —  Page  254.  Origin  of  the  name  Devonian.  —  Transition  be 
tween  Silurian  and  Devonian.  —  The  four  Periods  in  the  American  Devonian.  —  Lower 
and  Upper  Devonian;  distinction  in  rocks.  —  First  Period  of  the  Devonian. —  Three 
Epochs.  —  Kinds  of  rocks  of  the  first  two  Epochs.  —  255.  Rock  of  the  third  Epoch,  and 
its  distribution.  —  257.  Plants;  Protophytes.  —  257,258.  Kinds  of  terrestrial  plants. — 
259,  200.  Characteristic  animal  life.  —  261.  The  first  of  Vertebrates  yet  found  in  Ameri 
can  rocks.  —  261-263.  The  first  of  the  grand  divisions  represented,  and  the  character 
istics  of  the  species.  — 263.  The  second  of  the  grand  divisions  mentioned,   and  their 
characters.  —  264.  Characteristic  of  the  tails  of  the  ancient  Ganoids.  —  Third  division  of 
fishes  mentioned.  —  265.  The  ordinary  fishes  not  represented  in  the  Devonian.  —  Geog 
raphy.  —  266.  Second  Period  of  the  Devonian,  and  its  epochs.  —  Kinds  of  rocks  and 
their  distribution. — 267.  Ripple-marks,  joints. — 268.  Economical   importance  of    the 
Black  Shale.  —  Kinds  of  terrestrial  plants.  —  269.  Lepidodendrids;  Sigillarids.  —  270. 
Ferns.  —  Kinds  of  Equiseta.  —  Kinds  of   Gymnosperms.  —  271,272.  Predominant  fos 
sils. —  273.  Kinds  of  Articulates. —274.  Fishes.  —  275.  Geography.  —  276.  Life. 

XX.  DEVONIAN  AGE,  concluded. — Page  276.  Third  Period  of  the  Devonian.  —  The 
two  Epochs.  —  Kinds  and  distribution  of  rocks.  —  277.  Life.  —  278,  279.  Geographical, 
conclusions. —  279.  Fourth  Period  of  the  Devonian. —  279,  280.  Kinds  and  distribution 
of  rocks.  —  281.  Geographical  conclusions.  —  282.  Foreign  Devonian;  what  called  in 
Great  Britain.  —  283.  Plants.  —  Animals:  Coral  reef s.  —  284.  Vertebrates;  Placoderms. 

—  286,  287.  General  Geographical  features  of  America.  —  287.  Condition  of  the  region 
of  the  Rocky  Mountains  and  Appalachians.  —  Condition  as  to  rivers. —  287,  288.  Geo 
graphical  changes.  —  Difference  in  rocks  between  the  Appalachian  and  Interior  regions. 

—  Geographical  condition  of  Europe.  —  288.  Great  steps  of  progress  in  the  life  of  the 
world.  —  288,  289.  Changes  in  the  life  of  the  world  during  the  Devonian  Age.  —  289, 
290.  Disturbances  closing  the  Devonian  Age. 

XXI.  CARBONIFEROUS  AGE. — Page   291.  The  three  Periods;  succession  of  phases. 

—  291,  293.  Principal  areas  in  North  America.  —293.  First  Period.  —  Contrast  between 
the   Interior    and   Appalachian    regions    in   rocks.  —  296.    Plants.  —  297.    Prominent 
feativres  of  the   animal   life. — 300.  Trilobites;  Insects.  —  301.  Classes   of  Vertebrates 
represented.  —  301,  302    The  first  American  Reptiles;   the  division  of  Reptiles  to  which 
it  belonged,  and  the  conditions  under  which  the  tracks  were  formed.  —  304,  305.  Geog 
raphy   of  North  America.  —  306.  Resemblance  of  American  and  Foreign  Subcarbon- 
iferous.  —  308,  309.  Disturbances  preceding  the  Carboniferous  Period.  —  309.  Second 
Period;  the  Coal  areas  of   North  America.   -310,   311.  Kinds  of    rocks. — 312.  Pro 
portion   between    the  thickness   of   the   Coal-measures  and  that  of   the  Coal-beds.  — 
Evidence  that  beds  are  true  Carboniferous.  —  Under-clays;  trunks  of  trees.  — 314,  315. 
Kinds  of  Coal.  —  317.  Vegetable  remains  in  Coal.  —  318.    Iron-ore   beds. — 321,  323. 
Kinds  of  plants,  and  the  groups  to  which  they  belong.  — Relation  in  size  to  modern 
Cryptogamous   vegetation.  —  324.    Lepidodendrids.  —  325.   Sigillarids.  —  326.     Ferns. 
—^327.  Catamites.  —  329.  Conifers. —331,  332     General  character  of  the  animal   life. 

—  336.  Kinds  of  Vertebrates  represented.  —  Fishes. — 336,  340.  Kinds  of  Reptiles.— 


APPENDIX.  779 

341.  Eosaurus.  —  344,   345.    Extent  of  Coal-measures   in  Great  Britain,  as  compared, 
with  those  of  Europe.  —  347,  348.  Relations  of  the  Coal-plants  to  the  American. 

XXIV.  CARBONIFEROUS  AGE,  continued.  —Page  351.  Evidence  that  Coal  is  of 
vegetable  origin.  —  Plants.  — 352.  Evidences  as  to  the  climate  of  the  Coal  Period.  —  352, 
353.  Atmosphere.  —  Influence  of  the  growth  of  plants  on  the  atmosphere. — 353,354. 
Influence  of  the  climate  on  the  growth  of  plants.  —  354,  355.  Geography  of  North 
America  through  the  two  Epochs.  —  356.  General  conditions.  — 356,  357.  Evidences 
as  to  the  phases  in  the  progressing  period.  —  357,  358.  Kate  of  progress.  —  358,  359. 
Character  of  the  submergences  in  Nova  Scotia  and  the  Interior  basin.  —  359,  360. 
Recapitulation  as  to  the  characteristics  of  the  era.  —  360.  Nature  of  Mineral  Coal.  — 
361.  Composition  of  wood  and  coal.  —  363,  364.  Change  of  wood  to  coal.  —  363.  Loss 
in  making  bituminous  coal  and  anthracite.  —  364,  366.  Origin  of  impurities. 

XXIII.  CARBONIFEROUS  AGE,  continued.  —  367.  Third   Period  of  the  Carboniferous 
Age.  —  Origin  of  the  name.  —  Distribution   of  rocks   in  America,  and  their  kinds.  — 
Life.  —  368.  Evidences  as  to  the  origin  of  the  beds.  -  369.  Distribution  of  the  Permian 
in  Europe.  —370.  Relations  of  the  plants  to  the  Carboniferous.  —  371.  General  character 
of  the  animal  life. 

373.  Thickness  of  the  Paleozoic  rocks.  —  373,  374.  Diversities  of  the  three  great 
regions  as  to  rocks.  —  380.  Id.  as  tQ  the  thickness  of  the  rocks.  —  380,  381.  Relative 
duration  of  the  Paleozoic  ages.  —  381.  Life;  system  of  progress.  —  382.  First,  charac 
teristics  mentioned  of  the  earlier  species.  —  Second  id.,  with  examples.  —  383.  Third, 
as  to  size.  —  Fourth  and  fifth,  as  to  the  characters  of  the  species.  —  384.  Example  of 
the  harmony  in  the  life  of  the  era. — Methods  of  extermination.  —  384,  385.  Charac 
teristic  animal  life  of  the  Paleozoic.  —  385.  The  sub-kingdom  of  animals  to  which  the 
long-lived  genera  belong. 

XXIV.  PALEOZOIC    TIME.  —  Page   389.    Course   of   geographical   progress.  —  390. 
Mountains.  —  390,   391.  Rivers.  —  391.  Evidences   as  to  extent   of    subsidence    in  the 
course  of  the   Paleozoic.  —  392.  Oscillations.  —  392,   393.  Uplifts   and   dislocations.— 
393.  Direction  of  oscillations. — Relation   in  direction  to  the  forces  acting  in  Archaean 
time.  —  394.  Evidences  as  to  cotemporaneous  movements  in  Europe  and  America.  — 
Contrast  between  Europe  and  America.  —  395.  Results  of  the  disturbance  closing  the 
Paleozoic.  —  395,  396.  Evidence  as  to  extent  of  flexures  in  the  Coal-measures  of  the 
Appalachians.  —  398.    The   whole    Paleozoic    involved   in    the   flexures.  —  Facts   with 
regard  to   the    Appalachian    flexures.  —  First;  second;  third ;  fourth  ;  fifth  ;  sixth. — 
398,  399.  Examples   of  great  faults.  —  400.  Alterations   of  rocks   by  consolidation. — 
Evidences  as  to  debituminization  of  coal. — Crystallization  or   metamorphism.  — 400, 
401.  Characteristics  of  the  force  engaged :  first ;  second  ;  third  ;  fourth  ;  fifth.  —  Change 
in  the  scene  of  geological  progress  in  North  America.  —  402.  Disturbances  in  foreign 
countries. 

XXV.  REPTILIAN   AGE. — Page  403.    Mesozoic   Time.  —  Grand    characteristics  of 
the  Reptilian  Age.  —  The  three  Periods.  —  The  first  Period.  -  403,  404.  Distribution  of 
the  rocks  in  eastern  North  America.  —  404.  Kinds  of  rocks.  —  405.  Markings  on  the 
rocks.  — Rocks  west  of  the  Mississippi.  — 407.  General  fact  with  regard  to  the  life  of 
the  American  Triassic.  —  407,  408.  Plants,  as  contrasted  with  the  Carboniferous.  —  409, 
410.  Characteristics  of  the  Ammonite  group;  —  410,  411,  Articulates.  —  411.  Classes  of 
Vertebrates  represented.  —  Characteristics  of  the  Fishes.  —  412.  Kinds  of  evidence  of 
the  presence  of  Reptiles.  —  412,  413.  Kinds  of  Amphibian   Reptiles  indicated.  —  413. 
Id.   of   Dinosaurs. — 414.  Of   Birds.  —  415.   Of   Mammals.  —  417,  418.  Igneous   rocks 
associated  with  the  sandstone  on  the  Atlantic  Border. — 419.  Proofs  of   heat. —420. 
Conclusion  from  the  position  of  the  areas.  —  From  the  paucity  of  animal  remains.— 
Id.  from  mud-cracks,  etc.  —  421.  Id.  from  the  thickness  of  the  beds.  —  Id.  from  the 
trap-dikes,    and  the  tilted  position  of    the  sandstone.  —  422.  Ancient  channel   of  the 
Hudson  River,   now  submarine. — 423.  Condition  over  the  Triassic  areas  west  of  the 
Mississippi.  —423,  424.  Distribution  of  the  European  Triassic.  — 425.   Prevailing  forms 
of  plants.  —  426,  427.  Characteristic   animal  life  — Vertebrates. — 429,  430.    General 
observations  on  the  Life.  — 430.  Climate. 


780  APPENDIX. 

XXVI.  REPTILIAN  AGE,   continued.  —  430.  Second  Period  of  the  Beptilian  Age.— 
431.  Question  as  to  rocks  of  this  period  existing  or  not  on  the  Atlantic  Border.  —  Id. 
west  of  the  Mississippi.  — 432.  Life:  Ammonites;  Belcmnites.  —  433.  Foreign  Jurassic. 

—  434.  Subdivisions  into  three  Epochs. — 436.  Characteristic  plants;  whether  Angio- 
sperms,    or   not.  —  437,    438.  Animal  life.  —  439,    440.  Characteristic  Cephalopods.  — 
441.  Characteristic  kinds  of  Fishes.  —  442,  443.  Varieties  of  Reptile  life:  Ichthyosaurs ; 
Plesiosaurs.  —  444.  Crocodilians.  —  444,    445.  Carnivorous  and  herbivorous  Dinosaurs. 

—  446.  Pterosaurs.  —  446.  Kinds  of  Birds. — 440-448.  Types  of  Mammals  represented. 

—  450,  451.  Conclusions,  with  regard  to  American  Geography.  —  451.  Different  char 
acter  of  European. — 451,  452.  Characteristic  life.  —  452.  Evidences  as  to  climate. — 
452,  453.  Disturbances  and  mountain-making  closing  the  Jurassic  period. 

XXVII.  REPTILIAN  AGE,  concluded.  —  Page  453   Third  Period  of  the  Reptilian  Age. 

—  454.  Origin  of  name  Cretaceous. — Epochs  in  America.  —  Distribution  of  the  beds. 

—  455.  Kinds  of  rocks.  —  458,  459.  Change    in   the  vegetation    of  America  with  the 
opening  of  the  Period.  —  460.  Important  Protozoans.  — Characteristic  Mollusks.  —  462. 
Cepholopods.  —  Fishes.  —464,  465.  Kinds  of  Reptiles.  —  466.  Kinds  of  Birds. —469. 
Rocks  of  the  foreign  Cretaceous;  chalk;  flint.  —  471.  Plants.  —  Rhizopods.  —  472.  Spic- 
nles  of  Sponges.  —  473.  Fishes.  —  474.  Reptiles.  —  477.  Origin  of  the  chalk.  —  478.  Id. 
of  the  flint.  —  478,  479.  Conclusions  as  to  Ameriqan  Geography.  —  480.    Id.  Foreign 
Geography.  —  480,    481.   Evidences   as    to   climate.  —  481.    Relative  duration  of  the 
Paleozoic  and  Mesozoic.  — 481,  482.  Geography  of  North  America. — 482.  Contrast  of 
Mesozoic  with  Paleozoic  lire,  as  to  plants.  —  Id.   as  to  Crinoids  and  Brachiopods.  — 
483.  Id.  as  to  Cephalopods.  —  484.  Id.  as  to  Fishes.  —  484,  485.  Id.  as  to  Reptiles.  — 
485,  486.  Id.  as  to  Birds.  — 486,  487.  Evidence  of  disturbances  during  Mesozoic  time.  — 
487,488.  Disturbances  closing  Mesozoic  time. — 488.  Cause  of  destruction  of  life  clos 
ing  the  Cretaceous  era. 

XXVIII.  CEXOZOIC  TIME.  —  Page  488.  Contrast  in  life  between  Cenozoic  and  Meso 
zoic   time.  —  489.  The   two   Ages   of    the   Cenozoic. — The  first  of    these   Ages:  its 
Periods. — 490.  Subdivisions   of    the  American   Tertiary. — 490,  491.  General   distri 
bution  of  the  rocks.  —  492.  Kinds  of  rocks.  —  496.  Protophytes.  —  496,  497.  General 
character  of  other  plants.  —  501,  502.  Kinds  of  Vertebrates.  —  503,  504.  Eocene  Mam 
mals. —  505.  Horses.  —  506,  507.  Miocene  Mammals.  —  507,  508.  Pliocene  Mammals. — 
511,    512.  Foreign  Tertiary  rocks.  —  512.  Importance   of  Nummulites   in   the  foreign 
Tertiary.  —  514.  Contrast  between  the  Eocene,  Miocene,  and  more  modern  vegetation 
of  Europe. —516.  Tertiary  Birds.  —  516,  517.  Mammals.  —  518.  The  Dinothere.  —  520, 
521.  American  Geography.  —  522,  523.  European  Geography.  —  523,  524.  Disturbances 
during  the  Tertiary  in  North  America.  —  525.  Id.  in  Eui'ope.  — Elevation  of  mountains. 

—  526.  Evidence  as  to  climate  in  America  and  Europe. 

XXIX.  CENOZOIC  TIME,  continued. — Page  527.  Three  Periods  of  the  Quaternary. 

—  Drift.  — 528.  Its  distribution.  — 529.  Its  material.  —  Its  source  and  course  of  travel. 

—  530,  531.  Character  and  general  direction  of  scratches.  — 532,  533.  Distribution  in  for 
eign  countries.  —  533.  Fiords.  —  554.  The  two  theories.  —  Arguments  for  and  against 
the  Iceberg  theory.  —  535.  The  Glacier  theory,  how  sustained.  —  536.  An  inclined  sur 
face  beneath  not  required  for  motion.  —  537.  Probable  head  of  the  New  England  gla 
cier. —  538.  Method  of  abrasion,  and  of  gathering  material  for  transportation.  —  539. 
Aid  of  icebergs.  —  539,  540.    Geographical  conditions  during  the  Glacial  era. — 541. 
Source  of  the  cold.  —  542,  543.  Second  Period  of  the  Quaternary.  —  General  character 
of  the  era.  —  543.  Subdivisions.  —  Kinds  of  deposits  and  their  distribution.  —  544,  545. 
Terraces  along  rivers  and  lakes.  —  545,  546.  Character  of  the  Diluvian  deposits.  — 547. 
Id.  of  the  Alluvian.  —  548.  Level  of  the  formations.  —  549.  Sea-border  formations.  — 
550.  Their  height.  —  551,  552.   American  Geography.  —  543,  544.  Circumstances  attend 
ing  the  Diluvian  depositions;  the  flood. — 554.  Exterminations.  —  555,556.  Champlain 
deposits  in   foreign  countries.  —  556.  Third  Period.  —  556,  557.  Kinds  of  deposits.  — 
558,559.  Terraces;  their  formation.  —  560.  Geographical   conditions  in  the  early  part 
of  the  Recent  Period  in  North  America.  —  561,  562.  Evidence  as  to   a  second  Glacial 
Epoch  in  Europe  and  Great  Britain.  —  562.  Terraces;  dwindled  rivers. 


APPENDIX.  781 

XXX.  CENOZOIC  TIME,  continued.  —Pages  563-565.   Mammalian  life  of  the  Qua 
ternary,  in  Europe  and  Siberia.  —  565-567.  Id.  in  North  America.  —568-570.  Id.  in 
South  America.  —  570,   571.  Id.  in  Australia.  —  571.  General  character  of  the  life.  — 
Climate. — 572.  Evidence   from  the  life  as  to  the  Reindeer  era.  —  573.  Ancient  relics 
of  Man.  —  574.  Subdivisions  of  the  "  Stone  Age." — 574.  Occurrence  of  human  relics 
with   those   of   extinct    Quaternary   Mammals. — 574,    575.    Human   skeletons.  —  576. 
Neolithic  remains.  —  578.  Man's  relations  to  the  system  of  life.  —  579,  580.  Extinction 
of  species  in  modern  times.  —  582.  Modern  changes  pf  level  of  two  kinds;  in  Sweden.  — 
583.  Id.  in   Greenland,   and  the  Pacific.  —  584,  585.  Id.  at  Pozzuoli.  —  586.  Probable 
time-ratio  for  the  Paleozoic,  Mesozoic,  and  Cenozoic.  —  586.  Geographical  progress  in 
the  Tertiary.  —  586,  587.  Great  events  in  the  Quaternary.  —  587.  Agencies  intensified 
in  the  Quaternary.  —  588.  Culmination  of  Mammals. 

XXXI.  GEOLOGICAL  HISTOKY.  — Page  590.  Evidence  from  Niagara  as  to  the  length 
of    Geological   time. — 591.    Evidence   from   Coral-reefs. — 593.   Fact  of  progress  in 
the  life  of  the  globe.  —  593,  594.  Relation  of  progress  to  changes  in  climate,  etc.  — 
594.  The  progress  systematic.  —  595.  Examples  of  a  parallelism  with  the  successive 
phases  in  embryonic   development. — 596.  Progress  in  cephalization.  —  597.  Compre 
hensive  types.  —  597,  598.  The  progress  involved  the  culmination  and  decline  of  many 
types.  —  598.  The  earlier  species  under  a  type  not  necessarily  the  lowest.  —  599.  Con 
tinental  peculiarities  continued.  —  Representative  species  in  different  regions  through 
migration.  —  600.    The  same  may  exist  independent   of   migrations.  —  600,  601.   The 
geological   record   imperfect.  —  602.   Examples   of    abrupt   transitions.  —  603.   Abrupt 
transition  as  regards  Man. — 603,604.  First  conclusion ;  second;  third;  fourth. 

XXXII.  DYNAMICAL   GEOLOGY.  —  Page   605.    Subjects   treated   under  Dynamical 
Geology. — 606.  LIFE:    its   protective   effects.  —  607.  Its   transporting  effects. — 607, 
608.   Its  destructive   effects.  —  608,    609.   Conditions   determining   its   importance  in 
rock-making. — 609.  Limiting  influence   of  climate. — 610.  Id.  of   soil.  —  Id.   of   the 
nature  and  purity  of  the  water.  —  610,  611.  Id.  of  the  temperature  and  depth  of  the 
ocean.  —  612.  Kinds  of  organic  products  from  plants;  shells;  corals:  bones;  diatoms; 
sponges.  —  613.  Reasons  why  aquatic  species  have  contributed  most  to  rocks.  —  614.  The 
grade  of   species  best  fitted   for  rock-making.  —  Methods  of   fossilization.  —  615.  The 
method  of  rock-making  in  the  case  of  minute  fossils. — Id.  in  the  case  of  corals  and 
shells.  —  616.  Formation  of  peat. — 617.  Causes  limiting  the  distribution  of  coral  reefs 
and  islands.  —  618.  Description  of  a  coral  island.  — 619.  Reef -rock.  —  620    Beach-made 
rock.  —  620-622.  Formation  of  the  coral  structure.  —  622.  Kinds  of  coral-reefs.  —  623. 
Extent  and  thickness.  —  624.   Origin  of  the  forms  of  reefs.  —  626.  Recapitulation.  — 
627.  COHESIVE  ATTRACTION:  its  identity  with  the  poAver  of  crystallization.  —  Cleavage 
in  minerals  and  in  rocks.  —  628.  Cause  of  the  concretionary  structure;  origin  of  the 
columnar  forms  of  trap.  —  630.  THE  ATMOSPHERE:  its  destructive  effects  through  the 
transportation  of   sands.  —  631.  Its   method  of  adding  to  lands. — 631,  632.  Dunes. — 
Dust-showers.  —  634.  Effects  of  changes  in  atmospheric  pressure. 

XXXIII  WATER.  —Page  635.  Source  of  the  water  of  RIVERS,  and  the  conditions 
on  which  the  amount  depends. —636,  637.  Floods  and  flow.  —  Pitch  of  rivers.  —  637, 
638.  General  effects  of  erosion. —  638.  Progress  of  erosion  in  forming  valleys. —639. 
Distinction  of  torrent-portion  and  river-portion. —643.  Pot-holes.  —  644.  Conditions 
on  which  the  topographical  effects  of  erosion  depend.  —  647.  Extent  of  erosion.  —  647, 
648.  Materials  transported. —649.  Origin  of  alluvial  formations,  and  their  features. 

—  651.  Origin  of  deltas.  —  653.  The  manner  in  which  waters  become  subterranean. — 
653,  654.  The  principles  on  which  Artesian  wells  are  based.  —  654.  Erosion.  — 655.  The 
three   kinds   of   land-slides.  —  Other  effects  of   land-slides  —656,  657.    Moisture  con 
fined  in  rocks.  —657.  The  OCEAN:  means  by  which  the  ocean  exerts  mechanical  force. 

—  658.  General  system  of   currents;    their  universality;    rate  and   position.  —  659.   In 
what,  way  their  positions  might  be  changed. —Effects  of  ordinary  tidal  action.  —  660. 
Translation-character  of  waves  on  coasts.  —  In-flowing  currents.  —  660,  661.  Eagre.  — 

—  661.  Out-flowing   currents.  —  Waves,  their  force. —661,  662.    Currents  caused  by 
winds.  —  662.  Under-currents  id.  —  Earthquake-waves. 


782  APPENDIX. 

XXXIV.  WATER,  concluded.  —  663.   Erosion   by  currents. —663,  664.   Erosion   by 
waves ;  its  extent ;  height  of  line  of  greatest  action  above  low-tide  level.  —  665.  Amount 
of  transportation  by  oceanic  currents,  and  the  materials  transported.  —  Transportation 
by  waves.  —  666.  Formations  over  the  bed  of  the  ocean.  —  667.  Formations  on  sound 
ings  and  along  coasts.  —  Beach  deposits.  —  668.  Action  of  tidal  and  wind  currents  in 
determining  the  forms  of    accumulations.  —  669.  Results   from    the   combination  with 
those  of  the  currents  of  rivers.  —  669,  670.  The  consequent  features  of  the  eastern  coast 
of  the  United  States. — Rill-marks.  —  671.  Oblique  lamination. — 672.  Ripple-marks; 
rill-marks. — 672,   673.  Erosion  during  the  slow  sinking  or  rising  of   a  continent,  or 
when  slightly  submerged.  —  673.  Effects  if  the  surface  of  a  continent  were  nearly  level, 
there  being  no   mountains.  —  674.   Effects  of  water  freezing.  —  Effects  from  floating 
ice  of  rivers  and  lakes.  —  675.  Nature  of  GLACIERS.  —677,  678.  General  characters  and 
movement.  —  678,  679.  Circumstances  influencing  their  formation.  —  679.  Law  of  flow. 

—  080.  Rate  of  flow.  —  681,  082.  The  three  principles  on  which  the  capabilitv  of  mo 
tion  depends. — 682,  683.  Cause  of  the  veined  or  laminated  structure  of   a  glacier. — 
683,  084.  Method  of  transportation,  and  the  materials  transported.  —  684,  685.  Methods 
and  results  of  erosion.  —  686.  Origin  and  effects  of  ICEBERGS. 

XXXV.  WATER  AS  A  CHEMICAL.  AGENT.  —  See   headings   through   this   chapter, 
pages  687  to  696,  for  the  Synopsis. 

XXXVI.  HEAT. — Page  697.  Three  sources  of  heat. — From  the  sun. — 698.  From 
chemical  and  mechanical  action.  —  699.  From  the  earth's  internal  heat.  —  Proofs  of  the 
existence  of  internal  heat. — Rate  of  increase  with  the  depth.  —  700.  Evidence,  from 
volcanoes,  of  internal  heat.  —  700,  701.  Effects  from  expansion  and  contraction.  —  702. 
A  volcano ;  lava ;  cinders ;  crater.  —  Ejections ;  tufa.  —  703.  General  geographical  dis 
tribution  of  volcanoes,  and  where  few.  — 704.  Material  of  a  volcanic  mountain;  lava- 
cones. —  706.  Tufa-cones.  —  Cinder-cones. — Mixed-cones.  —  707.  Lava;  scoria.  —  Liq 
uidity  of  lava. — 708.  Vapors  or  gases. — 708,   709.  Effects  of  vapors.  —  709.   Move 
ments. —  710,  711.  Causes  of  eruptions.  — 714.  Eruptions  mostly  through  fissures,  and 
results.  —  715.  Origin  of  forms  of  volcanic  cones.  —  716.  Non-volcanic  igneous  ejec 
tions.  —  717.  Mode  of  occurrence  of  beds.  —  718.  Solfataras.  —  719,  720.  Hot  springs. 

—  Cause  of  action  of  Geysers.  —  721,  722.  Sources  of  igneous  eruptions. 

XXXVII.  METAMORPHISM.  —724,  725.  Effects.  — 725.  Changes  by  loss  of  water,  or 
other  vaporizable  ingredient.  —  725,  726.  Obliteration  of  fossils,  and  crj'stallization.  — 
726.  Origin  of   metamorphic  changes ;   amount  of  heat   required.  —  727,  728.    Effects 
from  the  water  present.  —  729.  Conditions  attending  metamorphism  productive  of  heat. 

—  730.    Diverse  effects.  —  731.    Veins.'  — Three   methods  of   filling  veins.  —  732.    The 
method  by  which  veins  have  most  commonly  been  formed,  and  evidence  of  filling  by 
successive  supplies  of  material.  —  Sources  of  material,  and  how  carried  into  open  spaces. 

—  733.  Alterations  of  veins.  —  734.  Faulted  veins 

XXXVIII.  THE  EARTH  A  COOLING  GLOBE  :  ITS  CONSEQUENCES.  —  735.  Seat  of  the 
organizing  agency  of  contraction. — The  resulting  force.  —  736,737.    The  earth's  in 
terior.  —  738.  Formation  of  continents  and  oceanic  basins.  —  739.  Results  of  contraction. 
Flexures.  —  740,    741.   Fractures;  faults.  —  741,  742.  Earthquakes.  —  742.  Earthquake 
oceanic  waves.  — 743.  Cause  of  earthquakes.  —  744.  Evolution  of  the  eai-th's  features; 
facts  to  be  explained  respecting  reliefs  of  continents;  concerning  position  of  volcanoes; 
concerning  the   forms   of  the   folds   in  the  Appalachians;  concerning  the  relation  of 
ancient  and  later  changes  of  level.  —  745.  Concerning  the  courses  of  the  earth's  feature- 
lines;  concerning  a  belt  of  volcanic  islands.  —  Effect  of  pressure  against  the  continental 
borders.  —  745,  746.  Relation  of  effects  to  extent  of  the  oceans  adjoining.  —  746.  Ex 
amples  of  the  comprehensiveness  of  the  action.  —  748.  Why  America  was  simple  in  its 
system  of  evolution. 

XXXIX.  MAKING  OF  MOUNTAIN  CHAINS.  —  Page  748.  First  step  in  mountain-mak 
ing. —  749.  Effect  on  the  bottom  of  the  geosynclinal;  reinforcement  of  the  heat.  — The 
consequence  of  the  weakening  below.  —  The  kind  of  mountain  made.  — 750.  A  mountain 
chain  a  combination  of  synclinoria.  —  750,  751.  Metamorphism  and  attendant  effects.— 
751.  Addition  of  the  synclinorium  to  the  stable  part  of  the  continent;  examples.  —  751, 


APPENDIX.  783 

752.  Geanticlinals  concerned  in  mountain-making. — 752.  Anticlinoria  of  the  Atlantic 
Border  of  North  America.  —752,  753.  What  effects  greatest  in  the  Tertiary  and  Qua 
ternary. —  753.  Fractures;  igneous  ejections.  —  754.  Mountain-making  slow  work. — 
Changes  in  climate,  from  the  slow  refrigeration  of  the  earth.  —  755.  The  Lyellian  prin 
ciple.  —  Effects  from  change  of  oceanic  currents;  examples.  —  756.  Progress  in  accord 
ance  with  the  universal  law  of  development,  as  shown  in  the  features  of  the  continents; 
and  in  the  history  of  fresh  waters.  —  757.  As  shown  in  the  climates;  and  the  organic 
history.  —  757,  758.  Conclusion. 

The  pages  under  the  heading  of  "Effects  Referred  to  their  Causes,"  may  be  used  for 
a  general  review  of  the  Dynamical  part  of  the  work. 

D.  —  Authorities  for  the  Sections,  Views,  and  Figures  of  Fossils  in 

this  work. 

The  following  are  the  authorities  for  the  more  important  illustrations  of  this  Manual. 
The  works  mentioned  are  those  from  which  the  figures  or  views  have  been  taken;  and, 
although  generally  the  original  publications,  they  are -not  all  so.  When  the  figures  have 
been  made  from  original  drawings  not  before  published  (the  fact  with  regard  to  about 
150),  the  reference  is  distinguished  by  annexing  a  point  of  interjection  ( !).  Many  of 
the  new  figures  by  Meek  under  the  Mesozoic  and  Cenozoic,  are  from  a  manuscript  Pale- 
ontological  Report  of  Lieut.  G.  K.  Warren's  Expedition  to  the  Upper  Missouri,  by 
Messrs.  Meek  and  Hayden,  the  publication  of  which,  unfortunately  for  science,  has  been 
deferred. 

The  authorities  mentioned  in  the  tables  that  are  not  the  original  sources  of  the  figures 
cited,  are  Vogt,  Naumann,  Phillips,  Bronn,  Pictet,  and,  in  part,  D' Orbiyntj  and  Mur- 
chison.. 

1.  List  of  the  Works  from  ivhich  the  Illustrations  have  been  taken. 
Anthony,  J.  G. :  Amer.  Jour.  Sci.,  II.  i. 

Author:  Report  of  Wilkes's  Exploring  Expedition  on  Geology;  id.  on  Zoophytes; 
id.  on  Crustacea;  American  Jour.  Sci.,  II.  v.  386;  III.  iv.  v. 
Bailey,  J.  W. :  Amer.  Jour.  Sci.,  II.  i. 
Bayle :  Bull.  Geol.  Soc.  de  France,  1856-57 
Billings,  E. :  Rep.  Geol.  Canada;  Canadian  Journal. 
Bradley,  F.  H. :  Amer.  Jour.  Sci.,  III.  iv. 
Bronn,  H.  G. :  Lethsea  Geognostica. 
Buckland,  W. :  Bridgewater  Treatise. 
Conrad,  T.  A. :  Jour.  Acad.  Nat.  Sci.  Philad. 
Cope,  E.  D.:  Worthen's  Report  on  the  Geology  of  Illinois,  vol.  ii. 
Cox.  E.  T. :  Owen's  Rep.  Geol.  Kentucky,  vol.  iii. 
Crisand,  E.:  Engraver  at  New  Haven,  Conn.,  on  work  for  0.  C.  Marsh. 
Darwin,  C. :  on  Coral  Islands. 


Davidson,  T.:  Publications  of  the  Paleontographical  Society. 

Dawson,  J.  W.:  Acadian  Geology;  Quart.  Journ.  Geol.  Soc.;  Fossil  Plants  of  the 
Devonian,  etc.,  formations  of  Canada;  Amer.  Jour.  Sci.,  III.  i.  256. 

D'Orbigny,  A.:  Paleontologie  et  Geologic. 

Edwards,  M.,  and  Haime:  Publications  of  the  Paleontographical  Societv;  Archives 
du  Mus.  d'Hist.  Nat. 

Emmons,  E. :  Rep.  Geol.  New  York;  Rep.  Geol.  N.  Carolina. 

poster  &  Whitney:  Rep.  Geol.  Lake  Superior  District. 

Geinitz,  H.  B.:  Verstein.  des  deutschen  Zechsteingebirges,  etc.,  1848. 

Sibbes,  R.  W.:    Fossil  Squalid*  of  United  States,  Jour.  Acad.  Nat.  Sci.  Philad., 

lo-t  J. 

Hall,  J.:  Rep.  Paleontology  of  New  York:  Rep.  Geol.  Iowa;  Regents'  Rep.  on  State 
Cabinet  of  New  York;  Canadian  Nat,  and  Geol. 
Harger,  0.:  Amer.  Jour.  Sci.,  III.  vii. 
Hartt,  C.  F. :  Dawson's  Acadian  Geology,  1868. 


784  APPENDIX. 

Hayden,  F.  V. :  Report  on  the  Geological  Survey  of  the  Territories  for  1873 

Hitchcock,  E. :  Rep.  Geol.  Massachusetts;  Fossil  Footmarks,  4to,  18i8;  Iclmologv  of 
New  England,  4to,  1858;  On  Surface  Geology;  Amer.  Jour.  Sci.,  xv. 

Hitchcock,  Jr.,  E. :  Amer.  Jour.  Sci.,  II.  xx. 

Holmes,  "W.  H. :  Hayden  and  Gardner's  Report  on  the  Geological  and  Geographical 
Survey  of  the  Territories  for  1873. 

Hooker,  J.  D. :  On  the  Wehvitschia ;  Hooker's  edition  of  the  General  System  of 
Botany  of  Maout  and  Decaisne,  1873. 

Ives,  J.  C. :  Colorado  Exploring  Expedition. 

Jackson,  W.  H.:  Photographs  connected  with  the  Geological  Survey  of  the  Territo 
ries  under  F.  V.  Hayden. 

Johnson,  G. :  On  Zoophytes. 

Jones,  T.  R. :  Paleontology  of  Canada,  Decade  III. 

Konmck,  L.  de :  Aniin.  Foss.  Carbonif. ;  Recherches  An.  Foss. ;  Mon.  Productus  & 
Chonetes. 

Lea,  I.:  Fossil  Footmarks  in  the  Red  Sandstone  of  Pottsville,  fol. 

Leidy,  J. :  Trans.  Amer.  Phil.  Soc.  Philad. ;  Smithsonian  Contrib.,  1853;  Geological 
Survey  of  the  Territories,  4to,  vol.  i. 

Lesley,  J.  P.:  Manual  of  Coal  and  its  Topography,  1856. 

Lesquereux,  L. :  Rogers's  Rep.  Geol.  Penn. ;  Owen's  Rep.  Geol.  Kentucky;  Owen's 
Rep.  Geol.  Arkansas. 

Logan,  W. :  Rep.  Geol.  Canada;  Canadian  Naturalist  and  Geologist.  Montreal;  Quart. 
Jour.  Geol.  Soc.,  1852-1857;  Esquisse  Geol.  du  Canada. 

Lyell,  C. :  Manual  of  Elementary  Geology. 

Mantell,  G.  A.:  Medals  of  Creation;  Wonders  of  Geology. 

Marsh,  0.  C. ;  Amer.  Jour.  Sci.,  II.  xxxiii.;  III.  iii.  and  v. 

Meek  &  Worthen :  Rep.  Geol.  Illinois.  1866-1873. 

Meek  &  Hayden:  Amer.  Jour.  Sci.,  II.  xxxiii. 

Meyer,  H.  von:  Fauna  der  Vorwelt. 

Morton,  S.  G. :  Jour.  Acad.  Nat.  Sci.  Philad.,  viii. ;  Amer.  Jour.  Sci.,  II.  xlviii. 

Murchison:  Siluria,  8vo. 

Mather,  W.  W. :  Rep.  Geol.  New  York. 

Naumann,  C.  F. :  Lehrbuch  der  Geognosie,  Leipzig,  1850. 

Newberry,  J.  S. :  Annals  of  Science,  Cleveland,  1852;  Report  on  the  Geology  of  Ohio : 
Dawson's  Report  on  Devonian  Plants,  Geol.  Survey  of  Canada,  1871. 

Norwood  &  Owen:  Amer.  Jour.  Sci.,  II.  ii. 

Owen,  D.  D. :  Rep.  Geol.  Wisconsin,  etc. 

Owen,  R. :  British  Fossils;  Intellectual  Observer,  December,  1862. 

Percival,  J.  G. :  Report  on  the  Geology  of  Connecticut,  8vo,  1842. 

Phillips,  John:  Manual  of  Geology;  Geology  of  Oxford,  1871. 

Pictet:  Traite"  du  Paleontologie. 

Prout,  H.  A. :  Amer.  Jour.  Sci.,  II.  xi. 

Redfield,  J.  H. :  Ann.  Lyceum  Nat.  Hi-t.  New  York,  vol.  iv. 

Roemer,  F. :  Kreidebildungen  von  Texas. 

Rogers,  H.  I).:  Rep.  Geol.  Pennsylvania. 

Rogers,  H.  D.  &  W.  B.:  Trans.  Amer.  Assoc.  Geol.  and  Nat.,  1843. 

Salter,  J.  W.:  Quart.  Journ.  Geol.  Soc.,  1861;  Pal.  Canada,  Decade  I. 

Sanford,  L. :  Engraver  at  NeAv  Haven,  Conn.,  on  work  for  the  Author. 

Scudder,  S.  H. :  Dawson's  Acadian  Geology;  Worthen's  Rep.  Geol.  Illinois,  vol.  iii. 

Sharpe,  D. :  Quart.  Journ.  Geol.  Soc.,  1847. 

Smith,  Russell:  Amer.  Jour.  Sci..  II.  ii.  130. 

Smith,  S.  J.:  Amer.  Jour.  Sci.,  III.  i.  44. 

Strickland,  H.  E. :  Dodo  and  its  Kindred. 

Swallow,  G.  C. :  Rep.  Geol.  Missouri. 

Taylor,  R.  C. :  Statistics  of  Coal. 

Thompson,  Z. :  History  of  Vermont,  Appendix. 


APPENDIX. 


785 


Tyndall,  J.:  Glaciers  of  the  Alps. 

Tuomey  &  Holmes:  Fossils  of  South  Carolina. 

Vanuxem:  New  York  Geological  Report. 

Verneuil,  E.  de :  Bull.  Geol.  Soc.  de  France. 

Vogt,  C. :  Lehrbuch  der  Geologic. 

Wyraan,  J. :  Amer.  Jour.  Sci.,  II.  xxv. 


List  of  Authorities. 
FRONTISPIECE.  —  From  a  photograph.     Riviere. 


PAGE    FIG. 

20     17 Percival. 

32     27 Author. 

34     28 Author. 

38     30 Author. 

42    31 Author. 

82  61(7,  e Whitney. 

83  63 Meek. 

84  64,65 Author. 

87  84,  85 Author. 

88  88 Hall. 

80  (  88  A Author. 

5J  j  89 Mather. 

90     90-93 De  la  Beche. 

93  98 H.  D.  &  W.  B.  Rogers. 

94  100 Logan. 

99     109 D.  Sharpe. 

108  115 Author. 

109  118 Hitchcock. 

110  120-122 Author. 

111  124-129 Author. 

112  130-132 Author. 

117  (  137,  138 Author. 

Li  j  144,  146 Hall. 

(145 Vogt. 

118  {  148 Buckland. 

(149 Hall. 

120  161-169 Author. 

127  169  A Johnston. 

130  169  B Johnston. 

131  170-182 D'Orbignr. 

132  184-186 Ehrenberg. 

133  188 Author. 

134  197,  198 Bailev. 

144  202! Meek,  Author. 

14o  (  203,  204 D.  D.  Owen. 

*°  J205 Logan. 

349     206 Author. 

!208 Foster  &  Whitner. 
209,  210 Emmons. 
211 C.  Whittleser,  in  Owen. 

154    212,  213 :.. Emmons. 

158     214 Dawson. 

165     215 Logan  (altered). 

171  218-225 Davidson. 

172  226-237 Davidson. 

17o  (  238,  239 Naumann. 

10  \  240-246 Davidson. 

1 74J  247  ! Sanford. 

'*  |  248-250 Hartt 

17-  251! Meek. 

/0  J252,  253 Billings. 

176  258,  259 Logan. 


17 


PAGE    FIG 

(261 Billings. 

I  262-265 Hall. 

^266! Bradley. 

|  208,  269 D.  D.  Owen. 

I  270.. Prout. 

(  272,  273 Meek  &  Harden. 

178  274 Meek  &  Harden. 

179  276-282 Murchison. 

183    283! J.  I).  Whitney. 

187  283-287 Hall. 

(285  Hall. 

188  I  296-298 T.  R.  Jones. 

(299-302 Billinirs. 

(  304,  305 Billings. 

1Q1  I  306-311,314,315 Hall. 

L  i  312,  313 Salter. 

(316 T.  R.  Jones. 

196     316  A Author. 

198  316  B,  C Hall. 

(317,  318 Hall. 

199  I  319-321 ! Meek. 

(  322-325 Billings. 

f  326-329 !  331-336 ! Meek. 

330 Salter. 

200  \  337-340 Hall. 

341,  342 Hall. 

(343 Billings. 

f344!    346! Meek. 

|  345,347 Salter. 

201  •{  348-352 Hall. 

|  353-357 Hall. 

[358! Author. 

(  360.  362,  364-366 Hall, 

202^361!  363! Meek. 

(367 T.  R.  Jones. 

203  368 Hall. 

(369-371,  373 Hall. 

204  <  372.! Meek. 

(374 Hall. 

375 J.  G.  Anthonv. 

376-379 Hall. 

206  '  380 !  381 ! Meek. 

on_  (  388,  3893  391-394 Murchison. 

^'  \  390 Davidson. 

213  395  A,  B,  C Author. 

215  395  D Logan. 

910  J  396 Hall. 

219  j  397 Hall 

223  399-403 Hall. 

i  405-409 Hall. 

|  410-422 Hall. 

(422  A Hall. 

225^423-428 Hall. 

(429-431 Hall. 


205 


224 


786 


APPENDIX. 


227 


238 


246 


247 
255 

257 

258 


PAGE    FIG. 

(  432-439,  441-444 .Hall. 

296  {  440 ! Meek. 

(444  A! Meek. 

445-447 Hall. 

448-452 Hall. 

233  453,  454 Hall. 

234  455,  456 Hall. 

457 Hall. 

|  458! Meek. 

(459,  460 Hall. 

239  I  460-469  ! Meek. 

(471-474! Meek. 

242  475,  476! Meek. 

f  477,  478 M.  Edwards  and  Haime. 

|  479 Murchison. 

480 Bronn. 

481 Naumann. 

482  Salter. 

483 Murchison. 

484 Salter. 

484! Meek. 

484  A  a-d,  h,  i,  k-o!. .  .M.  C.  White. 

484  A,  e-f/,j,  p!  ...  .F.  H.  Bradley. 

484  B,  a-'e Dawson. 

484  C, Newberry. 

f  485,  487,  489. .  .Edwards  and  Haime. 

or  r,  !  483  !  488 ! Meek. 

1  490,491 Billing. 

1492! Meek. 

(493-495! Meek. 

280/496!  497! Meek. 

(498! Meek. 

499 Hall. 

502-504,  508-512 Agassiz. 

505-507 Gibbes. 

522,  523 Newberry. 

513-521 Agassiz. 

522 Hall. 

(  525 Lesquereux. 

269^  526! Meek. 

(  527-530 .  .  .  Dawson. 

270  531,  532 Dawson. 

(  535 Edwards  and  Haime. 

272  \  537,  541-543 Hall. 

(  536 !  538-540 ! Meek. 

f544 Hall. 

I  545,  547 Conrad. 

273  -I  546    De  Verneuil. 

I  548-550 ! Meek. 

I  550  A Scudder. 

(550B Hall. 

277  <  551,  553,  554 Hall. 

(  552 Vanuxem. 

278  555-557 Hall. 

279  557  A  ! Lesquereux. 

557  B Lesquereux. 

558,  559 Leidy. 

560 Hall. 

561 Vanuxem. 

562 Vogt. 

563 D'Orbiffny. 

(564,  565 Votft. 

285  <  566 Pander. 

(567 Jukes. 

286  568-570 Bronn. 

290    571 J.W.Foster. 


262 

263 

264 

267 


PAGE    FIG. 

292    572 ! Meek,  Author. 

573-576,  578-585 Hall. 


280 

281 
284 


298 


577 ..Swallow. 


317 


586 Meek  &  Worthen. 

I  587 Meek  &  Worthen. 

(  587  a,  b Meek  &  Worthen. 

299^588! Meek. 

(589,  590 Hall. 

f  591-594 Hall. 

595 Koninck. 

300  {  596! Meek. 

597,  598 Swallow. 

[599 S.I.  Smith. 

(600! Meek. 

301  \  600  A Agassiz. 

(  601 !  602 !  603 ! Newberrv. 

302  604 LeL 

f  605-607 Koninck. 

on?  I  608 Koninck. 

6(}'}  609 Davidson. 

[610 D'Orbignv. 

(611 Koninck. 

308  <  612 Agassiz. 

(612  A Hall. 

310  613! Lesley. 

312  614 Dawson. 

(  615  a,  b,  c Bailey. 

j  616 Dawson. 

322  617  ! Russell  Smith. 

(619-621 Lesquereux. 

324  {622  Bronn. 

(  623,  624 Lesquereux. 

Q0,  (  625-627 Newberry. 

d25  j  628,  629 Lesquereux. 

Q™  (  630-632 Lesquereux. 

326  j  638 Brongniart. 

634-640 Lesquereux. 

641 Brongniart. 

642  a,  c Newberrv. 

328  <{  642  6 Dawson. 

(643 J.  D.  Hooker. 

329  644-646  A Newberry. 

646! Meek. 

647 Hall. 

332  -i  648-650 ! Meek. 

651   Cox. 

652! Meek. 

653,  655-657 Hall. 

654 Koninck. 

658 Dawson. 

659,  660 Bradley. 

j  661  Dawson. 

I  662 Meek  &  Worthen. 

(  663-665,  667,  668.  .Meek  &  Worthen. 

334  <  666 Dawson. 

(  668  A !   .  J.  H.  Emerton  (for  Harger). 
(669 Author. 

335  <  670 Scudder. 

(  671 Lesquereux. 

(  673,  674 Newberry. 

336  <  675,  677 Newberry  &  Worthen. 

(676! * Bradley. 

(678         Cope. 

340  \  679,  680 Wyman. 

(681... Marsh. 

344    681  A..  ..Rainsav. 


327 


APPENDIX. 


787 


350 

368 
370 
371 
373 
374 

396 


407 
408 

410 

411 
412 
414 

415 

416 
418 
422 

425 


426 


427 


428 
432 


436 
437 


438  ^ 

439 
440 
441 


f  682,  684,  685 Bronn. 

I  683 Murchison. 

]  686 Vogt. 

[686  A Salter. 

687-691! Meek. 

692-695 Geinitz. 

696 Murchison. 

697 Von  Meyer 

698 ! Author. 

f  699  Taylor. 

j  700 H.  D.  Rogers. 

1  701 Lesley. 

[702 H.  D.  &  W.  B.  Rogers. 

703! Lesley. 

704 Lesley. 

(  705,  706,  708,  709 Emmons. 

|  707 E.  Hitchcock,  jr. 

710 Hooker. 

(710  A-D Gabb. 

711 Lyell. 

\  711  a Emmons. 

i  711  b\ L.  Sanford. 

[712 Author. 

(  713-717 Hitchcock. 

718 Redfield. 

719-722 Hitchcock. 

(725 Leidy. 

/  726-728 Emmons. 

(  729,  730 Hitchcock. 

\  731 Emmons. 

732 Penny  Cyclopedia. 

733 Percival. 

735 ! Author. 

(737,  738 Vogt. 

|  739 Bronn. 

(740 D'Orbigny. 

(741 Vogt. 

I  742 Lvell. 

1  743 D'Orbigny. 

744,  745  D'Orbignv. 

[746,  747 Vogt. 

(748,  749 Bronn. 
750,  751 D'Orbigny. 
752 Mantell. 
753 Bronn. 

754 Naumann. 

755-760  ! Meek. 

761 Buckland. 

762 D'Orbigny  (from  Buckland). 

768-770 D'Orbigny. 

771,772 D'OrbignV. 

773 Vogt. 

74 Mantell. 

775,  Davidson. 

776,  777 Davidson. 

778! L.  Sanford. 

779  Mantell. 

780-782,  785 D'Orbignv. 

[783,  784 Vogt. 

(786 Lvell. 

\  787,  788,  789 D'Orbignv. 

(790 Lvell. 

(  792-794 Vogt. 

-{795,  796 Phillips. 

(797 Mantell. 

(798,  799 D'Orbigny. 

{  800,  802   Bronn. 

(801 ..Lvell. 


PAGE     FIG. 
(  803 


v  / 

1! 


442 


443 
444 

445 

446 

447 
448 
450 
459 


D'Orbigny. 

804 Bronn. 

805,  809 D'Orbigny. 

806,  810 Vogt. 

808 Pictet. 

^811 Vogt  (from  Buckland). 

812 Vogt. 

(.813 J.Phillips. 

j  814 Mantell. 

j  815 D'Orbigny. 

J  816 Buckland. 

817. .  .Intell.  Observer  (from  Owen). 

818,  819 Pictet. 

820,  821 Mantell. 

825-828  ! Newberry. 

,pn  (829 Roemer. 

460  j  830 !  831 ! Meek. 

(  832, 837 Roemer. 

|  833 D'Orbigny. 

461  \  834-836 ! Meek. 

|  838-841 !  843 !  844 ! Meek. 

[  842 Roemer. 

462  844 ! Meek. 

463  845-850 ! Meek. 

(  852 Gibbes. 

853 Morton. 

854  A Leidy. 

854  B!  C!  D! Marsh. 

856-859 D'Orbigny. 

861 D'Orbigny. 

(862,  864 Bayle.. 

472^865 Pictet. 

(866 D'Orbignv. 

(  867,  869,  870 Vogt. 

473  1  868,  871 D'Orbigny. 

(872 Mantell. 

474  873 D'Orbigny. 

479     874! -Author. 

496     882 Ehrenberg. 

A07  (  883-886  ! Lesquereux. 

Jt  I  887 E.  Hitchcock. 

498  888  ! L.  Sanford. 

(  889-893! Meek. 

499  \  894-896  !  898 ! Meek. 

(  897,  899,  900 Conrad 

901-904! Meek. 

/  905-907 Tuomey  &  Holmes. 

(  908-913 ! ." Meek. 


464 
465 
471 


914-916, 


Agassiz. 


600 

50] 

502  917 Russell  Smith. 

504  919 Crisand,  for  Marsh. 

505  920 ! Crisand,  for  Marsh. 

506  923,  924 Leidy. 

i  507  925 Leidy. 

j  517  927 Pictet. 

518     928 '.D'Orbigny. 

!  521     929  ! Author. 

I  530     940  ! L.  Sanford. 

i  544    941 ! R.  Bakewell. 

546     942 ! Author. 

558    943 ! Author 

(944! Author 

J945 E.  Hitchcock 

563     946 R.  Owen. 

-RR  (947!  948! Meek. 

bb|949 R.   Owen. 

!  568     950 Z.  Thompson. 

J569     951 Vogt. 


559 


788 


APPENDIX. 


570 

573 

580 
581 


PAGE    PIG. 

952 Leidy. 

953,  975 D'Orbigny. 

954 --Lye   • 

955,  846 Mantel]. 

957 * Strickland. 

584    958 ! . ! '. ','. From  a  photograph. 

i960 Author. 
961 Author. 
962  Darwin. 

619    963 Author. 

H22     964 Author. 

624  965 Author. 

625  966-969 Author. 

633     970-1075 Ehrenberg. 

638     1076,  1077 Author. 

641  1078 ! Mollhausen  ( New  berry ). 

642  1079    lyes. 

645     1080,   1081 Lesley. 

ftilfi  1 1Q82-1091 Lesley. 

j  1092 Holmes. 

Physiographic  Chart,  by  the  Author,  excepting  the  Topography  of  the  Continents  by 
A.  Guyot. 


PAGE 

652 
655 
664 
668 

676  j 

677 
685 
692 
704 
705 
706 

712  | 

707 
718 
719 
720 
730 


1U93 ! U.  S.  Coast  Survey. 

1095 Vanuxem. 

1096,  1097 Author. 

1098 ! J.  D.  Hague. 

1100! Guyot  (in  part). 

1101-1104 .Tyndall. 

1105 Agassiz. 

1 106 Holmes. 

1107 Photograph  by  Jackson. 

1108 Author. 

1109,  1110 Author. 

1111-1113 Author. 

1114 Author. 

1115 ! Coan  and  Judd. 

1 1 16 Author. 

1117 Holmes. 

1118-1120.  .  Photographs  by  Jackson. 

1121 .".  .Holmes. 

1122 Holmes,  Gardner. 


•INDEX. 


NOTE.  —  An  asterisk  (*)  after  the  number  of  a  page  indicates  that  there  is  a  reference  on  the  page 

to  a  figure  of  the  species  or  object  mentioned  ;  and  a  section-mark  (§)  implies  that  the  page  contains 

a  definition,  explanation,  or  characteristic  of  the  word  or  object  mentioned. 

Abich,     analysis    of    trachyte,  !  Actinoptychus  undulatus,  496.* 

Agnostus  nobilis,  178. 

77.                                                j      senarius,  134,*  496.* 

pisitbrmis,  208. 

Abies,  450,  497.                                Activity   in  matter,   beginning 

princeps,  180. 

Abyssal  zone,  611. 

of,  766. 

rex,  180.* 

Abyssinia,  plateau  of,  27- 

Adacna  vitrea,  610. 

Agraulos,  168,  178,  189. 

Acacia,  514,  515. 

Aderholt,  analyses  of  Lycopod 

Oweni,  178. 

Acadian  epoch,  163,  166. 

ash,  365,  366. 

Agriochosrus,  511. 

Triassic,  404. 

Adiantites,  348. 

antiquus,  511. 

Acalephs,  117,*  127,  §  129,§  341. 

Adipocere,  617- 

major,  511. 

range  of,  in  time,  386. 

Silurian,  612. 

Aiguille,  645  § 

Acanthospongia,  2l>7. 

Adirondack  iron  -mines,  151. 

Air,  oxygen  in,  49. 

Acanthotelson  Eveni,  3i2. 

mountains,  390,  750. 

Air-breathers,  first  of,  273,  301. 

Stimpsoni,  334,*  344. 

Adjutant,  516. 

Alabama,  Carboniferous  in,  291, 

Acanthoteuthis,  441. 

Admete  viridula,  551. 

311. 

antiquus,  44').* 

yEchmodus,  442.* 

Cincinnati  in,  197. 

Accipenser,  264. 

angulifer,  449. 

Clinton  in,  219. 

Accumulation  of  rock-material, 

Leachii,  449. 

Cretaceous  in,  455,  456. 

615. 

-fflglea,  350. 

glaciers  in,  537. 

Acephals,  124,  125.  § 

.Eglina  binodosa,  192. 

Millstone-grit  in  ,311.  320. 

range  of,  in  time,  337.* 

^Epyornis,  580. 

Subcarboniferous  in,  294,  305. 

Acer,  459,  497. 

-fEthophyllum  speciosum,  426. 

Tertiary  in,  491,  494. 

obtusilobum,  459. 

stipulare,  426. 

Triassic  in,  423. 

Aceratherium  occidentale,  507. 

Africa,  Cretaceous  in,  470. 

in  the  Cretaceous,  479. 

Acetabulifers,  439. 

mean  height  of,  14. 

period,  490,  494,  509,  523. 

Acidaspis,  240,  249,  253. 

plateaus  of,  22. 

Alabaster,  56.§ 

Barrandei,  247. 

system  in  reliefs  of,  27-* 

Alaska,  Triassic  in,  407. 

range  of,  in  time,  387.* 

Tertiary  in,  512. 

Albertite,  296,  315,  316. 

Acidic  series  of  igneous  rocks, 

Agalmatolite,  58.  § 

Albian  group,  470. 

79,§  736.                                  i  Agaricia,  620. 

Albite,  54.  § 

Acid-spring,  234.                           j  Agassiz,  A.,  Echini,  595. 

Albite-felsyte,  71.  § 

Aclis  robusta,  342.                         i  Agassiz,    L  ,    criteria    of    rank 

Alca  impennis,  580. 

Acrodonts,338.§ 

among  animals,  592. 

Alcionium,  130  § 

Acrodus,  428,  475. 

Drift,  537. 

Alcyonoid  Polvps,  130.§ 

minimus,  262,*  429.                       glaciers,  680. 

Alder,  515. 

nobilis,  262,*  449.                           Man's  position   in   classifica- 

Alethopteris,  330,  348,  370. 

Acrolepis,  372.                                        tion,  578. 

discrepans,  271. 

Sedgwickii,  372.                         !      names  of  Ages,  138. 

lonchitica,  326,*  330,  331. 

Acrostichites  oblongus,  409.              tails  of  fishes,  412. 

marginata,  331. 

Acrogens,  133.§                               Agassizocrinus,  341. 

Owenii,  297. 

Age  of,  139. 
range  of,  in  time,  140.* 
Acrotreta,  173  ,§  190. 

Agate,  53.  § 
Age  of  Acrogens,  139. 
of  Fishes,  140,  254. 

Serlii,  330. 
Aletornis  gracilis,  510. 
nobilis,  510. 

gemma,  250. 

of  Invertebrates,  162. 

Aleutian  Islands,  35. 

subconica,  250. 
Actgeonella,  475. 

of  Mammals,  589. 
of  Man,  141,527. 

Algae,  133,  134,§  139,*  140,  611, 
665. 

Actasonina,  475. 

of  Reptiles,  403. 

Carboniferous,  296,  331. 

Actinia,  117.* 
Actincid  Polyps,  130.§ 

Agelacrinites  Billingsii,  203. 
Buchianus,  207. 

Devonian,  257,  277. 
Silurian,  169,  186   223,  242. 

Actinolite,  54.§* 

Ages,  names  of,  140. 

the  earliest  plants,  140.* 

Actinolvte,  70.  § 

reality  of,  137. 

in  hot  waters,  611. 

Actinocrinus,  303,  341. 

subdivision  into,  138.  § 

Alleghany   Mts.,   in   Paleozoic, 

(Batocrinus)          longirostris, 

Aglaspis,  168,  178. 

390,  395,  750. 

118,*  129,  §  298,*  3t>3. 
proboscidians,  298,*  303. 

Agnostus    168,  178,  180,   188, 
190,  253. 

age  of,  754. 
Carboniferous  in,  291. 

pulcher,  247. 

Acadicus,  175  *  176. 

Alligator,  510. 

tenuiradUtus,  191.                          integer,  180.    ' 
Actinocyclus  Ehrenbergii,  496.    ;      lobatus,  202,*  204. 

Allorisma    subcuneata,     332,* 
342. 

790 


INDEX. 


Alluvial  fans,  651.§ 

formations,  origin  of,  649. 
Alluvian  epoch,  543,  547. 
Alluvium,  66, §  650. § 
Almond,  514. 
Alnus  497- 

Kefersteinii,  498,  514. 
Alpine  plants,  609. 

Trias,  445. 

Alps,  Cretaceous  in,  470. 
elevation  of,  512,  525. 
in  Cretaceous,  480. 
in  Quaternary,  562. 
Jurassic  in,  434. 
Quaternary  in.  533. 
Tertiary  in,  512. 
Triassic  in,  424. 
Altai  Mts.,  26. 

Alteration  of  rocks,  156,  400. 
Alumina,  364. 
Aluminum,  50. § 
Alum  shale,  66, §  268. 

slate,  163. 

Alveolites  fibrosa,  207 
Labechii,  206.  _ 
lycoperdon,  207- 
Amauropsis        paludinaeformis, 

469. 

Amazon,  flow  of,  651. 
Aniblypterus,  343,  351,  428. 
Amblyrhynchus,  485. 
Ambocoelia     umbonata,    272,* 

274. 
Ambonychia  bellistriata,  200,* 

203. 

radiata,  205,*  206. 
Triton,  208. 

Ambulacral  pieces,  128.§ 
America  and  Europe,  difference 

in  progress  of,  394. 
Silurian  genera  of,  identical, 

249. 

America,  as  a  continent,  13. 
mean  height  of,  15. 
Quaternary  Mammals  of,  565. 
Reptiles  in,  464. 
submerged  eastern  border  of, 

11,  422,*  671. 
system  in  reliefs  of,  23.* 
the  forest-continent,  394. 
trends  of  land  of,  36. 
See,  further,  N.  AMERICA,  S. 
AMERICA,    UNITED    STATES, 
etc. 
American  character  of  Miocene 

plants  of  Europe,  514. 
Amethvst,  53.§ 
Amia,  264. 
depressus,  510. 
Newberrianus,  510. 
Ammonites,  124,§  432,  462,  483, 

501. 
Cretaceous,  457, 462,  469, 473, 

483. 

Jurassic,  439. 
Tertiary,  501,  508. 
Triassic,  429. 
Altenensis,  449. 
auritus,  476. 
Ausseanus,  416. 
Billingsianus,  416. 
biplex,  433,  449,452. 
Blakei,  416. 
Bogotensis,  476. 
Braikenridgii,449. 
Brewerii.  467- 
Bucklandi,  439,*  448. 
bullatus,  449. 
Calloviensis,  449. 


Ammonites  caprinus,  449. 

couiplanatus,  4Y6- 

complexus,  468,  469. 

concavus,  433. 

Conybeari,  449. 

cordiformis,  432,*  433. 

coronatus,  449. 

decipiens,  449. 

Delawarensis,  468. 

dentatus,  476. 

Didayanus,  476. 

discus,  449. 

Dumasianus,  476. 

galeatus,  476. 

giganteus,  450. 

Haydenii,  467. 

heterophyllus,  449. 

Humphreysianus,  439,*  449 

Jason,  439,*  449. 

jugalis,  508. 

levidorsatus,  416. 

Lewesiensis,  473. 

lobatus,  469. 

McClintocki,  433. 

Martini,  476. 

Mississippiensis,  456. 

nisus,  476. 

Parkinsoni ,  449. 

peramplus,  476. 

percarinatus,  468,  477- 

placenta,  456,  463,*  467,  468, 
469. 

planorbis.  449. 

plica tilis,  449. 

praelongus,  476. 

radians,  449. 

Rhotomagensis,  476. 

rostratus,  476. 

rotundus,  449. 

serpentinus,  449. 

simplus,  476. 

spinatus,  439,*  449. 

splendens,  476. 

Tethys,  476. 

Texanus, 468. 

tornatus,  426,*  428. 

trisulcatus,  429. 

Vandeckii,  476. 

varians,  476. 

varicosus,  476. 

venustus,  476. 

vespertinus,    468,    469,    476, 
477. 

Woolgari,  477. 

Wosnessenski,  433. 
I  Ammontidae,  first  of,  288. 
Amphibamus  grandiceps,   340,* 

343. 

,  Amoeba,  132. 

I  Amphibians,  121,§  592, 595,  593. 
|      Carboniferous,  3  1,  337, §  343. 
j      classification  of,  337  § 
culmination  of,  484. 
Age  of,  139 

!      range  of,  in  time,  388.* 
Amphibian,  earliest  American, 

301,  302  * 
Amphibole,  54  § 
;  Amphicyon,  511,  519. 
;  Amphigenia  elongata,  261. 
i  Amphigenyte.  78,§  7(>7. 
I  Amphion,  178,  188,  189,  190. 
Barrandei,  190,  192. 
Canadensis,  192. 
Salteri,  190. 
Amphioxus,  265,§  602. 
Amphipods,  120  *  122,§  349. 
range  of,  in  time,  385.* 


Amphitherium  Broderipii,  446, 

448,*  449. 
Amphiuma,  337-§ 
Ampyx,  190. 
nudus,  208.* 
range  of,  in  time,  387-* 
Amusium  Mortoni,  5W,*  511. 
Amygdaloid,  707  § 
Amygdaloidal  cavities, filling  of, 

734. 

rocks.  64. § 
Anabacia  hemisphaerica,  449. 

Orbulites,  449. 
Analcite,  734. 
Analyses  of  bones,  60. 
coals,  316,  493. 
corals,  60. 
granite,  68. 

limestones,  74,  233,  237. 
plants,  361,  362,  365. 
j      shells,  60. 
|      volcanic  rocks,  77,  78. 
i  Anamesite,  78. § 
I  Ananchytes  cinctus,  466,  469. 
|      fimbriatus,  469 
)      ovatus,  476. 

Anarthrocanna  Perryana,  278. 
Anastrophia  interplicata,  226,* 

229,  248. 

Anatifa,  120,*  122.  § 
Anchitherium,  5u5,*§  on,  519. 
Bairdii,  511. 
Condoni,  511. 
Anchippodus  minor,  510. 

riparius,  511. 
Anchor-ice,  674. 
Anchura,  457,  508. 

Americana,  461,*  467. 
Ancyloceras,462.§ 
gigas,  476. 

Matheronianum,  473,*  475. 
Remondii,  467. 
spiniger,  476. 
Andalusite,  57,*§  728. 
Andes,  slopes  of,  17. 
glaciers  in,  675. 
heights  in,  703. 
Jurassic  in,  433,  434. 
in  the  Cretaceous,  480. 
Andesite,  54.  § 
Andesyte,  78. § 
Andrews,  E.  B.,  on  coal-plants, 

357- 
Andromeda  reticulata,  498. 

vaccinifolia,  498. 
Andromedites,  515. 
j  Andrias  Scheuchzeri,  337. 
Angelina,  192. 

Angiosperms,  134. §  45Q,  602. 
first  appearance  of,  4u3,  458. 
Tertiary,  497. 
Anglesite,  197. 

Anglo-Parisian  basin,  487,  523. 
Anhydrite,  56. § 
Animal  kingdom,  1,  116  § 
membranes,  decomposition  of, 

612. 
Animals  and  plants,  distinctions 

of,  115.§ 

distinguished  from  crystals,  1. 
Animals,  criteria  of  rank  among, 

592. 
extinction    of  species  of,  m 

modern  times,  579. 
of   Quaternary  cotemporane- 
ous  with    man,    574,    576, 

Anisopus  Deweyanus,  412.* 417- 
gracilis,  412.* 


INDEX. 


791 


Annelids,  123, §  60S. 
Annularia,  831,  370,  318. 

caritiata,  37«  .* 

sphenophylloides,  331. 
Anodonto  Jukesii,  284. 
Anogens,  133.  § 
Anolax  gigantea,  5f  9. 
Anoint  locardia  Mississippiemis, 

499.*  6' 9. 
Anomalocystites,  243. 

cornutus,  238*24.'. 
Anomia,  483,  5i8. 

Ruffini,  510. 

Anomoepus  scambus,  412,*  417. 
Anomourans,  range  of.  in  time, 

388.* 

Anoplothere,  517. 
Anoplotherium.  519,  521. 

commune,  519. 

tecundarium,  519. 
Anorthite,  54. § 
Anorthosyte,  (59. § 
Ant-eater,  518,§  568. 
Antholithes,  326,  348. 

Pitcairnese,325*329. 

priscus,  325,*  329. 
Anthophyllitic  rocks.  64. § 
Anthracerpes  typus,  342. 
Anthracerpeton   crassosteum, 

351. 

Anthracite,  61, §  315,  32),  346, 
363. 

analyses  of,  316. 

composition  of,  361. 

of  the  Calciferous,  186. 

region  of  Pennsylvania,  320. 
Anthracoptera  carbonaria,  342. 
Anthracosaurus  Russelli,  343, 

351. 

Anthrocotherium,  519. 
Anthrapalaemon  dubius,  350. 

gracilis,  334,*  342. 

Grossarti,  350. 

Salteri,  350.* 
Anticlinal,  95§*,  750. 
Anticlinorium,  752. § 
Anticosti,  Cincinnati  in,  197. 

Clinton  in,  235. 

Oneidain,  218. 

region.  217 

rocks,  197,  2"6, 223,  230. 
Aritigorite.  73.  § 
Antilope,  519,  520. 
Antliodus,  304. 
Aputeon  338.  § 

pedestris,  351. 
Apatichnus  bellus,  412.* 
Apatite,  5S,§  152,  726,  728. 
Apatornis,  468. 
Apennines,  elevation  of,  525. 

Tertiary  in,  512. 
Aphanyte,  70. § 
Apiocrinus,  437. 

elejrans,  449. 

Parkin  son  i,  449. 

Roissyanus.  437,*  449. 
Apiocystis  Gebhardi,  238,*  240. 
Apopolenus  Ilenrici,  180. 

Salteri,  18). 
Appalachian  coal-field,  3'9,  320. 

faults,  398  * 

flexures,  characters  of,  399. 

region,  146, §  167,  1*4,  196 
211,251,267,  276,280,295, 
320,373,391,393,4'.!. 

revolution,  403. 
Appalachians,  heights  of,  17. 

in  the  Carboniferous.  355. 

in  the  Cretaceous,  479,  480. 


Appalachians,   making  of,  748, 
750. 

not  existing  in  Devonian,  287. 
Aporrhais  occidentalis,  551. 

Sowerbii,  51*. 
Apteryx,  580. 
Aptian  group,  470. 
Apus  dubius,  350. 
Aquatic    life,    distribution   of, 
610. 

most  easily  fossilized,  613. 

of  lowgrad",  382. 
Aquila  Dananus,  511. 
Arago,  on  internal  heat,  699. 
Aralo-Caspian  deposits,  513. 

depression,  13,  26. 

life,  610. 
Aranea,  351. 
Araucaria,  450. 

Cunningham!,  134.* 
Araucarian  Pines,  134, §*  323. 
Araucarires,  337. 

Ouangondianum,  271. 
Araucaroxylon,  271,  349. 
Area,  253,  284,  385,  5U8. 

carinata,  476. 

hiana,  5oO  *  511. 

lienosa,  511. 
Arcania,  475. 

Archaean  map  of  North  America 
149. 

mountains,  750. 

nucleus  of  North  America. 
160. 

origin  of  later  rocks,  161. 

periods  of,  151. 

rocks,  distribution  of,  148. 

time,  139,  146. 
Archaeocaris,  267- 
Archfeocidaris.  372.  3  3,  341. 

Norwood!,  298,*  303. 

range  of,  in  time.  386.* 

Shumardana  298.*  3u3. 

Wortheni,  298,*  3>  3 
Archaeocyathellus    Kensselaeri- 

cus,  177. 
Archaeocyathus,  189  § 

Atlanticus.  Ii7.* 

Minganen>is,  188. 
Archaeomys,  519. 
Archaeoniscus  Brodiei  441,* 449. 
Archasopteryx    macrura,    446, 

447,*  449. 
Archegosaurus,  338.  § 

DecheDi,  351. 

minor,  351. 
Archimedes,  296,  299. 

Wortheni,  299,*  3'  3. 

limestone,  294,  379. 
Archimylacris  Acadicus,  343. 
Architarbus  rotundatus,  342. 

subovalis,  351 
Architectonica.  5f8 
Archiulus  xylobioides,  342. 
Arctic-border  region,  146. 
Arctic,    Carboniferous    in,   291, 
352. 

Chazy  in,  185. 

climate  of,  2n9,  255?,  2^9,  852, 
452,  480,  526,  541,  572,  594, 
755 

Corniferous  in,  265. 

Cretaceous  in,  480. 

ice  of,  675,  686. 

Jurassic  in,  431,  432,  452. 

Niagara  in,  221. 

Quaternary  of,  550,  551. 

Silurian  species  of,  occurring 
elsewhere,  249. 


Arctic,  terraces  in,  550. 

Trenton  in,  196. 

Triassic  in,  43it. 

zone,  609. 

Arctocvon  primsevus,  517,  519. 
Arctomys,  520. 
Arenaceous  rocks,  63. § 
Arenaria  Groenlaudica,  532. 

glabra,  532. 

Arenicola  marina,  120.*  123  § 
Arenicolites  didyma,  179. 

linearis,  192. 

spiralis,  176. 
Arenig  group,  163, 192. 
Arpres  armatus,  285.* 
Argillaceous  rocks,  64. § 

iron-ore,  220,  231.      ' 
Argile  plastique.  512,  519. 
Argil lyte,  69,§  72.§ 
Argiope,  171,  174. 
Aristolochia,  498. 
Arkansas,  Archaean  in.  l'/\ 

Carboniferous    in,    145,    291, 
321. 

Cretaceous  in,  455,  456. 

lead  mines  in, 186. 

Subcarboniferous  in,  293. 

Tertiary  in,  491. 
Armadillo,  569,  670. 
Artemia,  61t>. 

Artesian  wells,  653,  654,*  699. 
Arthrolycosa    amiquus,     b34,* 

342. 
Arthrophycus    Ilarlani,    223,* 

228. 
Arthrostigma,  271. § 

gracile,  271. 
Articulates,  118.§*  121. § 

range  of.  in  time,  140.* 
Artiodactyls,  504. § 

range  of,  in  time,  589.* 
Arundo, 499. 

Goepperti,  499. 
Arvicola,  520. 

Asaphus,   174,§   188.   189,  190, 
192,  228,  240,  253. 

Catiadensis,  2n6. 

canalis,  189,  190, 192. 

gigas,  202,*  21 4. 

megistos,  2<  6,  228. 

obtusus,  192. 

platycephalus,  190, 196,  202,* 
2>  4,  2U6. 

Powisii,  208  * 

range  of,  in  time,  387.* 

tyrannus,  2('8. 
Asbestus,  55. § 
j  Ascidians,  123,§  126,§  602. 
I      a  comprehensive  type,  597. 
Ascoceras,  228. 

Canadense,  250. 

Newberryi,  250. 
Ash  of  plants,  61,  365,  366. 

volcsmic,  66.  § 
Ashburton  group,  282 
Asia,  Cretaceous   in,  470. 

eastern,  island-chains  of,  35, 
747. 

Jurassic  in,  433. 

mean  height  of,  14. 

system  in  reliefs  of,  25,  26.* 

Tertiary  in,  512. 

trends  of  land  of,  37. 

volcanoes  of  central,  704. 
Asilus.  449. 

Aspidella  Terra-no vica,  176. 
Aspidium  filix,  365. 
Aspidocrinus,  240. 


792 


INDEX. 


Aspidorhvnchus,  442,*  449. 

Atrypn      reticularis,    206,    20", 

FfaJwri,  450. 

224  *  228,§   229.   230,   240, 

Aspidur.i  loricata,  428. 

243.  247.  248,  249,  256,  261, 

Aspleniuui  filix,  365. 

272,*  274. 

Assorting  of  material,  758. 

spinosa,  261. 

Astacus,  428,  611. 

range  of,  in  time,  386.* 

Astarte,  385.  433,  475. 

Aturia  ziczac,  518. 

Arctica,  551. 
Banksii,  551. 

Aucella  Erringtoni,  432. 
Augite,  55,§*  737. 

borealis,  519 

rock,  70.  § 

Conradi,  499,*  509. 

Auk,  extinction  of,  580. 

elegans,  449.                                   Aulopora,  2U6. 
elliptica  551.                                    arachnoidea,  202.  204. 

Laurentiana,  551. 

cornuta,  259,*  261. 

minima,  435,  438,*  449. 

serpens,  284. 

Omalii,  519. 

Aulosteges,  173.§ 

ovata,  449. 

Auriferous  quartz,  age  of,  453. 

Astartella,  342. 

Aurochs,  564,  565,  571,  572,577, 

Astartian  group,  435. 

581. 

Asterias  arenicola.  561. 

Auroral  series,  375. 

Asterioids,  128.  §  303. 

Austin,  G.,    on   Cretaceous  ice, 

Asterocarpus,  348. 

481. 

Asterolepis  Asmusi,  286.                 Austin  limestone,  457. 

Asterophyllites,  328,§  331,  348, 
370.  § 

Australia,  Carboniferous  in,  345. 
Cretaceous  in,  470. 

acicularis,  271. 

Devonian  in.  283. 

latifolia,  *70.*  271. 

Jurassic  in,  438. 

ovalis,  327.*  330. 

mean  height  of,  14. 

sublevis,  327,*  330. 

Permian  in,  370. 

Astraea,  620.  §  621. 

Quaternary  life  of,  570,  571. 

family,  482. 

reefs  about,  622. 

Astraeospongia,  228. 

system  of  reliefs  of,  28. 

meniscus,  229. 

Tertiary  in,  515. 

Astrocoenia  Guadaloupae,  466. 

Australian  types  in  Europe,  515. 

Sancti-Sabaa,  466. 

Australasian    chain   of  islands, 

Astronomy,   conclusions   from, 

33.* 

765. 

Austria,  Carboniferous  in,  346. 

Astylospongia,  228. 

Tertiary  of,  513,  515. 

parvula,  202. 

Triassic  of,  425. 

Atacama  desert,  45. 

Authorities  of  figures,  783. 

Athyris,  171,*  252. 

Auvergne  beds,  519. 

concentrica,  171.* 

eruptions  in,  525. 

congesta.  224,*  228. 

Avalanche,  678.  § 

lamellosa,  3>)7.*  308. 

Avellana,  475. 

spiriferoides.  272.*  274. 

Cassis,  472  *  475. 

subtilita,  332,*  311,  350,  352. 

Avicula,  226,  240,  243,  253,  278, 

range  of,  in  time.  386.* 

284.  385,  428,  46J,  475,  508. 

Atlantic    Border    of    continent 

contorta,  429. 

under  water,  422,*  671.                contorta  beds,  425. 

Atlantic-border  region,  401,  4°3,  i      Danbyi,  247. 

407,  409,  431,  454,  455,  490,        enncerata,  226,*  229. 

491,  524,  752,  754. 

gastrodes,  508. 

Atlantic  ocean,  11.  35. 

inaequivalvis,  429. 

bottom  of.  663,  671. 

intermedia,  429. 

currents,  40,  658,  665. 

Kazanensis,  372. 

trends  of  islands  of,  37. 

longa,  342. 

volcanoes,  704. 

pellucida.  458. 

Atlantochelys  gigas,  466. 

rhomboidea,  224,*  228. 

Atlas  Mountains,  27. 

Trentonensis,  200,*  2  3. 

Atmospheric  pressure,  effect  of 

Aviculopecten.  278,  284,303. 

changes  of,  634. 

duplicatus,  279  * 

Atmosphere,  agency  of,  630. 

rectilaterarius,  342. 

currents  of,  43. 

Aximea,  483,  5  8. 

of  the  Carboniferous.  352,  353. 

Siouxensis,  468. 

of  the  Primordial,  181. 

tumulus,  510. 

oftheTriassic,  429. 

Axinus  angulatus,  518. 

Atoll,  618.  §*  622,  625.* 

Axolotl,  337.  § 

Atops  trilineatus,  178. 

Aymestrv  limestone,  164. 

Atrypa,  171,*  249.  252,  284,  288. 

Azoic,  148  § 

aspera,  261.  272,*  274,  352. 

See  further,  ARCHAEAN. 

aprinis,  248. 

Azores,  37.* 

concentrica,  272.*  274. 

Azurite,  197. 

congesta,  2<)6,  224,*  228. 

crassa,  208. 

Babbage,     distribution    of   de 

fallax,  352. 

tritus.  666. 

hemisphaerica.  228,  247. 

Bache,  A.  D.,  formation  of  San 

hystrix,  278.* 

dy  Hook.  668. 

impressa,  261. 

on  the  oceanic  waves  of  the 

nodostriata,  226,*  229. 

Simoda  earthquake,  742. 

Bacillaria  paradoxa,  13i.* 
Baculites,   457,  462,§  469,  475, 
483. 

anceps,  475,  476. 

Chicoen>is,  467. 

compressus,  463,*  467,  468. 

inoruatus,  467. 

ovatus,  462,  463,*  467,   468, 
469. 

Spillmani,  456. 
Bad  Lands,  492,  495. 
Baer,  analysis  of  coal,  316. 
Bag.-hot  beds,  512,  513. 
Bailey,  J.  W.,  Atlantic-bottom 
Rhizopods,  071. 

on  structure  of  coal.  318. 
Baird,  S.  F.,  bone-caves,  167. 
Bajocirm  group,  435. 
Bakewellia  antiqua,  372. 

parva,  308.* 
Bala  formation,  164,  206. 
Balaena,  520. 

palseatlantica,  511. 

prif-ca,  611. 
Balajnodon,  ,"20. 
Baltic  Sea  in   the  Quaternary, 

555,  562. 
Baitic    provinces,    Silurian    in, 

207. 

Banana,  594,  609. 
Baphetes  planiceps,  339,  343. 
Baptosaurus  fraternus,  468. 

platyspondylus,  468. 
Barbatia  hyans,  511. 

Lima,  509. 

Mississippiensis,  509. 
Barite,  58,§  197. 
Bark,  composition  of,  361. 
Barnacles,  122, §  608. 
Barrande,  J.,  Bohemian  fossils, 
249. 

Silurian  fossils,  249. 

Silurian  adipocere,  612. 
Barriers,  sand,  of  coasts,  670. 
Barrier- reefs,  622, §*  624. 
Barton  clay,  513.  519. 
Barite  58.§  420. 
Basalt,  78. § 
Basaltic   columns,   86,§*    108,* 

628,  717.* 

Basaltic  rocks,  64, §  77- § 
Basanite.  £3.§ 
Basic   series   of  igneous   rocks, 

79  §  735. 

Basin-deposits,  101. §* 
Basset  edges,  94  §* 
Bathonian  group,  435. 
Bath  oolyte,  435. 
Bathvgnathus     borealis,    414,* 

417. 

Bathynotus.  178,  190. 
Bathyurellus.  188. 

nitldus,  188,*  190. 
Bathvurns.  174,§  178,  188, 189, 
190,  204. 

Angelini,  192. 

conicus,  190. 

Cordai,  190. 

gregarius,  176. 

parvulus,  178. 

perplexus,  178. 

Saffordi,  1 88,*  190. 

senectus.  178. 

vetustu*.  178. 

range  of,  in  time,  387.* 
Batocrinus  Christy  i,  298.*  303. 

longiro«tris.  118,*  129,§  298.* 
Batrachians.  337, §  592. 

See,  further,  AMPHIBIANS. 


INDEX. 


793 


Batrachoids,  33T.§                            Bcllerophon     bilobatus,     2*1* 

Bats,  339,§  416,  506,  510,  518 
519,  564. 

203,   205,206,   228. 
carbonarius,  333,*  342. 

(Chiropters),  range  of,  in  time, 

carinatus,  208,  250. 

589. 

dilatatus,  268. 

Bavaria,  Archaean  in,  151,  157. 

expansus,  247,  250. 

Carboniferous  in,  309. 

patulus,  274. 

Jurassic  in,  433. 

rotundatus,  191.* 

Silurian  in,  20". 

Urii,  342,  352. 

Bay  of  Fundy,  tides  of,  660. 

Belodon,  428,  429. 

Beach  formations,  667- 

Carolinensis,  414,*  417. 

structure,  82.§* 

Leaii,  417. 

See  SEA-BEACHES. 

lepturus,  417. 

Bear,  519,  564,  565,  567,  576. 

priscus,  414,*  417. 

Brown,  564,  571,  577. 

Belonostomus,  417,  475. 

Cavern,  563,*  564. 

Belosepia  sepioidea,  618. 

Grizzly,  564,  571. 

Beluga  leucas,  568. 

Beatricea,  228,  § 

Verm  on  tan  a,  568.* 

Beaumont,  Elie  de,  on  systems 

Bembridge  beds,  513,  519. 

of  mountain-elevation,  217, 

Benches,  545,  555. 

402.  487,  525. 

Bentham,  on  Welwitschia,  330. 

Beavers,  506,  508,  564,  565,  567, 

Benton  group,  456. 

568,  571. 

Benzoin,  497- 

Beck,  T.  11.,  analyses  of  lime 

Bermuda  Islands,  42. 

stone,  75,  233,  237. 

Bernardston,  Mass.,  Helderberg 

specific  gravity  of  sea-water, 

at,  237. 

657. 

Beryl,  58.  § 

sulphur  springs  of  the  Salina, 

Beryx,  457,  464,  475,  508. 

234. 

insculptus.  467. 

Beds,  81.  § 

Lewcsiensis,  475,  476. 

structure  of,  82.  § 

puperbus,  475. 

of  ore,  113. 

Betula,  497. 

Beech,  459,  514. 

Beatriciana,  46°. 

Behring  Straits,  in  the  Quater 

Beyrichia,  240,  303. 

nary,  541. 

Americana,  342. 

widening  of,  756. 

Atlantica,  190. 

Beetles,  121,  §  349,  441,*  450. 

complicata,  2'  8. 

range  of,  in  time.  388.* 

symmetrica,  227,*  229. 

Beinertia,  348. 

Bible  cosmogony,  767- 

Bela  cxarata,  551. 

Biche-de-mar,  127.  § 

harpularia,  551. 

Biflustra,  466. 

robusta,  551. 

Big  Trees  of  California,  459. 

turricula,  551. 

Bil'in,  infusorial  beds  of,  513. 

Belemnitella   mucronata,   462,* 

Billings,  E.,  character  of  Silu 

467,  469,  475,  476,  477. 

rian  life,  250. 

plena,  476. 

distribution  of  species,  193. 

Belemnite,  osselet  of,  432.* 

Quebec  group,  184,  190,  193. 

Belemnites,  125,  429,  432,§  440, 

Stockbridge  limestone,  185. 

441,462,475,484. 

Tiotite,  54.  § 

acutus,  449. 

Birds,  121,  §332,  441,  485,  502, 

Brunswickensis,  476. 

595,  6ul,  613. 

clavatus,  440,*  449. 

Cretaceous,  466,  474. 

densus,43l,432,*433. 

culmination  of,  598. 

dilatatus,  476. 

first,  403,  411,  430,  485. 

first  of,  432. 

having  teeth,  466,§  516. 

giganteus,  449. 

Jurassic,  446. 

ha»tatus,  449. 

range  of,  in  time,  589. 

impressus,  467. 

Tertiary,  502,  516. 

irregularis,  449. 

Trhssic,  414.§ 

minimus,  476. 

Birdseye  limestone.75  §  163,  194. 

niger,  433. 

Bischof,  decomposition  of  wood, 

Pacific  us,  432. 

364. 

paxillosus,  433,  440,*  452. 

Bison.  565,  567,568,576. 

pistilliformis,  440.* 

latifrons,  567. 

Belgium,  Carboniferous  in,  345, 

priscus,  581. 

346. 

Bituminous  coal,  68,  314.  §  315,§ 

rret.-iceous  in,  47^. 

346. 

disturbances  in,  402. 

analyses  of,  316. 

human  remains  in,  575. 

composition  of,  361. 

in  Recent  period,  562,  573. 

shale,  66,§  198. 

Quaternary  in,  556. 

Bivnlves,  125.  § 

Subcarboniferous  in,  306. 

Black  Hills,  Archaean  in,  150, 

Tertiary  in,  512. 

390. 

Belinurus  arcuatus,  350. 

Jurassic  in,  431. 

reginae.  350. 

Potsdam  at,  168. 

trilobitoides,  350. 

Black  Mts.,  390. 

Bellerophon,  2^3,  253,  278,  284, 

Black  River  limestone,  163,  194, 

303,  333.  429. 

261. 

acutus,  206. 

shale,  266,  267,  304,  378,  379. 

Black-lead,  59. § 

Black-snake.  516. 

Bake,  J.,  life  in   hot   springs, 

611. 

Blake,  W.    P.,   California  Ter 
tiary,  495. 

sand-scratches,  632. 
Blaney,  J.   V.  Z.,  analyses   of 

coal,  316. 
Blastoidocrinus    carchariaedens, 

190. 
Blastids,  129,§  259,  297. 

first  of,  in  Europe,  284. 

range  of,  in  time,  386. 
.  Blatta,  342. 
!  Blattina  primseva,  350,*  351. 

venusta,  335,*  342. 
Blende,  59,§  197,  222,  734. 
Blind  life  in  caves,  611. 
Block  coal,  315. 
Blood-rains,  632  §  634. 
Blue  limestone,  377. 
Blue  Ridge,  390,  750. 
:  Bluff  formation,  547. 

gravel,  547. 

lignite,  493. 

loam  547. 
Boar,  564,  571,  577. 
Boavus  agilis,  510. 

brevis,  510. 

occidentalis,510. 
Bog  ore,  694. 
Bogs,  bursting  of,  650. 
Bohemia,  Archaean  in,  151. 

Carboniferous  in,  309,  346. 

Cretaceous  in,  470. 

disturbances  in,  290,  402. 

Primordial  in,  179. 

Silurian  in,  162,  207,  245,  249. 

Silurian  fossils  of,  249. 
Bojie  gneiss,  151. 
Bolivian  plateau,  21. 
Bombs,  volcanic,  709.§ 
Bonassus,  564. 
Bone-beds,  Trias=5c,  412,  424. 

Upper  Silurian,  244. 
Bone  caves,  563.  564,  567. 

implements,  573,  574. 
Bones,  613. 

analyses  of,  60. 
Boracfte,  76.  § 
Borax, 630, 722. 
Bore,  660  § 

Boring  animals,  608,  671. 
Bornholm  group,  164. 
Bornia,  348. 

radiata,  283. 
Bos,  520. 

Americanus.  582. 

primigenius,  564,  582. 

priscus,  565. 

Urus,  582. 
Bosco's  Den,  577. 
Bothriolepis  Taylori,  280,*  281. 
Botrychium,  271. 
Bottom-lands,  638 
Bottosaurus  Harlani,  467. 
Bouchardia,  171,  174. 
Bovine  family,  range  of,  in  time, 

589.*     ' 

Bovey  Tracey  beds,  513. 
Bowlders.  317, 356, 370, 527, 529, 
533.  5a5.  684,  758. 

in  coal,  317- 

See  DRIFT. 
Bowlder-clay,  527- § 
Brachiate  Mollusks.  124, §  126. § 
Brachiopods,  126,  §*  169,  §*  332, 
3S2,  482.  597. 


794 


INDEX. 


Brachiopods,    a  comprehensive 

type,  597. 

culmination  of,  594. 
families  of,  range  of,  in  time. 

386.* 

first  of,  174. 
number  and  character  of  Ter- 

tiar}',  515. 

number  of  Silurian.  249. 
range  of,  in  time,  386.*  494. 
structure  and  subdivisions  of. 

169.* 
Braehv  merusinterplicatus.226,* 

229. 

Brachymetopus,  308. 
Brachyurans,  122.§*  475. 

first  species  of.  372. 
Bracklesham  beds,  512. 
Bradley,   F.   H.,   Carboniferous 

erosion,  359. 

consolidation  of  gravel,  725. 
geyser  action,  721. 
Lake  Michigan  outlets,  540, 

553. 

Miocene  climate,  756. 
Pe  trod  us,  343. 
Quebec  group,  184. 
Branchiae,  J23.§ 
Brandon    Lignite    and     fruits. 

494,  498  * 
Brazil,  mountains  of,  24. 

human  relics  in,  578. 
Breaks  in  the  geological  record, 

602. 

Breccia,  65  § 
Brewer,    W.    II.,    life    in    hot 

springs,  61 1. 
Sierra  Nevada,  453. 
British  America,  Cretaceous  in. 

455. 

terraces  in,  549. 
Tertiary  in,  493. 
Brixham  Cave,  564. 
Broadhead,  G.  C.,  Missouri  Coal. 

321. 

St.  Louis  artesian  well,  654. 
Bromelia,  450. 

Brongniart,  on  Tertiary  vegeta 
tion,  515- 

Bronteus,  204,  249. 
Brontotherium,  507. 

gigas,  511. 
Brontozoum  giganteum,    415,* 

417. 

Bronze  Age,  574. 
Brooks,   T.   B.,   on  New  York 

Primordial,  167. 
Brooks   &  Pumpelly  on    Mar- 

quette  iron  region,  160. 
Brown,  R.    on  Joggins  section. 

319. 

Brown  coal,  61, §  361. 
Bruxellian  group,  512. 
Bryozoans,  127,§*  199,  303,  621. 
number  of  Silurian,  249. 
range  of,  in  time,  387.* 
Bubo  leptosteus,  500. 
Bucanella  trilobata,  223,*  228 
Bucania  rotundata,  191.* 
Buccinum  Groenlandicum,  551. 

undatum,  551. 
Buckland,  on  eyes  of  trilobites, 

181. 

Buckler,  123,§  174. 
Buff  limestone,  377. 
Buffalo,  American,  567,  582. 
Buhrstone,  74. § 
Carboniferous,  311 
Tertiary,  493. 


Bulimella,  303. 
Bulimus  ellipticus,  519. 
Bulla,  475,  508. 
Bulla  speciosa,  461,*  467. 
Bumastis  Barriensis,  248. 
Bumelia,  515- 

Bunker  Hill  Monument,  700. 
Bunter  Sandstein,  424. 
Buprestis,  441,*  449. 
Burlington  limestone,  294,  305 
377,  378. 

crinoids  of,  303. 
Busycon  incile,  511. 
Buthotrephis  gracilis,  198.* 

succulosus,  198.* 
Butterfly,  121. § 

Cainozoic.     See  CENOZOIC. 
Cadent  series,  375. 
Caking  coal ,  315. 

analyses  of,  316. 
Calamaries,  Ii9,*  125,§  441. 
Calamites,  270  *§  280,  296,  297. 
323,327,328,331,  348,349! 
351,  353,  356,  370,  409,  426! 

arenaceus,  429. 

cannaeformis.  271,  327,*  330. 

Cistii,  330. 

gigas,  370. 

Mougeoti,  429. 

nodosus,  330. 

pachyderma,  330. 

radiatus,  283,  307. 

Suckowii,  297. 

transitionis,  270,*  271. 
Calamocladus,  348. 
CalamoDsis,  497. 

Dan»,  497,*  498. 
Calamostachys,  348. 
Calathium,  19'J. 

Anstedi,  190. 

pannosum,  190. 
Calaveras  skull,  578. 
Calcaire  coquillicr,  424. 

grossier,  512,  513. 

lacnstre,  513. 

marin,  513. 

pisolitique,  470. 

dliceux,  513. 
Ca  careous  deposits,  692. 

mica-schist,  68.§ 

rock -materials,  59, §  60,  691. 

rocks,  63.  § 
Calceola,  174.* 

sandalina,  173  *  284. 

schist,  284. 

Calcite,  55, §*  197,222,  627,  734. 
Calcium,  50. § 
Calciferous  sandrock,  163,  182. 

epoch, 163, 182.      ' 

flags,  245. 

California      artesian    wells    in, 
654. 

Carboniferous  in,  293. 

Cretaceous  in,  455,  457. 

"  geysers '' of,  611,722. 

hot  springs  in,  611,  722. 

human  relics  in,  577- 

in  the  Cretaceous,  480,  520. 

in  the  Tertiary,  520,  521,  523. 

Jurassic  in,  431,432. 

Quaternary  in,  528. 

Subcarboniferous  in,  296. 

terraces  in,  549. 

Tertiarv  in,  491,492,495,501, 
5(>8,  510. 

Triassic  in,  406. 
Callianassa,  475,  477,  672. 

first  of,  477. 


Callipteris,271,331,348. 
pilosa,  271. 
Sullivanti,  297- 
Callista  imitabilis,  509. 

Sayana,  495,  5  A,*  510. 

sobrina,  509. 
Callitris,  515. 

Callocystites  Jewettii,  11",*  229. 
Callovian  group  435 
Calophyllum.230. 
Caljmene,  174.§  240,  247- 

Blumenbachii,  120*  202.* 
204,  206,  208,  228,  247,  248, 
253. 

Blumenbachii  vnr.  Nia^aren- 
sis,  229. 

crassimnrginata,  261. 

senaria,  209. 

range  of,  in  time,  387.* 
Calyptrophorns  velatus,  509. 
Carnai  ophoria,  171,  372,  373. 

crumena,  373. 

Schlotheimi,372,  373. 

superstes,  372. 

last  of,  373. 

range  of,  in  time,  386.* 
Cambrian  period,  163,  166,  179. 
Camel,  495,  506,  507,  508. 
Camelus,  507,  520. 
Camelopardalis,  519,  520. 
Camerella,  171,  190,203. 

antiquata,  177. 

caicifera,  189,  192. 

varians,  J92. 

Campophyllum  torquium,  341. 
Camptonectes,  431. 

lens,  449. 

Campy Icdiscus  clvpeus   634.* 
Canada,  Archaean  in,  150,  154, 
157,  159. 

Calciferous  in,  182,  183, 184. 

Chazy  in,  182,  184. 

Cincinnati  in,  196,  197. 

copper  mir.es  in,  186. 

Hamilton  in,  266. 

Iluronian  in,  159. 

iron-mines,  154,  186. 

Laurentian  in,  151. 

Lower  Ilelderberg  in,  237,  £38. 

Lower  Silurian  in,  211. 

Niagara  in,  221. 

oil  wells  in,  256. 

Oneidain,  220. 

Oriskany  in,  241. 

Potsdam  in,  167,  181. 

Quaternary  in,  528,  531,  587. 

Quebec  in,  182,  184. 

Sali na  in,  233,  234. 

terraces  in ,  548. 

Trenton  in,  195. 

uplifts  in,  289. 

Upper  Ileldtrberg  in,  255, 
256. 

Utica  shale  in,  196. 
Canadian  period,  1C3,  182. 

in  Europe,  192. 
Cancellaria  costellifera,  519. 
Cancer,  120.*§ 

Caninia  bilateralis,  224*  228. 
Canis,  511,519 

ParMensis,  518,  519. 
Cannel  coal,  68,§  315  § 

coal,  analyses  of,  316. 

coal,  formation  of,  359. 
Canon  of  the  Colorado,  640, 641.* 
Cape  Girardeau  limestone,  237. 
Cape  Ilatter.ts,  42. 
Oapelin,  551. 
Uapillury  attraction,  629. 


INDEX. 


795 


Capitosaurus,  428. 
Caprina,  469. 

adversa,  476. 

limestone,  457. 
Caprotina  Texana,  467- 

limestone,  457. 
Capulus,  178,  203. 
Carabids,  449. 

Caradoc  sandstone,  164,  206. 
Carbon,  51. § 

Archaean,  157. 
Carbonaceous        rock-material, 

eo.§  61. 

material  in  Utica  shale,  198. 
Carbonic  acid,  51,  §  353,  708. 

disintegrating  action  of,  689. 

sources  of,  353. 
Carboniferous  Age.  139.  291. 

areas  divided  by  the  Cincin 
nati  uplilt,  291,  355. 

period,  309. 

resting  upon  Potsdam,  232. 

thickness  of,  373,  381. 

unconformable  to  Devonian, 
289. 

vegetation,  322.* 
Carcharias,  475.    SeeCARCHARO- 

Carcharodon,  510. 

ansustideus,  262  *  501  *  509, 
518. 

mega  lotion,  502,  509,  510 
Carcharopsis,  304. 

Wortheni,  301,*  3  4. 
Cardiaster,  474. 

granulosus,  476. 
Cardinal  area,  170.§ 
Cardinia  Listeri,  448. 
Cardiocarpus,  271,  328,  329,  331, 
343. 

bicuspidatus,  329,*  330. 

bisectus,  328,*  330. 

elongatus,328,*330. 

samarsefnrmis,  328,*  330. 
Cardiornorpha       Missouriensis, 

342. 
Cardita,  475,  508. 

Blandingii,  509. 

densata,  509. 

planicosta,  499  *  509,  518. 

rotunda,  509. 

senilis,  519. 

sulcata,  519. 
Cardium,488,475,  508. 

family,  253.  610. 

divewum,  509. 

dissimile,  449. 

edule,  519,  610. 

Islandicum,  551. 

multistriatum,  468. 

Nicolleti,  509. 

Rhoeticum,  429. 

subcur turn,  508. 

tuberculatum,  577. 

Virginitnum,  510. 

vitreurn,  610. 
Carex,  499. 

Carnivores,  506,  510,  511,  516, 
518,519,  520,  571,592,593. 

range  of,  in  time,  589.* 
Carnivorous  Saurians,  464. 
Caroline  Archipelago,  34. 
Carpathians,  elevation  of,  525. 

Tertiary  in,  512. 
Carpenter,  on  Eozoon,  158. 
Car  pin  us,  497,  498. 
Carpolithes,331,349. 

Brandonensis,  498.* 

irregularis,  497,*  498. 


Carrara  marble,  724. 
Carruthers.on  Prototaxites,245. 

Sigillarid's,  33  >. 
Carter,  11.  J.,  Eozoon,  159. 
Carya.  497, 498. 

Caryocrinus  ornatus,  226,*  229. 
Cascade-portion    of    a    stream, 

639. § 
Cascade  Range,  peaks  of,  24. 

volcanic  rocks  of.  524. 
Cashaqua  shales,  276. 
Cassia,  515. 

Cassidulus,  first  of,  477. 
Castor,  519,  520. 

Canadensis,  567. 

tortus,  511. 

Castoroides  Ohioensis,  567. 
Casuarinaa,  515. 
Cat,  508,  571,  577. 
Catarractes  affinis,  568. 

antiquus,  510. 
Catarrhines,  610. 
Catenipora  catenulata,  221. 
Catopterus  gracilin,  411,*  417. 
Catskill  beds,  279. 

period,  254,  279. 

shaly  limestone.  237. 
Cat-tail  family  in  Triassic,  426. 
Caturus,  475. 
Cauda-galli  epoch,  254. 

fucoid,  243,  254,*  277. 

grit,  254. 
Caulerpites,  331. 
Caulopteris,  348. 

antiqua,  258.* 

Lockwoodi,  271,  278. 

peregrina,  258. 

punctata,  325,*  330. 

Worthenii,  297. 


Caverns,  containing  human  rel 
ics  with   bones  of   extinct 
mammals,  574,  577. 
Cavern  animals,  563,  566. 

formations,  75. 
Ceanothus,  497,  498,  515. 
Celastrus,  515. 
Celestine,  222. 
Cenomanian  group,  470. 
Cenozoic  time,  140,  488,  489. § 

characteristics  of  life  of,  587. 

geography,  586. 

time-ratios  of,  585. 
Centetodon  pulcher,  510. 
Centipede,  121, §  335,  592. 
Centracodon  delicatus,  510. 
Cenfcronella,  171  § 
Cephalaspids,  264. § 

a  comprehensive  type,  382. 
Cephalaspis,  245,  264,  274,  282. 

Lyellii,  286.* 

Murchisoni,  245,  246.* 
Cephalates,  124,  125. § 

range  of,  in  time,  387.* 
Cephalopods,  124,§  342,  598. 

culmination  of,  483. 

number  of  Silurian,  249. 

variable  forms  of,  462,  598. 

range  of,  in  time,  387.* 
Cephalization,  593, §  596. 
Ceratiocaris,  227,  240, 247  *  253, 
267,  303. 

Deweyi,  229. 

elliptic  us,  247. 

inornatus,  247. 

sinuatus,  342. 
Ceratites,  409,§  429. 


Ceratites  Americanus.  468. 

Haidingeri,410,*4l6. 

nodosus,  426,*  428,  429. 

Whitneyi,410,*416. 
Ceratodus,  428,  594. 
Ceraurus  (Cheirurus),174,§  190, 
192,  204,  208,  240,  249. 

insignis,  229,  248. 

prolificus,  170. 

range  of,  in  time,  387.* 
Cercoleptes,  519. 
Cerithidea  Californica,  510. 
Cerithiopsis,  508. 
Cerithiurn,  475,  513. 

concavum,  519. 

elegans,  519. 

mutabile,  519. 

plicatuin,  519. 
Cervus,  507,511,520. 

Americanus,  567. 

anoceros,  519. 

Browni,  571. 

elephus,  568. 

Polignacus,  571. 

Warreni,  508. 
Cestracion  Philippi,  262.* 
Cestracionts,  262,*§    304,   3  8, 
462,  474,  475,  484. 

range  of,  in  time,  388,*  589.* 
Cetaceans,  503,  5<>7,  511. 

range  of,  in  time,  589.* 
Cetiosaurus,  444,  450. 

Oxoniensis,  449. 

longus,  450. 
Chaeropotamus,  517. 
Chsetetes,  202, §  204,  224,*  228, 
240. 

lycoperdon,  199,*  202,  209. 

milleporaceus,  341. 

range  of,  in  time,  386. 
Cluetognaths,  123. § 
Chaetopods,  123.  § 
Chalcedony,  53. § 
Chain-coral.    See  HALYSITES. 
Chalcopyrite,  59,§  197,  733. 
Chalicomys,  511. 
Chalicotherium,  520. 
Chalk,  75,§  469. 

Gray,  470. 

in  America,  455. 

origin  of,  471,  477. 

period,  403. 

White,  470. 
Chalk-marl,  470. 
Chama,  462,  495,  500. 

corticosa,  510. 

f  quamosa,  519. 

shell  of,  analysis  of,  59. 
Chambered  shells,  124.§ 
Champlain  period,  542,  571, 574. 
Chamois,  572,  577. 
Chara,  135, §  364,  450. 

ash  of,  3(55. 

foetida,  365. 
Charcoal,  mineral,  316. 
Chariocephalus,  178. 
Charionella,  171. 
Chart,    physiographic,   11,    41, 

583. 

Chazy  epoch,  163,  182 
Cheirolepis  Traillii,  263.* 
Cheirotherinm,  427,*  428,  429. 

Reiteri,  343. 

Cheirurus  =  Ceraurus,  q.  v. 
Chelonians,  338, §  339. 

range  of,  in  time,  589.* 
Chemical  geology,  606,  635,  760. 

effects  of  life,  6U8. 
Chemnitzia,  431. 


796 


INDEX. 


Chemung  beds,  section  of,  277. 

epoch,  254,  276. 

group, 276. 

period,  254,  278. 
Chert,  73\§  222,  305. 
Chesapeake  Bay,  in  the  Cretace 
ous,  478. 

Chester  group,  294,  295,  378. 
Chevandier,   analyses   of  wood, 

362. 

Chico  group,  457,  458. 
Chilhowee  Mt.,  fault  in,  400. 
Chilhowee  sandstone,  163,  168, 

379. 

Chili,  recent  changes   of  level 
in,  584,  585. 

Cretaceous  in,  470 

Jurassic  in,  433. 
Chimseroids,  263. 
China,  Carboniferous  in,  345. 
Chiropters,  range  of,  iu   time, 

589. 
Chiton,  385. 

Canadcnsis,  203. 

carbonari  us,  342. 
Chlamydotherium,  570. 
Chlorargillyte,  72  § 
Chlorhydric  acid,  708. 
Chlorine,  52. 
Chlorite,  55,§  727,  728,  734. 

slate,  72,§  729. 
Choanites  Konigii   476. 
Choeropotamus,  511. 

Cuvieri,  519. 
Chomatodus,  304,  343. 
Chondrites,  513. 

Colletti,331. 
Chondrodite,  726,  728. 
Chonetes,  172  *  228,  243,  249, 
252,  271,  284. 

cornuta,  224,*  228. 

Dalmaniana,  308. 

hemisphserica,  261. 

lata,  173.* 

mesoloba,  332,*  341. 

ornata,  3'jO,*  303. 

setigera,  272,*  274. 

variolata,  300,*  303. 

range  of,  in  time,  386.* 
Chonophylluui        magnificum, 

Niagarense,  225,*  229. 
Chouteau  limestone,  294. 
Chrestotes  lapidea,  343. 
Chromic  iron,  458. 
Chronological   order  of   strata, 

101.  § 
Chrysalidina     gradata,      131  * 

471,*  474. 
Chrysolite,  57. § 

rocks,  71  § 
Chrysotile,  55. § 
Cicadae,  450. 
Cidaris,  300,  474. 

Blumenbachii,  437,*  449. 

corona ta,  449. 

Edwardsii,  448. 

hemigranosa,  468. 

vesiculosa,  476. 
Cimolicthys,  467. 
Cincinnati  epoch,  164,  194. 

group,  195. 

region  in  Carboniferous,  355. 

uplift,  217,  237,  291,  305,355, 

391,  752. 

Cinder-cones,  706  *§ 
Cinders,  66,  702. § 
Cinnabar,  458. 
Cinnamomum,  497,  498. 


Cinnamomum  affine,  498.               Clymenia,  284,  285-5 

Mississippiense,  497,*  498. 
Scheuchzeri,498. 

limestone,  282. 
Sedgwickii,  285.* 

Cinnamon,  497,  514. 

Clypeaster,  509. 

Circumdenudafion,  645.  § 

Rogers,  499,*  509. 

Cirripeds,  120,*  122.§     " 

Gabbii,  510. 

earliest  of,  247. 

Clypeus  Hugi,  118  *  449. 

Cithara    Mississippiensis,  499  * 

patella,  449. 

509. 

Coal,  61,  §  314,  360. 

Cladodus,  304,  343,  351. 

analyses  of,  316,  493. 

rnarginatus,  3U8. 

beds,   amount   of  vegetation 

spinosus,  3  1,*304. 

for,  363. 

Cladonia,  368. 

beds,  thickness  of,  313. 

rangiferina,  333. 

bowlders  in,  317,  356. 

Claiborne  group,  491,  494. 

Calciferous,  186. 

Clam,  126,§  510,  531. 

Carboniferous,  312. 

Clathraria  Lyellii,  450. 

composition  of,  360. 

Clathropora  flabellata,  203. 

Cretaceous,  458. 

Clathropteris,  409,  433. 

debituminized,  400. 

rectiuscula,  407,*  409. 

impurities  of,  316,  364,  366. 

Clay,  49,  58.§ 
ironstone,  293,  318. 

Jurassic,  435. 
origin  of,  351,  360. 

rocks,  62. 

Permian,  370. 

slate,  69,  §  729. 

plant-remains  in,  317,  321. 

Clayey  lasers,  plication  of,  655,* 

structure  of,  314,  359. 

656. 

Subcarbonilerous,  293. 

Clear  Creek  limestone,  237,  378. 

Tertiary,  491,  493. 

Cleavage,  52,§  627,  737. 

Triassic,  404,  406. 

in  rocks,  89,§  627,  737,  746. 
production    of,    in     glaciers, 

workable  areas  of    293,  309, 
345. 

683. 

Coal-fields  of  N.  America,  309. 

Cleodora,  119.* 

of  Europe,  345. 

Clepsysaurus     Pennsylvanicus, 

Coal-making  decomposition  only 

413,414*417. 

under  water,  362. 

Clidastes,  468. 

Coal-measures,  311,  355. 

iguanavus,  468. 

dirt-beds  of,  313. 

intermedius   468. 

divi.-ion  of,  314. 

pumilus,  468. 

false,  295. 

Clidophorus  Pallasi,  372. 

section  of,   near  Nesquehon- 

Cliff  limestone,  221,  237. 

ing,  Pa.,  396.* 

Cliffs,  wearing  of,  663. 

section  of,  at  Trevorton  Gap, 

Cliinactichnites    Wilsoni,   176,* 

Pa.,  396.* 

178. 

vegetation,  character  of,  351. 

Climate  affects  gpographical  dis 

Coal  -period,  summary  of,  359. 

tribution  of  life,  609. 

Coal-plants,  321. 

causes  determining,  43,  763. 

distribution  of  genera  of,  348. 

causes  of  the  serial  changes 

growth  of,  353. 

in,  through  the  geological 

Coaly  shale,  66.  § 

ages,  763. 

Coan,  T.,on  eruptions  on  Ha 

change  of,  at  close  of  Cretace 

waii,  713,  715. 

ous,  488,  521. 

Coast-  barriers,  669.* 

changes  of,  754,  757,  763. 

Coast-formations,  492. 

Carboniferous,  352. 

Coast  Range,  24,  490. 

Corniferous,  265. 

Coast  Survey  soundings,  422.* 

Cretaceous,  480. 

observations  on  Gulf  Stream, 

Devonian,  289. 

658. 

Glacial,  541. 

Coccoliths,  135,§  459,  471.  611. 

Jurassic,  452. 

CocconeTs  atmospherica,  634.* 

Potsdam,  181. 

lineata,  634.* 

Quaternary,  571. 

Cocconema  cymbiforme,  634.* 

Tertiary,  526. 

Coccostcus,  246,  275,  282,  283. 

Trenton,  209. 

decipiens,  285*  286. 

Upper  Silurian,  253. 

Cochliodus,  301,  304. 

Clinch     Mountain     sandstone, 

contortus,  301,*  308. 

379. 

nobilis,  301,*  304. 

Clinkers,  711. 

Cockroach.  335.  336,  342,  349. 

Clinkstone,  77.§                             !  Coecilians.  337.5 

Clinometer,  95.§* 

Cwlacanthns,  343,  372. 

use    of,    for    measuring    the 

elegans,  336,*  342. 

slopes  of  distant  mountains. 

granulatus,  372. 

18. 

Coalorhynchus  ornatus,  509. 

Clinton  American  species  occur 

Coffee  group,  456. 

ring  elsewhere,  248. 

Cohesive  attraction,  627. 

epoch,  164,  220. 

Coins,  fossil,  579,  580.* 

iron-ore.  220. 

Coke,  61.  § 

Clione,  207. 

Cold,  sources  of,  541. 

Clupea,  475- 

Cold-temperate     regions,    41,§ 

humilis,  510. 

609. 

pusilla,  510. 

Coleopters,  351. 

INDEX. 


797 


Colonoceras  agreste,  510. 
Colonomys  celer,  510. 
Color   lost    iu    mttamorphism, 
725. 

of  rocks,  759. 

original,  ou  fossil  shells,  308, 

515- 
Colorado,  Carboniferous  in,  293. 

Cretaceous  in  454. 

Jurassic  in,  433. 

Ligniticin,457. 

Quaternary  in,  532. 

Subcarboniferous  in,  296. 

terraces  in,  549. 

Tertiary  in,  491,  493,  495. 

Triassic  in,  406. 

upheaval  in,  740* 
Colorado  River,  Canons  of,  640, 
641.* 

Cretaceous  on,  455. 

Triassic  on,  407. 
Colossochelys  Atlas,  516,  520. 
Colpocaris,  267. 
Colubridfe,  516. 
Columbella  sulcata,  519. 
Columbia  River,  volcanic  rocks 

of,  524. 
Columnaria,  190,  204. 

alveolate,  199,*  202. 
Columnar  structure,  87,§*  108.* 

surfaces  in  Niagara  group,  222. 
Comanche  Peak  group,  457. 
Comarocystites  Shumardi,  203. 
Comatulids,  128, §  437,  595. 
Comb,  114  § 
Compact  rocks,  63.  § 
Compound  bedding,  82. § 
Comprehensive  types,  382,  597. 
Compsacanthus  levis,  343. 
Compsemys,  5U9. 
Comptonia,  515. 
Conchifers.         See        LAMELLI- 

BRANCHS. 

Conchiosaurus,  428. 
Concretionary  rocks,  63. § 

structure,  85, §*  222,  628. 
Concretions,  origin  of,  339,  478, 

628. 

Condrusian  group,  306. 
Cones,  fossil,  329. 
Confervse,  611. 
Conformability,  100.  §* 
Conformity  of  strata,  101. §* 
Conglomerate,    62,    65, §   230,§ 

limestone,  167,  184. 
Conifers,  134,  §  321,  330. 

ash  of,  365. 

Carboniferous,  296,  323,  328, 
330.  356,  332. 

Hamilton,  270. 

pith  of,  331. 

range  of,  in  time,  140.* 

Tertiary,  497- 

Triassic,  403 
Coniosaurus,  475. 
Coniston  grits,  244. 
Connecticut,  Archaean  in,  150. 

Quaternary  in,  530,  531,  549, 

terraces  in,  548. 
trap  dikes  of,  20  *  418  *  452. 
Triassic  in,  405,  419. 
Connecticut  Valley,  Devonian 

in,  290. 

of  Triassic  age,  420. 
submarine    continuation    of. 

540. 
terraces  in,  559.* 


Connecticut  Valley,  trap  dikes 

of,  20,*  418,*  452. 
Tria<sic  in,  404. 
Connell,   analysis  of  coprolite, 

61. 

Conocardium,284,  610. 
aequicostatum,  247. 
Blumenbachii,  189,  190. 
dipterum,  208.* 
immaturum,  203. 
Meekanum,303. 
trigonale,  260,*  261. 
Conocephalus.     See    CONOCORY- 

PHE. 
Conocoryphe,  168, 178, 180, 188, 

189,  190,  192. 
Adamsii,  178. 
applanata,  180. 
bulb,  180. 
humerosa,  180. 
invita,  180. 
lowens-is,  177,*  178. 
Matthewi,  175,*  176. 
minuta,  177,*  178. 
striata,  180. 
Teucer,  178. 
trilineata,  178. 
variolaris,  180. 
Vulcanus,  178. 
Conodont  teeth,  208. 
Conophyllum,  229. 
Conoteuthis,  475. 
Conrad,   T.   A.,    on    California 

Cretaceous,  458. 
Consolidation    of    strata,    400, 

725. 
causes  of,  692,  693,  694,  695, 

760. 

Constituents  of  rocks,  47  § 
Continent,  definition  of,  29. § 
erosion  over,  when  near  the 

ocean's  level,  672. 
Continents   and    oceans,    early 

outlined,  160. 
arrangement  of,  11, 13. 
distinctive    animal   types  of, 

610. 

formation  of,  738. 
growth  of,  250,  286. 
independent,  666. 
mean  heights  of,  14. 
position  of  outlines  of,  38. 
pressure  against,  745. 
submerged    borders    of,    11, 

422,*  671. 

system  in  reliefs  of,  23,  744. 
volcanoes  within,  704 
Contraction,    change    of    level 

from,  701. 
effects  of,  in  a  cooling  sphere, 

712,  735. 

in  glass  and  rock,  702. 
Conularia,  203,§  229,  253,  303, 

371. 

subtilis,  247. 
Trentonensis,  203.* 
last  of,  449. 
Conus,  475,  508. 
adversarius,  511. 
deperditus,  518. 
tortilis,  509. 
Cook,   G.   H.,    on   New  Jersey 

Cretaceous,  457. 
on  subsidence  of  U.  S.  coast, 

583. 
Cooling  of  the  globe,  147,  754. 

its  consequences,  735. 
Coomhala  grit,  306. 
Coos  group,  237,  256. 


Cope,  E.  D.,  Bathygnathus,  41". 

Cretaceous  turtles,  466. 

evolution,  604. 

Lselaps,  464. 

Mosasaurs,  468. 

papers  by,  468. 

Port  Kennedy  bone-cave ,  567. 

Rhabdopelix,  417. 

Triassic  Dinosaurs,  413,  414. 
Copper,  bowlders  of,  529. 

of  Lake  Superior,  185. 
Copper  ore  in  the  Oneida,  222. 

in  Triassic,  420. 

in  Cretaceous,  458. 
Copperas,  268. 
Coprolites,  60. § 

analyses  of,  61. 

Jurassic,  445,  446.* 

Permian,  373. 

Saurian,  445,  446.* 

Triassic,  417,  428. 

Upper  Silurian,  247. 
Coralliar-  group  435. 
Corallines,   60,  135. § 
Coralline  Crag,  513,  519. 

limestone,  221,  230. 
Coralline  zone,  611. 
Corallium  nobile,  60. 
Coral  animals  destroyed  by  sub 
sidence,  *209. 

limits  of  growth  of,  617. 
Coral  islands,  617,  618.* 

chalk  on,  477,  619. 

evidence  from,  of  change  of 
level  iu  the  Pacific,  583, 
735,  753. 

gypsum  on,  235. 

sections  of,  619,*  624.* 

works  on,  625. 
:  Coral  limestone,  75,§  617. 
i     Rag,  433. 
Coral  reefs,  617,  620,  622.  624. 

rate  of  increase  of,  591. 

reef  seas,  isothermal  line  lim 
iting,  43,  617. 

i      temperature  1'miting,  610. 
i      thickness  of,  623. 
i  Coral  rocks,  619. 
Corbicula,468,  493,  508. 

aequilateralis,  508. 

fracta,  508. 

intermedia,  501,*  508. 

securis,  508. 
Corbis,  483. 
Corbula,  475,  508. 

bicarinata,  509. 

gibbosa,  509 

longirostris,  518. 

mactriformis,  501,*  508. 

pisum,  519. 
Cordaites,  328,§  329,  349,  351. 

borasMlblia,297,  330,  331. 

Robbii,  269,*  271. 
Cordillera,  15. § 
Cork,  the  composition  of,  361, 

362. 

Cormorants  iu  the  Cretaceous, 
466. 

in  the  Tertiary,  503,  511. 
Cornbrash,435. 
Corniferous  epoch,  254. 

limestone,  254,  256. 

period,  254. 
Cornstone,  282. 
Cornus,  497. 

Corsica  range,  elevation  of,  525. 
Corydalis  Urongniarti,  351. 
Corylus,  497. 

McQuarryi,  498. 


798 


INDEX. 


Coryphodon,  516.  § 

Eocaenus,  518. 
Coscinodiscus,  634.* 

apiculatus,  496.* 

atmosphericus,  634.* 

gigas,  496.* 
Cosmogony,  765. 
Cotopaxi,  703. 
Country-rock,  114.  § 
Cox,    E.    T.,   analyses  of  coal, 

316. 

Crab,  120,*  122,§  500,  592,  593, 
611. 

first,  441,  483. 
Crag  of  England,  513. 
Crane,  511,  516. 

Crania,  173, §*  174,  200,  385, 
448\  474. 

antiqua,  173.* 

divaricata,  207-  * 

range  of,  in  time,  387.* 
Crannoges   576. 
Crassatella,  475,  483,  508. 

alta,  499,*  508,  509. 

Mississippiensis,  509. 

sulcata,  519. 
Craters,  702,  706.*§ 

See,  further,  VOLCANOES. 
Craw-fish,  608. 
Crawfordsville  crinoids,  303. 
Creation  unexplained,  758. 
Credner,    II.,    Marquette    iron 
region,  160. 

Appalachian  Huronian,  160. 
Crepicephalus,  178,  190. 
Crepidula    costata,    495,    500,* 
510. 

fornicata,  561. 

Cretaceous  N.  American,  map 
of,  479.* 

period,  403,  453. § 

species,  distribution  of,  476. 
Crevasse,  678,  682.§ 
Crickets,  450. 
Cricodus,  264.* 
Cricopora,  474. 
Crinideans,  128. § 

number  in  L.  Silurian,  203. 

range  of,  in  time,  386.* 
Crinoidal  period,  297. 
Crinoids,  117,*  128,§  225,  249, 
297,    332,  341,    382,§  482, 
595,  597,  611. 

a  comprehensive  type,  597. 

first,  175. 

Primordial,  177- 
Crioceras,  462.  § 

Duvalii,  413,*  475,  476. 
Cristellaria  rotulata,  466,  476. 
Criteria  of  rank ,  592. 
Crocodiles,  509,  510,  516,  520. 

first  of,  433. 

Tertiary,  502. 

Crocodilians,  121, §  338, §  371, 
433,  443,  444,  450,  464,  481, 
510,598. 

range  of,  in  time,  589.* 
Crocodilus,  450,  509. 

Hastingsiae,  519. 

macrorhynchus,  509. 

range  of,  in  time,  589. 

Squankensis,  509. 

toliapicus,  518. 

Croll^  effects  of  eccentricity  of 
earth's  orbit,  698. 

Gulf  Stream,  755. 
Crotalocrinus      rugosus,      245, 

246,*  247- 
Cromer  forest-bed,  556,  571. 


Crust  on  rocks,  691.  § 

Cyathophyllum,  206,  230. 

Crustaceans,    121,  §   122,§   283, 

caespitosum,  284. 

383,§   483,   592,    595,   608, 

helianthoides,  265. 

610,  611,  671. 

rugosum,  259,*  261. 

culmination  of,  598. 

truncatum,  247. 

number  of  Silurian,  249. 

Cybele,  208. 

range  of,  in  time,  387-* 

Cycadeoidea      megalophylla, 

rank  of  earliest,  253. 

436.* 

Crustacean   tracks    of  Triassic, 

411.* 

Cycads,  349,  408,§  458,  459,  471, 
597. 

of  Potsdam,  169,  176.* 

a  comprehensive    type,   383, 

of  Subcarboniferous,  304. 

597. 

Cruziana  bilobata,  225.* 

culmination  of,  482. 

Crypheus,  174.  § 

in  Maryland  beds,  459. 

Cryptacanthia  compacta,  341. 

range  of,  in  time,  140.* 

Cryptoceras,  203  § 

Cycas  circinalis,  408.* 

Cryptoceras     undatum,     201,* 

Cyclas  rivularis,  548. 

203. 

Cyclocardia  borealis,  551. 

Cryptocrystalline,  64.  § 

Cyclocladia,  348. 

Cryptodon  angulatum,  618. 

Cycloids,  265.§* 

Cryptogams,  133.§ 

Cyclonema,  203. 

existing,  323. 

bilix,  206. 

Crystal  kingdom,  l.§ 

cancellatum,  224,*  228. 

Crystalline  rocks,  62,§  489. 

quadristriatum,  247. 

characters  of,  (54. 

Cyclophthalrnus    senior,    350,* 

formation  of,  63,  706. 

351. 

Crystallization,  627,  §  760. 

Cyclops  group.  122.  §* 

a    result  of   metamorphism, 

range  of,  in  time.  388*. 

214,  400,  726. 

Cyclopoid  Crustaceans,  249. 

of  rocks,  156,  214. 

Cyclopteris,  348,  433. 

Crystallizations,     alongside     of 

AcadSca,  297. 

dikes,  419. 

Bockschii,  297. 

Crystals,  627  § 

Brownii,  278. 

Ctenacanthus,  275,  304,  351. 

elegans,  327  *  330. 

major,  308.* 

Gilboensis  277. 

vetustus,  274. 

Halliana,  278. 

Ctenodonta  Angela,  190. 

Hibernica,  283. 

varicosa,  208. 

Jacksoni,  269,*  271,  278. 

Ctenodus,  282,  351. 

linnaaifolia,  407,*  409. 

Ctenoid*,  265.  §* 

minor,  280.* 

Ctenoptychius,  343,  351. 
Cucullsea  capax,  456. 

obtusa,  279,  297. 
Roerneriana,  283,  307. 

Culmination  of  types,  386  *  588, 

Rogersi,  278. 

597. 

Cyclostigma  minutum,  283. 

Cumberland  Mrs.  ,  faults  in,  398. 

Kiltorkense,  283. 

Cuneolina  pavonia,  131,*  471,* 

Cyclostoma  lapidnria,  548. 

474. 

Cylindrites  acutus,  449. 

Tup-corals.      See    CYATIIOPHYL- 

Cymbella  maculata,  634.* 

LOIDS. 

Cymbophora  Ashburnerii,  458. 

Cupressus,  450. 

Cynodon,  519.  § 

Curculioides  Ansticii,  351. 

Parisiensis,  519. 

Curculionids,  449. 

Cyperites,  499. 

Curculionires,  428. 

Cyperus,  499. 

Currents,  atmospheric,  43. 

Cyphaspis,  249. 

Atlantic  in   the    Quaternary, 

Cyphosoma,  466,  474. 

541. 

Cyprsea,  483,  5'  0,  508. 

Atlantic    in    the   Cretaceous, 

first  of,  475,  477. 

451. 

Carolinensis,  500,*  511. 

oceanic,   38  *    658,   661,   665, 

Europsea,  519. 

754. 

fenestralis,  509. 

oceanic,  erosion  bv,  663. 

lintea,  509. 

tidal,  660,  665,  668. 

pediculus,  511. 

Curtis,  J.,  on  life  in  hot  springs, 

spheroides,509. 

612. 

Cypress,  526. 

Cutch,  recent  changes  of  level 

Cypricardia  angusta,  281.* 

in,  584. 

Cypricardina  Indianensis,  303. 

Cuttle-fish,  124,  f  125,  483. 
Cuvier  on   Tertiary  Mammals, 

Cypridina  serrato-striata,  285.* 
slates,  282,  285. 

517. 

Cyprimera  isonema,  508. 

Cyanite,  57,§  723. 

CyprSna,  475. 

Cyathaxonia  Siluriensis.  247., 

arenaria,  468. 

Cyathea  compta,  325,*  330. 

Islandica,  519. 

Cyathina,  474. 

Morrisii,  518. 

Bowerbankii,  476 

rustica,  519. 

Cyathocrinus,  372,  303,  341. 
Cyathophvlloids,  225,  249,  252, 

Cypris,  122§,  450. 
in  Triassic,  416. 

255,  259,  283,  371,  482. 

Cyrena,  450,  508. 

range  of,  in  time,  385,  386.* 

arenaria,  468. 

last  of,  371. 

Carltoni,  508. 

INDEX. 


799 


Cyrena  cuueiformis,  518. 

intermedia,  501. 

pulchra,  519. 

semistriata,  513,  519. 

shale,  513. 

tellinella,  518. 
Cyrtia,  171, §  429. 
Cyrtina,  171. 

rostrata,  256. 

umbouata,  274. 
Cyrtoceras,  228,  229,  429. 

annulatum,  201,*  203. 

imiequiseptum,  208. 

multicameratum,  208. 

sacculum,  274. 

undulatum,  261. 
Cyrtodonta,  203,  243. 

Hindi,  205. 
Cyrtolites,  203. 

compressus,  201,*  203. 

imbricatus,  203. 

ornatus,  206. 

Trantoneoris,  201,*  203. 
Cystideans,    or    Cystids,   129,§ 
332.§ 

a  comprehensive  type,  382. 

last  of,  288. 

number    of,    in  L.   Silurian, 
203. 

range  of,  in  time,  385,  386. 
Cystiphyllum,  230. 

Siluriense,  245,  246,*  247. 
Cy there,  304. 

Americana,  120.* 
Cytherea.  475. 

Sayana',  495. 

Dachstein  beds,  425,  429. 
Dacite,  78.§ 
Dadoxylon,  349,  371. 

Brandling!,  331. 

Ouangondianum.  271. 
Dakota,  Archaean  in,  150. 

Cretaceous  in.  456. 

Jurassic  in,  431. 

Triassic  in,  403 
Dakota  group,  456. 
Dalmanites,  174,5  204,  228,  229, 
249,  253,  285. 

Boothii,  274. 

callitelea,  273,*  274. 

Hausmanni,  174,*  240. 

limulurus,  227,*  229. 

nasuta,  248. 

pleuroptyx,238,240,  243 

selennrus,  261. 
Damour,  A.  on  composition  of 

Millepores,  60. 
Darnourito,  54.  § 
Danian  group,  470. 
Dan  River  coal-field,  408. 
Dapedius  politus,  449. 
Darien,  Isthmus  of,  659,  756. 
Dartmouth  group,  282. 
Darwin,   C.,  on    Atlantic   dust- 
shower,  634. 

on  coral  islands,  625. 
Dasyceps  Bucklandi,  372. 
Dasypus  group,  570. 
Data  of  geology,  4.§ 
Datolite,  734. 

Daubree,  formation  of  silicates 
by  means  of  superheated 
steam,  727. 

on  chrysolite.  736. 
Davidson,   T.,  on  Brachiopods 

169. 

Davidsonia,  173.§ 
Davis,  effects  of  tidal  action,  668. 


Dawsonella  Meeki,  333*,  342. 
Dawson,  J.  W.,  Annelids  in  Ar 
chaean,  159. 

carbon  in  Archaean,  157. 

Devonian  life,  274. 

Eozoic  time,  148. 

Eozoon,  158. 

tosi-il  wood,  258,  270,  331. 

iron-ores  in  Nova  Scotia,  74. 

Joggins  section,  319, 

land-snails,   Carboniferous, 
341,  358. 

metamorphic  Devonian,  289. 

origin  of  coal,  362. 

Quaternary  mollusks,  551. 

Rhizopods,  189. 

spores  in  coal,  318. 

Xylobius,  350. 
Day,  768. 
Dead  Sea,  14. 

Deane,on  tracks  of  Insects,  41 6. 
Death's  Valley,  15. 
Debituminization,  400,  725. 
Decapods,  122,§  335. 

range  of,  in  time,  388.* 
Decomposition  of  wood,  362. 

of  rocks,  688. 
Deep  River  coal-field,  406. 
Deep-sea  Coral  zone,  611. 
Deer,  506,  507,  508,  518,  520, 

564,  568,  577. 

Delaware,  Cretaceous  in,  455. 
Delaware   River,   in   the  Creta 
ceous,  478. 

Delesse,  on  contraction  in  rocks, 
702.  _ 

on  moisture  in  rocks,  656.   . 
Delphinus,  520. 

Com-adi,  511. 
Delta  formations,  651,  670 

of  the  Indus,  recent  changes 

of  level  in,  585. 
Delthyris  shaly  limestone,  164, 

237. 

Delthyris.     See  SPIRIFEB. 
Deltidium,  170.§ 
Deltodus,  304. 
Dendrerpeton  Acadianum,  343. 

Oweni,  343. 
Dendrocrinus    204. 
Dendrodus,  286. 
Dendrograptus  Hallianus    177- 
Dendruphyllia,  117,*  619. 
Denmark,  Cretaceous  in,  470. 

human  remains  in   576. 

Quaternary  in,  532. 
Dentalina  pulchra,  466. 
Dentalium,  385. 

Meekianum,  342. 

Mississippiense,  499  *  509. 

obsoletum,333.*342. 
Denudation    complicating    out 
crops,  96.§ 
Deoxydation,  696. 
Depth  of  growing  corals.  617. 

of  species,  zones  in,  611. 

See  OCEAN. 

Descent  of  rivers,  636. 
Deserts,  distribution  of,  45. 

sands  of,  631. 
Desmids,  135  § 

in  hornstone  or  flint,  257,  302, 

471. 

Desor,  E.    on  Niagara  retroces 
sion,  590. 

Destruction  of  life.     See  EXTER 
MINATIONS 

Determination  of  age  of  strata, 
102.  § 


Detritus,  66,§  648. § 
along  sea-shores,  667,  668. 
of  rivers,  648. § 
Development,    law    of,  in    the 

earth's  history,  756. 
Devonian  Age,  139,  254. 
and     Carboniferous     plainly 

separated,  281. 
and      Carboniferous     uncon- 

formable,  289. 
and  Silurian    united  by   the 

Ludlow  beds,  244. 
foreign,  282. 

in  New  England,  237,  256. 
life  of,  288. 
thickness    of   rocks    of,  373, 

381. 

I      wanting  in  Dakota,  232. 
Diabase,  78,§  736. 
j  Diabasyte,  70,§  78. 
iDiadema,466,474. 
Bennettiae,  476. 
seriale,  437,*.  448. 
Diallage  rock,  73.§ 
Diatoms,  59,  60, 135,§  496,*  611, 

617,  632.* 
in  flint,  257,*  471. 
of  Virginia  Tertiary,  496.* 
Dibranchs,  124. §  439,  483. 
Dicellocephalus,  168,  174, §'178, 

188,  190,  192. 
Minnesotensis,  177,*  178. 
Die-eras  arietinum,  438,*  449. 
Dichobune,  519. 
cervinum,  619. 
Dichocriuus,  303. 
Dichodon,519. 
j      cuspidatus,  519. 
Dichotomizing  ribs  on  Brachio 
pods,  243. 

j  Dick,  analysis  of  coal,  316. 
I  Dicotyledons,  134, §  609. 
!      range  of,  in  time,  140.* 
,  Dicotyles,  511.  565. 
,antiquus,  511. 
Hesperius,  511. 
priftinus,  511. 
Dictjochacrux,496.* 
Dictyoneura         anthracophila, 

350  *  331. 
Humboldtiana,  351. 
libelluloides,  351. 
Dictyopteris,  348. 
Didymograptns  geminus,  192. 

hirundo,  192. 
Difficulties   in   determining  age 

of  rocks,  101. § 
Dikes,  formation  of,  716. 
structure  of,  109, §  lll.§* 
of  Connecticut  valley,  origin 

of,  716. 

Diluvian  epoch,  543. 
Dimorphodon  macronyx,  449. 
Dim  varies,  126  § 

range  of,  in  ti'me,  387.* 
|  Dinicthys  Hertzeri,  274,  275. 
Dinictis,511. 
Dinoceras,  494,  504,§*  510. 

mirabile,  504,*  610. 
Dinophis  grandis,  509. 
Halidanua,  509. 
littoralis,  509. 
Dinornis,  580. § 

giganteus,  580. 

Dinosaurs,  338,?  413.$  443,444, 
450,  457,  464,  484,  501,  509, 
592: 

last  of,  484. 
range  of,  in  time,  589.* 


800 


INDEX. 


Dinothere  (D.  giganteum),518,* 

520. 

Diorite,  70.§ 
Dioritic  slate.  70. § 
Diospyros,  515. 
Dip,  94,§*  97-§* 
Diphyphyllum    arundinaceum, 
256. 

stramineum,  256. 
Diplocynodus,  510. 
Diplodus,  304,  343. 

compressus,  343. 

gracilis,  343. 

latus,  343. 
Diplograptus,  207. 
Diplopterus.  286. 
Diplostylus  Dawsoni,  342. 
Diploxylon,  349. 
DipristisMiersii,467. 
Diprotodon,  571. 
Dipters,449,  450,  610. 
Dipterus,  282. 

macrolepidotus,  286.* 
Dirt-bed,  Portland,  452. 
Dirt-beds  of  the  Coal-measures, 

313,  319. 

Discina.   173,§*  174,   190,   199, 
203',  271,385,  500,  597. 

Acadica,  174  *  176. 

family,  170. §*  199,  386,*  594. 

lamellosa,  173.* 

punctata,  207. 

range  of,  in  time,  386.* 
Discosaurus,  464. 

carinatus,  467. 

Disintegration     from     freezing, 
674. 

without  decomposition,  701 
Dislocations,  92. §* 

See  DISTURBANCES. 
Distortions  of  fossils,  98,§  99.* 
Disturbances    after    Devonian, 
289,  754. 

after  Jurassic,  452. 

after  Lower  Silurian,  211,  212, 
754. 

after  Mesozoic,  48". 

after  Paleozoic,  395. 

during  Mesozoic,  486. 

during  Paleozoic,  392. 

during  Primordial,  181. 

during  Subcarboniferous,  306. 

during  Tertiary,  523.  740. 

in  Recent  period,  582. 

preceding  Carboniferous,  308. 

of  Archaean  rocks,  155. 

of  Triassic,  417. 
Dithyrocaris  carbonarius,  342. 
Diversity   of  rocks  in  different 

regions,  373. 
Divine  origin  of  the   universe, 

596. 

Dodo,  580,§  581.* 
Dog,  562,  568. 
Dog-tooth  spar,  222. 
Dog-wood,  497. 
Dolabra  Sterlingensis,  205. 
Doleryte,  78.§  707,  722,  736. 
Dolerytic  glass,  78. § 
Dolichosaurus,  476. 
Dolomite,  55,§*  74,§  222,  696. 
Dolphin,  507. 
Donax,  508. 

D'Orbigny's  subdivisions  of  Ju 
rassic,  435. 

subdivisions    of    Cretaceous, 

470. 

Dorsal  valve,  170. § 
Dorsibrancbs,  123' § 


Dorycrinus     unicornis,      298  * 

303. 

Dosinia,  508. 

Dove,  on  temperature,  44. 
Dracasna,  450. 
Dragon-fly,    fossil,    349,    441  * 

450. 

Dreissena,  610. 
Drepanacanthus,  304. 

anceps,  343. 
Drepanocheilus       Americanus, 

461,*  467. 
Drepanodon, 511. 
Drew,  on  alluvial  fans,  651. 
Drift,  527.§ 

deposition  of,  543. 
distribution  of,  528. 
origin  of,  534. 
period,  534. § 
scratches,  530.* 
stratified,  544. 
unstratifled,  544. 

See.  further.   GLACIAL   and 

GLACIER. 

Drift-sand  hills,  631. 
Dromatherium  sylvestre,  415,* 

417. 

Dry-bone,  197. 
Dryopithecus,  519. § 
Dublisian  group,  435. 
Dugong,  518. 
Dumenil,  analysis  of  fish-bones, 

60. 

Dunes,  631. § 
Dunyte,  71.§ 
Dupont,  E.,  on  Belgium  in  the 

Recent  period,  562. 
on  fossil  man,  576. 
Durability  of  rocks,  645.  » 
Durocher,  on  moisture  in  rocks, 

656. 

Dust-showers,  632.* 
Dust,  transportation  of,  630. 
Dyas,  369. §     See  PERMIAN. 
Dyestone  group,  379. 
Dynamical  Geology,  7.§  605. 
agencies    intensified    in    the 

Quaternary,  587. 
Dysaster  ringens,  449. 

Eagle,  503,  511. 
Eagre,  660,§  666. 
Earth,  as  an  individual,  2. 
relation  of,  to  the  universe,  3. 
form  of,  and  arrangement  of 

land  of,  9. 

evolution  of  features  of,  744. 
system  in  reliefs  of,  23. 
svstem     in     the    courses    of 
"  feature-lines  of,  29,  744. 
Earth's  crust,  effects  on,  of  con 
traction,  737,  739. 
development,  law  of,  in  geo 
logical  history,  756 
Earthquake  oceanic  waves,  662, 

665,  742. 
Earthquakes,  nature  and  origin 

of,  741. 

Earth-worm,  122,  123. § 
Eastern-border  region,' 146, 167, 
197,  210,  232,  238,  241,  250, 
251,  266,  289,  291,  319,  380, 
401. 

reality  of.  210,  250. 
East  Indies,   trends  of  islands 

in,  33,  35. 
volcanoes  in,  704. 
Eatonia,  171. 
peculiaris,  243. 


I  Eatonia  singularis,  239,*  240. 
!  Eaton,D.  C.,on  focsil  ferns, 271. 
Ebb-and-flow  structure,  S3.§* 
Eccentricity    of   earth's    orbit, 

697. 

Ecculiomphalus        Canadensis, 
189. 

Bucklandi,  208. 

intortus,  189. 
Echinoderms,  127, §  598. 

number  of  Silurian,  249. 

range  of,  in  time,  386.* 
Echinoids,  127,§  472,  482. 
Echinorhinus,  510. 
Echinosphse rites,  207. 
Echinostachys  cylindrica,  426. 

oblonga,  426. 

Echinus,  117,*  127,§  297,  595, 
608,  611. 

granulosus,  476. 
Eclogyte,  71. § 

Economical  products,  Archaean, 
153,  159. 

Canadian,  185. 

Carboniferous.  313,  318. 

Corniferous,  256. 

Cretaceous,  458. 

Hamilton,  268. 

Niagara,  222. 

Primordial,  169. 

Salina,  234. 

1  ertiary,  495. 

Trenton, 197. 

Triassic,  406,  420. 
Edaphodon  mirificus  467. 
Eddy-marks,  S5.§ 
Edentates,  569,  592,  610. 

characteristic  of  Quaternary 
South  America,  570,  571. 

earliest  of,  518. 

range  of,  in  time,  589.* 
Edestosaurus,  468. 

dispar,  468. 
Edriocrinus,  240,  243. 
Edwards,   A.     Milne,    Tertiary 

birds,  516. 

Effects  referred  to  causes,  758. 
Egypt,  Tertiary  in,  512. 
Ehrenberg,    Diatoms    of   Rich 
mond,  496. 

dust-showers,  632.* 

Foraminifers  in  chalk,  471. 

growth  of  Diatoms,  etc.,  615. 

Polyc\  stines,  615. 
Eifel,'Devonian  in,  282. 
Elaeacrinus,  261. 
Elasmosaurus  platyurus,  464. 
Elements    cons-tituting    rocks, 
48.  § 

made  stable  by  oxygen,  48  § 
Elephant,    416,  495,  5<  3,  50*8, 
518,    561,    56i.  565,§  567, 
571,  572,  576,  577. 

family ,  range  of,  in  time,  589.  * 

preserved  in  ice,  565 
Elephas,  519,  520. 

Africanus,  565. 

Americanus,  508,  565,  566-* 

antiquus,  565,  571. 

imperator,  511. 

meridionalis,  513,  519,  571. 

primigenius,  564,  565, §  571, 

573,*  581. 
Elevations,  causes  of,  735,  761. 

extensive,  735. 

modern,  582. 

of  Pacific  islands,  583. 

Tertiary,  in  Europe,  533. 

See  HEIGHTS. 


INDEX. 


801 


Elk,  564,  563,  576,  577. 
Elliptocephalus  asaphoides,  178. 

depressus,  180. 
Elotherium,  507,  511. 

crassum,  511. 

Leidyanuui,  511. 

Mortoni,  511. 
Elvanyte,  71  § 

Embalorhvnchus  Kinnei,  509. 
Emery,  K.^  analyses  of  coal,  316, 

317. 

Emmons,  E.,  disturbances  after 
Primordial,  182. 

labradorite  localities,  152. 

sections  of  Azoic  by,  153  * 

Taconic    in  North    Carolina, 
160. 

Taconic  in  Vermont  and  New 
York,  167. 

Triassic  in  N.  Carolina,  406. 
Emys,  5U9,  510,  519. 
Enaliosaurs,    339,§     341,    343, 
414. 

range  of,  in  time,  388,*  589.* 
Enchodus,  467. 

semistriatus,  467- 
Encrinal  limestone,  237,  267. 
Encrinital  limestone,  379. 
Encrinites,  128. § 
Encrinurus,  2<J4,  228. 

levis,  249. 

puuctatus,  247. 

variolaris,  247. 
Encrinus  liliiformis,  117,*  426,* 

428,  429. 
Endoceras,  203. § 

proteiforine,  203. 
Endogens,  134. § 
Endopachys  Maclurii,  509. 
Kuglaud,  Carboniferous  in,  309, 
344,*  315,  347,  647. 

climate  of,  44. § 

coast-erosion  in,  653. 

Cretaceous  in,  469. 

Devonian  in,  282. 

disturbances  in,  290,  4  »2,  525. 

in  the  Cretaceous,  480,  485. 

in  the  Quaternary,  541,  555, 
564,  572. 

Jurassic  in,  433,  450. 

Permian  in,  3'39,  402. 

Primordial  in,  179. 

Quaternary  in,  532,  533 

Quaternary  Mammals  of,  563. 

rock-salt  in,  424. 

sand-hills  of,  631. 

Silurian  in,  162,  203,  244. 

Subcarboniferous  in,  303. 

Tertiary  in,  511. 

Triassic  in,  423,  425,  429. 

geological  map  of,  314.* 
Enhydriodon,  520. 
Entolium  aviculatum,  342. 
Entomostracans,  122.  §* 

range  of,  in  time,  3S7-* 
Eobasileus  pressicornis.  510. 
Eocene,  489,5  493,499,  503,  512, 
514,  518. 

See,  further,  TERTIARY. 
Eocidaris,  372. 
Eolian  limestone,  196. 
Eophrymus  Prestwichii,  351. 
Eophy ton  Linneanum ,  176. 

sandstone,  180. 
Eopteria  typica,  190. 
Eosaurus  Acadianus,  340,*  3i3. 
Eoscorpius    carbonarius,    334* 

342. 
Eospongia  Roemeri,  190. 

51 


Eospongia  varians,  190. 

Eozoic,  148. § 

Eozoon,  148,  158,§  189,  208. 

Eavaricum,  159,  180. 

Canadense.  158.* 
Ephemera,  273,  411,  449. 
Epiaster  elegans,  468. 
Epidote,  57, §  727,  728. 
Epidote-euphotide,  71  •§ 
Epiornis.     See  ^EPVORMS. 
Epithemia  Argus,  634.* 

gibba,  634.* 

gibberula,  634.* 

longicornis,  631.* 
Epochs,  142.* 
Epsom  salts,  63 0. 
Equisetites,  348. 
Equisetum,  133,§  321,  323,  327, 
354,  370,  426,  429. 

arvense,  3^o. 

ashes  of,  8t>5,  336. 

composition  of.  361 

hyemale,  332,  366. 

llogersii,  409. 

telmateia,  365. 
Equatorial  Zone,  6^9. 
Equus  506,  5'»7,  511,  519,  52). 

caballus,  564. 

excelsus,  511. 

fossilis,  564. 
Erdmann,  Swedish  Quaternary, 

541. 

Eremopferis,  343. 
Erie  clays  545. 

shales,  376 
Erinaceus,  519, §  520. 
Erisocrinus,  341. 
Erosion  by  action  of  rivers,  637. 

by  glaciers,  538,  684 

by  oceanic   movements,  663, 
664.* 

by  drift  sand*.  632. 

extent    of,    over    continents, 
647. 

increase  of,  in   the  Post-ter 
tiary,  587. 

in  the  Carboniferous,  358. 

modified   by  rock-characters, 
640. 

over  continents,   when    near 
the  ocean's  level,  672 

topographical  effects  of,  644. 

of   the  channel  of   Niagara, 
590. 

of  the  channel   of  the  Colo 
rado,  640.* 
Erubescite,  733 
Eruptions,  volcanic,  710,  712.* 

in  the  Tertiary,  524. 
Eruptive  rocks,  76. 
Erynnis  venulosa,  ISO. 
Eryon  arctiformis,  441,*  449. 

Barrowensis,  449. 
Eschara,  119,*  127, §  474. 
Escharina,  474. 
Escharipora,  466. 
Esopus  millstones,  220. 
Estheria    minuta,     426*     428, 
429. 

ovalis,  410,*  416. 

ovata,  410,*  416. 

parva,  410,*  416. 
Ettingshausen,  climate  of  Eu 
rope  in  the  Tertiary,  526. 
Eocene  plants,  515. 
Eucalyptocrinus  decorus,  247- 
Eucalyptus,  497,  498. 
i  Euchasma  Blumenbachii,  190. 
|  Eucvrtidiuin  Mongolfieri,  132.* 


Eugnathu?,  417. 
Euliuia,  5'"'S. 

chrysalis,  508. 

funicula,  508. 

inconspicua,  5C8. 
Eumys,  511  § 
Euiiema,  263. 
Eunice,  123- 
Eunotia  amphioxys,  634.* 

grauulata,  634.* 

levis,  634.* 

tridentula,  634.* 

zebrina,  634.* 

zygodon.  634.* 
Euomphalus,  168,  281,  284,  429. 

Spergeuensis,  303. 

subrugosus,  342 

uuiaugulatus,  189.* 

vatidmis,  178. 
Eupacliycrinus,  341. 
Eupagurus  longicarpus.  561. 
Euphemerites  affiuis,  343. 

gigas.  343. 

simplex,  343. 
Etiphoberia  anthrax,  350. 

armigera,  334,*  342. 

Brownii,  350. 

major,  342. 
Euphotide,  7U,  71.  § 
Euproops  Danaj,  333,*  342. 
Euronectes  fimbriatus,  350.* 
Euryte,  68. § 

Europe,  American  types  in.  514. 
526. 

and  America  contrasted,  394. 

and  Asia  one  continent,  25 

Archaean  in,  151. 

Australian  types  in,  515,  526. 

disturbances  in,  after  Paleo 
zoic,  402. 

geography  of,  217,  288,  480, 
488,522,525,541,555,  562. 

in  the  Cretaceous,  480. 

mean  height  of,  14. 

Quaternary  in,  532. 

Quaternary  Mammals  of,  563. 

Tertiary  climate  of,  526. 

Tertiary  disturbances  in,  525. 

through  the  Mesozoic,  481,487. 

trends  in,  37.* 

European    types    in   American 
fossils,  250. 

in  Greenland,  514. 
Eurylepis,  343. 

tuberculatus,  336  *  342. 
Eurypterus,  253,  282,  283. 

family,  249. 

Mazonensis,  342. 

pulicaris,  274 

range  of,  in  time,  388.* 

remipes,  239,*  240,  248. 
Eutaw  group,  456. 
Excrements  of  animals,  613. 
Exogens,  133.  § 
Exogyra,  460,§  469,  473. 

arietina,461,*467. 

Boussingaultii,  476. 

columba,  476. 

conica,  476. 

costata,  461,*  467,  468,  46t>. 

Couloni,  475. 

lateralis,  476. 

levigata,  476. 

parasitica,  467. 

sinuata,  475. 

virgula,  483,*  449. 
Expansion ,  change  of  level  from, 

from  heat,  7uO. 


802 


INDEX. 


Extermination   of   tribes,   fam- 

Fingal's  Cave.  716. 

ilies,   genera,   species, 

181, 

Finland,  Archaean  in,  151. 

209,  364,  487,  542,  554, 

746, 

Fin-spines,  262,  §  274. 

763. 

Fiord  valleys,  533,  540. 

causes  of,  488. 

Fir-cones  in  Triassic,  409. 

modern  examples  of,  579. 

Fir,  609. 

Fire-clay,  312. 

Facial  suture,  174.  § 

Firn,  678.  § 

Fagus,  459,  497,  498,  515. 

Fishes,  12l,§  a36,  351,  484,  592, 

Deucalionis,  498,  514. 

594,  595,  602. 

ferruginea,  497,*  498. 

age  of,  139. 

polycladus,  460. 

classification  of,  261. 

Fahlbands,  114.  § 

first  of,  247. 

Fahlunian  beds,  513. 

first  American,  261,  262.* 

Falls  of  the  Ohio,  coral  reef  of, 
255. 

first  Osseous,  442. 
fossil,  localities  of,  520. 

False  Coal-measures,  295,  320. 

number  of  Silurian,  249. 

Fan-palm,  497. 

range  of,  in  time,  140,  388.* 

Fasciolaria,  5v8. 

rarely  exterminated,  614. 

first  of,  475,  477. 

Fish-scales,  composition  of,  61. 

buccinoides,  461,*  467. 

Fish-teeth  in   the   Lower   Silu 

rhomboidea,  oil. 

rian,  supposed,  208. 

Faults,  93,§  90. 

Fissures,  dikes  formed  in,  714. 

origin  of,  741. 

See  FRACTURES. 

in  the  Appalachians,  184. 

214, 

Flabellaria,  349,  497. 

395,  647. 

Eocenica,  498. 

Fauna.     See  LIFE. 

latania  498. 

Favistella,  288. 

Zinkeni,  498. 

stellata,  204.* 

Flabellina   rugosa,   131,*  471  * 

Favosites,  225  *§  240,  249, 

252, 

474. 

256,  259,  283. 

Flabellum  Warlesii,  509. 

alveolaris,  2U7,  247. 

striatum,  466. 

basaltica,  243,  256. 

Flagging-stone,  267. 

cervicornis,  243. 

Flamingo,  516 

favosa,  2U6. 

Flatwoods  group,  493. 

Goldfussi,  259,*  261. 

Flexibility  of  ice,  681. 

Gothiaudica,    206,    207, 

208, 

of  rocks,  740. 

230,  243,  247,  249,  256, 

205. 

Flexible  sandstone,  73.  § 

Niagareusis,  225,*  229,  230. 

Flexures,  760. 

pol^morpha,  249. 

See  PLICATIONS. 

range  of,  in  time,  386. 

Flint,  53.§ 

Faxoe  Kalke,  470. 

in  Cretaceous,  469. 

Feature-lines,  system  in  courses 

origin  of,  478. 

of,  29. 

Flint  implements,  573. 

evolution  of,  744. 

localities  of,  564. 

Feejee  Islands,  34,  623,  625. 

Flinty  rocks,  63.  § 

Feldspar,  49,  53,§  54,*  627, 

727, 

Floods,  636. 

728. 

Flood  closing  the  Glacial   553. 

decomposition    of,    687, 

690, 

Flood-plain  of  rivers,  558,  638, 

695. 

643. 

Feldspar-euphotide,  71.  § 

Flora.     See  PLANTS. 

porph.vry,  71,  §  77-§ 

harmony  of,  in  ages,  384. 

Feldspathic    series    of    igneous 

Florida,  elevation  of,  524. 

rocks,  76.  § 

limestones  of,  492. 

Felis,  519,§  520,  567. 

Tertiary  in,  494. 

atrox,  567. 

trend  of,  36,  524. 

augustus,  508,  511. 

Flow-and-plungc      structure, 

leo,  564. 

546* 

pardoides,  519. 

of  rivers,  637. 

^pelaea,  564. 

Flowers,  fossil,  325- 

Felsyte,  68,$  70.  § 

Flower-like  animals,  383. 

Feuestella,  229. 

Fluccan,]14.§ 

autiqua,  207. 

Fluorite,  or    Fluor  spar,    58,  § 

prisca,  224,*  228.' 

222,  734. 

retiformis,  372. 

Flustra.  127,^474. 

Ferns,  133,  §  296,  354,  362. 

Flustrella,  466. 

ash  of,  365,  366- 

Fluvio-marine  formations,  651, 

in  coal-shales,  321,  326,  §  351. 

669.* 

Triassic,  409. 
Ferruginous  rocks,  64.  § 

Fly,  121.§ 
Flying  lizards,  446. 

sandstone.  379. 

Fly  sen.  513. 

FScus,  459,  497,  5'  8. 

Folds,  92.  §* 

corylifolius,  498. 

See  PLICATIONS. 

Sternbergii,  459. 

Foliation,  90,  §  628. 

tilisefolia,  498. 

Foot,  126.  § 

Fig,    459,    471,    497,    498,^514 

Footprints,  Clinton,  224,*  228. 

594. 

Coal-measure,  341,  343. 

Filling  of  veins,  731. 
Findlay,  on  Gulf  Stream,  755. 

Hamilton,  267. 
Permian,  373. 

Footprints,  Potsdam,  168,  176.* 
Subearboniferous,  3^2,*  304. 
Triassic.  411,*  412,*  420. 
!  Foot-wall,  113.§ 
Foramen,  169.  § 
Foraminifers,    60,    131,§*  341, 

46U,  471,  515,  611. 
Forbes,    E.,    on    colored    fossil 

shells,  308. 

Forbt-s,  J.  D.,  on  glaciers,  680. 
i  Forbesiocrinus,  303. 
i  Force    causing    volcanic    erup 
tion,  711. 
engaged    in    foldings,    216, 

401. 
of  running  water,  648,  661, 

663. 

!  Forces,  the  same  through  geo 
logical  history,  6. 
intensified     in     Quaternary, 

537. 
Forchhammer,  composition    of 

corals,  60. 
ash  of  plants,  61. 
!  Ford,   S.   W.,    on     Primordial, 

167. 

Forest-bed,  513,  556. 
Forest-continent,  44,  394. 
Forest-marble  group,  435. 
,  Forest-regions,  distribution  of, 

44. 

Formation,  81. § 
Fossiliferous  rocks,  62. 
Fossilizatiou,  methods  of,  614. 
Fossils,  5,§  47,§  62,  612. 
American  localities  of,  775. 
chronological  data,  1U4.§ 
distortion  of,  98. §* 
obliteration  of,  by  inetamor- 

phism,  725. 
Foster  &  Whitney  name  Azoic, 

148. 

Archaean  iron  ores,  153.* 
Lake  Superior  trap,  185. 
Fox,  506,  508,564,  571,577. 
Fox  Hill  group,  456. 
.  Fractures,  direction  of,   as   re 
lated  to  the  tension  causing 
them,  747. 

origin  of,  739,  740,  753,  760. 
system  in,  747. 
Fragillaria  pinnata,  634. 
.  Fragmental  rocks,  62. § 

deposits,  758. 
France,   Carboniferous  in,  309, 

344,  346. 

Cretaceous  in,  469. 
disturbances  in,  402. 
flint  implements  in,  574. 
in  the  Quaternary,  555. 
Jurassic  in,  433. 
Quaternary  in   533. 
rock-salt  in,  424. 
Second  Glacial  epoch  in,  561. 
Subcarboniferous  in,  318. 
Tertiary  in,  512,  516. 
Triassic  in,  424. 
Franklinite.  74,§  152,  156. § 
Frazier,  P.  Jr.,  analysis  of  coal, 

493. 

Freeport  coals,  311. 
Freestone,  404. 
Freezing,  effects  of,  674. 
Frenela,  515. 
Fremy,  analysis  of  lobster-shell, 

analysis  offish-scales,  61. 
Frerichs,    analysis    of    human 
bones,  60. 


INDEX. 


803 


Fresh-water  action,  635,  756. 
Friable  rocks,  63.§ 
Frigid  Zone,  41  § 
Fringing  reefs,  622.§* 
Fritsch,  life  of  Archaean,  159. 
Frog,  121§,592,  599. 
Frondicularia  annularis,  131.* 
Fruits,  Carboniferous,  325,* 326, 

328,*  329,  330. 
Tertiary,  497,*  498. 
Fuci,  135.  § 

Fucoidal  sandstone,  163. 
Fucoids,    135, §    169,  176,   177,  I 

198,*  223,*  242,  255  *  257, 

296. 
Fucoides  Cauda-galii.     See  SPI- 

IIOPHYTON. 

duplex,  i78. 
Fucus,  content  of    phosphoric 

acid,  61. 

Fulier'a-earth  group,  435. 
F umaroles    708. 
Fungi,  133, §  321,  331,  365,  366, 

608. 

Fungia,  621. § 
Fustiliua.  131,*  307,  332. 

cylindrica,   131,*   308,    332,* 
341,  350. 

gradlis,  341. 

robusta,  308,  341,  350. 
Fusus,  508,  611. 

antiquus,  519. 

contrarius,  533. 

Labradorensis,  551. 

Newberryi,  477.* 

tornatus,  551. 

Gabb,  W.  M.,  California  Creta 
ceous,  457,  458. 

California  Tertiary,  508.  510. 

San  Domingo  Tertiary,  524. 
Gabbro,  71. § 
Gad  us,  508. 
Galapagos  Islands,  485. 

temperature  of,  41, §  42. 
Galastes,  448. 
Galathea,  350. 
Galena,  59. § 
Galena  limestone,  163,  196, 197, 

377,  378. 

Galenite,  59, §  197. 
Galeocerdo,  510. 

latidens,  509,  510,  519. 
Galerites,  474. 

albogalerus,  476. 

conicus,  476. 
Galerus,  508. 
Gait  limestone,  221. 
Gampsonyx  fimbriatus,  350.* 
Ganges,  sediment  of,  648. 
Gangue,  113.§ 
Gannet,  503. 
Ganocephala,  338.  § 
Ganoids,  262,§*  301,  336,  343, 
349,371,411,42;,  441,450, 
462,  475,  484,  502,  516,  592,  j 
597. 

a  comprehensive    type,  382,  j 
597. 

range  of,  in  time,  388,*  589.*  j 
Ganoid     teeth,     structure     of,  ; 

264.* 

Gardeau  shales,  276. 
Gardiner's  River  S]_ 
Garnet,  57,§*  726,  721 
Garnet-euphotide,  71. § 
Garnet-felsyte,  71.  § 
ftarnetiferous  rocks,  64. 
Gars,  278,§  510,  592,  594 


Gas-wells,  268. 

Gaspe,  Hamilton,  at,  267. 

limestone,  221,  255.  256. 

Lower  Helderberg  at,  238. 

Niagara  at,  221. 

Oriskany  at,  256. 
Gisteropods,   125, §   189,   253,§ 
342,  472,  482,  tiOS. 

culmination  of,  483,  598. 

dental     apparatus     of,     208, 
257.* 

number  of  Silurian, _249. 

range  of,  in  time,  387.* 
Gastornis  Parisiensis,  519. 
Gastridiuin  vetustum,  5U9. 
Gastroobsena,  608, 
Gault,  470. 
Gavialis  Dixoni,  519. 

minor,  509. 

Gay  Head,  Tertiary  at,  495. 
Gay-lussite,  630. 
Geanticlinal,  740,§  751. 
Geinitz,  on  Permian,  371,  373. 
Gemellaria  loricata,  127.* 
Genera    commencing     in      the 

Cretaceous,  483. 
Genera     commencing     in      the 
Jurassic,  482. 

modern,  in  Silurian,  253. 
Genesee  epoch,  254,  266. 

Falls,  section  at,  79,*  219.* 

shale,  257,  266. 
Genesis,  cosmogony  of,  767. 
Geodes,  222.  § 

Geographical  distribution  of  life, 
principles  in,  609. 

of   oceanic   species,   as   illus 
trated  by  the  Physiographic 
Chart,  43. 
Geography,  as  a  science,  2. 

Carboniferous,  354. 

Catskill,  281. 

Cenozoic,  586. 

Champlain,  551,  555. 

Chemung,  279. 

Corniferous,  265. 

Cretaceous,  478. 

Devonian,  286. 

Glacial,  539. 

Hamilton,  275. 

Jurassic,  450. 

Lower  Helderberg,  240. 

Mesozoic,  481. 

Niagara,  230. 

Oriskany,  243. 

Paleozoic,  389. 

Permian,  368. 

Primordial,  180. 

Quaternary,  586. 

Recent,  560. 

Salina,  235. 

Subcarboniferous,  304. 

Tertiary,  520,*  586. 

Trenton,  208. 

Triassic,  422. 

Upper  Silurian,  250. 
Geological  map  of  United  States, 

144. 
Geological     record      imperfect, 

600.§ 

Geology,  methods  of  reasoning 
in,4.§ 

does    not    explain    Creation, 

objects  of,  2,§  4. 
subdivisions  of,  7.§ 
Georgia,  Archaean  in,  150. 
Cretaceous  in,  455. 
glaciers,  537. 


Georgia,  in  Cretaceous,  479. 

Tertiary  in,  491. 
Georgia  (Vt.}  shales,  163.  166. 
Geosynclinal,    740,§    748,    750, 
I         751. 

I  Geoteuthis  Bollensis,  449. 
|  Germany,  Carboniferous  in,  344, 

346. 

Cretaceous  in,  469. 
Devonian  in,  282. 
i      Jurassic  in,  433. 
;      Permian  in,  369. 
',      Quaternary  in,  532. 
!      Subcarboniferous  in,  307. 
I      Triassic  in,  424. 

Geryon,  611. 
i  Gervillia,  475. 
anceps,  475. 
crassa,  448. 
ensiformis,  456. 
inflata,  429. 
longa,  342. 

socialis,  426,*  428,  429. 
Gesner,  A.,  on  modern  changes 

of  level,  583. 
Geysers,  719.§ 
action  of,  721. 
siliceous   deposits  from,  612, 

719. 
Ge\  ser-basins    of    Yellowstone 

National  Park,  611,  719- 
Giants'  Causeway,  107,  716. 
Gibraltar,  currents  at,  659. 
Gieseckite,  156.§ 
Gilbert,   G.  K.,   on    Lake  Erie 

outlet,  540. 

Rocky  Mountain   Carbonifer 
ous,  296. 

Gill,  T.,  on  Reptiles,  337. 
Glabella,  123, §  174.§* 
Glacial  Period,  527,  571,  756. 
Drift,  supposed,  in   the   Per 
mian,  370. 

era,  second,  556,  561,  574. 
scratches,  535,  684. 
theory  of  the  Drift.  535. 
Glacier  of  Switzerland,  reaching 

to  the  Juras,  533. 
of  Zermatt,  677.* 
regions,  675. 
Glaciers,  characters,  origin,  and 

effects  of,  675,  676,*  677.* 
I      conditions    favoring    increase 
I         of,  678. 

increase  of,    in   the    Quater 
nary,  540. 

investigators  of,  680. 
limit  of,  679. 
motion  of,  536. 
Quaternary  in  America,  537. 
Glaphyroptera,  428. 
Glaris,  fishes  at,  529. 
!  Glass  state,  702. 
volcanic,  708. § 
i  Glauber  salt,  630. 
!  Glauconie  grossiere,  512. 
i  Glauconite,  58,§  458,§  759.§ 

See  GREEN-SAND. 
I  Gleditschia,  515. 
Glen  Roy,  benches  of.  555. § 
Globigerina,  477,  611,  615. 
bulloides,  477. 
ooze,  611. 
rubra,  131.* 

!  Globuliferous  rocks,  63  § 
Glossoceras,  228. 

desideratum,  250. 
Glyphea  dubia,  350. 
Liassina,  449. 


804 


INDEX. 


Glyptocrinus,  189. 

basalis,  207. 

decadactylus,  204.* 
Glyptodon^570. 

clavipes,  570.* 
Glyptolepis,  283.  286. 
Glvptosaurus  princeps,  510. 
Glyptostrobus,  497. 
Gneiss,  49,  68,§  237,  729. 
Goat,  564,  571,  577. 
Gold-bearing  veins,  734. 
Gold-quartz,  age  of,  453. 

in  Cretaceous,  458. 
Goinphoceras,  229. 

turbiniforme,  274. 
Gomphonema  gracile,  634.* 
Goniatite  limestone,  294. 
Goniatites,  272, §  278,  284,  288, 
300,  303,  332,  371,  409,  429, 
484. 

compile  tus,  342. 

Haidingeri,  416- 

levidorsatus,  416. 

Marcellensis,  273,*  274. 

parvus,  342. 

politus,  342. 

punctatus,  274. 

retrorsus,  285  * 

uuiangularis,  274. 

first  of,  272,  284. 

range  of,  in  time,  385,  387.* 
Goniobasis,  508. 
Gonioceras,  '203. § 

anceps,  203. 
Goniopholis,  449,  450- 

crassidens,  450. 
Goniopteris,  348. 
Gonoplax,  611. 
Gorgonia,  117,*  130, §  620. 
Gothic  Mt.,  718.*     ' 
Gothland.     See  SCANDINAVIA. 

Niagara  in,  245. 
Graculavus,468. 
Graculus  Idahensis,  511. 
Grahamite,  315. 

Grammarophora  marina,  134,* 
496.* 

bisulcata,  273,*  274. 
Granimysia,  284. 

cingulata,  245,  246,*  247,  250. 

Hamiltonensis,  273,*  274. 

triangulata,  250. 
Grammostomuni          phyllodfs. 

131,*  466. 

Grand  Gulf  group,  494,  522. 
Granyte,  49,  67, §  76, §  628,  645, 

728,  729,  730. 
Granyte-porphyry,  71. § 
Granytic  rocks',  63.§ 

veins.  110.§* 
Granytoid  rocks,  64. § 
Granular  limestone,  75, §  729. 

rocks,  64,§ 
Granulyte,  68,§  76. § 
Graphic  granyte,  68. § 
Graphite,  59. § 

in  Archjean,  152,  157. 
Grapsus.  475. 

Graptolites,  130, §  175,  187, 189, 
199,  249,  252,  384. 

earliest,  of,  168. 

range  of,  in  time,  384,  386. 
Graptolithus         amplexicaulis, 
199,*  202. 

Clintonensis,  224  *  228. 

Logani,  187  *  190. 

priodon,  247. 

pristis,  204.* 
Graptolitic  slates,  164. 


Grass,  protection  by,  606. 
Grauliegende,  369. 
Gravel,  66, §  758. 
Gravitation,  effects  of,  630. 
Gray,  A.,  Tertiary  climate,  526. 

migration  of  plants,  532. 

Sequoia,  582. 
Gray  band,  79,  220. 
Gray  rabbit,  568. 
Great  Basin,  16. 
Great  Britain.     See  ENGLAND. 
Great)-  Lakes,  location  of,  394. 

in  the  Quaternary,  541,  552, 
553. 

tides  in,  634. 
Great  Oolyte,  435. 
Great  Salt  Lake,  16,  23,  561. 
Green-earth,  58. § 
Greenland,  Cretaceous  in,  470. 

fiords  in,  534. 

glaciers  of,  53S,  675. 

recent  changes   of   level    in, 
583. 

Tertiary  in,  513,  514. 
Green  Mountains,  age  of,  215, 
750,  754. 

Chazy  in,  182,  185. 

Cincinnati  in,  195,  196- 

heights  in,  195. 

in  Lower  Silurian,  211. 

island  in  Oriskany,  244. 

in  Paleozoic,  355,  389,  390, 392. 

Quebec  in,  182. 

revolution,  212. 
Green  River,  Tertiary  on,  493, 

494. 

Green  River  shales,  494. 
Green-sand,  composition  of,  58, 
455,  458. 

Cretaceous,  455,  458,  469. 

Lower  Silurian,  168,  177,  208. 

Rhizopodsi n,177,  208. 

Tertiary,  493. 
Gregory  &  Walker,  analyses  of 

coprolites,  61. 
Gres  bigarre,  424. 

de  Beauchamp,  513. 

de  Fontainebleau,  513. 

des  Vosges.  402.     • 
;  Grifflthides,  308. 

range  of,  in  time,  388.* 
Grindstone  grit,  65. § 
Grit,  65,§  645. 
Grobkalk,  512. 
Groovings.     See  SCRATCHES. 
Ground-pine,  133,§  598. 
t  Grouse,  573. 

Groves,  protection  by,  607. 
Growth  of  the  continent,   250 

286. 
Grus  Haydeni,  511. 

proavus,  568. 

Gryllacris  lithanthraca,  351. 
Gryllus,  449. 
Grypha?a,  433,  460,  475. 

convexa,  456. 

cymbium,  448. 

dilatata,  438.*  449. 

gigantea,  448. 

incurva,  435,  438,*  448. 

lateralis.  468.  469,  477. 

mutabilis,  456. 

Pitcherii,  456*  461  *  467,  468. 

vesicularis,    433,    461,*    467, 
468,  469,  476,  477. 

vesiculosa,  476. 

Vomer,  468. 

first  of,  433,  438. 
Gryphite  limestone,  435. 


|  Guadaloupe,  skeletons   of,  579, 

580.* 

Guano.  60.§ 
;  Guelph  formation,  or  Gait,  164, 

221. 

Guillemot,  503. 
Gulf-border    region,    401,    431, 

454,  490,  523. 

Gulf  of  Mexico,  in  the  Creta 
ceous,  479.* 

iu  the  Tertiary,  521,*  523. 
in  the  Permian,  368. 
tide  in,  67.0. 

Gulf  Stream,  40,  208,  452,  481, 
541,  572,  668,  659,  665,  666, 
755. 

'  Gulielmites,  371. § 
Guttenstein  beds,  425. 
Guttulina,  208. 
;  Guyot,  A.,  Africa,  27. 

American  forests,  44,  394. 
Cosmogony,  766. 
Great  Swiss  Glacier,  533. 
South  America,  25. 
Gymnocopa,  123. § 
Gymnosperms,  138.5 
i  Gypseous  group  of  Montmartre, 

513. 
I  Gypsum,  55, §*  75, §   222,  627, 

630,696. 

j      in  the  Salina,  233.  234. 
mode  of  formation  of,  234. 
formed  on  coral  islands.  235. 
!  Gyracanthus,  304,  351. 
Gyroceras  Burliugtoneuse,  303. 

constrictuni,  274. 
Gyrodes.  457. 

depressa,  508. 
Gyrodus,  475. 

umbilicus,  264.* 
Gvrolepis,  428. 

tenuistriata,  429. 
|  Gyroniyces  ammonis,  342. 

Haddock  bones,  analysis  of,  60. 
Hadrosaurus,  338,§  464. 

agilis,  467. 

Fbulkii,  467. 

minor,  467. 

Hague,  J.  D.,  on  effects  of 
oceanic  currents,  669.* 

on  formation  of  gypsum  on  a 

coral  island.  235. 
Hairy  elephant,  577.* 
Halicalyptra  fimbriata,  132.* 
Halitherium,  520.  § 
Hall,J.,  Carboniferous  uncon- 
formable  with  lower  beds, 
309. 

Clinton,  231. 

Devonian,  241. 

Graptolites,  187, 190. 

Lake  Superior  sandstone,  193. 

mountain-making,  74$ 

Niagara  retrocession,  590. 

Oriskany,  241. 

Palfeotrochis,  160. 

Primordial,  168. 

Subearboniferous  geography , 
305. 

thickness  of  Paleozoic,  380. 
Halobia  dubia,  416. 

Lommeli,  429. 
Halonia,  348. 

pulchella,  324,*  329. 
Halvsites,   202,    225,   238,   240, 
"249,  252,  288.      ' 

eaten ulata,  20R,  207,  208,  221, 
225,*  229, 230,  247,  248, 249. 


Halysites  gracilis,  204.* 
la"st  of,  238. 
range  of,  in  time,  386. 
Hamilton   beds,   section  of,   on 

Lake  Erie,  267.* 
epoch,  254,  266. 
group,  254,  266. 
period,  254,  266. 
Hamites,  462.§ 
attenuatus,  473,*  475,  476. 
Fremont! ,  468. 
rotundus,  416. 
simplex,  476. 
Vancouverensis,  467. 
Hanging-wall,  113. § 
Haplophlebium,  336. 

Barnesii,  343. 
Haploscapha  grandis,  467. 
Hare,  506,  564,  577. 
Harlech  beds.  163,  179. 
Harmony    of    the    Fauna    s 
Flora  of  an  age,  384,  430. 
Harpes,  190,  204,  208,  228,  249. 
Harpides,  190. 
Allan ticus,  250. 
rugosus,  250. 
Hastings  Sand,  435. 
Haughtou,  analyses  of  granyte, 

68. 
Hawaian  group,  map  of  33. 

origin  of,  723. 
Hawaii,  erosion  on,  640. 
map  of  part  of,  705,*  712. 
profile  of,  704.* 
volcanic  action  on,  704,*  7 
711,  712,*  713,  714,  715. 
recent  changes    of   level 

584. 
Ilawes,    G.     W.,    analyses 

plants,  362,  366. 
Hawlea,  348. 

Hay  den,    F.    V.,    Lignitic 
"  Rocky  Mts.,  458. 
Potsdam  in  Dakota,  168. 
Tertiary  lakes  in  Rocky  Mts., 

491. 
Triassic  in  Colorado,  406. 

See,  further,  MEEK. 
Hayesine,  76. § 
Hazel,  514. 

Headless  Mollusks,  125. § 
Headou  beds,  513,  519. 
Heat,   agency  of,  in  metamor- 

phism,  726. 
effects  of,  697,  749. 
endured  by  life,  611. 
from  crushing,  698,  749. 
internal,  of  globe,  699. 
sources  of,  697,  762. 
Heavy  spar,  58. § 
Hedgehog,  577. 
Heer,  on  Arctic  Devonian,  283. 

on  Arctic  Tertiary,  526. 
Height    about    heart  waters   of 

the  Mississippi,  22 
mean,  of  Hiinala  as,  26. 
of  Andes,  21,  22. 
of  Gothic  Mt,  718. 
of  Green  Mts. ,195,  214. 
of  Hawaian  Mts.,  703. 
of  Mt.  Katahdin,  530. 
of  Mt.  Whitney,  453. 
of  Rocky  Mts.,  685,  740. 
of  Sierra  Nevada.  24. 
of  some  volcanoes,  703,  704. 
Heights    of    plateaus,    16. 

22 

of  terraces,  548.  550. 
of  Drift  deposits,  528. 


INDEX. 

SUD 

Ilelderberg,    Lower,    142,    164, 

[lipparion,  505,*  50o,§  511,  519. 

236. 

occidentale,  511. 

American   species  of,   occur 

parvulum,  511. 

on 

ring  elsewjiere,  248. 
Helderberg,  Upper,  limestones,  ! 

Hippopotamus,  519,    520,  564, 
576. 

254. 

major,  571. 

a  coral-reef  pe'iod,  255. 

Hippotherium,  520. 

llelicoceras,  462.  § 

Hippurites,  460,  §  469. 

Mortoni.  468. 

dilatatus,  472,'*  475. 

Ilelicopsyche,  612. 

organisans,  476 

;  Helicotoma     planulata.     201,*  i 

Texanus,  467. 

203. 

Toucasianus,  472,*  475. 

uniangulata,  188,*  189. 
Ileliolites.    206,   207,  229,  230, 

Hippurite  limestone,  470. 
Hirnant  limestone,  206. 

288. 

Histioderma  Ilibernicum,  180. 

Grayi,  247. 
interstincta,  208,  247. 

Histiophorus  gracilis,  509. 
Historical  Geology,  7,§  136. 

porosa,  265,  284. 

History,  nature  of  subdivisions 

pyriformis,  248. 

in,  136. 

spinipora,  225,*  229. 

Hitchcock,   C.   II.,    Cham  plain 

ml 

Ileliophvllum,  256. 

period,  542. 

Halli,"272.*  274. 

Helderberg,  256. 

19. 

Helix,  119.*§ 

Hitchcock,  E.,  Brandon  lignite, 

labyrinthica,  519. 

494. 

occlusa,  519. 

Carboniferous,  319. 

Ilelinholz',   on    temperature   of 

footprints,  411. 

glaciers,  682. 

terraces,  539. 

te, 

Helminths,  123.  § 

Triassic,  406. 

Ilelodus,  S04.  351. 

Hitchcock,   E..   Jr  ,  on   Clath- 

i 

Hematite,   59,§   74,  §   318,   688, 

ropteris,  433. 

727. 

Hog,  503,  506,  507,   511,  517, 

Ilemeristia  occidentalis,  343. 

568. 

Ilemiaster,  466,  474 

Hog  family,  504. 

Bailyi,  476. 

Holnster,  474.  _ 

'10 

Humphrevsianus,  469. 

cariuatus,  476. 

Hemicardium  AVulfeni,  429. 

cinctus.  466. 

in,    Hemicidaris  intermedia,  449. 

simplex,  486,  468. 

Purbeckensis,  450. 

subglobosus,  476. 

Of 

Hemipristis,  510. 

Holectypus,  466. 

serra,  510. 

Holly,  47.1. 

of 

Ilemipronites  crassa,  341. 
crenistria,  303,  307,*  308. 
magnifica,  243. 

Holocystis  elegans,  475. 
Ilolometopus  Angelini,  250. 
limbatus,  250. 

punctulifera,  240. 

Holopea,  203,  240. 

to., 

radiata.  23i)  *  240. 

concinna,  208. 

;  Ilemipters,  450. 

depressa,  274. 

Hemitrochiscus  piradoxus,  372. 

dilucula,  188,*  189,  192. 

1  Ilempstead  beds,  513,  519. 

Ilolopella,  429. 

Herbivores,  503,  506,  571,  593. 

IIolops  brevispinis,  467. 

1      range  of,  in  time,  589.* 

obscurus,  467. 

Ilercynian  gneiss,  151. 

Holoptychius,    263,     282,    286, 

Herons,  436.  § 

351. 

ior-    Herring,  475- 

Americanus,280,*281. 

Herschel,   theorv    of   metfimor- 

Holothurioids,  127,§  448. 

1         phisin    proposed    by,    730, 

Homacanthus,  304. 

749. 

Houiacodon  vagans,  510. 

IK-sperornis,  466,  468. 

Ilomalonotus,    174,§   228,  240, 

Heterocercal  fishes,  range  of,  in 

253,  285. 

!      time,  589  * 

armatus,  285. 

Ileterocrinus,  204. 

delphinocephalus,  227,*  229. 

Ileteropods,  203,  249. 

247,  248. 

53.     .  Heusser,  analysis   of   doleryte, 

Knkhtii,  247,  250. 

78. 

range  of,  in  time,  388.* 

of 

Hexaprotodon,  520. 

sulcatus,  208. 

Hickory,  459,  497. 

Homocamelus,  511. 

Hilgard,  E.  W.  ,  Cretaceous,  456. 

Homo  diluvii  testis,  512.  § 

Mississippi  Tertiary,  493,  494, 

Homooreneous  rocks,  64.4 

522. 

HomotaxiaJ  strata,  101  § 

mud-lumps,  656. 

Hooker,    on     coal-plants,    326 

Quaternary.  553,  554. 

329. 

Hils-conglonierat,  470. 

Hornblende,  54,$*  7^8,  737. 

Himalayas,  26. 

Hornblende  rock,  237,  729. 

glaciers  in,  675. 

1     schi<t.  70.  § 

in  the  Cretaceous,  480. 

series  of  rocks,  69,  §  77.  § 

4. 

snow-line  in,  679. 

Horn  Men  dyte,  70.  § 

a, 

Tertiarv  in.  512. 

Horn  rock,  70.  § 

Himantidium  arcus,  634.* 

Ilornstone.  53,§  255,  455. 

monodon,  634.* 

in    Corniferous,    with    Proto- 

Hinge-line,  170. 

phytes,  257. 

806 


INDP;X. 


Hornstone,  in  Oriskany,  241. 

origin  of,  257,  265. 
Horse,  114, §  495,  505, •  506-510, 
564,  565,  567,  568,  571,  572, 
576,  577,  601. 
first,  505. 

Horse-shoe  crab,  122,$  333. 
Horse-tails,  327- § 
Horton  series,  296. 
Hot -springs,  692,  719,  729. 
deposits  from,  b92,  693   721 
life  of,  611. 

Hot  waters,  action  of,  453. 
Houghite,  157. 
Housatonic      Talley,      sections 

across,  213.* 
Hubbard,  0.  P.,  on  Triassic  coal, 

406. 

Hudson  River,  in  existence,  287. 
Hudson  River  epoch,  164. 
shales,  1^5,  196. 
slates,  Cakiferous  in  age,  196. 
valley,    submarine  continua 
tion  of,  422,*  540,  673. 
Human  bones,  analysis  of,  60. 

relics,  573.* 
Humboldt  Mis.   453,  751. 

in  the  Mesozoic,  486. 
Humming-birds,  6lD. 
Humphreys  and  Abbot,  on  the 
Mississippi  River  deita  etc. 
636,  648,  652,  669. 
Hunt,  E.  B.,  on  Carboniferous 

temperature,  353. 
Hunt,  T.  S.,  age  of  lead  veins 

151. 

analyses  by,  60,  61,  71,  73,  74. 
anorthosyte,  69. 
Archaean  origin  of  later  rocks, 

161. 

carbon  in  Archaean,  157. 
carbonic    acid    disintegrating 

rocks,  156. 
decomposition   of  rocks    156 

687,  696. 
Eozoon,  158. 
igneous  Archaean,  157. 
moisture  in  rocks,  656. 
mountain-making,  749. 
white  trap,  76. 
Huron  group,  376,  377. 
Huronia  vertebralis,  209. 
Ilnronian  period,  159. 

fossils  in,  167- 
Huttonia,  348. 

Huxley,  T.  II..  fossil  man,  575. 
Eosaurus,  343. 

Rhizopods  of  N.  Atlantic,  615. 
Hyaena,  519  §  520. 
crocuta,  564. 

spelaea,  or  Cave  Ilvama,  563. 
Hyaenarctos,  519, §  520. 
Hyaenodon,  511,  519. 
dasyuroides,  518. § 
leptorhynchus,  5J9. 
Hyatt,  A.,  on  Bentricea,  228. 

on  evolution.  604. 
Ilybocrinus,  204. 
Hybodus  major,  429. 
minor,  262,*  428. 
Mougeoti.  429. 
plicatilis,262,*428,  429. 
reticulatus,  449. 
strictus,  450. 
snhcarinatus,  450.  • 
Hybortonts,     263,  «*    304,    308, 

343,  475. 

range  of,  in  time.  388  *  539.*   i 
Hydra,  117,*  130.§* 


Hydraulic  limestone,  75. § 

analyses  of,  233,  237. 
Hydrogen,  62. § 
Hydroids,  130.§* 
Hydromica,  54. § 
slate,  69, §  729. 
Hydrotalcite,  157. 
Hydrous  aluminous  series,  73. § 
magnesian    series    of    rocks, 

72.§ 

Hyena,  506,  564,571,576. 
Hylaeosaur,  338,§  445, §  450. 
Hylerpeton  Dawsoni,  343. 
Hylonomus  aciedentatus,  343. 
Lyelli,  343. 
Wymani,  343. 
Hymeuocaris      vermicauda 

180.* 

Hymenophvllites,  330. 
Clarkii,  297. 
furcatus,  331. 
Gersdorffli,  271. 
Hildretlii,  326,*  330,  331. 
obtuMlobus,  271. 
spinosus,  331. 
Hvmenopters,  441,  484. 
Ily elites,  208. 
Americanus,  178. 
gregarius,  1V8. 
impar,  178. 
Hyopotamus,  511,  519. 

bovinus,  519. 
Hypanthocrinus    decorus     229 

247. 

Hypersthenyte,  70, §  736. 
Hypuum;616.     " 
Hyposaurus    338. § 
Rogerd,  467. 
ferox,  467. 
Hypostome,174.§ 
Hyposyenyte,  70.  § 
Ilvrachyus,  504. § 
eximius,  510. 
implicatus,  510. 
princeps,  5:0. 
Hyracodon,  511. 

Nebrascensis,  506,*  507,  611. 
Hyracothere,  516. 
Hyracotherium  leporiuum,  518. 
Hyrax,  510. 
II>strix,  511,  520. 


Ibex,  572. 
Ibis,  516. 
Ice,  737,  740. 

of  rivers   and    lakes,   effects 

of,  674. 

See,  further,  GLACIERS. 
Icebergs,  origin  and  action  of, 

535,  686. 
transported  by  the  Labrador  i 

current,  534,  665. 
transportation   of  stones    by.  ' 

534,  605,  666. 
Iceberg  theory  of  the  Drift,  534, 

539. 
Iceland,  geysers  of,  719. 

glaciers  in,  675. 
Ichthvocrinus  levis,  226  *  229 

248. 

Tchthyodectes,  467. 
Tchthyornis,  468. 
"chthvosaurus,  339,§  343,  428,! 
4^9,  443,  449,  450,  474,  475,  I 
476,  484. 
Arctic,  452. 
communis.  442,*  449. 
intermedjus,  449. 
tenuirostris,  449. 


Idaho,  Jurassic  in,  431. 
Potsdam  in.  182,  184 
Quebec  in,  182,184 
Subcarboniferouo  in,  296. 
terraces  in,  549. 
Idocrase,  726. 
Igneous     action    in    Archaean 

157. 

in  Canadian,  185. 
in  Mesozoic,  417,  486. 
in  Tertiary,  524. 
Igneous      eruptions,     non-vol 
canic,  716.     See  TOLCAMC. 
interior    of    the    globe     evi 
dences  of,  699,  722,  735. 
rocks,  e3,§  76,§  736. 
Iguana,  338§,445. 
Iguanodon,'  338, §    445, §    450 

464,  4J4,  475,  476. 
Mantelli,  445.* 
Ilex,  497,  498 
Illaeuurus,  178. 
Illaenus,    174, §    188,  190,   22S, 

253. 

Arcturus,  191. 
Barriensis,  227  *  229  248 
Bay fieldi,  ]92. 
Bowmani,  208. 
crassicauda   204. 
Davisii,  208.* 
j      range  of,  in  time,  387.* 
;  Illiciuni,  498. 
Illinois,  Carboniferous  in,  291 

321,  3-^8. 

Hamilton  in,  267. 
lead  mines  of,  197. 
Lower  Helderberg  in.  237. 
Lower  Silurian  in,  210. 
Niagara  in,  221. 
Oriskany  in,  242. 
Quaternary  in,  528,  529. 
rocks  of,  378. 
Subcarbouiferous      in.      293, 

294. 

Tertiary  in,  491. 
Trenton  in,  196. 
uplifts  in,  290 ,*8f)S. 
Upper  Helderberg  in,  256. 
Ilyanassa  obsoleta,  561. 
Independent  regions  of  progress, 

145. 
India,  Quaternary  in,  533. 

Tertiary  Mammals  of,  520. 
Indian  Ocean,  25. 
currents  of,  40,  658,  756. 
in  the  Triassic,  430. 
volcanoes  in,  704. 
Indiana,  Carboniferous  in,  291, 

321,  345,  358. 
Clinton  in,  220. 
Lower  Heldt-rberg  in   237- 
Oriskany  in,  242. 
oil  wells  in,  257- 
Quaternary  in,  528,  529. 
Subcarboniferous  iu/293.  303, 

304. 

L'pper  Helderberg  in,  256. 
Individualities  in  nature,  1. 
Infusoria.  See  PROTOZOANS, 

RHIZOPODS,  PROTOPHYTES 
Infusorial   beds,  Tertiary.   493, 

495,  514. 

dust-showers.  632  * 
Ink-brig     of     Calauiary,    440.* 

441. 
Inocer°mus,  433.  457,  458,  460, 

475,  50°. 
first  of.  433. 
aviculoides,  468. 


INDEX. 


807 


Inoceramus  Barabini,  469 

Iron  hat,  734. 

Jura  Mts.,  Jurassic  in,  434 

biformis,  468. 

Mountain,  151. 

Jurassic  period,  431. 

Brongniarti,  476. 
capulus,  468. 

Iron-bearing    rocks    character 
istic  of  Archaean,  151. 

Kankakee  Swamp,  560. 

concentricus.  476. 

Iron  ores,  59,§  74,  §  688. 

Kanawha  Salines,  321. 

confertim-annulatus,  468. 

Iron  ore,  fossiliferous,  231. 

Kangaroo-rat,  448. 

Crispii,  476. 

in  Archaean,  153. 

Kansas,  Carboniferous  in,  291, 

Cuvieri,  476. 

in  Carboniferous,  293,  318. 

320. 

latus,  469,  476,  477. 

argillaceous,  iu  Clinton  group, 

chalk  in,  455. 

mytiloides,  476. 

220,  231. 

Cretaceous  in,  456. 

obliquus,  433. 

Ironstone,  318. 

Permian  in,  367. 

problemadcus,  457,  461,*  467, 
468,  477,  501,  508. 

Isastraaa  explanata,  449. 
oblonga,  449. 

Triassic  in,  423. 
Kaolin.  695.  § 

pseud'o-mytiloides,  468. 
rectangulus,  433- 
striatus,  476. 
sublevis,  468. 

Stricklandi,  448. 
Ischypterus,  417. 
Ischyromys,  511. 
Isinglass.  53.  § 

Kaskaskia  limestone,  294. 
Katahdin,  height  ot,  530. 
Kelloway  rock,  435. 
Kendall  group,  244. 

sulciitus  476. 

Isis  nobilis,  60.§ 

Kent's  Cave,  564,  576. 

unibonatus,  463. 

Inorganic  kingdom,  48.  § 

Island  -chains,   curves    in,   30,* 
31,*  32,*  34. 

Kentucky,     Carboniferous     in, 
291,  314,  321. 

Insectt!«ins    121.^ 

Islands,  Coral,  618. 

Hamilton  in,  267. 

Insects,   121,§    331,    351,    360, 

in  rivers,  651.  § 

in  the  Carboniferous,  354. 

483,  500,  592,  596,  608,  613. 

oceanic,  14.                                         Quaternary  in,  528. 

first  of,  273. 

parts  of  continents,  14.                    Subcarboniferous  in,  293,  294, 

culmination  of,  598. 

Isle  of  Mull  leaf-bed,  513. 

304,  305. 

most  easily  fossilized.  613. 

Isocardia,  475. 

terraces  in,  548. 

range  of,  in  time.  388.* 

Isocrvmal  chart,  41.  § 

Tertiary  in,  493. 

Carboniferous,  335,  351. 

Isoetes,  270.  §                                       Upper  Helderberg  in,  256. 

Devonian,  273,  274. 

Isouema  depressa,  274.                     Keokuk     limestone,    294,    305, 

tracks   of,  iu  Triassic,  411,* 

Tsopods,  120,*  122.  §                               377,378. 

416. 

Isotelus  gigas,  204.                            Keuper,  424,  429. 

Insectivores,     486,    506,     510, 

Isothermal  chart  of  the  ocean,    Keweenaw  Point,  copper  of,  185. 

519,  520. 

41.  §                                            Kilauea,   706,*  706,*  71U,  715, 

range  of,  in  time,  589.* 

Isothermal    lines,     Cretaceous,           7^2,  723. 

Insular  climate,  43. 

481.                                               Kimmeridge  clay,  433. 

Iiitegripallial,  189.  § 
Interior  Continental  region,  146. 

Tertiary,  526. 
Isthmus  of  Darien,  659,  756. 

Kimmeridgian  group,  43o. 
Kinderhook    group,    294,    305, 

168,  183,  184,  196,  210,  231, 

Itacolumyte,  73.  § 

377,  378. 

251,  267,  275,  276,  279,  291, 

Italy,  Cretaceous'  in,  470. 

King,  A.  T.,on  Carboniferous 

294,  321,  355,  359,  367,  370, 
373,  380,  390,  391,  392,  401, 

changes   of  level  iu  Serapis, 
584. 

footprints,  343. 
Ki  ng  &  Rowney  ,  on  Eozoon  ,  159. 

480.  See  WESTERN  INTERIOR. 

in  the  Quaternary,  573. 

King,  C.,  on  Triassic  iu  Rocky 

fire-seas,  722. 

lulus,  342. 

Mts.,  4U6. 

Intrusive  rocks,  63.  § 

Ives,  on  the  Colorado,  641.* 

on    Wahsatch     and     Uiutah 

Invertebrates,  116.  § 

Ivory,  fossil,  565. 

Mts.,  453. 

Age  of,  139,  162. 

Kingdoms  of  nature,  1. 

only  animal  life  of  Primordial, 
169. 

Jackson,  C.  T.,  on  Rhode  Island 
Carboniferous,  319. 

Kirkdale  Cavern,  564. 
Kitchen-middens,  562,  577- 

Iowa,  Carboniferous  in,  291. 

Jackson  group,  494. 

Kittanning  Coal-bed,  311. 

Chazvin,182. 

Janassa  bituminosa,  372. 

Kjokkeu-moddings,  562,  577. 

Cincinnati  in,  197. 

Janira  hemicyclica,  511. 

Knox  group,  163,  379. 

Cretaceous  in,  455. 

Janthiua,  243. 

sandstone,  163. 

Hamilton  in,  267- 

Japan,  Tertiary  in,  512. 

Koninckina,  171.  § 

lead  mines  of,  197. 
Lower  Silurian  in,  210. 

Jasper,  53,§  74  § 
Java,  Tertiarv  in,  512. 

Kossen  beds,  425,  429. 
Knorria,  307,  348. 

Niagara  in,  221. 

Jelly-fish,  117.  § 

acicularis,  283. 

Quaternary  in,  528,  529. 

Jenzsch,  G.,  analysis  of  phono- 

imbricata,  283,  297. 

rocks  of,  377. 

lyte,  77. 

Kraussia,  171,  174. 

Subcarboniferous  in,  293,294, 

Jet,  62.§                                          |  Kupferschiefer,  369. 

303. 

Jogsnns,  Carboniferous  at,  319,    Kupfier     on     composition     of 

Trenton  in,  196. 

Obolus,  61. 

Upper  Helderberg  in,  256.          Johnson,   W.   B.,  analyses    of 

Kutorga  on  Russian  Devonian, 

Ireland,  Carboniferous  in,  345,           coal,  316. 

283. 

346. 

Johnson,  S.  W.,  formation  of 

Kutorgina  cingulata,  177,  250. 

Devonian  in,  282. 

coal,  364. 

Kyanite.     See  CYAMTE. 

eruptions  in,  525. 

Jointed  structure,  88.  § 

in  the  Quaternary,  555,  572. 

Joints,  origin  of,  741. 

Labrador  current,  40,  208,  534, 

Jurassic  in,  433. 

in  the  Hamilton,  267. 

552,  554.  658. 

peat-beds  of,  616. 

Jones,     T.     11.,    on     Estheria, 

fiords  in,  534. 

Permian  in,  369. 

416. 

Primordial  in,  167. 

Silurian  in,  244. 

Juglans,  459.  497,  498,  515. 

terraces  in,  550. 

Subcarboniferous  in,  306. 

appressa,  498. 

Labrador}  te,  54.  § 

Ireleth  slates,  244. 

acuminata,  498. 

Labyrinthine       structure       of 

Iridea  edulis.  ash  of,  61. 

denticulata.  499. 

Ganoid  teeth,  264,*  338. 

Irish  deer,  564,  565,  571. 

Schimperi,  499. 

Labvrinyiodon,  427,*  428. 

Iron,  51,  §  365. 

Jukes,  on  Irish  Devonian,  282. 

Lab\  rinthodonts,  337,  338,$  349, 

abundance  of,  737. 

Juniperus,  450. 

351,  427,  §  484,  598,  599. 

in  plants,  364. 

Jura  Mts.,  bowlders  on,  533. 

a  comprehensive  type,  382. 

Iron  Age,  574. 

Cretaceous  in,  470. 

in  Triassic,  412. 

808 


INDEX. 


Labyrinthouonts,  last  of,  484. 

range  of,  in  time,  38S,*  58y.* 
Laccopteris  falcata,  409. 

germinans,  409. 
Lacertians,  3:38, §  443,  484. 

range  of,  in  time,  388.* 
Lacertilians,  510. 
Lacustrine  group,  513. 
Laekenian  group,  513. 
Laelaps,  464  § 
Lagomys,  520.  § 

spel.neus,  564 
Lagrange  group,  493. 
Lake-basins,  formation  of,  539, 

762. 

Lake-border  formations,  544. 
Lake  Cham  plain  outlined,  215. 

an    arm    of   the    sea  in   the 
Quaternary,  552. 

terraces  on,  550. 
Lake  of  Geneva,  color  of,  685. § 
Lake  Memphremagog,  corals  at, 

225. 
Lake,    Salt.      See    GREAT   SALT 

LAKE. 

Lake  Superior    Archasan,    150, 
159. 

copper,  184,  185. 

Chazy,  183. 

trap,  185. 

sandstone,  376. 

silver,  186. 
Lake-dwellings,  576. 
Lakes,  positions  of,  22. 

change  of  level  in  surface  of, 
634. 

bun-ting  of,  636,  650. 

elevations  of,  23. 

Tertiary,  491. 

the    great,    of  N.    America, 
origin  of,  394. 

without  outlets,  usually  salt, 

23. 

Lama,  506,  568. 

Lamellibranchs,     125,§     253,5 
333,  342,  482. 

culmination  of,  483. 

range  of,  in  time,  387.* 
Laminaria,  ash  of,  61,  611. 
Laminarian  zone,  611. 
Laminated  rocks,  63  § 

structure,  82. § 

structure,  cause  of,  741. 

structure  of  glaciers,  produc 
tion  of,  683. 
Lamination    oblique,  of  layers, 

82,*  83,  671. 
Lamna,  467,  475,  510. 

acuminata,  477- 

elegans,  262*  501*  509,  518, 

519. 

Landenian  group,  512. 
Land  affects  climate,  755. 

arrangement  of,  10,  13. 

below  sea-level,  13,  14. 

first,  above  water,  160. 

mean  height  of,  14. 
Land-plants.     See  PLANTS. 
Landscape-marble,  425. 
Land-snails,  first  of,  in  Carbo 
niferous,  332,  342. 
Land-slides,  655. 
Laornis,  468. 

Lapland,  Primordial  in,  179. 
Laramie  Mts.,  Archaean  in,  150. 

Jurassic  in,  431. 

See  MISSOURI,  UPPER. 
Lartet,   E.    on  Amiens   gravel, 
576. 


Lartet,  E.,  on  migrations,  572. 
Larve,  592. 
Laurel,  594,  609. 
Lauren  tian  Period,  151. 
Lauroph\  Hum  reticulatum,  460 
Laurus,  497,  498,  514. 

obovata,  498. 

pedata,  498. 
Lauzon  group,  184. 
Lava,  49,  79. §  702,§  707,§  715. 
Lava-cones,  704.* 
Layer,  81.  § 

Layers,  structure  of,  82. § 
Leader,  114.§ 

Lead-mines  in  Illinois  and  Wis 
consin,  197- 

in  Missouri,  186. 

in  New  York,  222. 

in  the  Oneida,  222. 

in  the  Trenton,  207. 
Leaf-beds,  512. 
Leaia  tricarinata,  342. 
Lebanon  limestone,  163. 
Lebanon  Mt.,  fishes  of,  520. 
Lecanocrinus  elegans,  199,*  203. 
Leclaire  limestone,  221. 
LeConte,  J.  L.,  on  fossil  Ephem 
era,  416. 
LeConte,  J. ,  anal}  sis  of  coal,  493. 

on  mountain  making,  749. 
Leda,  385. 

amygdaloides,  518. 

minuta,  551. 

multilineata,  509. 

pernula,  551. 
Leda  clavs,  550,  555. 
Leech,  122.  § 
Legumiuosites     Marcouanus, 

459.* 
Leidy,  J.,  Bathygnathus,  417. 

publications  of,  468. 

Tertiary  Mammals,  506,  507. 
Leiodon,  475. 

dyspelor,  468. 

proriger,  468. 
Lemming,  571. 
Lemurs,  506,  510. 
Length  of  time,  590.  . 
Lenticular  iron-ore,  220. 
Leopard,  564. 
Leperditia,  180. 

alta,  239,*  240. 

amygdalina,  192. 

Anna,  188*  189. 

Baltica,  230,  249. 

Cauadensis,  192. 

concinnula,  190. 

cylindrica,  228. 

Fabulites,  202,*,  204. 

Josephiana,  204. 

Solvensis,  180. 

Trojensis,  178. 

ventralis,  190. 

Lepidodendrids,  269, §  324,  325, 
328,  351,  354,  356,  359,  362, 
407. 

a  comprehensive  type,  382. 
Lepidodendron,  245,§  280,  29<}, 
297,    307,    323,*'  329,  331, 
348,  349,  356. 

aculeatum,297,  324,*  329. 

Chemungense,  278 

clypeatum,  324,*  329. 

corrugatum,  297. 

costatum,  297. 

diplotegioidcs.  297- 

forulatum,  297 

Gaspianum,  271,278. 

obscuruui,  297. 


Lepidodendron      primsevum 

269,*  271. 
Serlii,  349. 

Stern  bergii,  297,  329. 
tetragon um,  297. 
turbinatum,  297. 
Veltbeimianum.283,  297. 
Worthianum,  297. 
Lepidomelane,  54. § 
Lepidophloios,  348. 
Lepidophyllum,  348. 
Lei>ido.>trobus,  297,  329,  348. 
Lepidopteris       Stuttgiirfen.-i*, 

407,*  409. 

Lepidosteus,  61,  264, §*  519. 
glaber,  510. 
osseus,  264.* 
Whitneyi,  510. 
Lepidotus,  475,  508. 

Fittoni,  450. 
Leptacanthus,  275,  304. 
Leptsena,   172,§*  1S9,  190,  199, 
2?8,    249,     252,    437,    448, 
597! 

depressa,  203,*  248. 
iucrassata,  190. 
Moorei,  438,*  448. 
plicifera,  191.* 
rugosa,  2UU.* 
sericea,  200  *  203,  205,  206, 

207,  2U8,  209,  228. 
trausversalis,  208,  226  *  229, 

248. 

last  of,  437. 

range  of,  in  time,  386.* 
Leptarctus,  511. 

primus,  511. 
Leptauchenia,  511. 
Leptochoarus,  511. 
Leptocoelia,  171. 
concava, 243. 
disparilis,  226,*  229. 
flabellites,  243. 

Leptophleum  rhombicum,  278. 
Leptosolen  Conradi,  468. 
Leptynyte,  68. § 
Lepus,  519, §  520. 
Lescuropteris,  348. 
\  Lesley,  J.   P.,   sections  by,   of 
Coal-measures  in  Pa.,  311, 
320,  396.* 

axes  of  flexure    in  Pennsyl 
vania,  397.* 

Coal  and  its  Topography,  320. 
Coal-measure  iron-ores,  318. 
fault  at  Chambersburg,  Pa., 

399. 

faults   in    southwestern  Vir 
ginia,  399,*  400. 
topographical  effects  of  ero 
sion,  645. 
Lesquereux,     L.,     coal-plants, 

331,  356. 

equivalency  of  coal-beds.  321. 
Liirnitic  of  Rocky  Mts.,  457, 

458,  493. 

Lignitic  flora,  497,  498. 
table  of  coal-plants,  331,  348. 
Tertiary    plants    and    fruits, 

493,  494. 

Lestosaurus  simus,  465,*  468. 
Leucite.  56. § 
Leucitophyre,  78.§ 
Levant  series.  375. 
Level,  changes   of,  in  the  bot 
tom  of  the  ocean,  vary  the 
water-line  along    the  con 
tinents,  761. 
origin  of  changes  of,  761. 


INDEX. 


809 


Level,  oscillations  of,  in  Quater 

Life,  Salina,  235- 

nary,  586. 

Subcarboniferous,  296,  306. 

recent  changes  of,  582. 

Tertiary,  489,  496,  514,  526. 

See,  further,  ELEVATIONS  and 

Trenton,  198. 

HEIGHT. 

Triassie,  407,  425. 

Levis  formation,  163,  184. 

Upper  Silurian.  245,  252. 

Lherzolyte,  70,  §  72. 

Light  affecting  life,  612. 

Lias,  434,  §  435. 

creation  of,  767- 

Liassian  group,  435. 

Lignite,  61,  §491,  494,  512. 

Liassic  epoch,  434. 

beds,  521. 

Libellula,  441,*  449. 

of  Hrandon,  494. 

West  woodii,  449. 

Lignitic  group  of  Rocky  Mts., 

Libocedrus  decurrens,  526. 

457,490,493,501,508,  523. 

Lichas,  174.  $  228,  240,  249,  253. 

period,  490,  493. 

Anglicus,247. 

Lima,  385,  433,  475. 

Boltoni,  227,*  229. 

gigantea,  42y,  438,*  448. 

cucuilus   204. 

Hoperi,  476. 

Hibernicus,  208. 

retifera  ,  342. 

laxatus,  2u8. 

striata,  428. 

Trentonensis,  202,*  204. 

Limaria  clathrata,  248. 

range  of  in  time,  388.* 

fruticosa,  248. 

Lichenalia,  240. 

Lime,  50,  §  364. 

Lichens,  133,§  331,  760. 

phosphate  of,  59,  §  60. 

ash  of,  365,  366. 

Lime-making  sea,  304. 

Life,  adapted  to  conditions,  593. 

Limestone,  49,  62,  §  74,  §  619. 

characteristics  of,  1,  114.  § 

from  corals   atid  shells,  193, 

destructive  effects  of,  607. 

198,  615,  619. 

distribution  of,  139,  742. 
dynamical  effects  of,  C03. 

from  Rhizopods.  194. 
metamorphic,  156. 

earliest  species,  rank  of,  382. 

of  Coral  islnnds,  619. 

earliest     species     are     water- 

rate  of  formation  of,  626. 

species,  382. 

ratio  of,  to  sandstones,  211. 

extinction  of  species  of,  181. 

source  of,  193.  198. 

209,  253,  288,  384,  579,  763. 

Lime-tree.  515. 

geographical  distribution  of, 

Limna>a,  450,  617. 

43,  609. 

caudata,  519. 

introduction  of,  766. 

elongata,  548. 

kinds  of,  most   likely  to  be 

Liuinocyon  riparius,  510. 

come  fossilized,  613. 

Limiiofelis  ferox,  510. 

lowest  kinds  of,  the  best  rock- 
makers,  614. 

Linmohyus  paludosus,  510. 
diaconus,  510. 

materials  of  rocks  from,  59. 

Limnophis  crassus,  510- 

number  of  species  of,  in  Silu 

Limnoria,  608. 

rian,  249. 

Limnosaurns,  510. 

oceanic,  distribution  of,  illus 

Limnotherium,  510. 

trated  by  the  Physiographic 

Limonite,  59,  §  318,  688,  694,  759. 

Chart,  43. 

Limulus,  122,§  333. 

origin.-itiou  of  species  of,  600. 

Lingula     or     Lingulella.    119,* 

products  contributed   by,  to 

126,§   168,    174,   175,    187, 

rock  formations,  612. 

190,228,252,3*5,  448,469, 

protective  effects  of,  606. 

592,  594,  597_. 

relation    of    progress    in,    to 

acuminata,  177,  189. 

the  physical  history  of  the 

antiqua,  177.* 

globe,  593. 
system  of,  114.§ 

composition  of  shell  of,  60. 
cuneata,  223,*  22*. 

system  of,  progress  of,  in  the 

Davisii,  180,*  192,  207. 

course  of  geological    time, 

Dumortieri,  519. 

382,  592. 

family,  170,  §*  199. 

transitions  in  forms  of,  600. 

Huronensis,  191. 

transporting  effects  of,  607. 

lamellata,  229. 

Archaean,  157. 

Lewisii,  247. 

Canadian,  186. 

Lyelli,  191. 

Carboniferous,  321,  347. 

Mantelli,  192. 

Catskill,  280. 

Matthewi,  174,*  176. 

Cenozoic,  588. 

nitida,  467. 

Chemung,  278. 

ovalis,  60. 

Corniferous,  257. 

prima,  177.* 

Cretaceous,  458,  470. 
Devonian,  foreign,  283,  288. 
Hamilton,  268,  276. 

quadrata,  200,*  203. 
subspatulata,  271. 
range  of,  in  time,  386.* 

Jurassic,  432,  436,  451. 

Lingula  flags,  163,  179. 

Lower  Helderberg,  238. 
Mesozoic,  482. 

Lion,  416,  564,  566,  567,  571. 
Liquidambar,  515. 

Niagara,  223. 

integrifolius,  459. 

Oriskany,  242. 

Liriodendron,459,  515. 

Paleozoic,  381. 

Meekii,  459.* 

Permian,  367,  370. 

Liskeard  group.  292. 

Potsdam,  169. 

Listriodon,  519. 

Quaternary,  563. 

Lithodomus,  608. 

Lithographic  limestone,  294, 378. 

slate  of  Soleuhofen,  436. 
Lithological  Geology.  7,§  47. 
Lithologv,  works  on.  79 
Lithophis  Sargenti,  510. 
Lithostrotion,  307,  352,  429. 

beds,  294. 

Canadense,  297,  299,*  302. 

mamillare,  302. 
Litorina  litorea,  519. 

ornata,  449. 

palliata,  551 
Littoral  zone,  611. 
Lituites,  203,§  229,  483. 

Americanus,  250. 

1'arnsworthi,  189. 

giganteus,  250. 

Hibernicus,  208. 

Imperator,  189. 

undatus,  203  * 
Lituola  nautiloidea,  131,*  471,* 

474. 

Lits  coquilliers,  512. 
Liverworts,  133. § 
Lizards,  121, §  338, §  592. 
Llandeilo  group,  163,  192,  206. 
Llandovery  beds,  lb'4,  206,  244, 

247. 

Llano  Estacado,  21. 
Lobster,  121, §  592,  593,  611. 
Lob-worm,  120.* 
Localities  of  fossils,  772. 

of  Tertiary  fishes,  520. 
Locust.  351. 
Lode, 113  § 
Loedonian,  435. 
Loess,  547,  548,  556. 
Logan,  W.  E.,  fault  along  the 
Hudson,  and  at  Montmor- 
ency,  214,  215. 

Archaean,  151. 

Joggins  section,  319. 

Lower  Ilelderbtrg,  241. 

Potsdam  tracks,  176.* 

Quebec  group.  184,  214. 
Loganellus,  190.' 
Loganite.  157- 
Logs,  649,  650. 
Loligo  vulgaris,  119.* 
London  clay,  512. 
Lonchopteris,  348. 
Longmynd  rocks,  179. 
Long  Island,  Cretaceous  in,  455. 

Quaternary  in,  528. 

sand-hills  of,  631. 

subsidence  of,  583. 

Tertiary  in ,  455. 
Lophiodon,  504,§  507,  511,  516, 
517. 

Bairdianus,  510. 

minimus,  518,  519. 

validus,  510. 

Lophoph\  Hum  proliferum,  341.  , 
Lorraine 'shales,  164,  195, 196. 
Louisiana,  terraces  in,  548. 
Loup  River  group,  495. 
Loven,  on  Cystids,  289. 
Low-lands,  15.  § 
Lower  Devonian.  254. 
Lower    Helderberg    limestones, 
237. 

American    species,   occurring 

elsewhere,  248. 
Lower  Helderberg  period,   164, 

236. 
Lower     Magnesian      limestone, 

163,  183,  193,  377,  378. 
Lower  Silurian.     See  SILURIAN. 
Loxomma  Allmanui,  351. 


810 


INDEX. 


Loxonema,  243,  284,  303,  429. 

semicostatum,  342. 

sinuosum,  247. 
Loxotrema,  508. 
Lubbock,  on  Stone  Age,  574. 
Luchm,  475,  508. 

borealis,  510. 

Portlandica,  449. 

proavia,  260,*  261. 

serrata,  518. 
Ludlow  beds,  164,  244,  247. 

beds,  land-plants  in,  245. 
Lunatia,  508. 

Groeulandica,  551. 

heros,  510,  551. 
Lutricola  alta,  510. 
Lychuocaniuni  Lucerna,  132.* 
Lyckholin  group,  164. 
Lycopodia, 133,§  242.  245,  257.? 
268,  318,  321,  323,  324,  354', 
364. 

ash,  composition  of,  365,  366. 

composition  of,  362. 

spores,  composition  of,  361. 
Lycopodites,  348. 

plumula,  297. 

Lycopodium   chamsecyparissus, 
366. 

clavatum,  365. 

complanatum,  362,  366. 

dendroitleuni,  242,  332,  366. 

selago,  532. 
Lycosa,  342. 
Lydian-stone,  53. § 
Lyell,  C.,  Champlain  in  Europe, 
555 

changes   of  level  in  Sweden, 
582. 

climate,  754. 

erosion,  643. 

expansion,  by  heat,  701. 

Glacial  period,  541. 

Neanderthal  skull,  575. 

Niagara  retrocession,  590. 

Recent    Period    in    England, 
562. 

Spit/.bergen    Tertiary   plants, 
515. 

Tertiary  periods,  489,  491. 
Lynx,  564. 
Lyrodesina  cuneata,  247. 

Machaera  patula,  510 
Machaeracanthus  sulcatus, 

262.* 

Machrerodus,  519,  520,  564. § 
latidens,  564,  571,  576.      ' 
Mackenzie  River  in  the  Creta 
ceous  period,  480. 
River  system,  22. 
Miiclurea  Arctica,  185,  209. 
limestone,  185. 
Logani,  191  *  208. 
magna,  185,  191,*  203,  209. 
matutiua,  189,  192. 
sordida,  192. 
Macoma  fragilis,  551. 
sabulo^H,  551,  555. 
Macrocheilus  fusiformis,  333,* 

342. 

Newberry  5,342. 
ventricosus,  342. 
Macrodon     carbonarius,    332,* 

342. 
Macropetalichthys      Sullivanti. 

263.* 
Macropterna    divaricans,   412,* 

417. 
Macrostachys,  348. 


Macrothere,  518. § 

Macrurans.  122,§*  335, 475, 593. 

first  of,  372. 

range  of,  in  time,  388.* 
Mactra  Ashburnerii,  458. 

funerata,  509. 

lateralis,  510. 

ovalis,  551. 

rostrata,  450. 

Madagascar,  /Epyornis  of,  580. 
Madison  River,  geysers  of,  719.* 
Madrepora,  620,§  621. 

palniata,  analysis  of,  60. 
Madreporic  body,  128. § 
i  Maestricht  beds,  470. 
i  Magas,  171- 
Magnesia,  364. 
.Vlagnesian  fossils    in    common 

limestone,  74. 
Magnesian  limestone,  74, §  369. 

o——     o-o 
OUjOtO. 

Magnesite,  58. § 
Magnesium,  50. § 
Magnetic  iron  ore,  74. § 
Magnetite,  59  § 
Magnolia,  471,  497,  514. 
Ililgardiana,  498. 
Inglefieldi,  498. 
Lesleyana,  498. 
tenuifolia,  460. 
!  Mahoning  sandstone,  311. 
!  Maine,  Archaean,  150- 
fiords  in,  534. 
in  Quaternary,  552. 
in  Recent  period,  531. 
Lower    lleiderberg    in,     237, 

238. 

Niagara  in,  221. 
Oriskany  in,  241. 
Quaternary  in,  531,  537. 
terraces  in,  550. 
uplifts  in,  289. 
i  Maioids,  593. 
!  Malachite,  733. 
Malaguti  &  Durocher,  analyses 

of  ashes.  365. 
Mallet,  on  heal  from  crushing, 

698. 

Mallotus  villosus,  551. 
Malmo  group,  164,  245. 
Malocvstis  Murchisoni,  190.* 
Mammals,  121, §  332,  592,  602. 
Age  of,  139. 
classification  of,  416. § 
culmination   of  the   type  of. 

587,  598 
first,  403,  411,  415,*  435,  489, 

600. 

first  Tertiary,  517. 
introduction  of,  766. 
Jurassic,  446. 
Mesozoic,  486. 

range  of,  in  time,,  140,  589.* 
Quaternary,  large  size  of,  563, 

565. 
Q  uaternary ,   cotemporaneous 

with  Man,  574,  576,  578 
Tertiary,  513.  516,  519,  602. 
Mammalian  age,  489. 
Mammoth    coal-bed,   311,    313. 

321,  331. 

Mammoth ,  564,  568. 
Mammoth  Cave,  river  in,  653. 

period,  562,  574. 
Man,  Age  of,  139,  527,  571. 
anterior  limbs  not  organs  of 

locomotion,  592. 
characteristics  of,  578. 
earliest  iu  Europe,  576. 


Man,  intellectual  character  of. 
how  expressed  iu  his  struc 
ture,  579. 

introduction  of,  766 
origin  of.  603. 
position  iu  classification,  578, 

592. 

Quaternary  mammals  cotem 
poraneous  with,  574,  576, 
577,  578. 

!      relics  of,  564,  573,*  574,  579. 
'      skeletons  of,  574,  575,*  579, 

580.* 

j      structure  of,  596. 
'  Man-apes,  603. 
'  Manatee,  extinction  of  a  species 

of,  581. 

Manatus,  518. § 
Mauitouliu  Islands,  220. 
Mangrove,  growth  of,  606. 
Mantellia  megalophylla,  436.* 
,  Mantle,  124. § 

!  Map  of  Archaean  North  Ameri 
ca,  149.* 

,      of  axes  of  folds  in  Pennsyl 
vania,  397.* 
of  Azores,  37.* 
of    Connecticut    trap   ridees 

20,*  418.* 
of  courses  of  Pacific  chains, 

32,*  34.* 
of   Cretaceous    N.    America 

479.* 

of  England,  344.* 
of  Hawaian  Islands,  31.* 
of  Hawaii,  705,*  712. 
of    land    and     water     hem 
ispheres,  10.* 
j      of  Loyalty  group,  30.  * 

of  Marquesas  Islands,  31.* 
I      of  New  Caledonia,  30.* 
!      of  New  Hebrides,  30.* 

of   New   York    and   Canada, 

165* 
of   Pennsylvania    coal-fields, 

310.* 

of  submerged  border  of  con 
tinent,  421.* 

'      of  Tertiary  X.  America,  521.* 
ofTahitiau  Islands,  31.* 
of  trap  of  Connecticut,  20  * 

418.* 

of  United  States,  144  *  292.* 
Maple,  459,  471,  497,  514. 
Maquoketa  shales,  377. 
j  Marble,  75,§  729. 
;  Marbles  of  Tennessee,  198. 

of  western  New  England,  214. 
Marcasite,  197. 
Marcellus  shale,  254,  266. 

epoch,  254,  266. 

Marchand,  analysis  of  bones,  60. 
Margarita    Xebrascensis,    461,* 

467. 

[      varicosa,  551. 
,  Margaritella,  508. 

angulata,  467. 
Margarodite,  54. § 
Manrinella  larvata,  509. 
Mariacrinus,  240,  243. 

nobilissimus,  238. 
Marine  formations,  666,  672. 
Marine   life  of  low  grade,   382, 

592. 

the  earliest,  593. 
Marl,  75, §  455.§ 

shell,  Quaternary,  617. 
Marmosets,  506,  510. 
Marmot,  572,  577. 


INDEX. 


811 


Marnes  irisees,  424. 

marines,  513. 
Marquesas  Wands,  map  of,  31.* 
Marquette  iron  region,  151,  153, 

159. 
Marsh,   0.   C.,    Cretaceous    in 

Utah,  457. 

Cretaceous  Birds,  466. 
Eosaurus,  343. 
Jurassic  in  Uintah  Mts.,  431. 
Mosasaurs,  468. 
Palaeotrochis,  160. 
papers  by,  468. 
petrified  trees,  693. 
Stylolites,  222. 
Tertiary  Horses,  505.* 
Tertiary  Monkeys,  506. 
Marshall  group,  295,  377. 
Marsupials,  416,$  446,  486,  506, 

571,  592,  610. 
first  of,  600. 
range  of,  in  time,  589.* 
Marsupiocrinus  coalatus,  247. 
Marsupites,  457,  474,  508. 

oruatus,  476. 
Martha's  Vineyard,  Tertiary  in, 

490,  495. 

Martinez  group,  457. 
Martinia  umbouata,  272.* 
Maryland,  Cretaceous  in,  455. 
Lower  Ilelderberg  in,  236. 
Oriskany  in,  243. 
Tertiary  in,  490,  494,  495. 
Triassic  in,  419. 
Marwood  sandstones,  282. 
Massachusetts,  Archasanin,  150. 
Carboniferous  in.  291,  319. 
Lower  Silurian  in,  196. 
peat-beds  in,  616. 
Potsdam  in,  167. 
Quaternary  in,  529,  531. 
sections  in  western,  213. 
Triassic  in,  404,  406,  409,  417, 

419. 
Upper    Ilelderberg    in,    237. 

256. 

terraces  in,  548,  550. 
Massive  limestone,  74. S 
rocks,  63.§ 
structure,  82.  § 

Mastodon,  507,  511,  518,  519, 
520,  565,  567, §  568,  571 
590. 

American  us,  508,  565,  566.* 
Arvernensis,  519. 
angustidens,  519. 
giganteus,  566.* 
longirostris,  519. 
mirificus,  508,  511. 
Ohioticus,  566.* 
tapiroides,  519. 
Mastodonsaurus      giganteus, 

427,*  428,  429. 
Mastogloia,  634.* 
Mather.    Cretaceous     in    Long 

Island,  455. 

Matthew,  G.  F.,  on  Acadian,  167.  j 
Matinal  series,  375. 
Mauritius,  extinct  birds  of,  580,  • 

581.* 

Mauvaises  terres,  492,  495. 
Maxville  limestone,  376. 
Mayence  basin,  513. 
May-Hill  sandstones,  164  244 
May-fly,  273,  335,  336,  349,  450. 
Maxonia  VVoodiana,  342. 
McClintochia.  497. 

Lyellii,4i)S. 
Meandriiia,  620, §  621. 


Medina  epoch,  164,  218. 

sandstone,  164,  218. 
Mediterranean  basin,  470. 
Mediterranean  sea,  temperature 
.  of,  42. 

volcanoes  in  and  about,  703- 
Medusse,  60,  117.* 
Meek,  F.  B.,  Chara,  258. 
Cretaceous,  457. 
Cretaceous  climate,  481. 
Meek    &    Hay  den,   Cretaceous, 

456. 

Jurassic,  450. 
Permian,  367. 

Tertiary   of  the   Upper   Mis 
souri,  493,  495. 
Meekella  striato-costata,  341. 
Megaceros.     See  CERVUS. 
Mega-lactylus,  413  § 
Megalicthys,  343. 
Megalobatrachus,  337. § 
Megalodou,  284,  429. 

triqueter,  429. 
Megalomus     Canadensis,    227  * 

229. 

Megalomeryx,  511. 
Megalonyx,  565,  567,  569, 

Jelfersouii,  5"<0.* 
Megalosaur,  33S,§  444,  449,  450, 

457,  501,  5U9. 
Megalosaurus    Bucklandi,    444, 

445,*  449. 
Megaphytum,  348. 
McLeayi,  325,*  330. 
protuberans,  297. 
Megasthenes,  593. 
Megathentomum      pustulatum 

343. 
Megatherium,   665,    569, §   570, 

571. 

Cuvieri,  569.* 
mirabile,  569. 
Megerlia,  171,  174 
Melampus,  508. 
antiquus,  508. 
Melania,  483,  493,  590. 
attenuata,  450. 
canaliculata,  548. 
costata,  519. 
fasciata,  519. 
inquinata,  518. 
Nebrascensis,  501,*  508. 
turritissima,  519. 
Melaphyre,  78. § 
Meleagris   antiquus,  511. 
altus,  568. 
celer,  568. 
Melonites,  303. 

multipora,  298,*  299,*  303. 
Melosira  granulata,  632.* 
decussata,  632.* 
Marchica,  632.* 
sulcata,  134,*  496.* 
distans,  632.* 
Melville    Island,    Carboniferous 

in,  293- 

Membranipora,  466. 
Memphremagog     Lake,     Upper 

Ilelderberg  at,  256. 
Menaccanite,  59.  § 
Menaspis  armata,  372. 
Menchikoff  Island,  618. 
Menevian  beds,  163,  179. 
Meniscus  limestone,  221,  379. 
Menobranchus  lateralis,  341. § 
Menocephalus,  178,  190. 
Menopoma,  337. § 
Mentone  skeleton,  575,  577. 
Mercury  mines,  458. 


,  Meretrix,  508. 
|  Mer  de  Glace,  677. 
1  Meridian  series,  375. 
Merista,  171. 

nitida,  226,*  229,  248. 
Meristella  augustifrons,  208. 
crassa,  208. 
levis,  239,*  240,  243. 
sulcata,  239,*  240. 
Merulina,  620. 
Merychippus,  511. 
Merychyus,  508. 
Merycodus,  511. 
Merycopotamus,  520. 
Mesa,  645.  § 

Mesonyx  obtusidens,  510. 
Mesozoic  time,  140,  403. 

general  facts  of,  481. 
Metallic  veins,  112. § 
Metamorphism,  724, §  750. 

after  Lower  Silurian,  214  217 
I      Archajan,  156. 
!     after  Paleozoic,  400. 

of  Devonian,  289. 
;     of  Jurassic,  453. 
Meta_morphic    rocks,    63,§    66, 

Meteoric'stones,  3. 
Metoptoma,  203. 
Mexican  plateau,  21. 
Mexico,  Archaean  in,  150. 
Meyen,  on  vertical  zones  of  life, 

609. 
Miamia  Bronsoni,  335  *  342. 

Dana?,  335,*  342.      ' 
Mica,  53, §,54,  627,  727,  728. 
schist,  49,  68, §  (i23,  729. 
Mica-bearing  series  of  rocks,  67. § 
Mica-slate,  69, §  237,  729. 
Micaceous  rocks,  63. § 
Michigan,  Archaean  i'n,  150. 
Carboniferous  in,  291. 
Cincinnati  in,  197. 
coal-field  in,  291,  293,  309. 
Hamilton  in,  266. 
Huronian  in,  159. 
iron-mines  in   152,  153,  159. 
Niagara  in,  221. 
Quaternary  in,  529. 
rocks  of,  376. 
Saliuain,  233. 
Salt  group,  295,  377. 
Subcarboniferous  in,  293,  298 

305. 

Upper  Ilelderberg  in,  256. 
Michigan,  Lake,  outlets  of,  540. 
Micrabacia,  474. 
Americana,  4^6. 
coronula,  476. 
Micraster,  474. 

Cor-anguinum,  476. 
Microchaerus  erinaceus,  519 
Microchoncus  carbonarius,  342. 
Microdiscus,  180. 
punctatus,  180. 
Microdon.     bellistriatus,     273,* 

Microlabis  Stern bergi,  351. 
Microlestes  antiquus,  427  *  429 
Migrations,  498,  526,  532,  538, 
535,  542,  561,  572,  599,  607. 
Millepores,  130,§*  621. §  . 

carbonate  of  magnesia*in,  60. 
Millstone  grit,  65,  311,  320,  331, 

354,  358. 
Mineral  charcoal,  316. 

coal,  61. §     See  COAL. 

constituents  of  rocks,  48. 

kingdom,  l.§ 


812 


INDEX. 


Mineral  oil,  197,  222,  253,  268. 

Minerals,  52.§ 

Minnesota,  Cretaceous  in,  455. 

Potsdam  in,  168- 

Quaternary  in,  528. 
Miocene.  489. §  494. 

Europe,  climate  of,  526. 

See,  further,  TERTIARY. 
Mississippi,    Carboniferous    in, 
291. 

in  Tertiary,  521. 

Quaternary  in,  529. 

Subcarboniferous  in,  293,  294, 
305. 

Tertiary  in,  491,  493,  494. 
Mississippi     basin,    section    of 
Paleozoic  rocks  in,  374.* 

Calciferous  in,  182,  193. 

Chazy  in,  182, 185. 

Cretaceous  in,  455,  456. 

Lower  Silurian  limestones  in, 
•209. 

Oriskany  in,  241. 

Salina  in.  233. 

Mississippi  River,  delta  of,  651, 
652.* 

discharge  aud   pitch  of,  635, 


in  the  Carboniferous,  355. 

in  the  Cretaceous,  419.  ' 

in  the  Quaternary,  547,  552 

553. 

in  tlie  Tertiary,  521,*  522. 
levees  along,  608. 
sediment  of,  648. 
Tertiary  along,  491. 
Mississippi  River-system,  22. 
Mississippi  Valley,  Subcarbonif- 

erous  in,  294. 

Missouri,  Archaean  in,  150. 
Calciferous  in,  183. 
Carboniferous  in,  291,  321. 
Cincinnati  in,  196. 
Hamilton  in,  267. 
iron-mountains  of,  151,  153. 
lead  mines  in,  186. 
Lower  Silurian  in,  210,  380. 
Oriskany  in,  242. 
rocks  of,  378. 

Subcarboniferous  in,  293,  294. 
terraces  in,  548. 
Trenton  in,  196. 
Upper  Ilelderberg  in,  256. 
Missouri,  Upper  (ir  eluding  Da 
kota,  Nebraska,  Black  Hills, 
etc.),  Archaean  in,  150. 
Cretaceous  in,  455. 
earlier  Paleozoic  largely  want 
ing  in.  232. 
Jurassic  in,  431. 
Permian  in,  367- 
Potsdam  in,  167. 
Tertiary  in,  492,  493.  495,  506, 

507. 

Triassicin,  406. 
Missouri  River,   discharge  and 

pitch  of,  636. 
in  the  Cretaceous,  479. 
in  the  Tertiary,  522. 
Mitra.  475,  508,  509. 
dumosa,  509. 
MUHngtoni,  509. 
scabra,  519. 
Mitscherlich,  analysis  of  cork, 

362. 

Mittelquader  group,  470. 
Moa,  of  New  Zealand,  579,  580. § 
Modern  era,  550,  574,  579. 
Modiola,  508. 


Jodiola  angusta,  281.* 
minima,  429. 
multilinigera,  508. 
plicatula,  561. 
Shawneensis,  342. 
\Vyomingensis,  342. 
Uodiolopsis,203,  243. 
antiqua,  247- 
complanata,  247- 
expansa,  207- 
modiolaris,  205,*  207. 
orthonota,  223.*  228. 
primigenia,  223,*  228. 
subalata,  229. 
Moisture  essential  to  metamor- 

phism,  727. 
in  rocks,  656. 
limiting  climate,  609. 
of  Carboniferous  atmosphere, 

352. 

Mole,  506.  564,  571,  ft  8. 
Molasse  of  Switzerland,  513. 
Mollusks,  117, §*  123,§  594,  598, 

611. 

culmination  of,  483,  594. 
destruction  by  ,'608. 
number  of,  in  the  Quebec,  190. 
range  of,  in  time,  14U.* 
shells  of  Tertiar> ,  515. 
teeth  of,  208. 
Monas,  132.  § 
Money,  fossil,  579,580.* 
Monitor,  338. § 
Monke\s,  416,  506,  518,  610. 

range  of,  in  time,  589.* 
Monocotyledons,  134. § 
Monomyaries,  126.  § 
j      range  of,  in  time,  387.* 

Monopteria,  342. 
1  Monotis.409,410. 
!      cui-ta,  432,*  433. 
decussata,  429. 
salinaria,  429. 
subdrcularis,  416. 
Montana,  Carboniferous  in,  293. 
Subcarbonlferous  in,  296. 
terraces  in,  549. 
Monte  Bolca,  fishes  of,  520. 
Montipora,  620. 

Montfivaltia  Atlantica,  466,  469. 
caryophyllata,436,*449. 
cuneata,  448. 
Guettardi,  448. 
mucronata,  448. 
trochoides,  449. 
Montmorency,  fault  at,  215-* 
i  Monument  Mt.,  section  of,  213. ' 

Park,  646.* 
i  Moon's  surface,  3. 
1  Moose,  568. 
!  Moraines,  537,  549,  678,§   680 


Morris,  111.,  fossils  of,  339. 

Morrisia,  171, 174. 

Morse,    E.  S.,  on  Brachiopods, 

382. 

Mortonia  Rogersi,  499,*  509. 
Morus,  497. 

Mosaic  cosmogony,  767- 
Mosasaur,  339.§  456,§  464,  465, 
468,  169,  474,  476,  477,  484. 

first  of,  477. 

Mosasaur  us     Ilofmanni,    474,* 
475. 

Maximiliaui,  478. 

maximus,  468. 

luinor,  468. 

Missouriensis,  468,  469. 

princeps,  465,*  468. 


Moschus,  520. 
Moscow  shale,  267. 
Mosses,  133,§  252,  321,598. 

ash  of,  366. 

Mottled  colors  in  rocks,  760. 
Mountain-chains,  ages  of,    16, 

523. 
composite  character  of,   19,* 

744. 

development  of,  748. 
parallel,  744. 
Mountain-elevation,  systems  of. 

See  SYSTEM. 

Mountain-limestone,  306,  307- 
Mountain-making  slow,  754. 
Mountains,  15, §  16. 

of  the  Tertiary,  523,  746. 
of  the  Paleozoic,  390. 
origin  of,  761. 
solid  dimensions  of,  21  §. 
height  of.     See  HEIGHTS. 
Mt.  Blanc  glacier-region,  676.* 
Mt.  Etna,  716. 
Mt.  Lebanon,  fishes  of,  520. 
Mt.  Shasta,  age  of,  753. 
Mouse,  416,  564. 
Movements  in  the  earth's  crust, 

716. 

Muck,  617. § 
Mud-cracks.  84,§*  168,  222,  234, 

420. 

Mud-marks,  85. 
Mud,  t<49.§ 
lumps,  656. 
volcanoes,  656. 
Mulinia  lateralis,  510. 
Mnltiplicate  spedes,  3S3.§ 
Mummies,  oldest,  612. 
Murchison,  disturbances    after 

Paleozoic,  402. 
Permian,  so  named  by,  370. 
Silurian,  so  earned  by,  138. 
Murchisonia,  189,  243,  284,  429. 
angulata,  247. 
Anna,  189. 

bellicincta,  189,  201.*  203. 
bicincta,  201,*  203,  205. 
minima,  342. 
simplex.  208. 
last  of,  371. 
Murray,  A.,  on  Newfoundland 

Primordial,  167. 
Murray,  J.  J.,  on  effects  of  ec 
centricity   of  earth's  orbit, 
698. 

Mus,  519. § 
Muschelkalk,424. 
Musci,133.§ 
Muscovite,  54. § 
Mushrooms,  133.§  321. 
Musk-deer,  508. 
Musk-ox,  506,  567,  571. 
Musk-rat,  568. 
Mussel,  126.  § 
Mustela,  519. § 
Mutilates,  520. 
Mya  arenaria,  551- 

truncata,  551. 
Myacites,  433. 
mandibula,  475. 
Pennsylvauicus,  416. 
Myalina,  303. 

perattenuata,   342,  368.* 
recurvirostri_s,  342. 
squamosa,  372. 
Mylacris  anthracophila,  343- 
Mvliobates,  278. § 
Edwardsi,  518. 
Mylocyprinus  robustus,  olO. 


INDEX. 


813 


My lodon,  565.  567,569. 

Harlani,  567,  570. 

robustus,  569. 
Myophoria,  409,  410,  429. 

alta,  416. 

vulgaris,  429. 

lineata,  426,*  428,  429. 
Mvriapods,  121, §  331,  335,  350, 

"    592. 

Carboniferous,  334,*  S35. 

range  of,  in  time,  388.* 
Myrica,  497,  498. 

Torreyi,  498. 
Myrmecobius,  416. § 

fasciatus,  416.* 
Myrmecophagus,  423.§ 
Myrtaceae,  515. 
Myrtle,  471,514.594.609. 
Mytilus,  253,  433,  508,  562. 

edulis,  551,  577,  610. 

family,  610. 

Shawneensis,  342. 
Mystriosaurus  Tiedmanni,  444.* 

Naiadites  carbonaria,  342. 

elongata,  342. 

levis,  342. 
Naocephalus,  510. 
Naphtha.     See  PETROLEUM. 
Napoleon  group,  294,  377. 
Nashville  group,  164,  379. 
Nassa,  508. 

fossiita,  510. 

helicoides,  519. 

reticosa,  519. 

trivittata,  510. 

Natatores  in  the  Cretaceous,  468. 
Natica,  303,  508,  475. 

JEtites,  509. 

clausa,  551,  555. 

elegans,  450. 

Vicksburgensis,  509. 
Naticina,  503. 
Naticopsis,  303,  342. 
Nature,  forces  of,  605. 
Nautilus,   119,  124;§   272,   284, 
300,  303,  332,  335,  429,  483, 
500,  594,  598. 

bidorsatus,  429. 

centralis,  518. 

Danicus,  476. 

Dekayi,  463,*  467,  468,  469. 

elegans,  477. 

ferox,  189. 

imperialis,  518. 

Lasallensis,  342. 

latus,  342. 

lineatus,  449. 

Koninckii,  307.*  308. 

Missouriensis,  342. 

planivolvus,  342. 

Pomporiius,  189. 

spectabilis,  303. 

Texanus,  467. 

Winslowi,  342. 

family,  range  of,  in  time,  387.* 
Nautilites  Yanuxemi,  509. 
Navicula,  496.* 

amphioxys,  634.* 

bacillum,  634.* 

lima,  509. 

serians,  634.* 

semen,  634.* 
Neaera,  508. 

Neanderthal  skeleton,  575. 
Nebraska,  Carboniferous  in,  291, 

321. 

Nebular  theory,  146,  765. 
Necturus,  337. 


'  Negundo,  497. 
Neithea,  475,  483. 
Mortoni,  456,  468,  469,   476, 

477. 

Neocomian,  470. 
Neolithic  era,  574. 
|  Nephelite,  56. § 
Nephelinyte,  78.  § 
Nephroma  Arcticum,  532. 
Nereites  Sedgwickii,  208. 
Nerinfea.  439, §  462,§  469,  475. 
Acus,  467. 

bisulcata,  472,*  475,  476. 
fasciata,  449. 
Goodhallii,  439  *  449. 
Gosse,  449. 
Texana,  461,*  467. 
Neriopteris,  348. 
Nentsi,  475,  483,  508. 
Neritina,  508. 
concava,  519. 
Fittoni,  450. 
I      pisum,  508. 
j  Neuropteris,  271,  330,  348,  370, 

409,  433. 
Dawsoni,  271. 
dilatata,  297. 
elegans,  429. 
flexuosa,  331. 
hirsuta,  327,*  330,  331. 
Loschii,  327,*  330,  370.* 
Moorii,  331. 
pachyrachis,  409. 
polymorpha,  269,*  271. 
rarinervis,  297- 
Neuropters,  300,  335,  343,  351, 

450,  613. 
Paleozoic,    a    comprehensive 

type,  382. 

range  of,  in  time,  388.* 
Nevada,  Carboniferous  in,  293. 
hot  springs  in,  611. 
Potsdam  in,  168. 
Quaternary  in,  528. 
1  Neve,  678. § 
Neverita,  508. 
saxea,  510. 

Newberry,    J.   S.,    cannel-coal, 
|         359. 
i      Colorado  River,  640.* 

fish  of  the  Corniferous,  263.* 
fish  of  the  Subcarboniferous. 

304. 

fish  of  the  Carboniferous,  353. 
fossil  flowers  and  fruit,  326.* 
river-valleys,  539. 
rocks  of  Ohio,  374,  376. 
rocks  of  the  Upper  Colorado, 

407. 

Tertiary  plants,  497. 
New   Brunswick,   Ai-chaean    in, 

150. 
Carboniferous    in,    145,    291, 

319,  355. 
Clinton  in,  221. 
Devonian  in,  266,  267,  271. 
Lower  Helderberg  in,  238. 
Primordial  in,  167. 
Subcarboniferous  in,  296,  304. 
terraces  in,  548. 
New. Caledonia,  map  of,  30.* 
New     England,    flexures     and 

faults  in,  212-216. 
in  the  Champlain,  551,  554. 
terraces  in,  548. 
Newfoundland,  Archaean  in.  150. 
Calciferousin,189,  193. 
in  the  Carboniferous,  356. 
Primordial  in,  167,  181. 


!  Newfound'anrJ,  Quebec  in,  184, 

192. 

New  Hampshire,  Corniferous  in, 
256. 

erosion  in,  647. 

Lower  Helderberg  in,  237. 

Niagara  in,  221. 

Quaternary  in,  529,  537. 

terraces  in,  548. 
New  Hebrides,  map  of,  30.* 
New  Jersey,  Archaean  in,  150. 

border  of  continent  off,  11. 

Cretaceous  in,  455,  457,  478. 

in  the  Cretaceous,  479. 

Lower  Helderberg  in,  236. 

Potsdam  in,  167. 

Quaternary  in,  528,  529. 

sand-hills  of.  631. 

soundings  off  coast  of,  422.* 

subsidence  of,  583. 

Tertiary  in,  490,  491,  494,  495. 

Triassic  in,  405,  419. 

Upper  Helderberg  in,  256. 
New  Mexico,  Cretaceous  iu,  456. 

in  the  Cretaceous,  480. 


Lower  Silurian  in,  232. 

Permian  in    367. 

Tertiary  in,  493. 

Upper  Silurian  and  Devonian 

wanting  in,  232. 
Newport,  rocks  at,  319. 
New  Red  Sandstone,  369,  424. 
New  South   Wales,    mountains 

of,  28. 
Newton,   II.    A.,   on  effects   of 

eccentricity  of  earth's  orbit, 

698. 

New  York,  Archaean  in,  150. 
Calciferous  in,  182,  183,  184, 

193. 

Carboniferous  in,  291.  311. 
Cauda-galli  grit  in,  256. 
Chazy  in,  182,  184. 
Chemung  in,  276. 
Cincinnati  in,  196. 
Clinton  in,  220. 
Hamilton  in,  267. 
iron  ores,  154. 
Lower  Helderberg  in,  237. 
Medina  in,  220. 
Niagara  in,  221. 
Oneidain,220. 
Oriskany  in,  241. 
Portage  in    276. 
Potsdam  in,  167,  181. 
Quaternary  in,  528,  531,  537, 

548. 

Quebec  in,  184. 
Salina  in,  233. 
Schoharie  in,  256. 
strata  of,  a  standard,  162, 
terraces  in,  548. 
Trenton  in,  194,  195. 
Triassic  in,  405. 
Upper  Helderberg  in,  256. 
Uticain,  196. 
New  York  harbor,  former  sites 

of,  422.* 
New  Zealand,  Moa  of,  580. 

chain  of  islands,  34. 
Niagara,    American   species  in, 

occurring  elsewhere,  248. 
and  Clinton,  species  common 

to,  229. 

epoch,  164,  218. 
period,  164,  218. 
Niagara  River,  ancient  channel 

of,    filled  with    drift.  553, 

590. 


814 


INDEX. 


Niagara  River,  recession  of  Falls  !  Notopocorystes,  475. 

Oceanic  forces,  657- 

of  219  590.                             '  Notornis,  580. 

formations,  666,  672. 

section  along,  219.*                   j  Nototherium  Mitchell  I,  571. 

impurities,  593. 

whirlpool  in,  637.                        '  Nova  Scotia,  Archaean  in,  150. 

islands,  14. 

Nicholson,  11.  A.,  English  Grap-        Carboniferous   in,    145,    291, 

life  not  easily  exterminated, 

tolites,  192. 

309,  310,  319,  339,  355,  358, 

614. 

Niles,    \\".    II.,    on    tension    in 

392. 

movement?,  system  of,  38.* 

rocks,  743. 

Clinton  in,  221. 

temperatures,  41.  § 

Nileus,  190. 

fiords  in,  534. 

water,  specific  gravity  of,  657- 

affiuis,  250. 

gold-bearing  rocks  of,  167.          Ocoee  gioup,  163,  379. 

armadillo,  250. 

in  the  Chauiplain,  552. 

Oculina  arbuscula,  analysis  of, 

macrops,  250. 

Lower  Helderberg  in,  238. 

60. 

scrutatus,  250. 

Niagara  in,  221. 

Mississippiensis,  509. 

Niobrara  group,  456. 
Nipa,  514. 

Oriskany  in,  242. 
Primordial  in,  166. 

Vicksburgensis,  509. 
Odontaspis,  475. 

Niso,  508. 

Subcarboniferous  in,  295,  304. 

Odontidium,  634.* 

Nitrogen,  52,  365. 
Noad,  analysis  of  coal,  316. 
Nodosaria,  474. 

Triassic  in,  405,  418. 
uplifts  in,  289. 
zeolites  of,  418. 

pinnulatum,  496.* 
Odontocephalus  selenurus,  261. 
Odontopteris,  331,  348. 

vulgaris,  131.* 

Nucleocrinus,  261,  288.                       crenulata,  331. 

Nodules,  phosphatic,  61.  § 

Verneuili,  259.*  264.                  i      Schlotheimii,  326,*  330. 

Noeggerathia,  271,  348,  349. 

Nucleolites  crucifer,  409,  477.        Odontopter  ,  x,  516. 

Eequalis,  349. 

Nucleospira,  171.                               Odontornith.es,  468. 

distans,  349. 

pisum,  248.                                    (Eningen,  fishes  at,  520. 

minor,  280.* 

Nucleus  of  continent,  160.              Ogygia,  174.  § 

Normandy  Crag,  513. 

of  earth,  737. 

Buchii,  208. 

North    American    coast,    sand 

Nucula,  284,  385. 

Selwynii,  192. 

bars  of,  669. 

Cobboldise,  519. 

Ohio,    Carboniferous    in,    291, 

North    America,    Carboniferous 

lirnatula,  494. 

314,  321. 

areas  of,  291. 

nasuta,  303. 

Cincinnati  in,  197. 

completed,  525. 

Shumardana,  303. 

Clinton  in,  220. 

elevations  in,  during  the  Ter 
tiary,  523,  524. 

truncata,  458. 
Nucnlaua,  303. 

Hamilton  in,  267. 
in  the  Carboniferous,  354. 

geological    record     imperfect 
in,  600. 

bellistriata,  342. 
Nullipores.  60,$  135,  §  607,  621. 

Lower  Helderberg  in,  23". 
Millstone  grit  in,  321. 

in  the  Carboniferous,  355.        ;  Nummulites,    131,  §    437,    500, 

mineral  oil  in,  268. 

in  the   Cretaceous,    map   of,           512,  515. 

Niagara  in,  221. 

479.*     . 

first  of,  437. 

Oriskany  in,  242. 

in  the  Quaternary,  527. 

nummularia,  131.* 

Portage     and    Chemung    in, 

mapof,  in  the  Archaean,  149.*       levigatus,  518. 

277. 

map  of,   in    the   Cretaceous,        radiatus,  519. 

Quaternary  in,  528,  529,  537. 

479.*                                             variolarius,  519. 

Salina  in,  233. 

map  of,  in  the  Tertiary,  521.*    Nummulitic  beds,  512,  525. 
mean  height  of,  14.      '                     limestone,  512. 

section  of  rocks  of,  376. 
Subcarboniferous  in,  293,295, 

peat-beds  of,  f!6.                         Nyctitheriutn  velox,  510. 

305. 

Quaternary  Mammals  of,  565,        priscum,  510. 
571.                                         I  Nyssa,  498,  515. 

terraces  in",  548. 
Upper  Helderberg  in,  256. 

recent  change  of  level  in,  583.  ! 

uplift  in,  217. 

separate  regions  of,  36.                Oahu,  chalk  in,  477,  755.                Ohio  River,  discharge  of,  636. 

Silurian  of,  162.                          '      map  of,  31.*                                     in  the  Champhin,  553. 

surface-form  of,  23.*                    Oak,  459,  497,  514.  515. 

in  the  Carboniferous,  355. 

the  continent  of  Herbivores,    Oberquader  group,  470. 

in  the  Cretaceous,  479.* 

571.                                            Obolella,  173.5  190.                          Oil,     mineral,    197,    222,     256, 

through  the  Mesozoic,  481. 
trends  in,  36. 

chromatica,  177- 
cingulata,  177. 

268. 
Oldhamia  antiqua,  180.* 

North   Carolina,    Archaean    in, 

desquamata,  177. 

radiata,  180.* 

150. 

nana,  177.* 

Old  Placer  mines,  493. 

coast  of,  669.* 

Phillipsii,  177. 

Old  Red  Sandstone,  282. 

Cretaceous  in.  455. 

plumbea,  192. 

Olea,  497 

iron  ores  of,  154. 

polita,  177. 

Olenus,  188,  192. 

Taconic  in,  160. 

range  of,  in  time,  386.* 

micrurus,  180.* 

Tertiary  in,  490,  495. 

transversa,  176. 

Olenellns,  178. 

Triassic  in,  404,  405,  406,  419. 

Obolus,  173.*$ 

asaphoides,  178. 

Norway,  Archaean  in,  151,  157. 
fiords  in,  534. 

Apollinis,  173,*  177,  208. 
composition  of  shell  of,  61. 

Thompson!.  178. 
Vermontana,  178. 

glaciers  in,  675- 
in  the  Cretaceous,  480. 

filosus,200,*203. 
Labradoricus.  177. 

Olicocarpia,  348. 
Oligocene,  490,$  513. 

iron-mines  of,  154. 
Primordial  in,  179. 

range  of,  in  time,  386.* 
Obsidian,  77,  §  78,§  722. 

Oligochaeta,  123.  § 
Oligoclase,  54.§ 

Quaternary  in,  532,  556. 
Silurian  in,  207,  245. 

Occident,  13. 
Oceans,  arrangement  of,  11. 

Oligoporus  Danae,  299,*  303. 
nobilis,  298,*  303. 

Norwich  Crag,  513,  514,  519. 

depth  of,  12,  739. 

Oliva,  475,  483. 

Noryte,  70.§ 

relation  between  the  size  of, 

litterata,  510. 

Not'harctus,  510. 

and     the    heights    of    the 

Olivanites,  261. 

Nothosaurus,  428,  429,  484.  § 

borders,  25. 

Olivella,  508. 

mirabilis,  428. 

trends  of,  35. 

Alabamensis,  509. 

Schimperi,  429. 
Notidanus    primigeuius,    262,* 
501,*  509. 

Oceanic  basins,  11,  12,  738. 
currents,  38,   658,   660,   663, 
665,  668. 

Olivine.     See  CHRYSOLITE. 
Omphvma      turbinatum,     245, 
246,*  247. 

INDEX. 


815 


Onchus,  282. 

Orohippus  agilis,  510. 

Orthoclase,  54.  §* 

Deweyi,  229. 

pumilus,  510. 

Orthoclase-felsvte.  71  § 

tenuistriutus,  246,*  247. 

Orthacanthus  arcuatus   343.        i  Orthonema,  first  dt   2P>1. 

Oncoceras,  '228. 

Orthis,  172,*$  175.  187.  190,  199, 

Orthonota  curta,  229. 

Oneida  conglomerate,  164.  218, 

228,  249/252,  283,  371. 

nasuta,  208. 

220. 

biforata.  207. 

parallela,  205.* 

Onondaga  limestone,  255. 

Billingsii,  174,*  176. 

undulata,  273,*  274. 

salt  group,  232. 

biloba,  226,*  229,  248. 

Orthophyre.  71.  S 

Onychodus,  263,*$*  279. 

calligramma,  207,  208. 

Orthopters,  335,  342,  351,  450. 

Oolyte,  75.  §  86,§  434,  §  435,  620. 

carbonaria,  341. 

range  c.f.  in  time,  388.* 

climate  of,  452. 

costalis,  191.* 

Osborne  group,  513. 

limestones,  256. 

electra,  192. 

Oscillations    of  level,  cause  of, 

Lower  and  Upper,  435. 

elegantula,    206,    207,*    208, 

761. 

OOlytic  epoch,  434. 

229,  230,  247,  248,  249.           I      of  water-level,  causes  of,  761. 

rocks,  63,§  62u. 

familv,  170,  §*  174.                            through  the  Cenozoic,  586. 

Opal,  53.§ 

flabellulum,  207,*  248.                     through  the  Meso/"ic,  482. 

Open-sea  formations,  304. 

granda-va,  188,*  189.                       through    the   Paleozoic,  391, 

Ophiderpeton  Brownriggii,  351. 

hybrida,  248.                                        392. 

Ophidians,  338.  § 

imperator,  191.                               Oscillatoria,  611. 

Ophileta  compacta,  178,  189. 

last  of,  371,  373.                           Osmeroides    Lewesiensis     473  * 

complanata,  189. 

lata,  247                                             475,  476. 

levata,  188,*  189. 

lynx,  200,*  203,  205,  206,  207,  ';      Mantelli,  475. 

Owenana,  203. 

228.                                          i  Osmerus,  475.§ 

uniangulata,  192. 

Michelini,  var.  Burlingtonen-    Osmunda  spicant,  ash  of,  365. 

Ophioglossum,  271.                        1          sis,  300  *  303.                          j  Osseous  fishes.  265.  S* 

Ophiolyte,  73.  §                               i      Michelini,'  308.                                 first  of.  403 

Ophiuroida,  128,  §  303. 

musculosa,  243.                           Ossipyte,  70,S  72. 

Opossum,  518,  519,  568. 

occidentalis,   200,*  203,   205,    Osteolepis,  282. 

Oracanthus  Milleri,  308. 

232.                                            i  Ostracoids.  122.S  188.  372.  47ft. 

Orange  Sand  beds,  546,  547,  554. 

parva,  189. 

range  of,  in  tiine,  387.* 

group,  493,  494. 

pepina,  178. 

Ostrea,  385,  460,  495,  508. 

Orbicula,  173. 

porcata,  207. 

acuminata.  449. 

filosa,  203.* 

range  of,  in  time,  386.* 

bellovacina,  513,  518. 

Orbis  rotella,  509. 

resupinata,  308. 

congesta,  457,  467,  508. 

Orbitoides,  131  ,§500. 

Salteri,  206. 

deltoidea,  449. 

limestone,  494. 

striatula,  172,*  207. 

distorta,  450. 

Mantelli,  499,*  509. 

testudinaria,   200  *  203,   205, 

divaricata,  509. 

Orbitolina,  460,§  474. 

207,  232. 

expansa,  449. 

Texana,  456,  460,*  466. 

tricenaria,  200,*  203. 

falcata,  456. 

Orbitolites,  132,  §  437. 

umbraculum,  303,  307,*  308. 

frons.  476. 

first  of,  437. 

Vanuxemi,  261.                                  Georgiana,  499  *  509. 

Orbulina  universa,  131.* 

varica,  239,*  240.                             ereearia.  449. 

Orchestia,  120.*§ 

vespertilio,  207- 

Knorri,  448. 

Order  of  strata,  92.  § 

virgata,  208. 

larva,  461,*  467,  468,  469,  476, 

Oregon,  Cretaceous  'in,  455.            Ortfafeinal  172.$  178.  199. 

477. 

Quaternary  in,  528. 

festinata,  178. 

Lejmerii,  475. 

terraces  in,  549. 

grandaeva,  188  *  189. 

Liassica,  429,  448. 

Tertiary  in,  490,  495. 
Oreocyon  latidens,  510. 

Orthoceras,     187,  §    200,5    205, 
228,  229,  243,  253,  274,  289, 

mallei  lormis,  467. 
Marshii,438,*449,  468. 

Oreodon,  507,  508.511. 

300,  303,  332,  371,  409,  428, 

panda,  509. 

Culbertsoni,  511. 

429,  483. 

princeps,  519. 

gracilis,  507,*  511. 

acicula,  279.* 

sellseformis,  494,  499,*  509. 

occidentalis,  511. 

analysis  of,  74. 

soleniscus,  508. 

superbus,  511. 

aculeatum,  342 

subovata,  468. 

Organic  acids,  action  of,  691. 

annulatum,  247.  248. 

vesicularis,  476. 

constituents    of   rock«,    47,  § 

Blakei,  416. 

Vicksburgensis,  509. 

59,  60,  61,   135,  t)04,  608, 
612,  613,  616. 

bullatum,247,  250. 
diffidens,  191. 

Virginiana,  510. 
Vomer,  509. 

nature,  essential  elements  of, 

first  of,  178. 

Otodus    appendiculatus,    464,* 

4S.§ 

ibex,  250. 

467. 

remains,  47.  § 

implicatum,  248. 

obliquus,  518. 

Orient,  13. 

junceum,  201,*  203. 

Otozoum   Moodii,    412  *    413  $ 

Origination  of  species,  600,  603. 

Lamarcki,  189. 

417. 

Origin  of  matter,  life,  spirit,  and 

laqueatum,  188,*  189. 

Ottawa  basin,  remarks  on,  194, 

of  the  spiritual  element  in 

moniliforme,  185,  209,  342. 

216,  380,  389,  587. 

the  earth's   arrangements, 

nobile,  303. 

Ottawa  River  in  existence,  287. 

not  explained  by  reference 

Ozarkense,  189. 

Outcrop,  94.  §* 

to   heat,  water,   or  attrac 

primigenium,  188,*  189. 

Outlining   of    laud  and   water, 

tion,  757. 

range  of,  in  time,  387.* 

767. 

Oriskany  period,  164,  241. 

recti-annulatum,  191. 

Overlap,  101,§  217. 

sandstone,  164. 

Rush  en  se,  342.      . 

Ovibos  bombifrons,  567. 

Ormoceras,  203,  253. 

tenuiseptum,  191. 

cavifrons,  567. 

crebriseptum,  209. 

undulatum,  248. 

Ovis,  520. 

tenuifilum,201,*203,  215. 

vagans,  208. 

Ovula,  483. 

Ormoxylon  Erianum,  279. 

velox,  191. 

first  of,  475. 

Ornithotarsus,  464. 

vertebra  le,  201,*  203. 

Owen,  D.  D.,  analysis  of  lime 

Orodus,  304,  351. 

virgatum,  248. 

stone,  74. 

maniillaris,  301,*  304. 

Orthooeratite     limestone,     163, 

Lake  Superior  trap,  185. 

Orohippus,  505.*§ 

208. 

Galena  lead-region,  197. 

816 


INDEX. 


Owen,    R.    (of   London),    Dro-    Palaeophycus,  177. 

Paradoxides  Bennetii.  176. 

matherium,  415,  417.                   congregatus,  177- 

Bohemicus,  180. 

Bathygnathus,  417.                        iucipiens,  177. 

Davidis,  180. 

Quaternary  Britain,  564.            Palseopteris  ,  271,  348. 

Harlani,  175,*  176. 

Owen,  R.  (of  U.  S.),  on  the  po-    Paheopyge  Ramsayi,  180. 

Hicksii,  180. 

sitions    of   the   outlines   of    Palaeosaur,  338.  § 

lamellatus,  176. 

continents,  38.                          Palaeosyops,  504.  § 

range  of,  in  time,  387.* 

Owl,  503,  510.                                        levidens,  510. 

Paragonite,  54.  § 

Ox,  416,  518,  565,  567,  568.           >     major.  510. 

slate,  69.  § 

familv,rangeof,in  time,  589.*    Paleeothere,  517.  §  518. 
Oxford  clay,  435.                              Palaeotherium,  504,  505,  517,§ 

Paramys  leptodus,  510 
robustus,  510. 

Oblyte,  435. 

519. 

Parasitic  cones,  710. 

Oxfordian  group,  435- 

crassum,  519. 

Parasmilia,  474. 

Oxydation,  688. 

curtum,  517,  519. 

Paris,  artesian  wells  in,  654. 

Oxvgen,  49 

magnum,  517,*  519. 

Paris  basin,  Jurassic  in,  433. 

Oxvrhina,  467,  475,  510. 

medium,  519. 

Tertiarv  of,  512,  513 

hastalis,  510 

minimum,  519 

Parks  in  Rocky  Mts.,  21. 

Oyster,  119,*  126,  §    500,    510, 

minus,  519. 

Parma  sandstone,  377. 

513,  561.                                 !  Palaeotringa,  468. 

Parophyte,  73,  §  152. 

Crab  found  in,  375.                       Palaeotrochis,  160. 

Paroxysmal   changes    of   level. 

family,  460,  469,  493. 

Palaeoxyris,  349.                                   584. 

shell,  analysis  of,  60. 

Palseozamia  megaphylla,  448.        Parrot,  516. 

Palagonite,  759.                              j      coal,  315. 

Pachyderms,  516,  519. 

Palapteryx,  580.                                Passalacodon  litoralis   510. 

Pachyodon  Listen,  448. 

Palasterina  Jamesii,  204,  205.*      Patella,  203. 

Pachypteris,  348. 

Paleozoic  ages,  lengths  of,  38  J,  '  Pearl-spar,  222. 

Pachytheca,  245- 

591. 

Peaiistone,  H.^ 

Pachytherium,  570. 

general  facts  of,  373. 

Peat,  62,$  616.  § 

Pacific  Ocean,  11,  25,  35- 

geography  of,  389. 

beds,  354,  616. 

active  volcanoes  in,  703. 

mountains,  390. 

composition  of,  361. 

change  of  level  in,  indicated 

rivers,  390. 

Pebbles  in  alluvium.  650. 

by  coral  islands,  583. 

rocks,  proportion  of,  to  other    Peccary,  506,  511,  565,  568. 

coral-formation  of,  618. 

rocks,  586,  591. 

Pecopteris,   330,   348,  349.  370, 

system    of    currents  in,   40, 

rocks,  thickness  of,  373,  380. 

433. 

658. 

section     of     the     31ississippi 

approximata,  449 

Pacific-border  region,  401,  409, 

basin,  374.* 

arborescens,  327,*   33',  331, 

452,  454,  491,  751. 

section  at  Bore  Springs,  Va., 

357. 

Pacific  island-chains,    29,*  32, 

396.* 

cyathea,  330,  331. 

748. 

section    at     Pottsville,    Pa., 

di  versa,  449. 

Pacific      islands,      elevations 

396* 

nervosa,  331. 

among,  584. 

species,  size  of,  383. 

pluniosa,  331. 

erosion  in,  639. 

time,  140,  162,  591. 

polymorpha,  331. 

Pacific  Railroad,  lignites  along, 

time-ratios,  381. 

preciosa,  271. 

491. 

Palephemera    mediaova,     410,* 

Silliumni,  331. 

PaUeacis,  302. 

416  § 

Stuttgartensis,  407,*  409. 

cuneata,  302. 

Palinurus,  shell  of,  60. 

unita,  330. 

obtusa,  302. 

Palisades,  Triassic  in,  404,  4jo, 

velutina,  331. 

Paheastacus,  475. 
Palrcaster,  207. 

418. 
Pali  ur  us  Colombi,  498 

Pecten,  428,  433,  475,  495,  508. 
eequivalvis,  448. 

matutina,  199,*  202. 

Pallial  impression.  126.  § 

asper,  476. 

Niagarensis,  117,*  229. 

Pallium,  123.  § 

circularis,  476. 

Pala?echinoids,     range    of,     in 

Palmieri,  on  volcanic  hematite. 

concentricus,  510. 

time,  386.* 

695. 

decennarius,  510. 

Palaeechinus,  303. 

Palms,  471,  497,  514,  526,  594, 

Groenlandicus,  551. 

Pakeinachus  lougipes,  441. 

609. 

irradians,  561. 

Palwlodi,  516. 

Palms,  first  of,  403,  459. 

Islandicus,  551,  555. 

Palajmon,  350. 

range  of.  in  time,  140.* 

Jacobseus,  577. 

Palaeocampus  anthrax,  342. 

Paloplotherium  annectens,  519. 

lens,  449. 

Paleeocaris  typus,  334,*  342. 

Palpipes  priscus,  441.* 

Liasinus,  429. 

Pahcocastor,  511. 

Paludina,  450,  482,  590. 

Lyelli,  509. 

Palaeocrinus,  204. 

carinifera,  450- 

maxim  us,  577. 

striatus,  190.* 

first  of,  453.                                      Mortoni,  500.*  oil. 

Palteocyon,  516,§  518. 

tiuviorum,450.* 

Poulsoni,  499,*  509. 

Palaeoeyclus    rotuloides,    224  * 

lenta,  519. 

propatulus.  510. 

238 

orbicularis,  519. 

5-costatus,  468,  476. 

Paheocystites  tenuiradiatus,191. 

ponderosa,  648. 

vagans.  449. 

Pala?olagus,  511. 

Pampas,  15. 

Yirginianus,  510 

Paleolithic  era,  574,  576. 

Pander,  on  Conodonts,  208. 

Valoniensis,  429. 

Palapomanon,  228. 

Pangolin,  518. 

Pectinated  rhombs,  129.  § 

Palteoniscus,  275,  343,  351,  372, 

Panopsea,  475. 

Pectunculus,  483. 

428. 

Norvegica,  519. 

glvcimeris.  577- 

comptus,  372. 
elegans,  372. 

oblongata,  509. 
rettexa,  495- 

va'riabilis,  519. 
Peculiarities  of  life  continuous. 

Freieslebeni,371,*372. 

Panther,  506,  568. 

599. 

lepidurus,  264.* 

Paolia  vetusta,  300  *  304.               Pegmatyte,  68.  § 

Palfeophis  Halidanus,  509. 
laticeps,  510. 

Parabatrachus  Colei.  351.             |  Pele's  hair,  708.  § 
Paradoxides,    172,    175,§*  178,    Pelican.  516. 

toliapicus   518. 

179,  180.  181,  188. 

Peltura  holopyga,  178. 

typhasus,  516,  519. 

Aurora,  180. 

Pemphigaspis,  178. 

INDEX. 


817 


Pemphix  Sueurii,  428,*  429. 
Pennant.  347. 
Pennine  fault,  399. 

range,  346. 
Pennsylvania,  Archstan  in,  150. 

Black  River  in,  184. 

Calciferous  in,  184. 

Carboniferous    in,    291,   309, 
320,  321,  355,  358,  647. 

Catskillin,280. 

Cauda-galli  grit  in,  256 

Chazy  in, 182, 184, 185. 

Chemung  in,  276. 

Cincinnati  in,  197. 

Clinton  in,  220. 

coal-field,  map  of,  310.* 

faults  in,  399. 

Hamilton  in.  267. 

Lower  Helderberg  in,  237. 

Lower  Silurian  in,  210. 

map   of  axes  of  flexures   in, 
397.* 

Medina  in,  218. 

Millstone  grit  in,  320. 

mineral  oil  in,  268. 

Niagara  in,  220. 

Oneidain,218. 

Potsdam  in,  168,  181. 

Quaternary  in,  528. 

section  of  rocks  of,  375. 

Subcarboniferous  in,  293,  295, 
297,  305. 

Trenton  in,  194. 

Triassicin,404,  405,  419. 

Upper  Helderberg  in,  256. 

Uticain,196. 
Pentacrinus,  432,  437. 

asteriscus.  432,*  433. 

basaltiformis,448. 

Briareus,  448. 

Caput-Medusse,  118.* 

Fittoni.  476. 
Pentamerella  arata,  261. 
PentAmerus,  171, §  228. 

Barrandei,  206. 

brevirostris,  248. 

conchidium,  230,  249. 

elongatus,  261. 

galeaius,237,  239,*  240,  247, 
248. 

globosus,  247. 

group,  164. 

Knightii,  245,  246,*  247,  248. 

lens,  208. 

levis,  248. 

oblongus,  206,  208,  224  *  228, 
229,  230,  247,  248. 

p«eudo-gaieatus,    237,     239,* 

range  of,  in  time,  386.* 

re  versus,  206. 

undatus,  208. 
Pen  tamer  us     limestones,     164, 

237. 

Pentremital  group,  294. 
Pentremites,    129, §    190,     260. 
284,  288,  297. 

floreali*,  298,*  3"3. 

Godonii,29S,*303. 

pyriformis,  298.*  302. 

range  of,  in  time,  386.* 

AVoodmani,  303. 
Peperino,  66.  § 
Perch,  474,  475. 
Percy,  analysis  of  coal,  316 
Peridotyte/72,§  78,§  7<»7,  736. 
Periods  and  Epochs,'  138,  141. § 
Perissodactyls,  504.§ 

range  of,  in  time,  589.* 

52 


j  Permian  period,  291,  367. 
Permian  and  Carboniferous  con 
formable,  402. 

and    Carboniferous     uncon- 
formable,  402. 

in    analogous     situations    in 

America  and  Russia,  370. 
PernaMulleti,  475. 
I  Perrey,  A.,  on  earthquakes,  as 
evidence  of  internal  waves, 
743. 

Persea,  497. 
Persia  a  plateau,  22. 
Peru,  Cretaceous  in,  470. 

earthquakes  in,  662,  742. 

Jurassic  in,  433. 
Petalodonts,  304,  336. 
Petalodus,  304,  342. 

destructor,  336,*  343. 
Petalorhynchus,  304. 
Peters,  analysis  of  coals,  316. 
Petersen  and  Schodler,  analyses 

of  wood,  361. 
Petherwin  group,  282. 
Petraia,  204. 

aperta,  202. 

bina,  247. 

corniculum,  199*  202. 

gracilis,  206. 

profunda,  202. 

subduplicata,  207,  208. 
Petricola,  483.  608. 
Petrifactions,  47, §  615,  693. 
Petrified  turtles,  88. § 
Petrodus  occidental,  336,*  343. 
Petroleum,  197,  222,  256,  268. 
Petrosilex,  68, §  70. § 
Phacops,  174,§  204,  208,  228, 
240,  243,  249,  253,  285. 

bufo,  261,  273,*  274. 

caudatus,  247. 

Dowuingii,  250. 

liuiulurus,  248. 

Orestes,  206. 

rana, 274. 

Phanerocrystalline,  64. § 
Phanerostomum  senariuin,  466. 
Pharella  Dakotensis,  468. 
Phascolotherium        Bucklandi, 

447,  448.*  449. 
Phenogains,  133.  § 
Philippine  Islands,  hot  springs 

in,  612 

Phillips,  J.,   on  Jurassic   Rep 
tiles,  444. 
Philipsastrea     Verneuili,    259* 

261. 
Phillipsia,  304,  308. 

Cliftonensis,  342. 

mHJor,  342. 

Missouriensis,  342. 

pustulata,  308. 

range  of,  in  time,  388.* 

scitula,  342. 

seminifera,  308.* 
Phlogopite,  54.§ 
Phoca,  520. § 

Wymani,511. 
Pholadomya  ambigua,  448. 

cuneata,  518. 

fidicula,  449. 

gibbosa,  449. 

occidentalis,  469. 

orbiculata,  432. 

papyracea,  468. 
Pholas,  475.  608. 

crispata  519,  551. 

lata,  519. 
Phonolyte,  77,§  707. 


Phosphatic  beds,  495. 

nodules,  61,  67. 

rock -material,    59,    60,    613, 

695,  696. 
Phosphatic  impurity  of  ocean, 

593. 
Phosphoric  acid  in  ash  of  plants, 

61. 

Phragmites  (Eningensis,  498. 
Phragmocone,  432. § 
Phragmoceras,  203. § 

immaturum,  203. 
Phronima,  611. 
Phyllograptus,  207. 

typus,  187,*  190. 
Phyllopods,  122, §  227,  342,  592, 
595. 

range  of,  in  time,  388.* 
Phyllopteris,  348. 
Physa,  508,  617. 

heterostropha,  341,  548. 
Physeter,  520  § 
Physiography,  2.§ 
Physiographic    Chart,    11.    41, 
583. 

Geology,  7,§  9. 
Phytolitharia,  632.* 
Picryte,  72.  § 

Pictured  rocks,  168, 181, 184. 
Pierre-a-bot,  533. 
Pierre  group,  456. 
Pillared  rocks,  168. 
Piloceras,  250. 
Pine,  594.  609. 
Pinites,  371. 

Brandlingi,  331. 
Pinna,  385. 

affinis,  518. 

folium,  429. 

Missouriensis,  303. 

peracuta,  342. 
Pinnotheres,  372. 
Pinnularia,  348. 

aequalis,  634.* 

borealis,  634  * 

peregrina.  134,*  496.* 

viridis,  634.* 

viridula,  634.* 
Pinus  abies,  362,  365. 

larix,  362. 

picea,  362. 

Strobus,  134.* 
Pisolite,  86.§ 
Pistosaurus,  428,  429. 
"  Pitch  T1  of  rivers,  636. 
Pitchstone,  77  § 
Pith  of  Conifers.  331. 
Pithecus,  520. 
Pittsbnrg    coal-bed,    312,    313, 

321,  331. 

PI  icoderms,  264, §*  284. 
Placodus,  429. 

impressus.  429. 
Placuna  scabra,  456. 
Placunopsis,  342. 
Plagiaulax,  428, §  448. 

Becklesii,  450. 

minor,  450. 

Plagiostoma  gigantea,  438,* 448. 
Plains,  15. 

Plan  in  the  earth's  features,  46. 
Pliinerkalk,  470. 
Plane  tree,  458,  497,  515. 
Planing    of    rocks.     See 

SCRATCHES. 
Planorbis,  450,  482,  617. 

bicarinata,  548. 

discus,  519. 

euomphalus,  519. 


818 


INDEX. 


Plant-beds,  514,  515,  546. 

Pleurotoma  attenuata,  518. 

Plant-growth   of  the  Carbonif 

fir>t  of,  477,  483. 

erous,  353. 

Pleurotomaria,  284,  303,  385 

Plant  kingdom,  1. 

Americana,  206. 

Plantless  zone,  609. 

Anglica,  448. 

Plant-remains  in  coal,  317. 

Calcifera,  Ifc9,  192. 

Plants,  subdivisions  of,  133.§ 

calyx,  191. 

affected  by  climate.  353. 

carbonaiia,  342. 

and  animals,  distinctions  of, 

carinata,  308. 

115.  § 

elongata,  449. 

in  Archaean,  157. 

expansa,  4i9,  448. 

in    Carboniferous,   321,    331, 

first  of.  178. 

347,  348.* 

gigantea,  475. 

in  Catskill,  280. 

granuiata,  449. 

in  Chemung,  277,  278. 

Grayvillen-is,  342. 

in  Corniferous,  527. 

gregaria,  189. 

in  Cretaceous,  458,  471. 

lenticularis,201,*203,  2C9. 

in  Devonian,  283. 

litorea,  *23.*  128. 

in  Hamilton,  268. 

Meekana,  303. 

in  Jurassic,  436. 

spharrulata,  333.*  342. 

in  Ludlow,  245. 

tabulata,  333,*  342. 

in  Oriskany,  242. 

Pleurotoniidae,  509. 

in  Permian,  370. 

Plicated  rocks,  effects  of  erosion 

in    Silurian     169,    176,   177, 

of,  646. 

198,  223,  242,  252.                  !  Plicating  force,  acting  from  the  ! 

in  Tertiary,  496,  514.                           ocean,  401. 

in  Triassic,  407. 

amount  of,  401. 

phosphoric  acid  in  ash  of,  61. 
protective  effects  of,  603. 

slow  and  long  continued,  401. 
Plication  of  clayey  la\ers,  655.* 

rank  of  earliest,  242,  252. 

of    layers,    caused   by    slides, 

Plasticity  in  ice,  680. 

655. 

Platanus,  459,  497,  498. 

Plications,  causes  of,  656,  739, 

aceroides,  459,  498,  514. 

761. 

Oulielmaa,  498,  499. 

Appalachian,    characters    of,  i 

Heerii   4g(). 

395. 

liaynoldsii,'498. 

map  of  axes  of,  in  Pennsylva 

Plateaus,  16,§  21. 

nia,  397.* 

Platephemera    antiqua,     273,* 

of  Archaean,  148,*  155. 

274.                                           j  Plicatula,  475. 

Plattendolomit.  369. 

inflata,  476. 

Platyceras,  240,  243.  §  303. 

placunea.  476. 

angulatum,  227,*  229. 

Pliocene,  490,§  495. 

dumosum,  260,*  261. 

plants  of,  in  Europe,  515. 

primordiale,  178. 

See,  further.  TERTIARY. 

ventricosum,  240,  274. 

Pliopithecus,  519.  § 

Platycnemic  tibia,  577. 

Pliosaurus,  443,  444,  449,  476. 

Platvcrinus,  240,  303. 

Plombieres,  zeolites  formed  at, 

Saffordi,298,*303. 

734. 

Platygnathus,  286. 

PI  urn,  514. 

Platygonus  Condoni,  511. 

Plumbago,  59.  §                 f 

Platyostoma,  240,  243. 

Plumbaginous  schist,  68.  § 

Niagarensis,  227,*  229. 

Plutonia  Sedgwickii,  180. 

Platyrrhines,  610 

Plymouth  group,  282. 

Platvschisma  helicites,  250. 

Poacites,  499. 

J'latysomus,  372.          » 

Pocillipora.  620,  §  621. 

gibbosus,  372. 

Podophthalmus,  475. 

macrurus,  372. 

Podopilunmus,  475. 

Platvtrochus  speciosus,  466. 

Podozamites   lanceolatus,  407,* 

Plectrodus  mirabilis,  246,*  247. 

409. 

pustuliferus,  247. 

Poebrotherium  AVilsoni,  511. 

P  eistocene,  513. 

Poecilitic  (Poikilitic)  group,  424. 

Plesiosaurns,    339,$    428,    429, 

Poecilopleuron,  450. 

443,  444,  449,  450,  464,  474, 

Point  Levi,  rocks  of,  184. 

475,  476,  484. 

Poland,  Cretaceous  in,  470. 

costatus,  428. 

Quaternary  in.  532. 

dolichodeirus,  442,*  444,  449. 

Triassic  in,  424. 

Hawkinsii,  428. 

Polar  current,  41,  658. 

macrocephalus,  443,*  444,  449. 

zone.  609. 

Pleta,  163,  208. 
Pleurocystis    squamosus,    199,* 

Pole  of  land-hemisphere,  10. 
Polishing      of      rocks.          See 

203. 

SCRATCHES. 

Pleurodictyum   problematicum, 

Pollicipes,  475. 

284. 

Polycotylus  latipinnis,  467. 

Pleurodonts,  338  .§ 

Polycystines,  132,§  496,  615. 

Pleuroinya  unioides,  433. 

of  Uarbadoes,  etc.,  615. 

Pleurophorus        subcuneatus, 

in  Richmond  'lertiary.  496. 

368.* 

Polyhalite,  76.  § 

Pleurosigma  angulatum,  134.* 

Polynesian     chain    of    islands, 

Pleurotoma,  611. 

32.* 

Polyps,  127,§  180, 189,  341,  472, 

698. 
'  first  of  true,  199. 

number  of  Silurian.  249. 

range  of,  in  time,  385,  386.* 
Polysporia,  349. 
Polypterus,  282. 
Polyptychodon,  474,  476. 
Polythalamia.     See  RHIZOPODS. 
Polyzoans,  127- § 
Ponent  series,  3'75. 
Poplar,  459,  497,  514. 
Populites,  459. 

fagifolia,  459. 
Populus,  497. 

Arctica,  498. 

decipiens,  498. 

lancifolia,  498. 

Zaddachi,  498. 
Porambonites,  171. § 
Porcelain  jasper,  71. § 
Porcelanyte,  71.§ 
Porcellia,  284,§  429. 
Porcellio,  120.* 
|  Porcupine,  508. 
!  Porites,  610,  620,§  621. 
i  Porocrinus,  204. 
'Porous  rocks,  63.§ 
Porphyritic  rocks,  64,§  306. 
Porphyry,  49.  7<»,§  76J§  730. 
Portage  epoch   254,  276. 

group,  254,  276. 
Porter's  Creek  group,  493. 
i  Portheus  molossus,  467. 
Port  Hudson  group,  547. 
Port  Kennedy  bone-cave,  567. 
Portland    dirt-bed,    435,    436* 
452. 

Oolyte,  435. 

stone,  435. 

Portlandian  group,  435. 
i  Portugal,  Carboniferous  in,  347. 
Posidonia  minuta,  416,  428. 

Stella,  416. 

Posidonomya.     See  POSIDOXIA. 
{  Positions  of  strata,  91. § 
Post-meridian  series,  375. 
Post-tertiary.    See  QUATERNARY. 
Pot-holes,  643. § 
Potamomya  mactriformis  501,* 

508. 

Potash  in  plants,  365. 
Potassium,  51. § 
Poteriocrinus,  303,  341. 

Missouriensis,  298,*  303. 

ornatissimus,  278. 
Potsdam  beds,  thickness  of,  381. 

beds  overlaid  by  Carbonifer 
ous,  232. 

epoch,  163, 166. 

green-sand  of,  177. 

life  of,  all  marine,  169. 

recent  genera  in,  174. 
Pourtales,    on     occurrence    of 

Rhizopods,  671. 
Pozzuolana,  66. § 
Pozzuoli,    change  of   level    at, 

584.* 

Praearcturus  gigas,  285. 
Prairies,  distribution  of,  44. 
Precious  coral,  60,  131. § 
Prehnite,  734. 
Pre-meridian  series,  375. 
Prersure     against     continents, 

745. 
Prestwich,  coal  of  Ei  gland,  346 

equivalency  of  coal-beds,  347- 
Prestwichia  anthrax,  350.* 

rotundata,  350.* 


INDEX. 


819 


Prevost,  on  volcanic  action,  709, 

715. 

Primal  series,  375. 
Primary,  489. § 
Primordial  period,  163,  166. 

European,  179. 

Prince  Edward's  Island,  Triassic 
in,  404. 

Rupert's  drop,  736. 
Prionastrea  oblonga,  436,*  449. 
Prionodon,  510. 
Pristis  bisulcatus,  518. 

brachiodon,  509. 

curvidens,  509. 

ensidens,  509. 
Proboscidians,  range  of,  in  time, 

589.* 

Procamelus,  5^8,  511. 
Productella  subalata,  274. 
Productus,  172,*§  256.  260,  261, 
278,  283,  284,  288,  299,  3U7, 
332,  371,  372. 

aculeatus,  173.* 

cora,  341. 

costatus,  350. 

elegans,  303. 

family,  170.§*  174. 

first  of,  260,  283. 

Flemingii,  303. 

horridus,  372. 

last  of,  371,  373. 

longispinus,    307  *  308,  350, 
352. 

Martini,  304,  362. 

muricatus,  341. 

Nebrascensis,  332,*  341. 

punctatus,  300,*  303,  341. 

range  of,  in  time,  386.* 

scabriculus,  308,  350. 

semireticulatus,  173,*  341,352. 

subalatus,  272,*  274. 

eulcatus,  352. 
Proems,  174,  §  204, 240, 243,249. 

cra«simarginatus,  261. 

Stokesii,  248. 

Progress  of  life,  the  basis  of  Fub- 
divisions  into  ages,  138. 

system  of,  in  geological  time 

592. 

Progress    in    earth's    develop 
ment,  756. 
Propylyte,  78.§ 
Prosoponiscus      problematic  us, 

372. 

Proteaceae,  514,  515. 
Protean  beds,  294. 
Proteus,  337.§ 
Protichnites.  176.* 

7-notatus,'l76,*  178. 
Proterosaur,  333, §  b73.§ 
Proterosaurus  Spcneri,  372.* 
Protocardium  Ilillanum,  476. 
Protohippus,  511. 
Protogine,  72.§ 
Protolycosa,  342. 

anthracophiln,  351. 
Protomeryx,  511. 
Protophytes,  135, §  496.* 

Corniferous,  25f.* 

Cretaceous,  471. 

Tertiary,  513. 
Protopteris  peregrina,  258. 
Protospongia  fenestrata,  180. 
Prototaxites,  245, §  258  271. 

Logani,  258.* 
Protozoans,  116,§  131  ,§  615. 

classification  of,  131. 

in  Tertiary,  499. 

number  of  Silurian,  249. 


Protozoic  schists,  179. 

Puffinus  Conradi.  510. 

Psammobia  lintea,  509. 

Pulaski  shales,  196. 

Psammodus,  304. 

Pullastra  arenicola,  429. 

Psaronius,  348,  371  § 

Pulmonates,  333.§ 

Erianus,  271. 

Pulvinites,  first  of,  477. 

Pseudobuccinum,  first  of,  477, 

Pumice,  77-§ 

483. 

Pumiceous  rocks,  64.  § 

Pseudoliva,  508. 

Pupa,  332,  §  358. 

vetusta,  509. 

Vermiliohensis,  333,*  342. 

Pseudomonotfc,  342,  367. 

vetusta,  333,*  339,  342. 

Hawnii,  367. 

Purbeck  beds,  435. 

speluncaria,  372. 

Purpura  tetragona,  519. 

Pseudomorphism,  695,§  724.§ 
Pseudo-scorpions,  349,  351. 

Purpuroidea  nodulata,  449. 
Putorius,  520.§ 

Pseudotomus  hians,  510. 

Pycnodonts,  475. 

Psilophyton,    257,§    268,    271, 

Pycnodus,  475. 

348. 

gigas,  428. 

princeps,  242,  258,*  271. 

Mantelli,  450. 

Psilotites,  348. 

Pychnophyllum.  328,  349. 

Psilotum,258. 

Pygaster  patelliformis,  449. 

Pteraspis,  247. 

Pygidium,  123,§  174. 

Banksii,245,  246,*  247. 

Pygocephalus  Couperi,  350. 

truncatus,  247. 

Pygopterus.  343,  372. 

Pterichthys,  246. 

mandibularis,  372. 

Asmusi,  286. 

Pyramids   of   Egypt,   rock    of, 

Milleri,285,*286. 

512. 

Pterinea,  2S4._ 

Pyrenean  basin,  470. 

demissa,  205.* 

Pyrenees,  elevation  of,  525. 

fiabella,  273,*  274. 

glaciers  in,  675. 

retroflexa,  247. 

in  the  Cretaceous.  480. 

sublevis,  247. 

Quaternary  in,  533- 

Pteris  aquilina,  365. 

Tertiary  in,  512. 

Pterocera,  483. 

Pyrifusus  Newberryi,  461,*  467. 

Fittoni,  475. 

Pyrites,  copper,  59.  § 

Oceani,  449. 

Pyrite,  59,§*  197,  268,  316,  365, 

Pterodactyl,  339,  §  446,  449,450, 

688,  734. 

474,  475,  476. 

in  coal,  316,  365- 

Pterodactylus        crassirostris, 

Pyritiferous  rocks,  64.  § 

446,*  449. 

Pyrophyllite,  58.  § 

Cuvieri,  476. 

Pyrophyllvte,  73.§ 

ingens,  464,  468. 

Pyrosclerite,  73.  § 

occidentalis,  468. 

Pyroxene.  55,$*'726,  727,  728- 

velox,  468. 

Pyroxenvte,  70.  § 

Pteronites  Chemungensis,  279.* 

Pyrrhotite,  59,§  688. 

Pterophyllum  Altaense,  349. 

graminoides.  407  *  409. 

Quadersandstein,  470. 

Haydenii,  460. 

Quadrat,  analysis  of  coprolite, 

inflexum,  349. 

61. 

Jaegeri,425,*426,429. 

Quadrumana,  506,  510,  519,  520. 

longifolium,  409,  429. 

range  of,  i:i  time,  589.* 

Munsteri,  429. 

Quahog,  561. 

Pteropods,  125.  §t 

Quartz.  49,  52,§*  627,  727,  728, 

in  green  sand,  208. 

734. 

number  of  Silurian,  249. 

crystals  in  Calciferous  sand- 

range  of,  in  time,  38".* 

rock,  186. 

Silurian,  203. 

reefs  or  veins,  453,  732. 

Pterosaurs,  339,§  443,  446,  464, 

Quartzose  rocks,  63.  § 

466,  476,  485. 

Quartz-porphvrv.  71  § 

range  of,  in  time,  589. 
Pterospermites  Sternbergii,  46X 

Quartzyte,  53',§'73,§  645,  730. 
Quartzytic  rocks,  63.  § 

Haydenii,  460. 

Quaternary  Age,  133,  489,  527. 

rugosus,  460 

Life  of,  563. 

Pterozamites  Munsteri,  429. 

Quebec  epoch,  163,  182. 

Pterygotus,  240,  245,  253,  282, 

group,  163,  182. 

283. 

in  Europe,  192. 

bilobus,  245,  246.* 

Quercus,  459,  497,  498,  515. 

Ptilocarpus,  349. 

angustiloba,  497- 

Ptilodictvj)  ,  203. 

chlorophylla,  498. 

acuta,*207. 

drymeia,  498. 

dichototna,  207. 

Laharpi,  498. 

fenestrata,  191.* 

Lyellii,  498. 

scalpellum.  247. 

myrtifolia.  497,*  498. 

Ptychaspis,  168,  178.  190. 

Olafseni,  498. 

Ptychoceras,  462. 

platania,  498. 

Ptvchodus,  475.  § 

primordialis,  460. 

Mortoni,  464,*'  467. 

suber,  361. 

occidentalis,  467. 

\Vyomingiana,  498. 

Ptychophyllum,  206. 

Quicksilver  mines,  458. 

Pudding-stone,  65.  § 

Quito,  plateau  about,  21. 

820 


INDEX. 


Rabbit,  564,  568. 
Raccoon,  566. 
Radaboj  beds,  513. 
Radiates,  117,§*  127. § 

range  of,  in  time,  140.* 
Radiolepis  speciosus,  417. 
Radiolites,  460,  462. 

Austinensis,  467. 

Bournoni,  472.*  475. 

lamellosus,  467. 

Mortoni,  472. 

Raft  of  the  Red  River,  649. 
Rain,    causes    influencing    the 

amount  of,  44. 
Rain-prints,  84,§*  420. 
Rammelsberg,  on  doleryte,  78. 

Permian  bowlders,  370. 
Ramsay,  coal  of  England,  346. 
Raniceps  Lyellii,  340,*  343. 
Raphiosaurus,  475. 
Raphistoma,  189,  203. 

lenticularis,  247. 
Rat,  564,  577. 
Rauchwacke,  369. 
Rauhkalk,  369. 
Rauracian  group,  435. 
Reading  beds,  512. 
Recent  period,  556,  574. 
Receptaculites,  190. 

Calciferus,  189. 

globuiaris.  202. 

Oweni,  202. 

Neptuni,  209,  249. 
Receptaculite    limestone.    196, 

0-Q 

Red  Bluff  beds,  494. 

Red  Crag,  513,  519. 

Red  River,  raft  of,  649. 

Red  Sand  rock,  167. 

Red  Sea.  current  through,  75G. 

volcanoes  along,  704. 
Redwood,  459,  582. 
Reef,  114.§     See  CORAL. 
Regelation,  682. § 
Regions  of    independent  prog 
ress,  145. 

Regnault,  analyses  of  coals,  316. 
Regnosaurus,  450. 
Reindeer,  562,    564,    568,    571, 

572,  573,  577. 
Reindeer  era,  556,  571,  572,  674, 

577. 

Reliefs  of  continents,  23.§ 
Remopleurides,  190. 

range  of,  in  time,  387.* 
Rensselaeria,  170, §  243, §  252. 
ovoides,  242,*  243. 
range  of,  in  time,  387.* 
Rensselaeryte,  72,§  152, 156. § 
Representative  species,  599,  600. 
Reptilian  Age,  403. 
Age,    contrast    of,   with    the 

present,  in  life,  485. 
Fishes,  382. 
footprints,    302*    341,    373, 

412,*  427.* 
Reptiles,  121, §    464,   484,   489, 

592,  598,  601. 
Age  of,  139. 
Carboniferous,  341,  351,  353, 

382. 
Carboniferous,  of  Nova  Scotia, 

341. 
characteristic  of  the  Jurassic, 

451. 

classification  of,  336.  § 
Cretaceous,  464.  474. 
culmination  of,  484,  4Q5,  594. 
first  of,  332,  341. 


Reptiles,  Jurassic,  443. 

range  of,  in  time,  140,  388,* 

rank  of  earliest,  301,  382. 

Subcarboniferous,  30 1. 

Tertiary,  502,  516. 

Triassic,  412,  427. 
Resins,  69. § 
Retepora,  127, §  203. 

Hisingeri,207. 

incepta,  196.* 
Retinyte,  77. § 
Retzia,  171. 

radians,  350. 

Verneuilana,  300,*  303. 
Rhabdocarpus,  381,  349. 
j  Rhabdopdix  longispinis,  417. 
Rhacophyllum,348. 
I  Rhacopteris,  348. 
Rhsetic  bed*,  424,  425. 
Rhamnus,  497. 
Rhamphorhyncus      Bucklandi, 

449. 

Rhine,  Quaternary  along,  556. 
Rhinoceros.  423,§*495,  503,  506, 
511,519,520,564,  572,576, 
57?. 

annectens,  511. 

crassus,  508,  511. 

Etruscus,  571. 

family,  507. 

hemitoechus,  565,  571. 

incisivus,  519. 

matutinus,  511. 

megarhinus,  571. 

Nebrascensis,  506.* 

occidentalis,  507. 

Oregonensis,  511. 

Pacificus,  511. 

preserved  in  ice.  565. 

Schleiermacheri,  519. 

tichorinus,  564,  565,  571,  577. 
Rhizocrinus  Lofotensis,  611. 
Rhizodus,  343. 
Rhizomopteris,  348. 
Rhizopods,  60,  131.§*307,  460, 
471.  477,  499,  595,  615,  671. 

Archaean,  158. 

Calciferous,  189. 

Cretaceous,  460,  471,*  474. 

first  of,  302. 

growth  of,  615. 

Jurassic,  437. 

of  bottom  of  ocean,  477,  615. 

Primordial,  177. 

Silurian.  208. 

Subcarboniferous,  302. 

Tertiary,  493,  515. 
i  Rhode   Island,    Archaean    in, 

150. 
I      Carboniferous  in.  291,  319. 

Quaternary  in.  529. 
Rhododendron,  609. 
!  Rhone,  sediment  of,  648. 
Rhus.  497,  515. 
!      bell'a,  498. 


474. 
family,  170.§* 
acuta.  448. 
angu«tifrons,  247. 
bidentata,  248. 
bisulcata,  200,*  203. 
capax,  200,*  203,  205,  232. 
cornigera,  429. 
cuneata,  226,*  229,  248. 
depressa,  475. 


Rynchonella  Gibbsiana,  475. 

gnathophora,  433. 

lamellata,  230. 

last  of,  437. 

latissima,  476. 

neglecta,  247. 

nitida,  248. 

nobilis,  240. 

nucula,  247. 

oblata,  243. 

pentagona,  247. 

plena,  191.* 

plicatella,  248. 

psittacea,  519,  551. 

range  of,  in  time,  386.* 

semiplicata,  240. 

spinosa,  449. 

Stricklandii,  250. 

sublepida,  249. 

ventricosa,  239,*  240. 

venustula,  261. 

Wilsoui,  247,  248,  250. 

Whitney  i,  467. 
Rhynchonellae  common   in  the 

Tertiary,  515. 
Rhynchosaur,  414,  428. 
Rhynchospira,  171. 

aprinis,  248. 
Rhyolyte,  77-§ 

Richmond  infusorial   bed,  495, 
496* 

Triassic  area,  405 
Rill-marks,  84,§*  222,  672. 
Rimella,  508. 
Rimula,  482. 
Ripley  group,  456. 
Ripple-marks,    84,§*  168,  222, 
672. 

in  Hamilton  beds,  267. 

in  Medina,  222. 

in     Portage    and    Chemung 
groups  276. 

in  Potsdam  beds,  168. 

in  Subcarboniferous,  302. 
Rissoa  Chastelii,  519. 
Ritthausen,    analysis    of  Lyco- 

pod  ash,  365,366. 
i  River-border  formations,  544. 
River-channel,  633. § 
River-flats,  558. 
River-systems,  22. 

completed,  587. 
Rivers,  erosion  by,  637- 

formation  and  flow  of,  635. 

increase  of,  in   the  Post-ter 
tiary,  587. 

of  the  Cretaceous,  479.* 

of  the  Paleozoic,  390. 

of  the  Quaternary,  545,  552. 

of  the  Tertiary,  521.* 

small  in  Devonian,  287. 
Riviere    on  Mentone    skeleton, 

575. 

Robinia,  515. 

Roches  moutonnees,  531, §  684  * 
Rochester,   N.   Y.,   section    at, 

79* 
Rochleder,  analysis  of  coprolite, 

61. 

Rock  City,  311. 
Rock-masses,  structure, etc.,  79 

transportation  of,  607. 
Rocks,  characteristics  of,  63. § 

constituents  of,  47,§  728. 

durability  of,  645,  664. 

expansion  of,  700. 

kinds  of,  62. § 

of  coral  reefs,  «20. 

structure  of,  82.  § 


INDEX. 


821 


Rocks,  volcanic,  707. 
Rock-salt,  234. 

Rocky-Mountain  region,  146. 
293,  488,  491,  493,  520,  528. 

Archaean  in,  150 
Rockv   Mts.,  Carboniferous  in, 
287. 

Cretaceous  in,  454,  478. 

disturbances  in,  740  * 

elevation  of,  524,  586. 

geysers  in,  719. 

glaciers  in,  536,  685: 

in  Carboniferous,  355. 

in  Cretaceous.  479,  752. 

in  Devonian,  287. 

in  Mesozoic,  486. 

in  Paleozoic,  390,  391. 

in  Triassic,  423. 

Jurassic  in,  431,  450. 

Lignites  in,  457- 

Oriskany  in,  232. 

Quaternary  in,  528,  532. 

section  of,  17,*  23.* 

Subcarboniferous  in,  296. 

terraces  in,  549. 

Tertiary  in,  491,  493. 

Triassic  in,  406. 

unconformability  in,  232. 

volcanoes  in,  704. 
Rodents,  506,  510.  511,  518,  519. 
520 

range  of,  in  time,  589.* 
Roedeer,  562. 

Rogers,  W.  B.  &  H.  D.,  Ap 
palachian  faults  and  flex 
ures,  395,  399,  400. 

metamorphism,  729. 

solvent  power  of  carbonic  acid, 
690. 

warm  springs,  729. 
Rogers,   II.  D.,  rocks  of  Penn 
sylvania,  374. 
Rozers,  W.  B.,  earthquake,  742. 

Alrginia  Tertiary,  495. 
Roofing  slate,  49,  69, §  72. 
Roots,  destruction  by,  607. 
Rose,  514. 
Rostellaria  Americana,  467.* 

carinata,  476. 

velata,  509. 
Rotalia,  208,  474. 

Bailey i,  302. 

Boucana,  131.* 

globulosa,  131.* 

lenticulina,  466. 

senaria,  466. 
Rotalina  ornata,  476. 
Rothliegende,  369. 
Rotten  limestone,  454. 

limestone  group,  456. 
Rowney,  analyses  of  coal,  316. 
Rudistes,  456,  460,  462.§  472, 

475. 

Ruined  City,  311. 
Ruminants,  511,  517,  520. 

range  of,  in  time,  589.* 
Rupelian  group,  513. 
Rusophycus  bilobatus,  225.* 
Russia, "Carboniferous   in,   3 
344,  347. 

Cretaceous  in,  470. 

Devonian  in,  283. 

disturbances  in.  290. 

Lower  Silurian  in,  207. 

Permian  in,  369,  402. 

Quaternary  in,  532. 

Subcarboniferous  in,  306. 

Triassic  in,  424. 
Rytina  Stelleri,  581. 


Sabal,  497,  498. 
Cainpbelli,  498. 
first  of,  459. 
Sables  de  Bracheux,  519. 

Moyens,  513. 
Saccammina  Carter! ,  307. 

sphaerica,  308. 
Saemann.  on  moisture  in  rocks, 

656. 

Saccocoma  pectinata,  437.* 
Safford,  J.  M.,  on  rocks  of  Ten 
nessee,  294,  374,  379,  493. 
Sagenaria,  245.  § 
Sagittee,  123.§ 
Sahara,  Desert  of,  45. 

plateau  of,  27. 
St.  Cassian  beds,  424,  429. 
St.  John  group,  163. 
St.  Lawrence  Gulf,  in  Devonian, 

389. 

St.  Lawrence  River,  in  the  Car 
boniferous,  356. 
in  the  Devonian,  287. 
in  the  Silurian,  216. 
St.  Lawrence  River-system,  22. 
St.  Lawrence  Valley,  glacier  in, 

536,  538. 

terraces  in,  550,  552. 
St.   Louis   limestone,   294,   377, 

378,  379. 

artesian  well  at,  654. 
St.  Peter's  sandstone,  163,  183, 

377,  378. 

St.  Pierre  group.     See  PIERRE. 
Salamander,  121, §  512. 
Salamandroids,  337,§  592. 
Saliferous   rocks,   how   formed, 

235. 

beds,  Triassic,  of  Europe,  424. 
Salina  period,  164,  232. 

salt-wells,  234. 
Saline  deposits,  630.  696. 
Salisburia,  329,§  497,  514. 
Salix,  459,  498. 
angusta,  499. 
Groenlandica,  498. 
macrophylla,  514. 
Meekii,  459.* 
proteifolia,  460. 
Salmon,  474,  475. 
Salt-Lake,  16,  23,  561. 
Salt  lakes,  23. 
life  of,  610. 
Salt-works  of  Europe,  424. 

of  Salina,  etc.,  234. 
Salt-group,  Onondaga,  232. 

Michigan,  295,  377. 
Salterella  Billingsii,  204. 
Maccullochi,  250. 
pulchella,  178. 
rugosa,  178,  250. 
Sand,  49,  53,  66, §  758. 
Sandalodus,  304. 
Sand-bars  of  coasts,  669,*  670, 

671. 

Sand-blast  carving,  632. 
Sand-drift  structure,  83- §* 
Sand-flats,  stability  of,  665. 
Sand-flea,  122.$* 
Sand-grouse,  516. 
Sand-hills  on  sea-shores,  631. 
Sandrock,  65.§ 
Sand-scratches,  632. 
Sand-spits,  increase  of,  668. 
Sandstone,  49,  53,  62,  65,§  645, 

730 

Sandy  Hook,  formation  of,  668. 
Sandwich  Is.     See  HAWAIAN. 
Saniva,  510. 


Santee  beds,  494. 
Sao  hirsuta,  180.* 
Sapindus,  497,  498. 
Sapphirina  Iris,  120,*  122. § 
Sarcinula  organuni,  207- 
Sardinia,  shell-beds  in,  562. 
Sargasso  Sea,  40,  665. 
Saskatchewan,    Cretaceous   on, 

456. 

Sassafras,  458. 
Cretaceum,459.* 
Mudgii.  460. 
uiirabile,  460. 
obtusum,  460. 
recurvatum,  460. 
Saurians,  338,§  592. 

See  REPTILES. 
Saurian  coprolite,  446.* 
Saurichnites  lacertoides,  373. 

salainandroides,  373. 
Saurichthys,  428. 

apicalis,  429. 
Sauripteris  Taylori.  281  * 
Suurocephalus,  467,  477. 

first  of,  477. 

lanciforrnis,  477. 
Sauropus  primaevus,  302,*  304. 
Saw-fishes,  509. 
Saxicava,  608. 

Arctica,  550.  551,  555. 

sands,  550.  555. 
Saxifraga  oppositifolia,  532. 
Saxony,  Carboniferous  in,  346. 

infusorial  bed  in,  514. 

Permian  in,  369. 
Scalaria,  508 

Bowerbankii,  518. 

Groenlandica,  519,  551. 
Scaglia,  470. 
Scalent  series,  375. 
Scales,  613. 
Scallops,  561. 
Scalites  Hngulatus,  191.* 
Scandinavia.      See    NORWAY, 

SWEDEN. 

Scapharca  hians,  SCO.* 
Scaphiocrinus,  303,  341. 
Scaphirhyncus,  264. 
Scaphites,  457,  462. § 

aequalis,  476,  477. 

Conradi,  456,  462.  463,*  467, 
469. 

Geinitzii,  476. 

larvseformis,  463  *  467,  477- 

Warreni,  477. 
Scapolite.  57, §*  726,  728. 
Scars  of  Lepidodendrids,  324.* 

of  Tree-ferns,  325.* 
Scelidotherium,  570. 
Schilleryte,  73.§ 
Schimper,  W.  P.,  on  coal-plants 

328,  330. 

Schist,  varieties  of,  68,§  70. § 
Schistose  rocks,  63.  § 
Schizodus,  303. 

amplus,  342. 

dubius,  372. 

last  of,  373. 

obscurus,  372. 

Schlotheimii,  372. 

truncatus,  372. 
Schizopods,  350. 

range  of,  in  time,  388.* 
Schizopteris.  348. 
Schoharie  grit,  254. 

epoch,  254. 
Schultz-Fleet,  analysis   of  ash, 

365. 
Schutzia,  348. 


822 


INDEX. 


Schweitzer,  on  ash  of  plants,  61. 

Section  of  Ohio  rocks,  376.           j 

Sciuravus  parvidens,  610. 

of  Paleozoic  at  Bore  Springs,  1 

Scolithus,  174,  §  176. 
liuearis,  177,*  178,  220. 

Va.,  396.* 
of     Paleozoic    rocks    in     the 

Sconsia  Hodgii,  511. 

Mississippi  basin.  374.* 

Scoria,  707.  § 

of  Paleozoic  at  Pottsville,  Pa., 

Scoriaceous  rocks,  64.  § 

396.* 

Scorpion,  121,§  335,  349,  351. 
Scotland,  Archaean  in,  151. 

of  Pennsylvania  rocks,  375. 
of  Tennessee  rocks,  379. 

Carboniferous  in,  345,  346. 

of  volcanic  cones,  706.* 

Devonian  in,  282. 

Sections  of  Coal-measures,  311, 

disturbances  in,  525. 

320,  396.* 

glaciers  in,  536. 

of     unconformable       Carbo 

in  the  Quaternary,  541,  555, 

niferous,  308.* 

572. 

of  Hamilton  beds,  267,*  277.* 

Permian  in,  339 

of     terraced     valleys,     558,* 

Quaternary  in,  533,  533. 

559.* 

Silurian  in,  244. 
Subcarboniferous  in,  303. 

Secular  changes  of  climate,  763. 
Sediment  of  rivers,  647  § 

Scratches,  90,§  762. 

Sedimentary  rocks,  62,  §  64. 

Drift,  630,  535. 

Sedgwick,  Devonian  in  England, 

glacial,  68i. 

282. 

Scratching    by  slides  of   rock, 

May  Hill  sandstone,  244. 

90,  655. 

Permian       unconforuiability. 

by  drifting  sand,  632. 

402. 

by  icebergs,  686. 

Sedum  KhodioK  532. 

Scrope,    on   liquidity   of  lavas, 

Seeds,  transportation  of,  607. 

70S. 

Segregated  veins,  733. 

Scudder,   S.   II.,  on    Devonian 

Selachians,  261,  §  301,  336,343, 

insects,  274. 

349,351,4^7,  441,450,484, 

Scutella,  509. 
Gibbsii,  510. 

range  of,  in  time,  388,*  589.* 
Selvage,  114.  § 

Scyllarus,  475. 

Semi-bituminous     coal,    315,  § 

Scymnus,  510. 

346. 

Scyphia,  474. 

analyses  of,  316. 

reticulata,  435,*  449._ 

Semi-ov:.parans,  413. 

Sea-anemone,  117,*  127-  § 

Semnopitliecus,  520.  § 

Sea-beaches     of     Champlain 

Senonian  group,  470. 

epoch,  549. 

Sepia,  441. 

Sea-border  formation,  549,  667. 

Septaria,  84.  § 

Sea-cucumbers,  127.  § 

Septerpeton  Dobbsii,  351. 

Sea-lilies,  297.                                   |  Sequanian  group,  435. 

Sea-saurians,  341  § 

Sequoia,  459,  497,  526,  582. 

Sea-slugs,  127-§ 

formosa,  459. 

Sea-urchins,  127.  § 

gigantea,  526. 

Sea-water,   specific    gravity  of, 
657. 

Langsdrrfii,  498,  514. 
Reichenbachi,  459. 

Sea-weeds.     See  ALG^E. 

Serai  series,  375. 

Seal,  121,507,  592. 

Serapis,  change  of  level  in  the 

Seam,  81.  § 

temple  of  Jupiter,  584.* 

Secondary,  489.  § 

Sericite  slate,  69  § 

Secretary-bird,  516. 

Serolis,  120,* 

Section,  general,  of   geological 

Serpentine,  55.  §  73.  §  233,  728. 

series,  142.* 

Serpent-stirs,  128.  § 

at  Genesee  Falls,  79,*  219.* 

Serpula,  122.§  123.§ 

at  Niagara  River,  219.* 

Serpulites,  Ib8. 

of  Appalachians,  ideal,  399.* 

dissolutus,  204. 

of  Archaean,  153.                             Murchisoni,  178. 

of  Chemung  beds,  277-*              Serripes  Groenlandicus,  551. 

of  Cincinnati  group,  at  Bar- 

Sertularia,  130.  § 

rington,  196. 

abietina.  13  i.* 

of  Coal-measures  at  Trevorton 

rosacea,'130.* 

Gap,  Pa.,  396.* 

Severn  Straits,  555. 

of   Coal-measures    near   Nes- 

Shale,  65.  §  649. 

quehoning,  Pa.,  396.* 

Shaly  rocks,  63.  § 

of  Coal-measures,  with  trees, 

structure,  82.  § 

312.* 

Shaler,   N.   S.,  on  rock-expan 

of  coral  island,  619.* 

sion,  701. 

of  Green  Mts.,  213.* 

Shark  bones,  analysis  of,  60. 

of  Hawaii,  704  * 

Sharks,  261,§  462,'  473,  484.  502, 

of  Illinois  rocks,  378. 

516. 

of  Iowa  rocks,  377. 

range  of,  in  time,  589.* 

of  Kilauea,  706.* 

Sharks'  teeth,  abundance  of,  in 

of  Michigan  rocks,  376. 

Tertiary,  502. 

of  Missouri  rocks,  378. 

Sharpies.  S.  P.,  »nalyses  by,  60. 

in  Massachusetts,  213.* 

Shasta  group,  457. 

of  New  York,  166.* 

Shavvanjiunk  grit,  222. 

of  New  York,  south  from  L. 

Sheep,  568. 

Ontario,  233.* 

Sheep-backs,  531,  §  684.* 

I  Shell-beds,  492,  608. 
.„_,  I  Shell-heaps,  561,  562,  577,  608. 
Shell-limestone,  75, §  424,  492. 
the  |  Shell-marl,  75,§  617. 

Shepard,  C.  U.,  on  phosph.itic 

deposits,  496. 

Sheppey,  fossil  fruits  of,  514. 
Shotover  sand,  435. 
Showers,  dust,  f32. 
Shrimp,  121,§  592. 
Shrinkage-cracks,  84, §*  168- 
Shumard,   B.   F.,   Texas  Creta 
ceous,  456. 

Texas  Primordial,  168. 
Shumardia,  190. 
Sicily,  elevation  of,  525. 

erosion  of  Simeto  in,  643. 

Pliocene  of,  512,  513. 
Siderite,  5S,§  318,  688. 
Sieboldia,  337. § 
Sierra,  15.  § 
Sierra  Nevada,  24,  751. 

glaciers  in,  533. 

in  the  Mesozoic,  486. 

in  the  Triassic,  423. 

Jurassic  in,  431,  432. 

Quaternary  in,  532. 

terraces  in,  549. 

Sigillaria,    280,    296,  331,    339, 
348,  349,  357. 

alveolaris,  331. 

Brochanti,  331. 

Ilallii,  269,*  271. 

obovata.  324,*  330. 

oculata,  324,*  330. 

palpebra.  271. 

Seilii,  331. 

simplicitas,  278. 

stellata,  331. 

tesselata,  331. 

Vanuxemi,  278.* 
Sigillariae.  or   Sigillarids.  269,§ 
325,  328,  351,  353,  356,  362. 
407. 

Sigillarioides.  348. 
Sigillariostrobus,  330. 
Silica,  364. 

as  a  solidifier,  50. 

soluble,  53,§  478.  § 
Siliceous  group,  294,  379. 

deposits,  693,  721. 

materials  of  rocks  from  living 
species  59,  60. 

rocks,  63.§ 

slate,  73  § 

solutions,  691. 
Silicon,  49. § 
Sillery  sandstone,  184. 
Silliman,  B..  on  obsidian,  78. 
Silt,  66,§  648. 

of  rivers,  amount  of,  648. § 
Silurian  age,  139,§  162. 

highest  animal  types  in.  252. 

number  of  species  in,  249. 

species  of  Lower  and  Upper 
mingled,  149,  253. 

subdivisions  of,  162,163. 

thickness  of,  373. 
Silurian,  Lower,  156. 

thickness  of,  381. 
Silurian,  Upper,  218. 

absent  from  Upper  Missouri, 
232. 

Arctic   American    species   of, 
occurring  elsewhere,  249. 

climate  of,  253. 

general  observations  on ,  249 

number  of  species  in,  253. 

thickness  of,  381. 


INDEX. 


823 


Silver  Islet,  186.                              South    Carolina,   Archaean    in,    Spirifer  alatus,  372. 

Silver  mines  of  Utah,  296.                      150. 

arenosus,  232,  242,*  243. 

Simeto,  erosion  of  the,  643.                 Cretaceous  in,  455. 

arrectus,  2*3. 

Simosaurus,  428,  429.                     :      in  the  Cretaceous,  479. 

biplicatus,  300,*  303. 

Sindree,  changes  of  level  at,  585.  !      phosphate  beds  of,  495  § 

bisulcatus,  300,*  303. 

Sinemurian  group,  435.                 1      Tertiary  in,  490,  491,  494,  495, 

cameratus,  332,*  341. 

Siak-holes,  654.                                       511. 

Clannyanus,  373. 

Sinupallial,  189.  §                             South  Sea.     See  PACIFIC. 

concinnus,  240. 

Siphonated  Mollusks,  482.             '  Southwest  Pass,  bar  at,  652. 

crispus.  23",  248. 

Siphonia  lobata,  471,*  474.           !  Sow-bug,  122.§* 

cultrijugatus,  261. 

pyriformis,  476.                            i  Spain,    Carboniferous    in,   344, 

cuspidatus,  306,  308. 

Siphonotreta,  173.*§ 

345,  347. 

disjunctus,  99,*  283,  306,  307, 

unguiculata,  173,*  208. 

Cretaceous  in,  470 

308. 

range  of,  in  time,  386.* 

in  the  Quaternary,  573. 

duodenarius,  256. 

Siphuncle,  124,§  201.                     i      Lower  Silurian  in,  207. 

fimbriatus,  261. 

Sired  on,  337.  §                                      plateau  of,  21. 

family,  170,§*  174. 

Siren,  337.  §                                          Triassic  in,  424. 

giganteus,  9y.* 

Sivatherium,  520.  §                           Spalacodon,  519. 

glaber,  304.  307,*  308. 

Siwalik  Hills,  Mammals  of,  520.    Spalacotherium  Brodiei,  450. 

grauuliferus,  274. 

Miocene  in,  513.                          1  Spathic  iron,  318,  688. 

gregarius,  256,  260,*  261. 

Skiddaw  slates,  163,  192.                 Spatularia,  264. 

Horn  fray  i,  416. 

Slate,  49,  69,  §  649.                           Species.      See    LIFE,    ANIMALS, 

incrassatus,  303. 

siliceous,  73.§                                     PLANTS,  MIGRATIONS. 

iucrebescens,  303. 

Slaty    cleavage     or     structure,        representative  599. 

Keokuk,  3  3. 

89,§  628,  741.                           ;  Specific  gravities  of  rooks,  65. 

last  of,  437. 

origin  of,  741.                                     heats  of  rocks.  698. 

lineatus,  341,  350. 

production   of,  in  glacier-ice,  <  Specular  iron,  59,  74. 

macropleura,  237,  239,*  240. 

683.                                               Speeton  clay,  476. 

Meusebachanus,  341. 

Slaty  rocks,  63.  §                            !  Sphserium,  617. 

mucronatus,  272,*  274. 

Slides,  655. 

Sphaeronites,  207. 

Miinsteri,  428,  429. 

Slope  of  loose  materials,  630. 

Sphagnum,  362,  364,  616. 

Niagarensis,  226,*  229. 

mountains,  16,  18.  §* 

ash  of,  365. 

perlamellosus,  240. 

llocky  Mountains,  17.* 

commune,  365. 

plicatus,  247. 

volcanic  mountains,  18.* 

composition  of,  362. 

pyxidatus,  243. 

Sloth,  565,  610. 

Sphagodus,  247. 

radiatus,  228,  229,  248 

tribe,  earliest  of,  518. 

Sphalerite,  197- 

range  of,  in  time,  386.* 

Smelt,  475. 

Sphenophyllum,  328,  331,  348. 

rostratus,  429. 

Smilax,  497. 

autiqtium,  271. 

rugosus,  240. 

Smithsonite,  197- 

emarginfttum,  331. 

speeiosus,  303. 

Snake  River,  volcanic  rocks  of, 

Schlotheimii,  827,*  330. 

spinosus,  303. 

524. 

Sphaenopoterium     obtusum. 

striatus,  171,*  341. 

Snakes,    121.  §  338  §  502,  509,      "     302-' 

sulcaf.us,  226,*  229,  248. 

510,  516,  592,  598. 

cuneatum,  302. 

umbonatus,  272,*  274. 

Snipes,  460.  § 
Snow-line  on  heights,  679. 

Sphserozoum  orientale,  133.* 
SphEerulites,  460,  452. 

Urii,  350,  373. 

AValcotti,  438,*  448. 

Snowy  Owl,  573. 
Soapstone,  55,  §  72.  § 

Hoeninghausi,  472,*  475. 
Sphenopteris,  271,  348,  349,  370, 

Spiriferina  cristata,  372,  373. 
Kentuckensis,  341. 

Soda  in  plants'  365. 

433. 

octoplicata,  300,*  303,  393. 

salts,  630. 

anthriscifolia,  349. 

Spirigera  lamellosa,  307*  308. 

Sodium,  51  § 

artemisi;e  folia,  331. 

subtilita,  341. 

Soils  limiting  life,  610. 

Eocenica,  497. 

Spiritual  element  in  the  earth's 

Soissonnais  beds,  513. 

glandulosa,  331. 

arrangements,  758. 

Solemya,  385. 

Gravenhorstii,  326,*  330.           .  Spirophyton,  296,331. 

Solen,  508. 

Harttii,  271. 

cauda-galli,  255,*  257,  331. 

Polenhofen  beds,  436,  446. 

Hitchcockiana,  271. 

Spirorbis,  333,  341,  358,  385. 

Solenocaris,  267. 

Hoeninghausi,  271. 

carbonarius,  333,*  342. 

Solenomya,  first  of,  261. 

Hookeri,  283. 

Spirula,  125.  § 

radiata,  342. 

Humphriesiana,  283. 

Spitsbergen,  Carboniferous   in, 

Solfataras,  718.§ 

latifolia,  331. 

293. 

Solitaire,  580,  581.* 

Mantelli,  450. 

glaciers  in,  675. 

Soluble  silica,  53,  §  478.  § 

Newberryi,  331. 

Permian  in,  370. 

Solvent  power  of  water,  687. 

obtusiloba,  331. 

Tertiary  plants  of,  514. 

Soundings  off  New  Jersey  and 

pluuiosa,  449. 

Triassic  in.  424,  429. 

Long  Island,  422.* 

polyphvlla,  331. 

Splint-bones,  601. 

South    America,  Carboniferous 

Schimperi,  283. 

Spondylus,  475 

in,  345. 

tridactylites,  330. 

Sponges,    132,§   177,   190,  202, 

Cretaceous  in,  470. 

Spherulites,  77,  §  86. 

228,  257,  261,  300,  436,  460, 

drainage  of,  25. 

Spicula  of  Sponges,  132*  257,* 

472,  608,  611. 

fiords  in,  534. 

472. 

Calciferous,  188. 

glaciers  in,  536. 

Spiders,  121,  §  331,  335,  349,  351, 

Chazy,  190. 

mean  height  <,f,  14. 

441,*  613. 

Corniferous,  257.* 

Quaternary  in,  532. 

first  of,  335.* 

Cretaceous,  471. 

Quaternary  Mammals  of,  568, 

range  of.  in  time,  388.* 

first,  175,  180. 

571. 

Spinax  Blainvillii,  262.* 

number  of  Silurian,  249. 

surface  form  of,  24.* 

Spirangium,  349. 

Potsdam,  175,  177.* 

temperature  of,  41.  § 

Spirifer,  171  ,*§  228,  243,§  252, 

Quebec.  190. 

trends  in,  36. 

278,  283,  ?84,  299,  307,  371, 

siliceous,  611,  612. 

Southbury   Triassic   area,   405, 

409,  448. 

spicula  of,  60,  132  *  257  *  261, 

419. 

acuminatus,  256,  260,*  261. 

300,  471,*  472. 

824 


INDEX. 


Sponges,  Trenton,  202. 

Spongia,  474. 

Spongiolituis      appendiculata, 

496.* 

Spore,  133.§ 
Spores  in  coal,  317. 
Springs,  653. 
thermal,  401. 
thermal,  in  inetamorphic  re 

gions,  729. 
thermal,  in  volcanic  region?, 

692,  719. 

sulphur.  '234,  268,  689. 
sulphuric  acid,  689. 
Squalodon,  520.  § 
Squalodonts,  402,  472,  475. 

range  of,  in  time,  5S9.* 
Squaloids,  263.§ 
Squalus  cornubicus,  60. 
Squid,  119,*  125.  § 
Squirrel,  606,  568,  577. 
Stag,  507,  517,  520,  562,  567, 

568,571,577. 
Stag  family,  range  of,  in  time, 

589.* 

Stalactite,  75.  § 
Stalagmite,  75,§  557,  563. 
Staphylopteris,  348. 
Star-fish,  117,*  128,  §  482,  611. 
Star-fishes,   range  of,  in   time, 

386.* 

Statuary  marble,  75.  § 
Staurolite,  57.  §*  728. 
Staurolitic  rocks,  64.§  237. 
Steam,  agency  of  superheated, 

in  metamorphism,  727. 
Steatite,  55.  § 
Steatyte,  72.§ 
Steffensia,  348. 
Stemmatopteris,  349. 
Stenaster  Huxleyi,  190. 
Steneofiber,  519  .'§ 
Steneosaurus,  449. 
Stenopora,  189,§  202,  372 
fibrosa,  190,    202,    206,   207, 

247. 
Stephanocrinus      angulatus, 

226,*  229. 
Stephanophyllia     Bowerbankii, 

476. 

Stereognathua,  447,  §  571. 
Sternbergia,  331.  § 
Stevenson,  on  force  of  waves, 

661,  665. 
Sthenorhines,  508,  §  510  511. 

range  of,  in  time,  589.* 
Stigmaria,  297,  307,  312,*  325, 

331,348. 
anabathra,  297. 
ficoides,  297,  324,*  330.  331. 
minor,  297. 
ininuta,  297. 
perlata,  271. 
pusilla,  278. 
umbonata,  297- 
Stigmarioides,  348. 


Stiper  stones,  163,  192. 
Stockbridge  marble,  185,  196. 
Stockwell,    on    eccentricity    of 

earth's  orbit,  697. 
Stone  Age,  574. 

implements,  573,  574. 

state.  702. 

Stonesfield  slate,  435,  446. 
Sto.«s,531.§ 

Straparollus.  189,  303,  372. 
Strata,  positions  of,  91.  §* 

dislocations  of,  92.  §*  | 


Strata,   method    of  calculating 
thickness  of,  99. §* 

order  of  arrangement  of.  101. 
Stratification,  79,  81. § 

affects  erosion,  645. 
Stratified  Drift,  527. 
Stratified  rocks,  62.§  79.§ 

formation  of,  758. 

thickness  of,  145. 
Stratum,  81. § 
Strong,  analyses  of  melaphyre, 

Streptacis  Whitfieldi,  342. 
Streptorhynchus     Cheuiungen- 

sis,  261. 

umbraculum,  303,  307,*  308. 
Striarca  centenaria,  495. 
Strickland  on  the  Dodo,  580. 
Stricklandinia,  171, §  190. 
elongata,  261. 
lens,  206,  208. 
Strike,  94. §* 
Stringocephalus,  171. §  284,  288. 

range  of,  in  time,  387.* 
Stroniatocerium  rugot-um.  202. 
Stromatopora,  133,§  189, §  225. 
compacta   190. 
concentrica,  206,  225  *    229, 

230,  248,  249. 
rugosa,  190. 
striatella,  20". 
Strombian  group,  435. 
Strophalosia.  172,§  372. 
excavata,  372. 
last  of,  373. 

Strophodonta  crenistria,  261. 
demissa,  261. 
perplana,  243,  261. 
Strophomena,   172,§*  189,  190, 

199,  284. 

alternata,  200,*  203,  205,  209. 
arenacea,  247. 
Becki,243. 
complanata,  207. 
compressa  247- 
concentrica.  247. 
demissa,  261. 
depressa ,  208. 
Leda,  £06. 
magnifioa,243. 
pecten,  206. 
perplana.  243,  £61. 
planumbona,  172.* 
radiata,239,*240. 
recta.  £06. 
rhomboidalis,  £06,  226,*  229, 

240,  243.  247.  248. 
rugosa,  200,*  £03, 247.248, 261. 
range  of,  in  time,  386.* 
subtenta,  206. 
Struckmann,  analysis   of   fern-  i 

ash,  365. 
Structure,    from    cooling,    708, 

716,  722. 
from     deposition,    82, §    546, 

631,  667. 

affects  erosion,  645. 
Structure-mill,  683. 
Stvlina  tubulifera,  449. 
Stylolites,  222. 
Styloneurus  Scoticus,  285. 
Stypolophus  pungens,  510. 
Subapennine  Tertiary,  513. 
Subarctic  zone,  609. 
Subcarboniferous    period,    291. 

293. 

COH!  in,  293,  295 
Subdivisions  of  time,  table   of, 
142.* 


Sub  frigid  region*,  41. § 
Submarine  eruptions,  711. 
Subsidence,  causes  of,  761. 
necessary   for  the    formation 
of  a  thick  series  of  strata, 
625,  626. 

through  the  Paleozoic,  391. 
of  N.  America  during  the  Drift 
epoch,     evidence     against, 
534 

in  the  Champlain  period.  551. 
of  Isthmus  of  Darien,  756. 
of    the   Pacific    indicated  by 

coral  islands,  583. 
originating  the  depressions  of 

Lake  Champlain,  215. 
modern,  583. 

rate  of,  in  coral  islands,  625. 
of  wide  extent,  735. 
Sub-temperate  regions.  41. § 
Subterranean  waters,  653. 
Sub-torrid  regions,  41. § 
Sub-tropical  zone,  609. 
Subulites,  203. 
Suchosaurus,  450. 
Suessonian  group,  513. 
Suffolk  crag,  513. 
Suillines,  511. 
Sula  loxostyla,  511. 
Sulphids  of  iron,  decomposition 

of,  688. 

Sulphur,  52,§  365. 
in  coals,  317. 
springs,  234,  268,  689. 
Sulphuric  acid,  234,  691,  695. 

acid  springs,  689,  691. 
Sumter  period,  490,  495. 
Sun  a  source  of  heat,  697. 
Superposition,  order  of,  103. 
Surcula,  508. 
Surface-forms     of     continents, 

23.  § 

Surface  subdivisions,  15.  § 
Surgent  series,  375. 
Surirella  craticula,  634.* 
Sus,  519,  520. 
Swallows,  516. 
Swallow,  G.   C.,  on    Rocks    of 

Missouri,  183,  374,  378. 
Swallow  &  Hawn  on  Permian, 

367. 
Sweden,  recent  change  of  level 

in,  582. 

Archaean  in,  151, 157. 
Cretaceous  in,  469. 
in  the  Quaternary,  555. 
iron-mines  of,  1;~4. 
Primordial  in.  179 
Quaternary  in,  532,  556. 
Silurian  in,  207,  245. 
Swimming  Saurians,  339. § 
Switzerland,      Cretaceous       in 

470. 

glacier  regions  of,  675,  676. 
grtat  glacier  of,  533,  562. 
lake  dwellings  in,  576. 
Quaternary  in,  533. 
Tertiary  in,  512. 
Triassicin,424. 
Sword  fishes,  509. 
Sycamore,  459. 
Syenyte,  69.§ 
Syenytic  gneiss,  70.§ 
igneous  rocks,  77. § 
Symplocos,  515. 
Synclinal,  95. §*  645^.  750. 
Synclinoriurn,  749,  751. 
Syncoryna,  117.  *§ 
Synedra  ulna,  634.* 


INDEX. 


825 


Synthetic   types.     See   COMPRE 
HENSIVE. 

Syntrielasma  hemiplicata,  341. 
Syracuse,  metainorphic  rocks  at, 
233. 

salt-wells,  234. 
Syria,  Quaternary  in,  533. 
Syringophyllum  organum,  207. 
Syringopora,  230,  240. 

Mfurcata,  247. 

Hisingeri,  256. 

Maclurii,259,*261. 

multattenuata,  341. 

obsoleta,  204.* 
Syringoxylon  mirabile,  271. 
System  of  ocean-movements',  38. 
Systems     of     mountain-eleva 
tions,  American : 

of  the  Archsean,  155, 157, 159. 

of  the  Lake  Superior  trap,  185. 

of  the  Appalachians,  395. 

of  the  Cincinnati  uplift,  212. 

of  the  Coast  Range,  524. 

of  the  Green  Mountains,  212, 
395. 

of  the  Gulf  region,  523. 

of  the  main  mass  of  the 
Rocky  Mts.,  523,  524. 

of  the  Mesozoic  trap  and  sand 
stone,  417. 

of  the  Sierra  Nevada,  Hum- 
boldt,  and  Wahsittch  Mts., 
483. 

Systems  of  mountain  elevation, 
European : 

of  Westmoreland  and  the 
Hunsdruck,  217. 

of  the  N.  of  England.  402. 

of  the  Netherlands  or  of 
Hainault,  402. 

of  the  Rhine.  402. 

of  the  Thuringian  Forest,  487. 

of  the  Cute  d'Or,  487. 

of  the  Pyrenees  and  Julian 
Alps,  525. 

of  the  chain  of  Corsica,  525. 

of  the  Western  Alps,  525. 

of  the  Eastern  or  Principal 
Alps,  525. 

of  Sicily,  525. 

of  the  Hebrides  and  Antrim, 
525. 

Tabellaria,  634.* 
Table  of  formations,  142.* 
Tachylyte,  78.§ 
Taconic  range,  213,  750. 

rocks,  163. 

Taeniaster  spinosa,  199,*  203. 
Taggart,  W.  R.,  on  life  in  hot 

springs,  612. 

Tahitian  Islands,  map  of,  31.* 
Talc,  55,§  728. 
Talcoid  slate,  69. § 
Talcose  slate,  72.$ 
Talpa,  520.§ 
Talus,  B30.§ 

angle  of  slope  of,  630. 
Tancredia  Warreniana,  432,*  433. 
Tangle-weed,  611. 
Tapes,  508 
Tapir,  503,5*  506,  510,  516,  517 

565,  567,  568. 
Tapirus,  519 

American  us,  567. 

Arvernensi*,  519. 

Haysii,  567. 

Indicus,  503.* 

priscus,  519. 


Tarrannon  shales,  244. 
Tarantula,  3-L>. 

Taxodium,  497,  498,  514.  515, 
526. 

dubium,  514. 
Taylor,  R.   C.,  section  of  Coal 

measures,  395.* 
Teeth,  composition  of,  613. 

enamel  of,  61. 

Tejon  group,  457,  458,  491,  508. 
Teleosaur,  338, §  444,  449,  474, 

475,  476. 

Teleosaurs,  Arctic,  452. 
Teleosaurus  Chapmanni,  449. 
Telerpeton      Elginense,      427,* 

428  § 

Teliosts,  265,§*  442,  475,  484, 
502,  510. 

culmination  of,  598. 

first  species  of,  442. 
'     in  the  Cretaceous,  462,  473.* 

in  the  Tertiary,  516. 

range  of,  in  time,  589  * 
Tellina,  468,  475,  483,  508. 
I      congesta,  510. 

obliqua,  519. 

Tellinomya  nasuta,  200,*  203. 
Telmatolestes,  510. 
Temperate  zone,  41.§ 
Temperature,  causes  determin 
ing,  43. 

limiting  life,  609,  611. 

of  the  globe,  mean,  44. 

of  metamorphism,  726. 

of  the  ocean,  41. 

See  CLIMATE. 
Temple     of     Jupiter     Serapis, 

changes  of  level  at,  584.* 
Tennessee,  Archaean  in,  150. 

Calciferous  in,  184. 

Carboniferous   in,    291,    311 
320,  321. 

Chazy  in,  182,  185. 

Cincinnati  in,  197. 

Clinton  in,  221. 

Cretaceous  in,  455,  456. 

faults  in,  398,  400. 

Hamilton  in,  267. 

in  the  Tertiary,  521. 

Lower  Helderberg  in,  237. 

Lower  Silurian,  210. 

marbles  of,  198. 

Niagara  in,  221. 

Oneida  in,  220. 

Potsdam  in,  168,  181. 

Quaternary  in,  528. 

Quebec  in,  182,  184. 

rocks  of,  379. 

Subcarboniferous  in,  293,  294, 
305. 

terraces  in,  528,  548. 

Tertiary  in,  491,  493. 

Trenton  in,  196. 

zinc  ores  in,  186. 
Tension  in  earth's  crust,  743. 
Tentaculifers,  439. 
Tentaculite  limestone,  237. 
Tentaculites.  253. 

Anglicus,  208. 

irregularis.  239,*  240. 

ornatus,  247. 

Oswegoensis,  2"6. 

scalaris,  231. 

tenuistriatus,  206. 
Terebellum  fusiforme,  519. 

sopita,  519. 
Terebra,  £08. 
Terebratella,  170,§  173.  474. 

pectita  476. 


Terebratula,  170,§  173, 385, 433, 
448,  474,  482,  488,  500. 

analysis  of,  60. 

biplicata,  476. 

bovidens,  341. 

carnea,  476. 

caput-serpentis,  488. 

cornuta,  429. 

digona,  449. 

elongata,  373. 

family,  170.§* 

fimbria,  449. 

grandis,  519. 

gregaria,  429. 

Harlani,  4*5(1,*  467,  469. 

hastata,  307,*  308. 

impressa,  119.* 

last  of.  437. 

numismalis,  448. 

perovalis,  449. 

p.\riformis,  429. 

range  of,  in  time,  387.* 

rimosa.  448. 

sella,  475. 

striata,  488. 

vitrea.  171.* 

vulgaris,  428,  429. 
Terebratulae    common    in    the 

Tertiary,  515. 
Terebratulina,  170,*§  474. 

caput-serpentis,  171.* 

plicata,  460,*  4*i7,  469. 
Terebrirostra,  170.§ 
Teredo,  608. 

tibialis,  468. 
Termatornis,  468. 
Termatosaurus  429. 
Termes  Heeri,  351. 
Termination  yte  explained,  65. 
Termites,  349,  60S. 
Terrace    epoch.      See    RECENT 

PERIOD. 

Terraces   of  rivers,   lakes,  and 
sea-shores,  544,*  558. 

age  of  material  of,  560. 

elevations  of,  548. 

formation  of.  644. 

in  Great  Britain,  555. 
Terrain  Tertiare,  513. 
Terranes,  79,§  81. § 
Terricola,  123.  § 
Terrestrial  life  rarely  fossilized, 

613. 
Tertiary  age,  139,  489.§ 

N.  American,  map  of,  521.* 

divisions  of,  512. 

proportion  of  modern  species 
in,  513. 

and  Quaternary,  contrast  in, 

586. 
Testudo  Culbertsonii,  510. 

hemisphaerica,  510. 

lata,  510. 

Oweni,  510. 

Tetrabranchs,  439,  483. 
Tetradecapods,  122,§*  335. 

range  of,  in  time,  388.* 
Tetradium  columnare,  202. 

fibrosum,202,  204.* 
Tetragonolepis,  442.* 
Tetrapterus  priscus,  518. 
Textularia,  208,  474. 

globulosa,  131,*  4%. 

Missouriensis,  466. 
Texas.  Archaean  in,  150. 

Carboniferous  in,  291. 

Cretaceous  in,  455,  456,  478. 

in  the  Cretaceous,  479. 

Potsdam  in,  138. 


826 


INDEX. 


Texas,  Subcarboniferous  in  ,293. 

Tertiary  in,  491,  493. 

terraces  in,  548. 
Thallogens,  133.  § 
Thanet  sands,  512,  518. 
Theca,  180,  372. 

corrugata.  180. 

gregarea,  178.* 

triangularis.  208. 

vagi nu la,  208. 
Thecidea,  first  of,  448,  474. 
Thecidium,173,§  174. 
Thecocyathus  rugosus,  448. 
Thecodonts,  338,§371. 

first  of,  374,  376. 

range  of,  in  time,  589.*  592. 
Thecodontosaurus,  338,§  428. 
Thecosmilia  Tarquemi,  448. 
Thelodus  p;irvidens,  24(5.* 
Thenaropus  heterodactylus,  343. 
Thermal  springs,  401,  692,  719, 

729. 
Thickness   of   stratified    rocks, 

145,  657. 
Thinolestes,  f  10. 
Thinosaums  grandis,  510. 
Tnomson,   Win.,   on  length   of 
time,  591. 

on  earth's  loss  of  heat,  699. 
Thoracosaurus    Neocaesariensis, 

467. 

Thracia  Conradi,  551. 
Thrissops,  264.* 
Thuia,  497. 
Thuiopsis,  514. 
'J  huringia,  Permian  in,  369. 
Thuyites  articulatus,  449. 

divaricatus,  449. 
Thylacotherium  Broderipii,  446, 

448.* 

Tiaropsis,  117.* 
Tiburtine,  75. § 
Tick,  121. § 

Tides  and  tidal  currents,  659. 
Tiger,  506,  508,  564. 
Tile  Clay,  513. 
Tilestones,  164,  244. 
Till,  66.§ 

Tillotherium  hyracoides,  510. 
Time,  length  of  geological,  590. 
Time-ratios,  Cenozoic,  585. 

Mesozoic,  481. 

Paleozoic,  381. 
Tinoceras  grande,  510 
Titanic  iron,  59,§  74. 
Titanotherium,  495,  508. 

Proutii,  506,*  511. 
Tithonic  group,  435. 
Tivoli  travertine  beds,  692. 
Toarcian  group,  435- 
Todtliegende,  369. 
Tom    Ball    ridge,    sections    of, 

213.* 

Tombigby  sand,  456. 
Tomitherium,  510. 
Tomopteris,  123.§ 
Tongrian  group,  513. 
Tookey,  analysis  of  coal,  316. 
Topaz,  68,5*  728. 
Topographical  effects  cf  erosion, 

644. 

Torbanite,  315,  316. 
Torrent-portion    of  a    stream, 

638.§ 

Torr'd  zone,  41. § 
Totten,  expansion  of  rocks,  700. 
Tourmaline,  57,§*  727,  728. 
Toxaster  complanatus,  475,476. 

elcgaus,43J,  468. 


Toxoceras,  462. § 

bituberculatum,  473,*  475. 
Tracks.     See  FOOTPRINTS. 
Trachelomonas  levis,  634.* 
Trachium  cyathifortne,  190. 
Trachydoleryte,  78. § 
Trachyte,  77" ,§  707,  718,  736. 
Trails.     See  FOOTPRINTS. 
Trains  of  bowlders,  529. 
Translation- waves,  662. 

currents, 


Trigonocarpus,  271,    329,    331. 

349. 

ornatus,  329  *  330. 
!      tricuspidatus,  329,*  &30. 
I  Trigonosemus,  171. 
I  Trilobites,    122, §     174, §*    180, 
189,  190,  202,  253,  289,  300, 
307,  333,  350,  372,  592,  597. 
a    comprehensive    type,   382, 

culmination  of,  249,  594. 
number  of  Silurian,  249. 
range  of,  in  time,  387.* 
spinous,  285.* 
Triloculina  Josephina,  131.* 


Transportation     by 

665. 

by  icebergs,  686. 
j      by  rivers,  647. 
bv  waves,  665. 
Trap,  78, §  49,  306. 
!      at  Lake  Superior,  185. 
j      distribution  and  formation  of, 

716. 

minerals  of  Nova  Scotia.  418. 
in  Triassic  of  Connecticut  val 
ley,  etc.,  20,*    418, 
452,  486,  722. 
Triassic,  of  uniform   charac-    Triton,  509. 

ter,  417.  Tritonium,  508. 

Trapa  natans,  135.§  i  Trochoceras,  230. 

;      ash  of,  366. 
Travertine,  75, §  692. 
Trees,  erect  in  rocks,  296,  356,§ 

436.* 

!      protection  by,  607. 
silicified,  693. 


Trinucleus,  174. 
concentricus,  202  *  204,  206, 

208. 

range  of,  in  time,  387.* 
Trionyx,  509,  510,  519. 

Bakewelli,  450. 
421,    Triphyllopteris,  348. 
Tritia  trivittata,  510. 


Trochocyathus,  474. 
:      conulus,  476. 
Fittoni,  476. 
:  Trocholites,  203.  § 
I      Ammonius,  205,  201,*  203. 
i  Trochonema,  203. 


Tree-ferns,  258,  270,  323,  327,    Trochosmilia,  474. 


351,  356,  370,  408,  609. 
Tremadoc  slates,  163,  192. 
Trematis,  173,  §  203. 
1      cancellata,  L07. 
punctata,  207- 
Trematodiscus  Koninckii,  < 
308. 
Trematosaurus,  428,  429. 
Trematospira,  171. 
Tremolite,  54.  § 
Trends,  systems  of,  29. 
Trenton  epoch,  163,  194. 
period,  163,  194,  251. 

i      conoidea,  466. 
granulifera,  466. 
!      striata,  508. 
!      sulcata,  476. 
•      Texana,  466. 
!07,*    Trochus,  475. 
i      family,  189,  253. 
Trogon,  516. 
Trophon  antiquum,  519. 
i      clathratum,551,555. 
[  Tropical  zone,  609. 
;  Tropidoleptus    carinatus 
274. 

272, 


period,  hornstone  of,  contain-    Troxites  Germari   351. 
Trygon,  263. 
Tsien-tang,  eagre  of,  661,  666- 


ing  organisms,  261. 
i  Tretosternum  punctatum,  450- 
!  Triacodon  aculeatus,  510. 
'      fallax,  510. 

grandis.  510. 
Triarthrella,  168, 178. 
Triarthrus,  204. 
Beckii,  208.* 
range  of, in  time,  387.* 
Triassic  period,  403  § 

foreign,  423. 

Triceratium  obtusum,  493.* 
Trichomanites,  271. 
Trichospongia  sericea,  188. 
Tridymite,  53. § 
Trigonia,  431,  432,  433,  475. 
aliformis,  476. 
Bronnii,449. 
caudata,  475. 
cl.-ivellata,  438,*  449. 
Conradi,  432,*  433. 
I      costata,  449. 
I      daedalea,  475,  476. 

Evausana,  458. 
i      gibbosa,  449. 
limbata,  476. 
I      longa,  476. 
I      muricata,  449. 
|      pandicosta,  433. 
j      scabra,  476. 
Tryoniana,  467- 
vulgarly  429 


Tubicinella,  475. 

Tubicola,  123. § 

Tubipora,  620. 

Tufa,  62,§  66.§  306,  702,  718. 

Tufa-cones,  706,*  712.* 

Tulip-tree,  458. 

Tully  limestone,  267. 

Tunicates.     See  ASCIDIANS. 

Tunneling  by  animals,  60S. 

Tuomey  &  Holmes,  on  Pliocene- 

of  South  Carolina,  495. 
Turbinella  Wilsoni,  509. 
Turbinolia  caulifera,  509. 
Turbo  heliciformis,  448. 

subduplicatus,  448. 
Turf,  protection  by,  606. 
Turkey,  511. 
Turonian  group,  470. 
Turrilites,  462.  § 

Brazoensis,  468. 

catenatus,  473,*  475. 

costatus,  476. 

Oregonensis,  467. 

polyplocus,  476. 
Turris,483. 
Turritella,  508. 

alticostata,  495. 

carinata,  499*  509. 

Coalvillensis,  508. 

communis,  519. 


INDEX. 


827 


Turritella  erosa,  551. 
Hotfmanni,  510. 
multisulcata,  518. 
reticulata,  551. 
spironema,  508. 
variata,  51<>. 
Turseodu*,  41". 

Turtles,   121, §   338, §   339,  443, 
450,  464,485,  5U2,  509,  516. 
first  of,  428. 
range  of,  in  time,  589. 
Tylosaurus  dyspelor,  468. 
micromus,  465,*  468. 
proriger,  468. 

Tyndall  on  glaciers,  681,  683. 
Types,  comprehensive,  382,  597. 
culmination  of,  385,  482,  588, 

594,  597. 
expansion  of,  288,  383,  483, 

588,  594,  597. 
extinction  of,  288,  384,  588, 

597. 
range  of  different,  385,  386,* 

588*597. 
Typhis,  508. 

pungens,  519. 
Tyrol,  plant-beds  of,  514. 
Tyson,   P.    T.,    on    Cycads 
Maryland,  459. 


j  Urosalpynx  cinerea,  561. 
j  Ursa  beds,  283,  307. 
iUrsus,520.§ 
amplidens,  567. 
Arctos,  564. 
Arvernensis,  571. 
^      ferox.  564. 
I      pristinus,  567. 
|     spelaeus  or  Cave  Bear,  563,* 

564. 

Urus,  562,  565,  571,582. 
Utah,  Carboniferous  in,  293. 
Cretaceous  in,  454,  456. 
lignites  in.  457. 
'      silver-mines  of,  296. 

Subcarboniferous  in,  296. 
terraces  in,  549. 
Tertiary  in,  491,  493. 
Triassic  in,  406. 
See,  further,  GREAT   SALT 

LAKE. 

Utica  epoch,  164,  194. 
shale,  194. 


UintahMts.,453. 

in  the  Mesozoio,  488. 
Uintah  basin,  492,  493. 
Uintatherium,  494,  504, § 

robustum,  51". 
Uintornis  lucaris,  510. 
Ullmannia,  371. 
Ulmus,  497. 
Ulodendron,  348. 


Valleys,  excavation  of,  539,  638, 

761. 

Valvata,  508. 
in        tricarinata,  548. 

Vanuxemia  Montrealensis,  191. 
,  Vanuxem,  L.,    plicated    clayey 
!      layers,  656. 
I      metamorphic     rocks     in     the 

Salina,  233. 

>10.      i  Variegated  sandstone,  424. 
Vaux,  analyses  of  coal,  316. 
j  Vegetable  kingdom,  1,  133.§ 
relation  to  animal,  115  § 
Vegetable  remains.     See  PLANTS. 
|  Vegetation,  protection  by, 


Ulster  lead  and  copper  mines,    Veins,     nature    and     form    of, 


222. 

Umbral  series,  295,  375. 
Unakyte,  70. § 
Uncites,  171. § 
Uncompacted  rocks,  63.  § 
Unconformable    strata,     100,§* 
181, 183,  210,  215,  217,  232, 
289,  308  *  486, 487. 
Under-clay,  312.§ 
Under -currents,  662.  § 
Under-tow,  662.§ 
Unexplained  facts,  757- 
Ungulite  grit,  163,  218. 
Unicardium,  433. 
Unio,  359,  450,  508,  548,  590. 

Liassinus,  433. 

Nebrascensis,  468. 

prise  us,  501,*  503. 

Valdensis,  450.* 
United  States,  Geological  map  of, 

144,  292 
Unity  in  the  life  of  the  different 


108, 

alterations  of "733. 

faulting*  of,  109,*  734. 

formation  of,  731. 

of  Lake  Superior  region,  186. 

false,  113.§ 

works  on.  114. 
Vein-stone,  H3.§ 
Vein-structure  of  glaciers,  682. 
Venericardia      planicosta,     491, 
509. 

rotundn ,  509. 
Ventral  valve,  170  § 
Ventriculites,  472,  474. 

decurrens,  476. 

radiatus,  476. 
Venus,  475,  483.  500,  508. 

cancellata,  510. 

capax,  510. 

difformis,  495. 

mercenaria,  510,  561. 

tridacnoides,  510. 


ages,  594.  Vergent  series,  375. 

Universality    of    pressure    and  i  Vermicular  sandstone.  294 


movements,  748. 
Univalves,  125.§ 
Unstratified  rocks,  107.§ 
Unterquader  group,  470. 
Uplift,  Cincinnati,  axis  of,  391. 
Uplifts,  92.§ 

See  ELEVATION,  DISTURBANCES. 
Upper  Devonian,  254. 
Upper  Silurian.     See  SILURIAJ*. 
Urals,  Carboniferous  in,  347. 

elevation  of,  347. 

in  the  Cretaceous,  480. 

position  of,  26. 
Uie-Ox,  582. 
Urocordylus  Wandesfordii,  351. 


Vermont,  Chazy  in,  182. 

Eolian  limestone  in,  196. 

fossil  fruits  of  Brandon,  494, 
497,  498.* 

Helderbcrg  in,  237,  255,  256. 

Niagara  in,  221. 

Potsdam  in,  167, 181. 

Quaternary  in,  529,  531,  537. 

terraces  in,  548. 

Tertiary  in,  494. 

Trenton  in,  196. 
Verneuil.  on  commencement  of 

Devonian,  241. 

Verrill,  A.  E..  «>n  Gulf  Stream 
in  the  Quaternary,  541. 


Verrill,  on  Ascidians,  602. 
Vertebrate  types,  range  of  588.* 
Vertebrates,  120,  121, §  578,  594, 

595. 

first  of,  247,  602. 
first  American   261. 
lowest  of,  265. 
range  of,  588. 
rarely  preserved,  614. 
Verticillites  anastomosans,  476. 
Vespert'ne  series,  295,  375. 
Vesulian  group,  435. 
Vesuvius,  716. 

eruptions  of,  709,  714. 
Viburnum,  497. 
dichotomum,  498. 
Why m peri,  498. 
Vicksbnrg  group,  491,  494 
Vienna   Miocene  plants  of,  515, 

526. 

Vincularia,  474. 
Virginia,  Archaean  in,  150. 
Carboniferous    in,    311,   314, 

320,  321. 
Cat-kill  in,  280. 
Chazy  in,  182. 
Cincinnati  in.  197. 
Clinton  in,  218. 
Cretaceous  in,  455. 
faults  in,  399. 
folds  in,  396.* 
Lower  Helderberg  in ,  236. 
Millstone  grit  in,  311. 
monoclinal  faults  in,  399. 
Potsdam  in,  168. 
Salina  in.  233. 

Subcarboniferous  in, V93.  295. 
Tertiary  in,    490,    491,    495, 

511. 

thermal  springs  in,  401. 
Triassic  in,  405.  406,  419. 
zinc  ores  in,  186. 
Virgulian  group,  435. 
Vitis  Islandica,  498. 

Olriki,  498. 
Viverra,  519.§ 
Viviparous  Mammals,  416- 
VivSparus,  493,  508. 
fluviorum.  450.* 
Leai,  501,*  508. 
retusns.  501,*  508. 
trochiformis.  £08. 
Vohl,  II.,  analysis  of  ash,  365. 
Volcanic  cones,  715. 
bombs,  709.  § 
glass,  708,§  722. 
sand,  66. § 
slag,  707. § 
A'olcanoes,   nature    and    action 

of,  702,  707. 

active,  in  the  Pacific,  7(3. 
distribution  of,  703,  744. 
evidence    from,    of    internal 

heat  of  globe,  700. 
source  of,  722. 
Voluta,  483,  500. 
ambigua,  519. 
athleta,  519. 
dumosa,  509. 
first  of,  475. 
Lamberti,  519. 
nodosa,  518. 
petrosa,  509. 
Wetherellii,  518. 
Volutilithes  petrosa,  509. 
Voltzia,  408,  409  § 
heterophylla,  4'/9,  425,*  429. 

Wacke,  66,§  79. § 


828 


INDEX. 


Waders  easily  fossilized.  613. 

in  the  CreUceous.  466.  468. 

in  the  Tertiary,  503,  510. 
Wahsatch  Mrs..  453,  751. 

in  the  Mesozoic,  486. 

Tertiary  in,  493. 
Walchia,  349,  370,  371. § 

piniformis,  370,*  371. 
Waldheimia,  170  ,*§  173. 

compacta,  341. 

Wales,    Carboniferous  in,   345, 
346 

Devonian  in,  282. 

disturbances  in,  402. 

geological  map  of,  344.* 

in  the  Triassic,  423. 

Primordial  in,  179. 

Quaternary  in,  533,  555. 

Silurian  in,  207,  244. 

Subcarboniferous  in,  308. 
Wallace,  A.  R.,  on  Creation  of 

Man,  601. 
Wall-rock,  114  § 
Walnut,  471.  514. 
Walrus,  50". 
Warm  temperate  regions,  41, § 

603. 
Warren,  skeleton  of  Mastodon, 

567. 

Warren  &  St^rer  on  oils,  362. 
Warsaw  limestone,  294. 
Washita  limestone,  457. 
Wasp,  121. § 
Water,  arrangement  of,  10. 

as  a  chemical  agent,  687. 

as  a  dynamical  agent,  635. 

lost  in  metamorphism,  725. 

oxygen  in,  49. 

See,  further,  RIVERS,  OCEANS, 
GLACIERS,  AQUATIC,  GEY 
SERS. 

Waters,  of  ocean,  specific  gravity 
of,  657. 

freezing,  674. 

hot,  action  of,  453,  719,  721. 

subterranean,  653. 
Waterlime  group,  164,  236. 
Water-rat,  577. 
Water-species  inferior,  592. 
Wave-action  on  coral  reefs,  621. 
Wave-marks,  84,§  222,  267,  671. 
Waves,    force    and    action    of, 
661.  663. 

tidal,  660. 

earthquake,  662. 
Waverly  sandstone.  295,  376. 
Weald  clay,  435. 
Wealden  epoch,  434,  470,  485. 
Wear.     See  EROSIOX. 
Weasel,  577. 
Websky,  analysis  of  peat,  316. 

analysis  of  marsh-gas,  364. 

analysis  of  Sphagnum,  362. 
Weevils.  349. 
VVeinhold,  analysis  of  fern-ash, 

3o5- 

Weissliegende,  369. 
Wells,  Artesian.  653,  654.* 
Welwitschia,  329,  330. 

mirabilis,  328.* 
Wenlock  group,  164,  244,  247. 
Werfen  beds,  425. 
Wesenburg  group,  164. 
West  Indies    trends  of  islands 
in,  35. 

volcanoes  in,  703. 


West  Virginia,  Carboniferous  in, 
291. 

Quaternary  in,  528,  532. 

Subcarbouiferous  in,  295,  305. 
Western-border  region,  146,  401. 
Western-interior      region,    401, 
406,  407,  431,  454. 

Islands,  37.* 

Whale,  121,  416,  507,  568,  665. 
Whales,  range  of.,  in  time,  589.* 
Whetstone  beds,  304. 
White,  C.   A.,  on    Iowa   rocks, 

294,  305,  374,  377. 
White,  M.  C.,  on  Protophytes, 
etc. ,  in  hornstone,  257,  *260. 
White  Lias,  425. 
White   Mountains,    Quaternary 

in,  537,  538. 
White  Oak  Mountain  sandstone, 

379. 
White  River  group,  495,  506. 

trap   "6. § 
Whittleseysi,  349. 

elegans,  330. 

Whittlesey,     C.,      combustible 
matter  in  shales,  198. 

iron  ores.  153. 

Lake  Superior  rocks,  184. 
Whitney,    J.    D  ,    analysis   of 
limestone,  222. 

borax  deposits,  722. 

Cretaceous  in  California,  457. 

Drift  in  California,  528. 

Missouri  iron -ores,  153,  159. 

ore-deposits  of  Galena,  113. 

Primordial  in  Nevada,  168. 

Triassic    in    California,    406, 

407. 

Whortleberry,  514. 
Wild-boar,  562,  664,  571,  577. 
Wild-cat,  564. 

Wilkes,  C.,  on  icebergs,  686. 
Williamsite,  73.§ 
Willow,  459,  471. 
Winchell,  A.,  on  rocks  of  Mich 
igan,  374,  376. 
Windings  of  streams,  643. 
Wind  River  group,  495. 
Wind  River  Mts.,  Archaean  in, 
150,  390. 

Chazy  in,  185. 

Jurassic  in,  431. 

Upper  Silurian  in,  232. 
Windsor  series,  296. 
Winnipeg  Lake.  Upper  Silurian 
fossils  at,  230. 

terraces  at,  548. 

Trenton  at,  194. 
Winooski  limestone,  167. 
Wisconsin,  Calciferous  in,  183. 

Chazy  in,  182. 

Clinton  in,  220. 

lead-mines  of,  197. 

Potsdam  in,  168. 

Quaternary  in,  529. 

Trenton  in,  196. 

Upper  Helderbergin,  256. 
Wittig,   K.,   analyses   of  ashes, 

365 

Wodnika  striatula.  372. 
Wolf,  506,  507,  518,  562,  564, 

568,  571,  577. 
Wood,  composition  of,  361. 

decomposition  of.  362. 
Woodpecker,  503,  510. 
Woodville  sandstone,  377 


Woodward,  on  Atrypa,  171. 
Woolhope  limestone,  244. 
!  Woolwich  beds,  512. 
World  Kingdom,  l.§ 
Worm-holes  in  Potsdam  beds, 

168. 
Worm  ley ,  anal\  ses  of  coals,  316, 

317. 

Worms,  122 ,§  123, §  333,  342, 
475,  592,  o96. 

number  of  Silurian,  249. 

range  of,  in  time,  387.* 
Worthen,  A.  II.,  on  rocks   of 
Illinois,  294,374.378. 

Illinois  Devonian,  256. 

oil  in  the  Niagara,  222. 
Writing  slate,  69.§ 
Wurtemberg,  salt-works  in,  424. 
Wurtz.  metamorphic  heat,  729. 

albertite  and  grahamite,  315. 
Wyman,  J.,  on  fossil  man,  578. 
Wyoming,  Canadian  in,  182. 

Carboniferous  in,  293. 

Cretaceous  in,  454,  456. 

geysers  in,  719. 

Lignites  in.  457. 

Subcarboniferous  in,  296. 

Tertiary  in,  491,  493. 

I  Xanthidia,  257,*  471. 
:  Xenoneura  antiquorum,  274. 
iXiphodon,517,§519. 
!      gracilis,  519. 
Xylobius  Dawsoui,  342. 
fractus,  342. 
similis,  342. 

Sigillarije,  334  *  342,  350. 
Xylophaga,  first  of,  477. 

Yellowstone  National  Park,  611, 
692,  719. 

River,  in  the  Cretaceous,  479. 
Yoldia,  303,  468. 

Arctica,  562. 

glacialis,  551,  555. 

impressa,  510. 

limatula,  495,  500,*  510. 
York  town  period,  490,  494. 
Yosemite  valley,  453. 
Ypresian  group,  512. 
Yucca,  450. 

Zamia,  514. 

Zamites  graminioides,  407,*  409. 

megalophylla,  436,*  450. 
Zaphrentis,  240,  243,  256. 

bilateralis,  224,*  228. 

Canadensis,  204. 

gigantea,  256,  259,*  261. 

Riitinesquii,259,*26L 

Stokesi,  206. 
Zeacrinus,  303,  341. 

elegans,298,*303. 
Zechstein,  369. 
Zeolites,  77,  186,  418. 

formed    in    a    brick    wall  at 
Plombieres,  734. 

origin  of,  734. 
Zeuglodon,  494. 

cetoides,502,*503,509. 
Zinc-ores,  186,  197. 
Zircon-syenyte,  70.§ 
Zizyphus  hyperboreus,  498. 
Zones    of    depth,    for    oceanic 

species,  611. 
Zygobates,  510. 


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